drivers/tty/vt/vt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Copyright (C) 1991, 1992  Linus Torvalds
   4  */
   5
   6 /*
   7  * Hopefully this will be a rather complete VT102 implementation.
   8  *
   9  * Beeping thanks to John T Kohl.
  10  *
  11  * Virtual Consoles, Screen Blanking, Screen Dumping, Color, Graphics
  12  *   Chars, and VT100 enhancements by Peter MacDonald.
  13  *
  14  * Copy and paste function by Andrew Haylett,
  15  *   some enhancements by Alessandro Rubini.
  16  *
  17  * Code to check for different video-cards mostly by Galen Hunt,
  18  * <[email protected]>
  19  *
  20  * Rudimentary ISO 10646/Unicode/UTF-8 character set support by
  21  * Markus Kuhn, <[email protected]>.
  22  *
  23  * Dynamic allocation of consoles, [email protected], May 1994
  24  * Resizing of consoles, aeb, 940926
  25  *
  26  * Code for xterm like mouse click reporting by Peter Orbaek 20-Jul-94
  27  * <[email protected]>
  28  *
  29  * User-defined bell sound, new setterm control sequences and printk
  30  * redirection by Martin Mares <[email protected]> 19-Nov-95
  31  *
  32  * APM screenblank bug fixed Takashi Manabe <[email protected]>
  33  *
  34  * Merge with the abstract console driver by Geert Uytterhoeven
  35  * <[email protected]>, Jan 1997.
  36  *
  37  *   Original m68k console driver modifications by
  38  *
  39  *     - Arno Griffioen <[email protected]>
  40  *     - David Carter <[email protected]>
  41  *
  42  *   The abstract console driver provides a generic interface for a text
  43  *   console. It supports VGA text mode, frame buffer based graphical consoles
  44  *   and special graphics processors that are only accessible through some
  45  *   registers (e.g. a TMS340x0 GSP).
  46  *
  47  *   The interface to the hardware is specified using a special structure
  48  *   (struct consw) which contains function pointers to console operations
  49  *   (see <linux/console.h> for more information).
  50  *
  51  * Support for changeable cursor shape
  52  * by Pavel Machek <[email protected]>, August 1997
  53  *
  54  * Ported to i386 and con_scrolldelta fixed
  55  * by Emmanuel Marty <[email protected]>, April 1998
  56  *
  57  * Resurrected character buffers in videoram plus lots of other trickery
  58  * by Martin Mares <[email protected]>, July 1998
  59  *
  60  * Removed old-style timers, introduced console_timer, made timer
  61  * deletion SMP-safe.  17Jun00, Andrew Morton
  62  *
  63  * Removed console_lock, enabled interrupts across all console operations
  64  * 13 March 2001, Andrew Morton
  65  *
  66  * Fixed UTF-8 mode so alternate charset modes always work according
  67  * to control sequences interpreted in do_con_trol function
  68  * preserving backward VT100 semigraphics compatibility,
  69  * malformed UTF sequences represented as sequences of replacement glyphs,
  70  * original codes or '?' as a last resort if replacement glyph is undefined
  71  * by Adam Tla/lka <[email protected]>, Aug 2006
  72  */
  73
  74 #include <linux/module.h>
  75 #include <linux/types.h>
  76 #include <linux/sched/signal.h>
  77 #include <linux/tty.h>
  78 #include <linux/tty_flip.h>
  79 #include <linux/kernel.h>
  80 #include <linux/string.h>
  81 #include <linux/errno.h>
  82 #include <linux/kd.h>
  83 #include <linux/slab.h>
  84 #include <linux/vmalloc.h>
  85 #include <linux/major.h>
  86 #include <linux/mm.h>
  87 #include <linux/console.h>
  88 #include <linux/init.h>
  89 #include <linux/mutex.h>
  90 #include <linux/vt_kern.h>
  91 #include <linux/selection.h>
  92 #include <linux/tiocl.h>
  93 #include <linux/kbd_kern.h>
  94 #include <linux/consolemap.h>
  95 #include <linux/timer.h>
  96 #include <linux/interrupt.h>
  97 #include <linux/workqueue.h>
  98 #include <linux/pm.h>
  99 #include <linux/font.h>
 100 #include <linux/bitops.h>
 101 #include <linux/notifier.h>
 102 #include <linux/device.h>
 103 #include <linux/io.h>
 104 #include <linux/uaccess.h>
 105 #include <linux/kdb.h>
 106 #include <linux/ctype.h>
 107 #include <linux/bsearch.h>
 108 #include <linux/gcd.h>
 109
 110 #define MAX_NR_CON_DRIVER 16
 111
 112 #define CON_DRIVER_FLAG_MODULE 1
 113 #define CON_DRIVER_FLAG_INIT   2
 114 #define CON_DRIVER_FLAG_ATTR   4
 115 #define CON_DRIVER_FLAG_ZOMBIE 8
 116
 117 struct con_driver {
 118         const struct consw *con;
 119         const char *desc;
 120         struct device *dev;
 121         int node;
 122         int first;
 123         int last;
 124         int flag;
 125 };
 126
 127 static struct con_driver registered_con_driver[MAX_NR_CON_DRIVER];
 128 const struct consw *conswitchp;
 129
 130 /*
 131  * Here is the default bell parameters: 750HZ, 1/8th of a second
 132  */
 133 #define DEFAULT_BELL_PITCH      750
 134 #define DEFAULT_BELL_DURATION   (HZ/8)
 135 #define DEFAULT_CURSOR_BLINK_MS 200
 136
 137 struct vc vc_cons [MAX_NR_CONSOLES];
 138 EXPORT_SYMBOL(vc_cons);
 139
 140 static const struct consw *con_driver_map[MAX_NR_CONSOLES];
 141
 142 static int con_open(struct tty_struct *, struct file *);
 143 static void vc_init(struct vc_data *vc, int do_clear);
 144 static void gotoxy(struct vc_data *vc, int new_x, int new_y);
 145 static void save_cur(struct vc_data *vc);
 146 static void reset_terminal(struct vc_data *vc, int do_clear);
 147 static void con_flush_chars(struct tty_struct *tty);
 148 static int set_vesa_blanking(char __user *p);
 149 static void set_cursor(struct vc_data *vc);
 150 static void hide_cursor(struct vc_data *vc);
 151 static void console_callback(struct work_struct *ignored);
 152 static void con_driver_unregister_callback(struct work_struct *ignored);
 153 static void blank_screen_t(struct timer_list *unused);
 154 static void set_palette(struct vc_data *vc);
 155 static void unblank_screen(void);
 156
 157 #define vt_get_kmsg_redirect() vt_kmsg_redirect(-1)
 158
 159 int default_utf8 = true;
 160 module_param(default_utf8, int, S_IRUGO | S_IWUSR);
 161 int global_cursor_default = -1;
 162 module_param(global_cursor_default, int, S_IRUGO | S_IWUSR);
 163 EXPORT_SYMBOL(global_cursor_default);
 164
 165 static int cur_default = CUR_UNDERLINE;
 166 module_param(cur_default, int, S_IRUGO | S_IWUSR);
 167
 168 /*
 169  * ignore_poke: don't unblank the screen when things are typed.  This is
 170  * mainly for the privacy of braille terminal users.
 171  */
 172 static int ignore_poke;
 173
 174 int do_poke_blanked_console;
 175 int console_blanked;
 176 EXPORT_SYMBOL(console_blanked);
 177
 178 static int vesa_blank_mode; /* 0:none 1:suspendV 2:suspendH 3:powerdown */
 179 static int vesa_off_interval;
 180 static int blankinterval;
 181 core_param(consoleblank, blankinterval, int, 0444);
 182
 183 static DECLARE_WORK(console_work, console_callback);
 184 static DECLARE_WORK(con_driver_unregister_work, con_driver_unregister_callback);
 185
 186 /*
 187  * fg_console is the current virtual console,
 188  * last_console is the last used one,
 189  * want_console is the console we want to switch to,
 190  * saved_* variants are for save/restore around kernel debugger enter/leave
 191  */
 192 int fg_console;
 193 EXPORT_SYMBOL(fg_console);
 194 int last_console;
 195 int want_console = -1;
 196
 197 static int saved_fg_console;
 198 static int saved_last_console;
 199 static int saved_want_console;
 200 static int saved_vc_mode;
 201 static int saved_console_blanked;
 202
 203 /*
 204  * For each existing display, we have a pointer to console currently visible
 205  * on that display, allowing consoles other than fg_console to be refreshed
 206  * appropriately. Unless the low-level driver supplies its own display_fg
 207  * variable, we use this one for the "master display".
 208  */
 209 static struct vc_data *master_display_fg;
 210
 211 /*
 212  * Unfortunately, we need to delay tty echo when we're currently writing to the
 213  * console since the code is (and always was) not re-entrant, so we schedule
 214  * all flip requests to process context with schedule-task() and run it from
 215  * console_callback().
 216  */
 217
 218 /*
 219  * For the same reason, we defer scrollback to the console callback.
 220  */
 221 static int scrollback_delta;
 222
 223 /*
 224  * Hook so that the power management routines can (un)blank
 225  * the console on our behalf.
 226  */
 227 int (*console_blank_hook)(int);
 228 EXPORT_SYMBOL(console_blank_hook);
 229
 230 static DEFINE_TIMER(console_timer, blank_screen_t);
 231 static int blank_state;
 232 static int blank_timer_expired;
 233 enum {
 234         blank_off = 0,
 235         blank_normal_wait,
 236         blank_vesa_wait,
 237 };
 238
 239 /*
 240  * /sys/class/tty/tty0/
 241  *
 242  * the attribute 'active' contains the name of the current vc
 243  * console and it supports poll() to detect vc switches
 244  */
 245 static struct device *tty0dev;
 246
 247 /*
 248  * Notifier list for console events.
 249  */
 250 static ATOMIC_NOTIFIER_HEAD(vt_notifier_list);
 251
 252 int register_vt_notifier(struct notifier_block *nb)
 253 {
 254         return atomic_notifier_chain_register(&vt_notifier_list, nb);
 255 }
 256 EXPORT_SYMBOL_GPL(register_vt_notifier);
 257
 258 int unregister_vt_notifier(struct notifier_block *nb)
 259 {
 260         return atomic_notifier_chain_unregister(&vt_notifier_list, nb);
 261 }
 262 EXPORT_SYMBOL_GPL(unregister_vt_notifier);
 263
 264 static void notify_write(struct vc_data *vc, unsigned int unicode)
 265 {
 266         struct vt_notifier_param param = { .vc = vc, .c = unicode };
 267         atomic_notifier_call_chain(&vt_notifier_list, VT_WRITE, &param);
 268 }
 269
 270 static void notify_update(struct vc_data *vc)
 271 {
 272         struct vt_notifier_param param = { .vc = vc };
 273         atomic_notifier_call_chain(&vt_notifier_list, VT_UPDATE, &param);
 274 }
 275 /*
 276  *      Low-Level Functions
 277  */
 278
 279 static inline bool con_is_fg(const struct vc_data *vc)
 280 {
 281         return vc->vc_num == fg_console;
 282 }
 283
 284 static inline bool con_should_update(const struct vc_data *vc)
 285 {
 286         return con_is_visible(vc) && !console_blanked;
 287 }
 288
 289 static inline unsigned short *screenpos(const struct vc_data *vc, int offset,
 290                 bool viewed)
 291 {
 292         unsigned short *p;
 293
 294         if (!viewed)
 295                 p = (unsigned short *)(vc->vc_origin + offset);
 296         else if (!vc->vc_sw->con_screen_pos)
 297                 p = (unsigned short *)(vc->vc_visible_origin + offset);
 298         else
 299                 p = vc->vc_sw->con_screen_pos(vc, offset);
 300         return p;
 301 }
 302
 303 /* Called  from the keyboard irq path.. */
 304 static inline void scrolldelta(int lines)
 305 {
 306         /* FIXME */
 307         /* scrolldelta needs some kind of consistency lock, but the BKL was
 308            and still is not protecting versus the scheduled back end */
 309         scrollback_delta += lines;
 310         schedule_console_callback();
 311 }
 312
 313 void schedule_console_callback(void)
 314 {
 315         schedule_work(&console_work);
 316 }
 317
 318 /*
 319  * Code to manage unicode-based screen buffers
 320  */
 321
 322 /*
 323  * Our screen buffer is preceded by an array of line pointers so that
 324  * scrolling only implies some pointer shuffling.
 325  */
 326
 327 static u32 **vc_uniscr_alloc(unsigned int cols, unsigned int rows)
 328 {
 329         u32 **uni_lines;
 330         void *p;
 331         unsigned int memsize, i, col_size = cols * sizeof(**uni_lines);
 332
 333         /* allocate everything in one go */
 334         memsize = col_size * rows;
 335         memsize += rows * sizeof(*uni_lines);
 336         uni_lines = vzalloc(memsize);
 337         if (!uni_lines)
 338                 return NULL;
 339
 340         /* initial line pointers */
 341         p = uni_lines + rows;
 342         for (i = 0; i < rows; i++) {
 343                 uni_lines[i] = p;
 344                 p += col_size;
 345         }
 346
 347         return uni_lines;
 348 }
 349
 350 static void vc_uniscr_free(u32 **uni_lines)
 351 {
 352         vfree(uni_lines);
 353 }
 354
 355 static void vc_uniscr_set(struct vc_data *vc, u32 **new_uni_lines)
 356 {
 357         vc_uniscr_free(vc->vc_uni_lines);
 358         vc->vc_uni_lines = new_uni_lines;
 359 }
 360
 361 static void vc_uniscr_putc(struct vc_data *vc, u32 uc)
 362 {
 363         if (vc->vc_uni_lines)
 364                 vc->vc_uni_lines[vc->state.y][vc->state.x] = uc;
 365 }
 366
 367 static void vc_uniscr_insert(struct vc_data *vc, unsigned int nr)
 368 {
 369         if (vc->vc_uni_lines) {
 370                 u32 *ln = vc->vc_uni_lines[vc->state.y];
 371                 unsigned int x = vc->state.x, cols = vc->vc_cols;
 372
 373                 memmove(&ln[x + nr], &ln[x], (cols - x - nr) * sizeof(*ln));
 374                 memset32(&ln[x], ' ', nr);
 375         }
 376 }
 377
 378 static void vc_uniscr_delete(struct vc_data *vc, unsigned int nr)
 379 {
 380         if (vc->vc_uni_lines) {
 381                 u32 *ln = vc->vc_uni_lines[vc->state.y];
 382                 unsigned int x = vc->state.x, cols = vc->vc_cols;
 383
 384                 memcpy(&ln[x], &ln[x + nr], (cols - x - nr) * sizeof(*ln));
 385                 memset32(&ln[cols - nr], ' ', nr);
 386         }
 387 }
 388
 389 static void vc_uniscr_clear_line(struct vc_data *vc, unsigned int x,
 390                                  unsigned int nr)
 391 {
 392         if (vc->vc_uni_lines)
 393                 memset32(&vc->vc_uni_lines[vc->state.y][x], ' ', nr);
 394 }
 395
 396 static void vc_uniscr_clear_lines(struct vc_data *vc, unsigned int y,
 397                                   unsigned int nr)
 398 {
 399         if (vc->vc_uni_lines)
 400                 while (nr--)
 401                         memset32(vc->vc_uni_lines[y++], ' ', vc->vc_cols);
 402 }
 403
 404 /* juggling array rotation algorithm (complexity O(N), size complexity O(1)) */
 405 static void juggle_array(u32 **array, unsigned int size, unsigned int nr)
 406 {
 407         unsigned int gcd_idx;
 408
 409         for (gcd_idx = 0; gcd_idx < gcd(nr, size); gcd_idx++) {
 410                 u32 *gcd_idx_val = array[gcd_idx];
 411                 unsigned int dst_idx = gcd_idx;
 412
 413                 while (1) {
 414                         unsigned int src_idx = (dst_idx + nr) % size;
 415                         if (src_idx == gcd_idx)
 416                                 break;
 417
 418                         array[dst_idx] = array[src_idx];
 419                         dst_idx = src_idx;
 420                 }
 421
 422                 array[dst_idx] = gcd_idx_val;
 423         }
 424 }
 425
 426 static void vc_uniscr_scroll(struct vc_data *vc, unsigned int top,
 427                              unsigned int bottom, enum con_scroll dir,
 428                              unsigned int nr)
 429 {
 430         u32 **uni_lines = vc->vc_uni_lines;
 431         unsigned int size = bottom - top;
 432
 433         if (!uni_lines)
 434                 return;
 435
 436         if (dir == SM_DOWN) {
 437                 juggle_array(&uni_lines[top], size, size - nr);
 438                 vc_uniscr_clear_lines(vc, top, nr);
 439         } else {
 440                 juggle_array(&uni_lines[top], size, nr);
 441                 vc_uniscr_clear_lines(vc, bottom - nr, nr);
 442         }
 443 }
 444
 445 static void vc_uniscr_copy_area(u32 **dst_lines,
 446                                 unsigned int dst_cols,
 447                                 unsigned int dst_rows,
 448                                 u32 **src_lines,
 449                                 unsigned int src_cols,
 450                                 unsigned int src_top_row,
 451                                 unsigned int src_bot_row)
 452 {
 453         unsigned int dst_row = 0;
 454
 455         if (!dst_lines)
 456                 return;
 457
 458         while (src_top_row < src_bot_row) {
 459                 u32 *src_line = src_lines[src_top_row];
 460                 u32 *dst_line = dst_lines[dst_row];
 461
 462                 memcpy(dst_line, src_line, src_cols * sizeof(*src_line));
 463                 if (dst_cols - src_cols)
 464                         memset32(dst_line + src_cols, ' ', dst_cols - src_cols);
 465                 src_top_row++;
 466                 dst_row++;
 467         }
 468         while (dst_row < dst_rows) {
 469                 u32 *dst_line = dst_lines[dst_row];
 470
 471                 memset32(dst_line, ' ', dst_cols);
 472                 dst_row++;
 473         }
 474 }
 475
 476 /*
 477  * Called from vcs_read() to make sure unicode screen retrieval is possible.
 478  * This will initialize the unicode screen buffer if not already done.
 479  * This returns 0 if OK, or a negative error code otherwise.
 480  * In particular, -ENODATA is returned if the console is not in UTF-8 mode.
 481  */
 482 int vc_uniscr_check(struct vc_data *vc)
 483 {
 484         u32 **uni_lines;
 485         unsigned short *p;
 486         int x, y, mask;
 487
 488         WARN_CONSOLE_UNLOCKED();
 489
 490         if (!vc->vc_utf)
 491                 return -ENODATA;
 492
 493         if (vc->vc_uni_lines)
 494                 return 0;
 495
 496         uni_lines = vc_uniscr_alloc(vc->vc_cols, vc->vc_rows);
 497         if (!uni_lines)
 498                 return -ENOMEM;
 499
 500         /*
 501          * Let's populate it initially with (imperfect) reverse translation.
 502          * This is the next best thing we can do short of having it enabled
 503          * from the start even when no users rely on this functionality. True
 504          * unicode content will be available after a complete screen refresh.
 505          */
 506         p = (unsigned short *)vc->vc_origin;
 507         mask = vc->vc_hi_font_mask | 0xff;
 508         for (y = 0; y < vc->vc_rows; y++) {
 509                 u32 *line = uni_lines[y];
 510                 for (x = 0; x < vc->vc_cols; x++) {
 511                         u16 glyph = scr_readw(p++) & mask;
 512                         line[x] = inverse_translate(vc, glyph, true);
 513                 }
 514         }
 515
 516         vc->vc_uni_lines = uni_lines;
 517
 518         return 0;
 519 }
 520
 521 /*
 522  * Called from vcs_read() to get the unicode data from the screen.
 523  * This must be preceded by a successful call to vc_uniscr_check() once
 524  * the console lock has been taken.
 525  */
 526 void vc_uniscr_copy_line(const struct vc_data *vc, void *dest, bool viewed,
 527                          unsigned int row, unsigned int col, unsigned int nr)
 528 {
 529         u32 **uni_lines = vc->vc_uni_lines;
 530         int offset = row * vc->vc_size_row + col * 2;
 531         unsigned long pos;
 532
 533         if (WARN_ON_ONCE(!uni_lines))
 534                 return;
 535
 536         pos = (unsigned long)screenpos(vc, offset, viewed);
 537         if (pos >= vc->vc_origin && pos < vc->vc_scr_end) {
 538                 /*
 539                  * Desired position falls in the main screen buffer.
 540                  * However the actual row/col might be different if
 541                  * scrollback is active.
 542                  */
 543                 row = (pos - vc->vc_origin) / vc->vc_size_row;
 544                 col = ((pos - vc->vc_origin) % vc->vc_size_row) / 2;
 545                 memcpy(dest, &uni_lines[row][col], nr * sizeof(u32));
 546         } else {
 547                 /*
 548                  * Scrollback is active. For now let's simply backtranslate
 549                  * the screen glyphs until the unicode screen buffer does
 550                  * synchronize with console display drivers for a scrollback
 551                  * buffer of its own.
 552                  */
 553                 u16 *p = (u16 *)pos;
 554                 int mask = vc->vc_hi_font_mask | 0xff;
 555                 u32 *uni_buf = dest;
 556                 while (nr--) {
 557                         u16 glyph = scr_readw(p++) & mask;
 558                         *uni_buf++ = inverse_translate(vc, glyph, true);
 559                 }
 560         }
 561 }
 562
 563 static void con_scroll(struct vc_data *vc, unsigned int top,
 564                        unsigned int bottom, enum con_scroll dir,
 565                        unsigned int nr)
 566 {
 567         unsigned int rows = bottom - top;
 568         u16 *clear, *dst, *src;
 569
 570         if (top + nr >= bottom)
 571                 nr = rows - 1;
 572         if (bottom > vc->vc_rows || top >= bottom || nr < 1)
 573                 return;
 574
 575         vc_uniscr_scroll(vc, top, bottom, dir, nr);
 576         if (con_is_visible(vc) &&
 577                         vc->vc_sw->con_scroll(vc, top, bottom, dir, nr))
 578                 return;
 579
 580         src = clear = (u16 *)(vc->vc_origin + vc->vc_size_row * top);
 581         dst = (u16 *)(vc->vc_origin + vc->vc_size_row * (top + nr));
 582
 583         if (dir == SM_UP) {
 584                 clear = src + (rows - nr) * vc->vc_cols;
 585                 swap(src, dst);
 586         }
 587         scr_memmovew(dst, src, (rows - nr) * vc->vc_size_row);
 588         scr_memsetw(clear, vc->vc_video_erase_char, vc->vc_size_row * nr);
 589 }
 590
 591 static void do_update_region(struct vc_data *vc, unsigned long start, int count)
 592 {
 593         unsigned int xx, yy, offset;
 594         u16 *p;
 595
 596         p = (u16 *) start;
 597         if (!vc->vc_sw->con_getxy) {
 598                 offset = (start - vc->vc_origin) / 2;
 599                 xx = offset % vc->vc_cols;
 600                 yy = offset / vc->vc_cols;
 601         } else {
 602                 int nxx, nyy;
 603                 start = vc->vc_sw->con_getxy(vc, start, &nxx, &nyy);
 604                 xx = nxx; yy = nyy;
 605         }
 606         for(;;) {
 607                 u16 attrib = scr_readw(p) & 0xff00;
 608                 int startx = xx;
 609                 u16 *q = p;
 610                 while (xx < vc->vc_cols && count) {
 611                         if (attrib != (scr_readw(p) & 0xff00)) {
 612                                 if (p > q)
 613                                         vc->vc_sw->con_putcs(vc, q, p-q, yy, startx);
 614                                 startx = xx;
 615                                 q = p;
 616                                 attrib = scr_readw(p) & 0xff00;
 617                         }
 618                         p++;
 619                         xx++;
 620                         count--;
 621                 }
 622                 if (p > q)
 623                         vc->vc_sw->con_putcs(vc, q, p-q, yy, startx);
 624                 if (!count)
 625                         break;
 626                 xx = 0;
 627                 yy++;
 628                 if (vc->vc_sw->con_getxy) {
 629                         p = (u16 *)start;
 630                         start = vc->vc_sw->con_getxy(vc, start, NULL, NULL);
 631                 }
 632         }
 633 }
 634
 635 void update_region(struct vc_data *vc, unsigned long start, int count)
 636 {
 637         WARN_CONSOLE_UNLOCKED();
 638
 639         if (con_should_update(vc)) {
 640                 hide_cursor(vc);
 641                 do_update_region(vc, start, count);
 642                 set_cursor(vc);
 643         }
 644 }
 645 EXPORT_SYMBOL(update_region);
 646
 647 /* Structure of attributes is hardware-dependent */
 648
 649 static u8 build_attr(struct vc_data *vc, u8 _color,
 650                 enum vc_intensity _intensity, bool _blink, bool _underline,
 651                 bool _reverse, bool _italic)
 652 {
 653         if (vc->vc_sw->con_build_attr)
 654                 return vc->vc_sw->con_build_attr(vc, _color, _intensity,
 655                        _blink, _underline, _reverse, _italic);
 656
 657 /*
 658  * ++roman: I completely changed the attribute format for monochrome
 659  * mode (!can_do_color). The formerly used MDA (monochrome display
 660  * adapter) format didn't allow the combination of certain effects.
 661  * Now the attribute is just a bit vector:
 662  *  Bit 0..1: intensity (0..2)
 663  *  Bit 2   : underline
 664  *  Bit 3   : reverse
 665  *  Bit 7   : blink
 666  */
 667         {
 668         u8 a = _color;
 669         if (!vc->vc_can_do_color)
 670                 return _intensity |
 671                        (_italic    << 1) |
 672                        (_underline << 2) |
 673                        (_reverse   << 3) |
 674                        (_blink     << 7);
 675         if (_italic)
 676                 a = (a & 0xF0) | vc->vc_itcolor;
 677         else if (_underline)
 678                 a = (a & 0xf0) | vc->vc_ulcolor;
 679         else if (_intensity == VCI_HALF_BRIGHT)
 680                 a = (a & 0xf0) | vc->vc_halfcolor;
 681         if (_reverse)
 682                 a = (a & 0x88) | (((a >> 4) | (a << 4)) & 0x77);
 683         if (_blink)
 684                 a ^= 0x80;
 685         if (_intensity == VCI_BOLD)
 686                 a ^= 0x08;
 687         if (vc->vc_hi_font_mask == 0x100)
 688                 a <<= 1;
 689         return a;
 690         }
 691 }
 692
 693 static void update_attr(struct vc_data *vc)
 694 {
 695         vc->vc_attr = build_attr(vc, vc->state.color, vc->state.intensity,
 696                       vc->state.blink, vc->state.underline,
 697                       vc->state.reverse ^ vc->vc_decscnm, vc->state.italic);
 698         vc->vc_video_erase_char = ' ' | (build_attr(vc, vc->state.color,
 699                                 VCI_NORMAL, vc->state.blink, false,
 700                                 vc->vc_decscnm, false) << 8);
 701 }
 702
 703 /* Note: inverting the screen twice should revert to the original state */
 704 void invert_screen(struct vc_data *vc, int offset, int count, bool viewed)
 705 {
 706         unsigned short *p;
 707
 708         WARN_CONSOLE_UNLOCKED();
 709
 710         count /= 2;
 711         p = screenpos(vc, offset, viewed);
 712         if (vc->vc_sw->con_invert_region) {
 713                 vc->vc_sw->con_invert_region(vc, p, count);
 714         } else {
 715                 u16 *q = p;
 716                 int cnt = count;
 717                 u16 a;
 718
 719                 if (!vc->vc_can_do_color) {
 720                         while (cnt--) {
 721                             a = scr_readw(q);
 722                             a ^= 0x0800;
 723                             scr_writew(a, q);
 724                             q++;
 725                         }
 726                 } else if (vc->vc_hi_font_mask == 0x100) {
 727                         while (cnt--) {
 728                                 a = scr_readw(q);
 729                                 a = (a & 0x11ff) |
 730                                    ((a & 0xe000) >> 4) |
 731                                    ((a & 0x0e00) << 4);
 732                                 scr_writew(a, q);
 733                                 q++;
 734                         }
 735                 } else {
 736                         while (cnt--) {
 737                                 a = scr_readw(q);
 738                                 a = (a & 0x88ff) |
 739                                    ((a & 0x7000) >> 4) |
 740                                    ((a & 0x0700) << 4);
 741                                 scr_writew(a, q);
 742                                 q++;
 743                         }
 744                 }
 745         }
 746
 747         if (con_should_update(vc))
 748                 do_update_region(vc, (unsigned long) p, count);
 749         notify_update(vc);
 750 }
 751
 752 /* used by selection: complement pointer position */
 753 void complement_pos(struct vc_data *vc, int offset)
 754 {
 755         static int old_offset = -1;
 756         static unsigned short old;
 757         static unsigned short oldx, oldy;
 758
 759         WARN_CONSOLE_UNLOCKED();
 760
 761         if (old_offset != -1 && old_offset >= 0 &&
 762             old_offset < vc->vc_screenbuf_size) {
 763                 scr_writew(old, screenpos(vc, old_offset, true));
 764                 if (con_should_update(vc))
 765                         vc->vc_sw->con_putc(vc, old, oldy, oldx);
 766                 notify_update(vc);
 767         }
 768
 769         old_offset = offset;
 770
 771         if (offset != -1 && offset >= 0 &&
 772             offset < vc->vc_screenbuf_size) {
 773                 unsigned short new;
 774                 unsigned short *p;
 775                 p = screenpos(vc, offset, true);
 776                 old = scr_readw(p);
 777                 new = old ^ vc->vc_complement_mask;
 778                 scr_writew(new, p);
 779                 if (con_should_update(vc)) {
 780                         oldx = (offset >> 1) % vc->vc_cols;
 781                         oldy = (offset >> 1) / vc->vc_cols;
 782                         vc->vc_sw->con_putc(vc, new, oldy, oldx);
 783                 }
 784                 notify_update(vc);
 785         }
 786 }
 787
 788 static void insert_char(struct vc_data *vc, unsigned int nr)
 789 {
 790         unsigned short *p = (unsigned short *) vc->vc_pos;
 791
 792         vc_uniscr_insert(vc, nr);
 793         scr_memmovew(p + nr, p, (vc->vc_cols - vc->state.x - nr) * 2);
 794         scr_memsetw(p, vc->vc_video_erase_char, nr * 2);
 795         vc->vc_need_wrap = 0;
 796         if (con_should_update(vc))
 797                 do_update_region(vc, (unsigned long) p,
 798                         vc->vc_cols - vc->state.x);
 799 }
 800
 801 static void delete_char(struct vc_data *vc, unsigned int nr)
 802 {
 803         unsigned short *p = (unsigned short *) vc->vc_pos;
 804
 805         vc_uniscr_delete(vc, nr);
 806         scr_memmovew(p, p + nr, (vc->vc_cols - vc->state.x - nr) * 2);
 807         scr_memsetw(p + vc->vc_cols - vc->state.x - nr, vc->vc_video_erase_char,
 808                         nr * 2);
 809         vc->vc_need_wrap = 0;
 810         if (con_should_update(vc))
 811                 do_update_region(vc, (unsigned long) p,
 812                         vc->vc_cols - vc->state.x);
 813 }
 814
 815 static int softcursor_original = -1;
 816
 817 static void add_softcursor(struct vc_data *vc)
 818 {
 819         int i = scr_readw((u16 *) vc->vc_pos);
 820         u32 type = vc->vc_cursor_type;
 821
 822         if (!(type & CUR_SW))
 823                 return;
 824         if (softcursor_original != -1)
 825                 return;
 826         softcursor_original = i;
 827         i |= CUR_SET(type);
 828         i ^= CUR_CHANGE(type);
 829         if ((type & CUR_ALWAYS_BG) &&
 830                         (softcursor_original & CUR_BG) == (i & CUR_BG))
 831                 i ^= CUR_BG;
 832         if ((type & CUR_INVERT_FG_BG) && (i & CUR_FG) == ((i & CUR_BG) >> 4))
 833                 i ^= CUR_FG;
 834         scr_writew(i, (u16 *)vc->vc_pos);
 835         if (con_should_update(vc))
 836                 vc->vc_sw->con_putc(vc, i, vc->state.y, vc->state.x);
 837 }
 838
 839 static void hide_softcursor(struct vc_data *vc)
 840 {
 841         if (softcursor_original != -1) {
 842                 scr_writew(softcursor_original, (u16 *)vc->vc_pos);
 843                 if (con_should_update(vc))
 844                         vc->vc_sw->con_putc(vc, softcursor_original,
 845                                         vc->state.y, vc->state.x);
 846                 softcursor_original = -1;
 847         }
 848 }
 849
 850 static void hide_cursor(struct vc_data *vc)
 851 {
 852         if (vc_is_sel(vc))
 853                 clear_selection();
 854
 855         vc->vc_sw->con_cursor(vc, CM_ERASE);
 856         hide_softcursor(vc);
 857 }
 858
 859 static void set_cursor(struct vc_data *vc)
 860 {
 861         if (!con_is_fg(vc) || console_blanked || vc->vc_mode == KD_GRAPHICS)
 862                 return;
 863         if (vc->vc_deccm) {
 864                 if (vc_is_sel(vc))
 865                         clear_selection();
 866                 add_softcursor(vc);
 867                 if (CUR_SIZE(vc->vc_cursor_type) != CUR_NONE)
 868                         vc->vc_sw->con_cursor(vc, CM_DRAW);
 869         } else
 870                 hide_cursor(vc);
 871 }
 872
 873 static void set_origin(struct vc_data *vc)
 874 {
 875         WARN_CONSOLE_UNLOCKED();
 876
 877         if (!con_is_visible(vc) ||
 878             !vc->vc_sw->con_set_origin ||
 879             !vc->vc_sw->con_set_origin(vc))
 880                 vc->vc_origin = (unsigned long)vc->vc_screenbuf;
 881         vc->vc_visible_origin = vc->vc_origin;
 882         vc->vc_scr_end = vc->vc_origin + vc->vc_screenbuf_size;
 883         vc->vc_pos = vc->vc_origin + vc->vc_size_row * vc->state.y +
 884                 2 * vc->state.x;
 885 }
 886
 887 static void save_screen(struct vc_data *vc)
 888 {
 889         WARN_CONSOLE_UNLOCKED();
 890
 891         if (vc->vc_sw->con_save_screen)
 892                 vc->vc_sw->con_save_screen(vc);
 893 }
 894
 895 static void flush_scrollback(struct vc_data *vc)
 896 {
 897         WARN_CONSOLE_UNLOCKED();
 898
 899         set_origin(vc);
 900         if (vc->vc_sw->con_flush_scrollback) {
 901                 vc->vc_sw->con_flush_scrollback(vc);
 902         } else if (con_is_visible(vc)) {
 903                 /*
 904                  * When no con_flush_scrollback method is provided then the
 905                  * legacy way for flushing the scrollback buffer is to use
 906                  * a side effect of the con_switch method. We do it only on
 907                  * the foreground console as background consoles have no
 908                  * scrollback buffers in that case and we obviously don't
 909                  * want to switch to them.
 910                  */
 911                 hide_cursor(vc);
 912                 vc->vc_sw->con_switch(vc);
 913                 set_cursor(vc);
 914         }
 915 }
 916
 917 /*
 918  *      Redrawing of screen
 919  */
 920
 921 void clear_buffer_attributes(struct vc_data *vc)
 922 {
 923         unsigned short *p = (unsigned short *)vc->vc_origin;
 924         int count = vc->vc_screenbuf_size / 2;
 925         int mask = vc->vc_hi_font_mask | 0xff;
 926
 927         for (; count > 0; count--, p++) {
 928                 scr_writew((scr_readw(p)&mask) | (vc->vc_video_erase_char & ~mask), p);
 929         }
 930 }
 931
 932 void redraw_screen(struct vc_data *vc, int is_switch)
 933 {
 934         int redraw = 0;
 935
 936         WARN_CONSOLE_UNLOCKED();
 937
 938         if (!vc) {
 939                 /* strange ... */
 940                 /* printk("redraw_screen: tty %d not allocated ??\n", new_console+1); */
 941                 return;
 942         }
 943
 944         if (is_switch) {
 945                 struct vc_data *old_vc = vc_cons[fg_console].d;
 946                 if (old_vc == vc)
 947                         return;
 948                 if (!con_is_visible(vc))
 949                         redraw = 1;
 950                 *vc->vc_display_fg = vc;
 951                 fg_console = vc->vc_num;
 952                 hide_cursor(old_vc);
 953                 if (!con_is_visible(old_vc)) {
 954                         save_screen(old_vc);
 955                         set_origin(old_vc);
 956                 }
 957                 if (tty0dev)
 958                         sysfs_notify(&tty0dev->kobj, NULL, "active");
 959         } else {
 960                 hide_cursor(vc);
 961                 redraw = 1;
 962         }
 963
 964         if (redraw) {
 965                 int update;
 966                 int old_was_color = vc->vc_can_do_color;
 967
 968                 set_origin(vc);
 969                 update = vc->vc_sw->con_switch(vc);
 970                 set_palette(vc);
 971                 /*
 972                  * If console changed from mono<->color, the best we can do
 973                  * is to clear the buffer attributes. As it currently stands,
 974                  * rebuilding new attributes from the old buffer is not doable
 975                  * without overly complex code.
 976                  */
 977                 if (old_was_color != vc->vc_can_do_color) {
 978                         update_attr(vc);
 979                         clear_buffer_attributes(vc);
 980                 }
 981
 982                 if (update && vc->vc_mode != KD_GRAPHICS)
 983                         do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2);
 984         }
 985         set_cursor(vc);
 986         if (is_switch) {
 987                 vt_set_leds_compute_shiftstate();
 988                 notify_update(vc);
 989         }
 990 }
 991 EXPORT_SYMBOL(redraw_screen);
 992
 993 /*
 994  *      Allocation, freeing and resizing of VTs.
 995  */
 996
 997 int vc_cons_allocated(unsigned int i)
 998 {
 999         return (i < MAX_NR_CONSOLES && vc_cons[i].d);
1000 }
1001
1002 static void visual_init(struct vc_data *vc, int num, int init)
1003 {
1004         /* ++Geert: vc->vc_sw->con_init determines console size */
1005         if (vc->vc_sw)
1006                 module_put(vc->vc_sw->owner);
1007         vc->vc_sw = conswitchp;
1008
1009         if (con_driver_map[num])
1010                 vc->vc_sw = con_driver_map[num];
1011
1012         __module_get(vc->vc_sw->owner);
1013         vc->vc_num = num;
1014         vc->vc_display_fg = &master_display_fg;
1015         if (vc->uni_pagedict_loc)
1016                 con_free_unimap(vc);
1017         vc->uni_pagedict_loc = &vc->uni_pagedict;
1018         vc->uni_pagedict = NULL;
1019         vc->vc_hi_font_mask = 0;
1020         vc->vc_complement_mask = 0;
1021         vc->vc_can_do_color = 0;
1022         vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
1023         vc->vc_sw->con_init(vc, init);
1024         if (!vc->vc_complement_mask)
1025                 vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800;
1026         vc->vc_s_complement_mask = vc->vc_complement_mask;
1027         vc->vc_size_row = vc->vc_cols << 1;
1028         vc->vc_screenbuf_size = vc->vc_rows * vc->vc_size_row;
1029 }
1030
1031
1032 static void visual_deinit(struct vc_data *vc)
1033 {
1034         vc->vc_sw->con_deinit(vc);
1035         module_put(vc->vc_sw->owner);
1036 }
1037
1038 static void vc_port_destruct(struct tty_port *port)
1039 {
1040         struct vc_data *vc = container_of(port, struct vc_data, port);
1041
1042         kfree(vc);
1043 }
1044
1045 static const struct tty_port_operations vc_port_ops = {
1046         .destruct = vc_port_destruct,
1047 };
1048
1049 /*
1050  * Change # of rows and columns (0 means unchanged/the size of fg_console)
1051  * [this is to be used together with some user program
1052  * like resize that changes the hardware videomode]
1053  */
1054 #define VC_MAXCOL (32767)
1055 #define VC_MAXROW (32767)
1056
1057 int vc_allocate(unsigned int currcons)  /* return 0 on success */
1058 {
1059         struct vt_notifier_param param;
1060         struct vc_data *vc;
1061         int err;
1062
1063         WARN_CONSOLE_UNLOCKED();
1064
1065         if (currcons >= MAX_NR_CONSOLES)
1066                 return -ENXIO;
1067
1068         if (vc_cons[currcons].d)
1069                 return 0;
1070
1071         /* due to the granularity of kmalloc, we waste some memory here */
1072         /* the alloc is done in two steps, to optimize the common situation
1073            of a 25x80 console (structsize=216, screenbuf_size=4000) */
1074         /* although the numbers above are not valid since long ago, the
1075            point is still up-to-date and the comment still has its value
1076            even if only as a historical artifact.  --mj, July 1998 */
1077         param.vc = vc = kzalloc(sizeof(struct vc_data), GFP_KERNEL);
1078         if (!vc)
1079                 return -ENOMEM;
1080
1081         vc_cons[currcons].d = vc;
1082         tty_port_init(&vc->port);
1083         vc->port.ops = &vc_port_ops;
1084         INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
1085
1086         visual_init(vc, currcons, 1);
1087
1088         if (!*vc->uni_pagedict_loc)
1089                 con_set_default_unimap(vc);
1090
1091         err = -EINVAL;
1092         if (vc->vc_cols > VC_MAXCOL || vc->vc_rows > VC_MAXROW ||
1093             vc->vc_screenbuf_size > KMALLOC_MAX_SIZE || !vc->vc_screenbuf_size)
1094                 goto err_free;
1095         err = -ENOMEM;
1096         vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);
1097         if (!vc->vc_screenbuf)
1098                 goto err_free;
1099
1100         /* If no drivers have overridden us and the user didn't pass a
1101            boot option, default to displaying the cursor */
1102         if (global_cursor_default == -1)
1103                 global_cursor_default = 1;
1104
1105         vc_init(vc, 1);
1106         vcs_make_sysfs(currcons);
1107         atomic_notifier_call_chain(&vt_notifier_list, VT_ALLOCATE, &param);
1108
1109         return 0;
1110 err_free:
1111         visual_deinit(vc);
1112         kfree(vc);
1113         vc_cons[currcons].d = NULL;
1114         return err;
1115 }
1116
1117 static inline int resize_screen(struct vc_data *vc, int width, int height,
1118                                 int user)
1119 {
1120         /* Resizes the resolution of the display adapater */
1121         int err = 0;
1122
1123         if (vc->vc_sw->con_resize)
1124                 err = vc->vc_sw->con_resize(vc, width, height, user);
1125
1126         return err;
1127 }
1128
1129 /**
1130  *      vc_do_resize    -       resizing method for the tty
1131  *      @tty: tty being resized
1132  *      @vc: virtual console private data
1133  *      @cols: columns
1134  *      @lines: lines
1135  *
1136  *      Resize a virtual console, clipping according to the actual constraints.
1137  *      If the caller passes a tty structure then update the termios winsize
1138  *      information and perform any necessary signal handling.
1139  *
1140  *      Caller must hold the console semaphore. Takes the termios rwsem and
1141  *      ctrl.lock of the tty IFF a tty is passed.
1142  */
1143
1144 static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
1145                                 unsigned int cols, unsigned int lines)
1146 {
1147         unsigned long old_origin, new_origin, new_scr_end, rlth, rrem, err = 0;
1148         unsigned long end;
1149         unsigned int old_rows, old_row_size, first_copied_row;
1150         unsigned int new_cols, new_rows, new_row_size, new_screen_size;
1151         unsigned int user;
1152         unsigned short *oldscreen, *newscreen;
1153         u32 **new_uniscr = NULL;
1154
1155         WARN_CONSOLE_UNLOCKED();
1156
1157         if (!vc)
1158                 return -ENXIO;
1159
1160         user = vc->vc_resize_user;
1161         vc->vc_resize_user = 0;
1162
1163         if (cols > VC_MAXCOL || lines > VC_MAXROW)
1164                 return -EINVAL;
1165
1166         new_cols = (cols ? cols : vc->vc_cols);
1167         new_rows = (lines ? lines : vc->vc_rows);
1168         new_row_size = new_cols << 1;
1169         new_screen_size = new_row_size * new_rows;
1170
1171         if (new_cols == vc->vc_cols && new_rows == vc->vc_rows) {
1172                 /*
1173                  * This function is being called here to cover the case
1174                  * where the userspace calls the FBIOPUT_VSCREENINFO twice,
1175                  * passing the same fb_var_screeninfo containing the fields
1176                  * yres/xres equal to a number non-multiple of vc_font.height
1177                  * and yres_virtual/xres_virtual equal to number lesser than the
1178                  * vc_font.height and yres/xres.
1179                  * In the second call, the struct fb_var_screeninfo isn't
1180                  * being modified by the underlying driver because of the
1181                  * if above, and this causes the fbcon_display->vrows to become
1182                  * negative and it eventually leads to out-of-bound
1183                  * access by the imageblit function.
1184                  * To give the correct values to the struct and to not have
1185                  * to deal with possible errors from the code below, we call
1186                  * the resize_screen here as well.
1187                  */
1188                 return resize_screen(vc, new_cols, new_rows, user);
1189         }
1190
1191         if (new_screen_size > KMALLOC_MAX_SIZE || !new_screen_size)
1192                 return -EINVAL;
1193         newscreen = kzalloc(new_screen_size, GFP_USER);
1194         if (!newscreen)
1195                 return -ENOMEM;
1196
1197         if (vc->vc_uni_lines) {
1198                 new_uniscr = vc_uniscr_alloc(new_cols, new_rows);
1199                 if (!new_uniscr) {
1200                         kfree(newscreen);
1201                         return -ENOMEM;
1202                 }
1203         }
1204
1205         if (vc_is_sel(vc))
1206                 clear_selection();
1207
1208         old_rows = vc->vc_rows;
1209         old_row_size = vc->vc_size_row;
1210
1211         err = resize_screen(vc, new_cols, new_rows, user);
1212         if (err) {
1213                 kfree(newscreen);
1214                 vc_uniscr_free(new_uniscr);
1215                 return err;
1216         }
1217
1218         vc->vc_rows = new_rows;
1219         vc->vc_cols = new_cols;
1220         vc->vc_size_row = new_row_size;
1221         vc->vc_screenbuf_size = new_screen_size;
1222
1223         rlth = min(old_row_size, new_row_size);
1224         rrem = new_row_size - rlth;
1225         old_origin = vc->vc_origin;
1226         new_origin = (long) newscreen;
1227         new_scr_end = new_origin + new_screen_size;
1228
1229         if (vc->state.y > new_rows) {
1230                 if (old_rows - vc->state.y < new_rows) {
1231                         /*
1232                          * Cursor near the bottom, copy contents from the
1233                          * bottom of buffer
1234                          */
1235                         first_copied_row = (old_rows - new_rows);
1236                 } else {
1237                         /*
1238                          * Cursor is in no man's land, copy 1/2 screenful
1239                          * from the top and bottom of cursor position
1240                          */
1241                         first_copied_row = (vc->state.y - new_rows/2);
1242                 }
1243                 old_origin += first_copied_row * old_row_size;
1244         } else
1245                 first_copied_row = 0;
1246         end = old_origin + old_row_size * min(old_rows, new_rows);
1247
1248         vc_uniscr_copy_area(new_uniscr, new_cols, new_rows,
1249                             vc->vc_uni_lines, rlth/2, first_copied_row,
1250                             min(old_rows, new_rows));
1251         vc_uniscr_set(vc, new_uniscr);
1252
1253         update_attr(vc);
1254
1255         while (old_origin < end) {
1256                 scr_memcpyw((unsigned short *) new_origin,
1257                             (unsigned short *) old_origin, rlth);
1258                 if (rrem)
1259                         scr_memsetw((void *)(new_origin + rlth),
1260                                     vc->vc_video_erase_char, rrem);
1261                 old_origin += old_row_size;
1262                 new_origin += new_row_size;
1263         }
1264         if (new_scr_end > new_origin)
1265                 scr_memsetw((void *)new_origin, vc->vc_video_erase_char,
1266                             new_scr_end - new_origin);
1267         oldscreen = vc->vc_screenbuf;
1268         vc->vc_screenbuf = newscreen;
1269         vc->vc_screenbuf_size = new_screen_size;
1270         set_origin(vc);
1271         kfree(oldscreen);
1272
1273         /* do part of a reset_terminal() */
1274         vc->vc_top = 0;
1275         vc->vc_bottom = vc->vc_rows;
1276         gotoxy(vc, vc->state.x, vc->state.y);
1277         save_cur(vc);
1278
1279         if (tty) {
1280                 /* Rewrite the requested winsize data with the actual
1281                    resulting sizes */
1282                 struct winsize ws;
1283                 memset(&ws, 0, sizeof(ws));
1284                 ws.ws_row = vc->vc_rows;
1285                 ws.ws_col = vc->vc_cols;
1286                 ws.ws_ypixel = vc->vc_scan_lines;
1287                 tty_do_resize(tty, &ws);
1288         }
1289
1290         if (con_is_visible(vc))
1291                 update_screen(vc);
1292         vt_event_post(VT_EVENT_RESIZE, vc->vc_num, vc->vc_num);
1293         notify_update(vc);
1294         return err;
1295 }
1296
1297 /**
1298  *      vc_resize               -       resize a VT
1299  *      @vc: virtual console
1300  *      @cols: columns
1301  *      @rows: rows
1302  *
1303  *      Resize a virtual console as seen from the console end of things. We
1304  *      use the common vc_do_resize methods to update the structures. The
1305  *      caller must hold the console sem to protect console internals and
1306  *      vc->port.tty
1307  */
1308
1309 int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int rows)
1310 {
1311         return vc_do_resize(vc->port.tty, vc, cols, rows);
1312 }
1313 EXPORT_SYMBOL(vc_resize);
1314
1315 /**
1316  *      vt_resize               -       resize a VT
1317  *      @tty: tty to resize
1318  *      @ws: winsize attributes
1319  *
1320  *      Resize a virtual terminal. This is called by the tty layer as we
1321  *      register our own handler for resizing. The mutual helper does all
1322  *      the actual work.
1323  *
1324  *      Takes the console sem and the called methods then take the tty
1325  *      termios_rwsem and the tty ctrl.lock in that order.
1326  */
1327 static int vt_resize(struct tty_struct *tty, struct winsize *ws)
1328 {
1329         struct vc_data *vc = tty->driver_data;
1330         int ret;
1331
1332         console_lock();
1333         ret = vc_do_resize(tty, vc, ws->ws_col, ws->ws_row);
1334         console_unlock();
1335         return ret;
1336 }
1337
1338 struct vc_data *vc_deallocate(unsigned int currcons)
1339 {
1340         struct vc_data *vc = NULL;
1341
1342         WARN_CONSOLE_UNLOCKED();
1343
1344         if (vc_cons_allocated(currcons)) {
1345                 struct vt_notifier_param param;
1346
1347                 param.vc = vc = vc_cons[currcons].d;
1348                 atomic_notifier_call_chain(&vt_notifier_list, VT_DEALLOCATE, &param);
1349                 vcs_remove_sysfs(currcons);
1350                 visual_deinit(vc);
1351                 con_free_unimap(vc);
1352                 put_pid(vc->vt_pid);
1353                 vc_uniscr_set(vc, NULL);
1354                 kfree(vc->vc_screenbuf);
1355                 vc_cons[currcons].d = NULL;
1356         }
1357         return vc;
1358 }
1359
1360 /*
1361  *      VT102 emulator
1362  */
1363
1364 enum { EPecma = 0, EPdec, EPeq, EPgt, EPlt};
1365
1366 #define set_kbd(vc, x)  vt_set_kbd_mode_bit((vc)->vc_num, (x))
1367 #define clr_kbd(vc, x)  vt_clr_kbd_mode_bit((vc)->vc_num, (x))
1368 #define is_kbd(vc, x)   vt_get_kbd_mode_bit((vc)->vc_num, (x))
1369
1370 #define decarm          VC_REPEAT
1371 #define decckm          VC_CKMODE
1372 #define kbdapplic       VC_APPLIC
1373 #define lnm             VC_CRLF
1374
1375 const unsigned char color_table[] = { 0, 4, 2, 6, 1, 5, 3, 7,
1376                                        8,12,10,14, 9,13,11,15 };
1377 EXPORT_SYMBOL(color_table);
1378
1379 /* the default colour table, for VGA+ colour systems */
1380 unsigned char default_red[] = {
1381         0x00, 0xaa, 0x00, 0xaa, 0x00, 0xaa, 0x00, 0xaa,
1382         0x55, 0xff, 0x55, 0xff, 0x55, 0xff, 0x55, 0xff
1383 };
1384 module_param_array(default_red, byte, NULL, S_IRUGO | S_IWUSR);
1385 EXPORT_SYMBOL(default_red);
1386
1387 unsigned char default_grn[] = {
1388         0x00, 0x00, 0xaa, 0x55, 0x00, 0x00, 0xaa, 0xaa,
1389         0x55, 0x55, 0xff, 0xff, 0x55, 0x55, 0xff, 0xff
1390 };
1391 module_param_array(default_grn, byte, NULL, S_IRUGO | S_IWUSR);
1392 EXPORT_SYMBOL(default_grn);
1393
1394 unsigned char default_blu[] = {
1395         0x00, 0x00, 0x00, 0x00, 0xaa, 0xaa, 0xaa, 0xaa,
1396         0x55, 0x55, 0x55, 0x55, 0xff, 0xff, 0xff, 0xff
1397 };
1398 module_param_array(default_blu, byte, NULL, S_IRUGO | S_IWUSR);
1399 EXPORT_SYMBOL(default_blu);
1400
1401 /*
1402  * gotoxy() must verify all boundaries, because the arguments
1403  * might also be negative. If the given position is out of
1404  * bounds, the cursor is placed at the nearest margin.
1405  */
1406 static void gotoxy(struct vc_data *vc, int new_x, int new_y)
1407 {
1408         int min_y, max_y;
1409
1410         if (new_x < 0)
1411                 vc->state.x = 0;
1412         else {
1413                 if (new_x >= vc->vc_cols)
1414                         vc->state.x = vc->vc_cols - 1;
1415                 else
1416                         vc->state.x = new_x;
1417         }
1418
1419         if (vc->vc_decom) {
1420                 min_y = vc->vc_top;
1421                 max_y = vc->vc_bottom;
1422         } else {
1423                 min_y = 0;
1424                 max_y = vc->vc_rows;
1425         }
1426         if (new_y < min_y)
1427                 vc->state.y = min_y;
1428         else if (new_y >= max_y)
1429                 vc->state.y = max_y - 1;
1430         else
1431                 vc->state.y = new_y;
1432         vc->vc_pos = vc->vc_origin + vc->state.y * vc->vc_size_row +
1433                 (vc->state.x << 1);
1434         vc->vc_need_wrap = 0;
1435 }
1436
1437 /* for absolute user moves, when decom is set */
1438 static void gotoxay(struct vc_data *vc, int new_x, int new_y)
1439 {
1440         gotoxy(vc, new_x, vc->vc_decom ? (vc->vc_top + new_y) : new_y);
1441 }
1442
1443 void scrollback(struct vc_data *vc)
1444 {
1445         scrolldelta(-(vc->vc_rows / 2));
1446 }
1447
1448 void scrollfront(struct vc_data *vc, int lines)
1449 {
1450         if (!lines)
1451                 lines = vc->vc_rows / 2;
1452         scrolldelta(lines);
1453 }
1454
1455 static void lf(struct vc_data *vc)
1456 {
1457         /* don't scroll if above bottom of scrolling region, or
1458          * if below scrolling region
1459          */
1460         if (vc->state.y + 1 == vc->vc_bottom)
1461                 con_scroll(vc, vc->vc_top, vc->vc_bottom, SM_UP, 1);
1462         else if (vc->state.y < vc->vc_rows - 1) {
1463                 vc->state.y++;
1464                 vc->vc_pos += vc->vc_size_row;
1465         }
1466         vc->vc_need_wrap = 0;
1467         notify_write(vc, '\n');
1468 }
1469
1470 static void ri(struct vc_data *vc)
1471 {
1472         /* don't scroll if below top of scrolling region, or
1473          * if above scrolling region
1474          */
1475         if (vc->state.y == vc->vc_top)
1476                 con_scroll(vc, vc->vc_top, vc->vc_bottom, SM_DOWN, 1);
1477         else if (vc->state.y > 0) {
1478                 vc->state.y--;
1479                 vc->vc_pos -= vc->vc_size_row;
1480         }
1481         vc->vc_need_wrap = 0;
1482 }
1483
1484 static inline void cr(struct vc_data *vc)
1485 {
1486         vc->vc_pos -= vc->state.x << 1;
1487         vc->vc_need_wrap = vc->state.x = 0;
1488         notify_write(vc, '\r');
1489 }
1490
1491 static inline void bs(struct vc_data *vc)
1492 {
1493         if (vc->state.x) {
1494                 vc->vc_pos -= 2;
1495                 vc->state.x--;
1496                 vc->vc_need_wrap = 0;
1497                 notify_write(vc, '\b');
1498         }
1499 }
1500
1501 static inline void del(struct vc_data *vc)
1502 {
1503         /* ignored */
1504 }
1505
1506 static void csi_J(struct vc_data *vc, int vpar)
1507 {
1508         unsigned int count;
1509         unsigned short * start;
1510
1511         switch (vpar) {
1512                 case 0: /* erase from cursor to end of display */
1513                         vc_uniscr_clear_line(vc, vc->state.x,
1514                                              vc->vc_cols - vc->state.x);
1515                         vc_uniscr_clear_lines(vc, vc->state.y + 1,
1516                                               vc->vc_rows - vc->state.y - 1);
1517                         count = (vc->vc_scr_end - vc->vc_pos) >> 1;
1518                         start = (unsigned short *)vc->vc_pos;
1519                         break;
1520                 case 1: /* erase from start to cursor */
1521                         vc_uniscr_clear_line(vc, 0, vc->state.x + 1);
1522                         vc_uniscr_clear_lines(vc, 0, vc->state.y);
1523                         count = ((vc->vc_pos - vc->vc_origin) >> 1) + 1;
1524                         start = (unsigned short *)vc->vc_origin;
1525                         break;
1526                 case 3: /* include scrollback */
1527                         flush_scrollback(vc);
1528                         fallthrough;
1529                 case 2: /* erase whole display */
1530                         vc_uniscr_clear_lines(vc, 0, vc->vc_rows);
1531                         count = vc->vc_cols * vc->vc_rows;
1532                         start = (unsigned short *)vc->vc_origin;
1533                         break;
1534                 default:
1535                         return;
1536         }
1537         scr_memsetw(start, vc->vc_video_erase_char, 2 * count);
1538         if (con_should_update(vc))
1539                 do_update_region(vc, (unsigned long) start, count);
1540         vc->vc_need_wrap = 0;
1541 }
1542
1543 static void csi_K(struct vc_data *vc, int vpar)
1544 {
1545         unsigned int count;
1546         unsigned short *start = (unsigned short *)vc->vc_pos;
1547         int offset;
1548
1549         switch (vpar) {
1550                 case 0: /* erase from cursor to end of line */
1551                         offset = 0;
1552                         count = vc->vc_cols - vc->state.x;
1553                         break;
1554                 case 1: /* erase from start of line to cursor */
1555                         offset = -vc->state.x;
1556                         count = vc->state.x + 1;
1557                         break;
1558                 case 2: /* erase whole line */
1559                         offset = -vc->state.x;
1560                         count = vc->vc_cols;
1561                         break;
1562                 default:
1563                         return;
1564         }
1565         vc_uniscr_clear_line(vc, vc->state.x + offset, count);
1566         scr_memsetw(start + offset, vc->vc_video_erase_char, 2 * count);
1567         vc->vc_need_wrap = 0;
1568         if (con_should_update(vc))
1569                 do_update_region(vc, (unsigned long)(start + offset), count);
1570 }
1571
1572 /* erase the following vpar positions */
1573 static void csi_X(struct vc_data *vc, unsigned int vpar)
1574 {                                         /* not vt100? */
1575         unsigned int count;
1576
1577         if (!vpar)
1578                 vpar++;
1579
1580         count = min(vpar, vc->vc_cols - vc->state.x);
1581
1582         vc_uniscr_clear_line(vc, vc->state.x, count);
1583         scr_memsetw((unsigned short *)vc->vc_pos, vc->vc_video_erase_char, 2 * count);
1584         if (con_should_update(vc))
1585                 vc->vc_sw->con_clear(vc, vc->state.y, vc->state.x, 1, count);
1586         vc->vc_need_wrap = 0;
1587 }
1588
1589 static void default_attr(struct vc_data *vc)
1590 {
1591         vc->state.intensity = VCI_NORMAL;
1592         vc->state.italic = false;
1593         vc->state.underline = false;
1594         vc->state.reverse = false;
1595         vc->state.blink = false;
1596         vc->state.color = vc->vc_def_color;
1597 }
1598
1599 struct rgb { u8 r; u8 g; u8 b; };
1600
1601 static void rgb_from_256(int i, struct rgb *c)
1602 {
1603         if (i < 8) {            /* Standard colours. */
1604                 c->r = i&1 ? 0xaa : 0x00;
1605                 c->g = i&2 ? 0xaa : 0x00;
1606                 c->b = i&4 ? 0xaa : 0x00;
1607         } else if (i < 16) {
1608                 c->r = i&1 ? 0xff : 0x55;
1609                 c->g = i&2 ? 0xff : 0x55;
1610                 c->b = i&4 ? 0xff : 0x55;
1611         } else if (i < 232) {   /* 6x6x6 colour cube. */
1612                 c->r = (i - 16) / 36 * 85 / 2;
1613                 c->g = (i - 16) / 6 % 6 * 85 / 2;
1614                 c->b = (i - 16) % 6 * 85 / 2;
1615         } else                  /* Grayscale ramp. */
1616                 c->r = c->g = c->b = i * 10 - 2312;
1617 }
1618
1619 static void rgb_foreground(struct vc_data *vc, const struct rgb *c)
1620 {
1621         u8 hue = 0, max = max3(c->r, c->g, c->b);
1622
1623         if (c->r > max / 2)
1624                 hue |= 4;
1625         if (c->g > max / 2)
1626                 hue |= 2;
1627         if (c->b > max / 2)
1628                 hue |= 1;
1629
1630         if (hue == 7 && max <= 0x55) {
1631                 hue = 0;
1632                 vc->state.intensity = VCI_BOLD;
1633         } else if (max > 0xaa)
1634                 vc->state.intensity = VCI_BOLD;
1635         else
1636                 vc->state.intensity = VCI_NORMAL;
1637
1638         vc->state.color = (vc->state.color & 0xf0) | hue;
1639 }
1640
1641 static void rgb_background(struct vc_data *vc, const struct rgb *c)
1642 {
1643         /* For backgrounds, err on the dark side. */
1644         vc->state.color = (vc->state.color & 0x0f)
1645                 | (c->r&0x80) >> 1 | (c->g&0x80) >> 2 | (c->b&0x80) >> 3;
1646 }
1647
1648 /*
1649  * ITU T.416 Higher colour modes. They break the usual properties of SGR codes
1650  * and thus need to be detected and ignored by hand. That standard also
1651  * wants : rather than ; as separators but sequences containing : are currently
1652  * completely ignored by the parser.
1653  *
1654  * Subcommands 3 (CMY) and 4 (CMYK) are so insane there's no point in
1655  * supporting them.
1656  */
1657 static int vc_t416_color(struct vc_data *vc, int i,
1658                 void(*set_color)(struct vc_data *vc, const struct rgb *c))
1659 {
1660         struct rgb c;
1661
1662         i++;
1663         if (i > vc->vc_npar)
1664                 return i;
1665
1666         if (vc->vc_par[i] == 5 && i + 1 <= vc->vc_npar) {
1667                 /* 256 colours */
1668                 i++;
1669                 rgb_from_256(vc->vc_par[i], &c);
1670         } else if (vc->vc_par[i] == 2 && i + 3 <= vc->vc_npar) {
1671                 /* 24 bit */
1672                 c.r = vc->vc_par[i + 1];
1673                 c.g = vc->vc_par[i + 2];
1674                 c.b = vc->vc_par[i + 3];
1675                 i += 3;
1676         } else
1677                 return i;
1678
1679         set_color(vc, &c);
1680
1681         return i;
1682 }
1683
1684 /* console_lock is held */
1685 static void csi_m(struct vc_data *vc)
1686 {
1687         int i;
1688
1689         for (i = 0; i <= vc->vc_npar; i++)
1690                 switch (vc->vc_par[i]) {
1691                 case 0: /* all attributes off */
1692                         default_attr(vc);
1693                         break;
1694                 case 1:
1695                         vc->state.intensity = VCI_BOLD;
1696                         break;
1697                 case 2:
1698                         vc->state.intensity = VCI_HALF_BRIGHT;
1699                         break;
1700                 case 3:
1701                         vc->state.italic = true;
1702                         break;
1703                 case 21:
1704                         /*
1705                          * No console drivers support double underline, so
1706                          * convert it to a single underline.
1707                          */
1708                 case 4:
1709                         vc->state.underline = true;
1710                         break;
1711                 case 5:
1712                         vc->state.blink = true;
1713                         break;
1714                 case 7:
1715                         vc->state.reverse = true;
1716                         break;
1717                 case 10: /* ANSI X3.64-1979 (SCO-ish?)
1718                           * Select primary font, don't display control chars if
1719                           * defined, don't set bit 8 on output.
1720                           */
1721                         vc->vc_translate = set_translate(vc->state.Gx_charset[vc->state.charset], vc);
1722                         vc->vc_disp_ctrl = 0;
1723                         vc->vc_toggle_meta = 0;
1724                         break;
1725                 case 11: /* ANSI X3.64-1979 (SCO-ish?)
1726                           * Select first alternate font, lets chars < 32 be
1727                           * displayed as ROM chars.
1728                           */
1729                         vc->vc_translate = set_translate(IBMPC_MAP, vc);
1730                         vc->vc_disp_ctrl = 1;
1731                         vc->vc_toggle_meta = 0;
1732                         break;
1733                 case 12: /* ANSI X3.64-1979 (SCO-ish?)
1734                           * Select second alternate font, toggle high bit
1735                           * before displaying as ROM char.
1736                           */
1737                         vc->vc_translate = set_translate(IBMPC_MAP, vc);
1738                         vc->vc_disp_ctrl = 1;
1739                         vc->vc_toggle_meta = 1;
1740                         break;
1741                 case 22:
1742                         vc->state.intensity = VCI_NORMAL;
1743                         break;
1744                 case 23:
1745                         vc->state.italic = false;
1746                         break;
1747                 case 24:
1748                         vc->state.underline = false;
1749                         break;
1750                 case 25:
1751                         vc->state.blink = false;
1752                         break;
1753                 case 27:
1754                         vc->state.reverse = false;
1755                         break;
1756                 case 38:
1757                         i = vc_t416_color(vc, i, rgb_foreground);
1758                         break;
1759                 case 48:
1760                         i = vc_t416_color(vc, i, rgb_background);
1761                         break;
1762                 case 39:
1763                         vc->state.color = (vc->vc_def_color & 0x0f) |
1764                                 (vc->state.color & 0xf0);
1765                         break;
1766                 case 49:
1767                         vc->state.color = (vc->vc_def_color & 0xf0) |
1768                                 (vc->state.color & 0x0f);
1769                         break;
1770                 default:
1771                         if (vc->vc_par[i] >= 90 && vc->vc_par[i] <= 107) {
1772                                 if (vc->vc_par[i] < 100)
1773                                         vc->state.intensity = VCI_BOLD;
1774                                 vc->vc_par[i] -= 60;
1775                         }
1776                         if (vc->vc_par[i] >= 30 && vc->vc_par[i] <= 37)
1777                                 vc->state.color = color_table[vc->vc_par[i] - 30]
1778                                         | (vc->state.color & 0xf0);
1779                         else if (vc->vc_par[i] >= 40 && vc->vc_par[i] <= 47)
1780                                 vc->state.color = (color_table[vc->vc_par[i] - 40] << 4)
1781                                         | (vc->state.color & 0x0f);
1782                         break;
1783                 }
1784         update_attr(vc);
1785 }
1786
1787 static void respond_string(const char *p, size_t len, struct tty_port *port)
1788 {
1789         tty_insert_flip_string(port, p, len);
1790         tty_flip_buffer_push(port);
1791 }
1792
1793 static void cursor_report(struct vc_data *vc, struct tty_struct *tty)
1794 {
1795         char buf[40];
1796         int len;
1797
1798         len = sprintf(buf, "\033[%d;%dR", vc->state.y +
1799                         (vc->vc_decom ? vc->vc_top + 1 : 1),
1800                         vc->state.x + 1);
1801         respond_string(buf, len, tty->port);
1802 }
1803
1804 static inline void status_report(struct tty_struct *tty)
1805 {
1806         static const char teminal_ok[] = "\033[0n";
1807
1808         respond_string(teminal_ok, strlen(teminal_ok), tty->port);
1809 }
1810
1811 static inline void respond_ID(struct tty_struct *tty)
1812 {
1813         /* terminal answer to an ESC-Z or csi0c query. */
1814         static const char vt102_id[] = "\033[?6c";
1815
1816         respond_string(vt102_id, strlen(vt102_id), tty->port);
1817 }
1818
1819 void mouse_report(struct tty_struct *tty, int butt, int mrx, int mry)
1820 {
1821         char buf[8];
1822         int len;
1823
1824         len = sprintf(buf, "\033[M%c%c%c", (char)(' ' + butt),
1825                         (char)('!' + mrx), (char)('!' + mry));
1826         respond_string(buf, len, tty->port);
1827 }
1828
1829 /* invoked via ioctl(TIOCLINUX) and through set_selection_user */
1830 int mouse_reporting(void)
1831 {
1832         return vc_cons[fg_console].d->vc_report_mouse;
1833 }
1834
1835 /* console_lock is held */
1836 static void set_mode(struct vc_data *vc, int on_off)
1837 {
1838         int i;
1839
1840         for (i = 0; i <= vc->vc_npar; i++)
1841                 if (vc->vc_priv == EPdec) {
1842                         switch(vc->vc_par[i]) { /* DEC private modes set/reset */
1843                         case 1:                 /* Cursor keys send ^[Ox/^[[x */
1844                                 if (on_off)
1845                                         set_kbd(vc, decckm);
1846                                 else
1847                                         clr_kbd(vc, decckm);
1848                                 break;
1849                         case 3: /* 80/132 mode switch unimplemented */
1850 #if 0
1851                                 vc_resize(deccolm ? 132 : 80, vc->vc_rows);
1852                                 /* this alone does not suffice; some user mode
1853                                    utility has to change the hardware regs */
1854 #endif
1855                                 break;
1856                         case 5:                 /* Inverted screen on/off */
1857                                 if (vc->vc_decscnm != on_off) {
1858                                         vc->vc_decscnm = on_off;
1859                                         invert_screen(vc, 0,
1860                                                         vc->vc_screenbuf_size,
1861                                                         false);
1862                                         update_attr(vc);
1863                                 }
1864                                 break;
1865                         case 6:                 /* Origin relative/absolute */
1866                                 vc->vc_decom = on_off;
1867                                 gotoxay(vc, 0, 0);
1868                                 break;
1869                         case 7:                 /* Autowrap on/off */
1870                                 vc->vc_decawm = on_off;
1871                                 break;
1872                         case 8:                 /* Autorepeat on/off */
1873                                 if (on_off)
1874                                         set_kbd(vc, decarm);
1875                                 else
1876                                         clr_kbd(vc, decarm);
1877                                 break;
1878                         case 9:
1879                                 vc->vc_report_mouse = on_off ? 1 : 0;
1880                                 break;
1881                         case 25:                /* Cursor on/off */
1882                                 vc->vc_deccm = on_off;
1883                                 break;
1884                         case 1000:
1885                                 vc->vc_report_mouse = on_off ? 2 : 0;
1886                                 break;
1887                         }
1888                 } else {
1889                         switch(vc->vc_par[i]) { /* ANSI modes set/reset */
1890                         case 3:                 /* Monitor (display ctrls) */
1891                                 vc->vc_disp_ctrl = on_off;
1892                                 break;
1893                         case 4:                 /* Insert Mode on/off */
1894                                 vc->vc_decim = on_off;
1895                                 break;
1896                         case 20:                /* Lf, Enter == CrLf/Lf */
1897                                 if (on_off)
1898                                         set_kbd(vc, lnm);
1899                                 else
1900                                         clr_kbd(vc, lnm);
1901                                 break;
1902                         }
1903                 }
1904 }
1905
1906 /* console_lock is held */
1907 static void setterm_command(struct vc_data *vc)
1908 {
1909         switch (vc->vc_par[0]) {
1910         case 1: /* set color for underline mode */
1911                 if (vc->vc_can_do_color && vc->vc_par[1] < 16) {
1912                         vc->vc_ulcolor = color_table[vc->vc_par[1]];
1913                         if (vc->state.underline)
1914                                 update_attr(vc);
1915                 }
1916                 break;
1917         case 2: /* set color for half intensity mode */
1918                 if (vc->vc_can_do_color && vc->vc_par[1] < 16) {
1919                         vc->vc_halfcolor = color_table[vc->vc_par[1]];
1920                         if (vc->state.intensity == VCI_HALF_BRIGHT)
1921                                 update_attr(vc);
1922                 }
1923                 break;
1924         case 8: /* store colors as defaults */
1925                 vc->vc_def_color = vc->vc_attr;
1926                 if (vc->vc_hi_font_mask == 0x100)
1927                         vc->vc_def_color >>= 1;
1928                 default_attr(vc);
1929                 update_attr(vc);
1930                 break;
1931         case 9: /* set blanking interval */
1932                 blankinterval = min(vc->vc_par[1], 60U) * 60;
1933                 poke_blanked_console();
1934                 break;
1935         case 10: /* set bell frequency in Hz */
1936                 if (vc->vc_npar >= 1)
1937                         vc->vc_bell_pitch = vc->vc_par[1];
1938                 else
1939                         vc->vc_bell_pitch = DEFAULT_BELL_PITCH;
1940                 break;
1941         case 11: /* set bell duration in msec */
1942                 if (vc->vc_npar >= 1)
1943                         vc->vc_bell_duration = (vc->vc_par[1] < 2000) ?
1944                                 msecs_to_jiffies(vc->vc_par[1]) : 0;
1945                 else
1946                         vc->vc_bell_duration = DEFAULT_BELL_DURATION;
1947                 break;
1948         case 12: /* bring specified console to the front */
1949                 if (vc->vc_par[1] >= 1 && vc_cons_allocated(vc->vc_par[1] - 1))
1950                         set_console(vc->vc_par[1] - 1);
1951                 break;
1952         case 13: /* unblank the screen */
1953                 poke_blanked_console();
1954                 break;
1955         case 14: /* set vesa powerdown interval */
1956                 vesa_off_interval = min(vc->vc_par[1], 60U) * 60 * HZ;
1957                 break;
1958         case 15: /* activate the previous console */
1959                 set_console(last_console);
1960                 break;
1961         case 16: /* set cursor blink duration in msec */
1962                 if (vc->vc_npar >= 1 && vc->vc_par[1] >= 50 &&
1963                                 vc->vc_par[1] <= USHRT_MAX)
1964                         vc->vc_cur_blink_ms = vc->vc_par[1];
1965                 else
1966                         vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
1967                 break;
1968         }
1969 }
1970
1971 /* console_lock is held */
1972 static void csi_at(struct vc_data *vc, unsigned int nr)
1973 {
1974         if (nr > vc->vc_cols - vc->state.x)
1975                 nr = vc->vc_cols - vc->state.x;
1976         else if (!nr)
1977                 nr = 1;
1978         insert_char(vc, nr);
1979 }
1980
1981 /* console_lock is held */
1982 static void csi_L(struct vc_data *vc, unsigned int nr)
1983 {
1984         if (nr > vc->vc_rows - vc->state.y)
1985                 nr = vc->vc_rows - vc->state.y;
1986         else if (!nr)
1987                 nr = 1;
1988         con_scroll(vc, vc->state.y, vc->vc_bottom, SM_DOWN, nr);
1989         vc->vc_need_wrap = 0;
1990 }
1991
1992 /* console_lock is held */
1993 static void csi_P(struct vc_data *vc, unsigned int nr)
1994 {
1995         if (nr > vc->vc_cols - vc->state.x)
1996                 nr = vc->vc_cols - vc->state.x;
1997         else if (!nr)
1998                 nr = 1;
1999         delete_char(vc, nr);
2000 }
2001
2002 /* console_lock is held */
2003 static void csi_M(struct vc_data *vc, unsigned int nr)
2004 {
2005         if (nr > vc->vc_rows - vc->state.y)
2006                 nr = vc->vc_rows - vc->state.y;
2007         else if (!nr)
2008                 nr=1;
2009         con_scroll(vc, vc->state.y, vc->vc_bottom, SM_UP, nr);
2010         vc->vc_need_wrap = 0;
2011 }
2012
2013 /* console_lock is held (except via vc_init->reset_terminal */
2014 static void save_cur(struct vc_data *vc)
2015 {
2016         memcpy(&vc->saved_state, &vc->state, sizeof(vc->state));
2017 }
2018
2019 /* console_lock is held */
2020 static void restore_cur(struct vc_data *vc)
2021 {
2022         memcpy(&vc->state, &vc->saved_state, sizeof(vc->state));
2023
2024         gotoxy(vc, vc->state.x, vc->state.y);
2025         vc->vc_translate = set_translate(vc->state.Gx_charset[vc->state.charset],
2026                         vc);
2027         update_attr(vc);
2028         vc->vc_need_wrap = 0;
2029 }
2030
2031 enum { ESnormal, ESesc, ESsquare, ESgetpars, ESfunckey,
2032         EShash, ESsetG0, ESsetG1, ESpercent, EScsiignore, ESnonstd,
2033         ESpalette, ESosc, ESapc, ESpm, ESdcs };
2034
2035 /* console_lock is held (except via vc_init()) */
2036 static void reset_terminal(struct vc_data *vc, int do_clear)
2037 {
2038         unsigned int i;
2039
2040         vc->vc_top              = 0;
2041         vc->vc_bottom           = vc->vc_rows;
2042         vc->vc_state            = ESnormal;
2043         vc->vc_priv             = EPecma;
2044         vc->vc_translate        = set_translate(LAT1_MAP, vc);
2045         vc->state.Gx_charset[0] = LAT1_MAP;
2046         vc->state.Gx_charset[1] = GRAF_MAP;
2047         vc->state.charset       = 0;
2048         vc->vc_need_wrap        = 0;
2049         vc->vc_report_mouse     = 0;
2050         vc->vc_utf              = default_utf8;
2051         vc->vc_utf_count        = 0;
2052
2053         vc->vc_disp_ctrl        = 0;
2054         vc->vc_toggle_meta      = 0;
2055
2056         vc->vc_decscnm          = 0;
2057         vc->vc_decom            = 0;
2058         vc->vc_decawm           = 1;
2059         vc->vc_deccm            = global_cursor_default;
2060         vc->vc_decim            = 0;
2061
2062         vt_reset_keyboard(vc->vc_num);
2063
2064         vc->vc_cursor_type = cur_default;
2065         vc->vc_complement_mask = vc->vc_s_complement_mask;
2066
2067         default_attr(vc);
2068         update_attr(vc);
2069
2070         bitmap_zero(vc->vc_tab_stop, VC_TABSTOPS_COUNT);
2071         for (i = 0; i < VC_TABSTOPS_COUNT; i += 8)
2072                 set_bit(i, vc->vc_tab_stop);
2073
2074         vc->vc_bell_pitch = DEFAULT_BELL_PITCH;
2075         vc->vc_bell_duration = DEFAULT_BELL_DURATION;
2076         vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
2077
2078         gotoxy(vc, 0, 0);
2079         save_cur(vc);
2080         if (do_clear)
2081             csi_J(vc, 2);
2082 }
2083
2084 static void vc_setGx(struct vc_data *vc, unsigned int which, int c)
2085 {
2086         unsigned char *charset = &vc->state.Gx_charset[which];
2087
2088         switch (c) {
2089         case '0':
2090                 *charset = GRAF_MAP;
2091                 break;
2092         case 'B':
2093                 *charset = LAT1_MAP;
2094                 break;
2095         case 'U':
2096                 *charset = IBMPC_MAP;
2097                 break;
2098         case 'K':
2099                 *charset = USER_MAP;
2100                 break;
2101         }
2102
2103         if (vc->state.charset == which)
2104                 vc->vc_translate = set_translate(*charset, vc);
2105 }
2106
2107 /* is this state an ANSI control string? */
2108 static bool ansi_control_string(unsigned int state)
2109 {
2110         if (state == ESosc || state == ESapc || state == ESpm || state == ESdcs)
2111                 return true;
2112         return false;
2113 }
2114
2115 /* console_lock is held */
2116 static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
2117 {
2118         /*
2119          *  Control characters can be used in the _middle_
2120          *  of an escape sequence, aside from ANSI control strings.
2121          */
2122         if (ansi_control_string(vc->vc_state) && c >= 8 && c <= 13)
2123                 return;
2124         switch (c) {
2125         case 0:
2126                 return;
2127         case 7:
2128                 if (ansi_control_string(vc->vc_state))
2129                         vc->vc_state = ESnormal;
2130                 else if (vc->vc_bell_duration)
2131                         kd_mksound(vc->vc_bell_pitch, vc->vc_bell_duration);
2132                 return;
2133         case 8:
2134                 bs(vc);
2135                 return;
2136         case 9:
2137                 vc->vc_pos -= (vc->state.x << 1);
2138
2139                 vc->state.x = find_next_bit(vc->vc_tab_stop,
2140                                 min(vc->vc_cols - 1, VC_TABSTOPS_COUNT),
2141                                 vc->state.x + 1);
2142                 if (vc->state.x >= VC_TABSTOPS_COUNT)
2143                         vc->state.x = vc->vc_cols - 1;
2144
2145                 vc->vc_pos += (vc->state.x << 1);
2146                 notify_write(vc, '\t');
2147                 return;
2148         case 10: case 11: case 12:
2149                 lf(vc);
2150                 if (!is_kbd(vc, lnm))
2151                         return;
2152                 fallthrough;
2153         case 13:
2154                 cr(vc);
2155                 return;
2156         case 14:
2157                 vc->state.charset = 1;
2158                 vc->vc_translate = set_translate(vc->state.Gx_charset[1], vc);
2159                 vc->vc_disp_ctrl = 1;
2160                 return;
2161         case 15:
2162                 vc->state.charset = 0;
2163                 vc->vc_translate = set_translate(vc->state.Gx_charset[0], vc);
2164                 vc->vc_disp_ctrl = 0;
2165                 return;
2166         case 24: case 26:
2167                 vc->vc_state = ESnormal;
2168                 return;
2169         case 27:
2170                 vc->vc_state = ESesc;
2171                 return;
2172         case 127:
2173                 del(vc);
2174                 return;
2175         case 128+27:
2176                 vc->vc_state = ESsquare;
2177                 return;
2178         }
2179         switch(vc->vc_state) {
2180         case ESesc:
2181                 vc->vc_state = ESnormal;
2182                 switch (c) {
2183                 case '[':
2184                         vc->vc_state = ESsquare;
2185                         return;
2186                 case ']':
2187                         vc->vc_state = ESnonstd;
2188                         return;
2189                 case '_':
2190                         vc->vc_state = ESapc;
2191                         return;
2192                 case '^':
2193                         vc->vc_state = ESpm;
2194                         return;
2195                 case '%':
2196                         vc->vc_state = ESpercent;
2197                         return;
2198                 case 'E':
2199                         cr(vc);
2200                         lf(vc);
2201                         return;
2202                 case 'M':
2203                         ri(vc);
2204                         return;
2205                 case 'D':
2206                         lf(vc);
2207                         return;
2208                 case 'H':
2209                         if (vc->state.x < VC_TABSTOPS_COUNT)
2210                                 set_bit(vc->state.x, vc->vc_tab_stop);
2211                         return;
2212                 case 'P':
2213                         vc->vc_state = ESdcs;
2214                         return;
2215                 case 'Z':
2216                         respond_ID(tty);
2217                         return;
2218                 case '7':
2219                         save_cur(vc);
2220                         return;
2221                 case '8':
2222                         restore_cur(vc);
2223                         return;
2224                 case '(':
2225                         vc->vc_state = ESsetG0;
2226                         return;
2227                 case ')':
2228                         vc->vc_state = ESsetG1;
2229                         return;
2230                 case '#':
2231                         vc->vc_state = EShash;
2232                         return;
2233                 case 'c':
2234                         reset_terminal(vc, 1);
2235                         return;
2236                 case '>':  /* Numeric keypad */
2237                         clr_kbd(vc, kbdapplic);
2238                         return;
2239                 case '=':  /* Appl. keypad */
2240                         set_kbd(vc, kbdapplic);
2241                         return;
2242                 }
2243                 return;
2244         case ESnonstd:
2245                 if (c=='P') {   /* palette escape sequence */
2246                         for (vc->vc_npar = 0; vc->vc_npar < NPAR; vc->vc_npar++)
2247                                 vc->vc_par[vc->vc_npar] = 0;
2248                         vc->vc_npar = 0;
2249                         vc->vc_state = ESpalette;
2250                         return;
2251                 } else if (c=='R') {   /* reset palette */
2252                         reset_palette(vc);
2253                         vc->vc_state = ESnormal;
2254                 } else if (c>='0' && c<='9')
2255                         vc->vc_state = ESosc;
2256                 else
2257                         vc->vc_state = ESnormal;
2258                 return;
2259         case ESpalette:
2260                 if (isxdigit(c)) {
2261                         vc->vc_par[vc->vc_npar++] = hex_to_bin(c);
2262                         if (vc->vc_npar == 7) {
2263                                 int i = vc->vc_par[0] * 3, j = 1;
2264                                 vc->vc_palette[i] = 16 * vc->vc_par[j++];
2265                                 vc->vc_palette[i++] += vc->vc_par[j++];
2266                                 vc->vc_palette[i] = 16 * vc->vc_par[j++];
2267                                 vc->vc_palette[i++] += vc->vc_par[j++];
2268                                 vc->vc_palette[i] = 16 * vc->vc_par[j++];
2269                                 vc->vc_palette[i] += vc->vc_par[j];
2270                                 set_palette(vc);
2271                                 vc->vc_state = ESnormal;
2272                         }
2273                 } else
2274                         vc->vc_state = ESnormal;
2275                 return;
2276         case ESsquare:
2277                 for (vc->vc_npar = 0; vc->vc_npar < NPAR; vc->vc_npar++)
2278                         vc->vc_par[vc->vc_npar] = 0;
2279                 vc->vc_npar = 0;
2280                 vc->vc_state = ESgetpars;
2281                 if (c == '[') { /* Function key */
2282                         vc->vc_state=ESfunckey;
2283                         return;
2284                 }
2285                 switch (c) {
2286                 case '?':
2287                         vc->vc_priv = EPdec;
2288                         return;
2289                 case '>':
2290                         vc->vc_priv = EPgt;
2291                         return;
2292                 case '=':
2293                         vc->vc_priv = EPeq;
2294                         return;
2295                 case '<':
2296                         vc->vc_priv = EPlt;
2297                         return;
2298                 }
2299                 vc->vc_priv = EPecma;
2300                 fallthrough;
2301         case ESgetpars:
2302                 if (c == ';' && vc->vc_npar < NPAR - 1) {
2303                         vc->vc_npar++;
2304                         return;
2305                 } else if (c>='0' && c<='9') {
2306                         vc->vc_par[vc->vc_npar] *= 10;
2307                         vc->vc_par[vc->vc_npar] += c - '0';
2308                         return;
2309                 }
2310                 if (c >= 0x20 && c <= 0x3f) { /* 0x2x, 0x3a and 0x3c - 0x3f */
2311                         vc->vc_state = EScsiignore;
2312                         return;
2313                 }
2314                 vc->vc_state = ESnormal;
2315                 switch(c) {
2316                 case 'h':
2317                         if (vc->vc_priv <= EPdec)
2318                                 set_mode(vc, 1);
2319                         return;
2320                 case 'l':
2321                         if (vc->vc_priv <= EPdec)
2322                                 set_mode(vc, 0);
2323                         return;
2324                 case 'c':
2325                         if (vc->vc_priv == EPdec) {
2326                                 if (vc->vc_par[0])
2327                                         vc->vc_cursor_type =
2328                                                 CUR_MAKE(vc->vc_par[0],
2329                                                          vc->vc_par[1],
2330                                                          vc->vc_par[2]);
2331                                 else
2332                                         vc->vc_cursor_type = cur_default;
2333                                 return;
2334                         }
2335                         break;
2336                 case 'm':
2337                         if (vc->vc_priv == EPdec) {
2338                                 clear_selection();
2339                                 if (vc->vc_par[0])
2340                                         vc->vc_complement_mask = vc->vc_par[0] << 8 | vc->vc_par[1];
2341                                 else
2342                                         vc->vc_complement_mask = vc->vc_s_complement_mask;
2343                                 return;
2344                         }
2345                         break;
2346                 case 'n':
2347                         if (vc->vc_priv == EPecma) {
2348                                 if (vc->vc_par[0] == 5)
2349                                         status_report(tty);
2350                                 else if (vc->vc_par[0] == 6)
2351                                         cursor_report(vc, tty);
2352                         }
2353                         return;
2354                 }
2355                 if (vc->vc_priv != EPecma) {
2356                         vc->vc_priv = EPecma;
2357                         return;
2358                 }
2359                 switch(c) {
2360                 case 'G': case '`':
2361                         if (vc->vc_par[0])
2362                                 vc->vc_par[0]--;
2363                         gotoxy(vc, vc->vc_par[0], vc->state.y);
2364                         return;
2365                 case 'A':
2366                         if (!vc->vc_par[0])
2367                                 vc->vc_par[0]++;
2368                         gotoxy(vc, vc->state.x, vc->state.y - vc->vc_par[0]);
2369                         return;
2370                 case 'B': case 'e':
2371                         if (!vc->vc_par[0])
2372                                 vc->vc_par[0]++;
2373                         gotoxy(vc, vc->state.x, vc->state.y + vc->vc_par[0]);
2374                         return;
2375                 case 'C': case 'a':
2376                         if (!vc->vc_par[0])
2377                                 vc->vc_par[0]++;
2378                         gotoxy(vc, vc->state.x + vc->vc_par[0], vc->state.y);
2379                         return;
2380                 case 'D':
2381                         if (!vc->vc_par[0])
2382                                 vc->vc_par[0]++;
2383                         gotoxy(vc, vc->state.x - vc->vc_par[0], vc->state.y);
2384                         return;
2385                 case 'E':
2386                         if (!vc->vc_par[0])
2387                                 vc->vc_par[0]++;
2388                         gotoxy(vc, 0, vc->state.y + vc->vc_par[0]);
2389                         return;
2390                 case 'F':
2391                         if (!vc->vc_par[0])
2392                                 vc->vc_par[0]++;
2393                         gotoxy(vc, 0, vc->state.y - vc->vc_par[0]);
2394                         return;
2395                 case 'd':
2396                         if (vc->vc_par[0])
2397                                 vc->vc_par[0]--;
2398                         gotoxay(vc, vc->state.x ,vc->vc_par[0]);
2399                         return;
2400                 case 'H': case 'f':
2401                         if (vc->vc_par[0])
2402                                 vc->vc_par[0]--;
2403                         if (vc->vc_par[1])
2404                                 vc->vc_par[1]--;
2405                         gotoxay(vc, vc->vc_par[1], vc->vc_par[0]);
2406                         return;
2407                 case 'J':
2408                         csi_J(vc, vc->vc_par[0]);
2409                         return;
2410                 case 'K':
2411                         csi_K(vc, vc->vc_par[0]);
2412                         return;
2413                 case 'L':
2414                         csi_L(vc, vc->vc_par[0]);
2415                         return;
2416                 case 'M':
2417                         csi_M(vc, vc->vc_par[0]);
2418                         return;
2419                 case 'P':
2420                         csi_P(vc, vc->vc_par[0]);
2421                         return;
2422                 case 'c':
2423                         if (!vc->vc_par[0])
2424                                 respond_ID(tty);
2425                         return;
2426                 case 'g':
2427                         if (!vc->vc_par[0] && vc->state.x < VC_TABSTOPS_COUNT)
2428                                 set_bit(vc->state.x, vc->vc_tab_stop);
2429                         else if (vc->vc_par[0] == 3)
2430                                 bitmap_zero(vc->vc_tab_stop, VC_TABSTOPS_COUNT);
2431                         return;
2432                 case 'm':
2433                         csi_m(vc);
2434                         return;
2435                 case 'q': /* DECLL - but only 3 leds */
2436                         /* map 0,1,2,3 to 0,1,2,4 */
2437                         if (vc->vc_par[0] < 4)
2438                                 vt_set_led_state(vc->vc_num,
2439                                             (vc->vc_par[0] < 3) ? vc->vc_par[0] : 4);
2440                         return;
2441                 case 'r':
2442                         if (!vc->vc_par[0])
2443                                 vc->vc_par[0]++;
2444                         if (!vc->vc_par[1])
2445                                 vc->vc_par[1] = vc->vc_rows;
2446                         /* Minimum allowed region is 2 lines */
2447                         if (vc->vc_par[0] < vc->vc_par[1] &&
2448                             vc->vc_par[1] <= vc->vc_rows) {
2449                                 vc->vc_top = vc->vc_par[0] - 1;
2450                                 vc->vc_bottom = vc->vc_par[1];
2451                                 gotoxay(vc, 0, 0);
2452                         }
2453                         return;
2454                 case 's':
2455                         save_cur(vc);
2456                         return;
2457                 case 'u':
2458                         restore_cur(vc);
2459                         return;
2460                 case 'X':
2461                         csi_X(vc, vc->vc_par[0]);
2462                         return;
2463                 case '@':
2464                         csi_at(vc, vc->vc_par[0]);
2465                         return;
2466                 case ']': /* setterm functions */
2467                         setterm_command(vc);
2468                         return;
2469                 }
2470                 return;
2471         case EScsiignore:
2472                 if (c >= 20 && c <= 0x3f)
2473                         return;
2474                 vc->vc_state = ESnormal;
2475                 return;
2476         case ESpercent:
2477                 vc->vc_state = ESnormal;
2478                 switch (c) {
2479                 case '@':  /* defined in ISO 2022 */
2480                         vc->vc_utf = 0;
2481                         return;
2482                 case 'G':  /* prelim official escape code */
2483                 case '8':  /* retained for compatibility */
2484                         vc->vc_utf = 1;
2485                         return;
2486                 }
2487                 return;
2488         case ESfunckey:
2489                 vc->vc_state = ESnormal;
2490                 return;
2491         case EShash:
2492                 vc->vc_state = ESnormal;
2493                 if (c == '8') {
2494                         /* DEC screen alignment test. kludge :-) */
2495                         vc->vc_video_erase_char =
2496                                 (vc->vc_video_erase_char & 0xff00) | 'E';
2497                         csi_J(vc, 2);
2498                         vc->vc_video_erase_char =
2499                                 (vc->vc_video_erase_char & 0xff00) | ' ';
2500                         do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2);
2501                 }
2502                 return;
2503         case ESsetG0:
2504                 vc_setGx(vc, 0, c);
2505                 vc->vc_state = ESnormal;
2506                 return;
2507         case ESsetG1:
2508                 vc_setGx(vc, 1, c);
2509                 vc->vc_state = ESnormal;
2510                 return;
2511         case ESapc:
2512                 return;
2513         case ESosc:
2514                 return;
2515         case ESpm:
2516                 return;
2517         case ESdcs:
2518                 return;
2519         default:
2520                 vc->vc_state = ESnormal;
2521         }
2522 }
2523
2524 /* is_double_width() is based on the wcwidth() implementation by
2525  * Markus Kuhn -- 2007-05-26 (Unicode 5.0)
2526  * Latest version: https://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
2527  */
2528 struct interval {
2529         uint32_t first;
2530         uint32_t last;
2531 };
2532
2533 static int ucs_cmp(const void *key, const void *elt)
2534 {
2535         uint32_t ucs = *(uint32_t *)key;
2536         struct interval e = *(struct interval *) elt;
2537
2538         if (ucs > e.last)
2539                 return 1;
2540         else if (ucs < e.first)
2541                 return -1;
2542         return 0;
2543 }
2544
2545 static int is_double_width(uint32_t ucs)
2546 {
2547         static const struct interval double_width[] = {
2548                 { 0x1100, 0x115F }, { 0x2329, 0x232A }, { 0x2E80, 0x303E },
2549                 { 0x3040, 0xA4CF }, { 0xAC00, 0xD7A3 }, { 0xF900, 0xFAFF },
2550                 { 0xFE10, 0xFE19 }, { 0xFE30, 0xFE6F }, { 0xFF00, 0xFF60 },
2551                 { 0xFFE0, 0xFFE6 }, { 0x20000, 0x2FFFD }, { 0x30000, 0x3FFFD }
2552         };
2553         if (ucs < double_width[0].first ||
2554             ucs > double_width[ARRAY_SIZE(double_width) - 1].last)
2555                 return 0;
2556
2557         return bsearch(&ucs, double_width, ARRAY_SIZE(double_width),
2558                         sizeof(struct interval), ucs_cmp) != NULL;
2559 }
2560
2561 struct vc_draw_region {
2562         unsigned long from, to;
2563         int x;
2564 };
2565
2566 static void con_flush(struct vc_data *vc, struct vc_draw_region *draw)
2567 {
2568         if (draw->x < 0)
2569                 return;
2570
2571         vc->vc_sw->con_putcs(vc, (u16 *)draw->from,
2572                         (u16 *)draw->to - (u16 *)draw->from, vc->state.y,
2573                         draw->x);
2574         draw->x = -1;
2575 }
2576
2577 static inline int vc_translate_ascii(const struct vc_data *vc, int c)
2578 {
2579         if (IS_ENABLED(CONFIG_CONSOLE_TRANSLATIONS)) {
2580                 if (vc->vc_toggle_meta)
2581                         c |= 0x80;
2582
2583                 return vc->vc_translate[c];
2584         }
2585
2586         return c;
2587 }
2588
2589
2590 /**
2591  * vc_sanitize_unicode - Replace invalid Unicode code points with U+FFFD
2592  * @c: the received character, or U+FFFD for invalid sequences.
2593  */
2594 static inline int vc_sanitize_unicode(const int c)
2595 {
2596         if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff)
2597                 return 0xfffd;
2598
2599         return c;
2600 }
2601
2602 /**
2603  * vc_translate_unicode - Combine UTF-8 into Unicode in @vc_utf_char
2604  * @vc: virtual console
2605  * @c: character to translate
2606  * @rescan: we return true if we need more (continuation) data
2607  *
2608  * @vc_utf_char is the being-constructed unicode character.
2609  * @vc_utf_count is the number of continuation bytes still expected to arrive.
2610  * @vc_npar is the number of continuation bytes arrived so far.
2611  */
2612 static int vc_translate_unicode(struct vc_data *vc, int c, bool *rescan)
2613 {
2614         static const u32 utf8_length_changes[] = {
2615                 0x0000007f, 0x000007ff, 0x0000ffff,
2616                 0x001fffff, 0x03ffffff, 0x7fffffff
2617         };
2618
2619         /* Continuation byte received */
2620         if ((c & 0xc0) == 0x80) {
2621                 /* Unexpected continuation byte? */
2622                 if (!vc->vc_utf_count)
2623                         return 0xfffd;
2624
2625                 vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);
2626                 vc->vc_npar++;
2627                 if (--vc->vc_utf_count)
2628                         goto need_more_bytes;
2629
2630                 /* Got a whole character */
2631                 c = vc->vc_utf_char;
2632                 /* Reject overlong sequences */
2633                 if (c <= utf8_length_changes[vc->vc_npar - 1] ||
2634                                 c > utf8_length_changes[vc->vc_npar])
2635                         return 0xfffd;
2636
2637                 return vc_sanitize_unicode(c);
2638         }
2639
2640         /* Single ASCII byte or first byte of a sequence received */
2641         if (vc->vc_utf_count) {
2642                 /* Continuation byte expected */
2643                 *rescan = true;
2644                 vc->vc_utf_count = 0;
2645                 return 0xfffd;
2646         }
2647
2648         /* Nothing to do if an ASCII byte was received */
2649         if (c <= 0x7f)
2650                 return c;
2651
2652         /* First byte of a multibyte sequence received */
2653         vc->vc_npar = 0;
2654         if ((c & 0xe0) == 0xc0) {
2655                 vc->vc_utf_count = 1;
2656                 vc->vc_utf_char = (c & 0x1f);
2657         } else if ((c & 0xf0) == 0xe0) {
2658                 vc->vc_utf_count = 2;
2659                 vc->vc_utf_char = (c & 0x0f);
2660         } else if ((c & 0xf8) == 0xf0) {
2661                 vc->vc_utf_count = 3;
2662                 vc->vc_utf_char = (c & 0x07);
2663         } else if ((c & 0xfc) == 0xf8) {
2664                 vc->vc_utf_count = 4;
2665                 vc->vc_utf_char = (c & 0x03);
2666         } else if ((c & 0xfe) == 0xfc) {
2667                 vc->vc_utf_count = 5;
2668                 vc->vc_utf_char = (c & 0x01);
2669         } else {
2670                 /* 254 and 255 are invalid */
2671                 return 0xfffd;
2672         }
2673
2674 need_more_bytes:
2675         return -1;
2676 }
2677
2678 static int vc_translate(struct vc_data *vc, int *c, bool *rescan)
2679 {
2680         /* Do no translation at all in control states */
2681         if (vc->vc_state != ESnormal)
2682                 return *c;
2683
2684         if (vc->vc_utf && !vc->vc_disp_ctrl)
2685                 return *c = vc_translate_unicode(vc, *c, rescan);
2686
2687         /* no utf or alternate charset mode */
2688         return vc_translate_ascii(vc, *c);
2689 }
2690
2691 static inline unsigned char vc_invert_attr(const struct vc_data *vc)
2692 {
2693         if (!vc->vc_can_do_color)
2694                 return vc->vc_attr ^ 0x08;
2695
2696         if (vc->vc_hi_font_mask == 0x100)
2697                 return   (vc->vc_attr & 0x11) |
2698                         ((vc->vc_attr & 0xe0) >> 4) |
2699                         ((vc->vc_attr & 0x0e) << 4);
2700
2701         return   (vc->vc_attr & 0x88) |
2702                 ((vc->vc_attr & 0x70) >> 4) |
2703                 ((vc->vc_attr & 0x07) << 4);
2704 }
2705
2706 static bool vc_is_control(struct vc_data *vc, int tc, int c)
2707 {
2708         /*
2709          * A bitmap for codes <32. A bit of 1 indicates that the code
2710          * corresponding to that bit number invokes some special action (such
2711          * as cursor movement) and should not be displayed as a glyph unless
2712          * the disp_ctrl mode is explicitly enabled.
2713          */
2714         static const u32 CTRL_ACTION = 0x0d00ff81;
2715         /* Cannot be overridden by disp_ctrl */
2716         static const u32 CTRL_ALWAYS = 0x0800f501;
2717
2718         if (vc->vc_state != ESnormal)
2719                 return true;
2720
2721         if (!tc)
2722                 return true;
2723
2724         /*
2725          * If the original code was a control character we only allow a glyph
2726          * to be displayed if the code is not normally used (such as for cursor
2727          * movement) or if the disp_ctrl mode has been explicitly enabled.
2728          * Certain characters (as given by the CTRL_ALWAYS bitmap) are always
2729          * displayed as control characters, as the console would be pretty
2730          * useless without them; to display an arbitrary font position use the
2731          * direct-to-font zone in UTF-8 mode.
2732          */
2733         if (c < 32) {
2734                 if (vc->vc_disp_ctrl)
2735                         return CTRL_ALWAYS & BIT(c);
2736                 else
2737                         return vc->vc_utf || (CTRL_ACTION & BIT(c));
2738         }
2739
2740         if (c == 127 && !vc->vc_disp_ctrl)
2741                 return true;
2742
2743         if (c == 128 + 27)
2744                 return true;
2745
2746         return false;
2747 }
2748
2749 static int vc_con_write_normal(struct vc_data *vc, int tc, int c,
2750                 struct vc_draw_region *draw)
2751 {
2752         int next_c;
2753         unsigned char vc_attr = vc->vc_attr;
2754         u16 himask = vc->vc_hi_font_mask, charmask = himask ? 0x1ff : 0xff;
2755         u8 width = 1;
2756         bool inverse = false;
2757
2758         if (vc->vc_utf && !vc->vc_disp_ctrl) {
2759                 if (is_double_width(c))
2760                         width = 2;
2761         }
2762
2763         /* Now try to find out how to display it */
2764         tc = conv_uni_to_pc(vc, tc);
2765         if (tc & ~charmask) {
2766                 if (tc == -1 || tc == -2)
2767                         return -1; /* nothing to display */
2768
2769                 /* Glyph not found */
2770                 if ((!vc->vc_utf || vc->vc_disp_ctrl || c < 128) &&
2771                                 !(c & ~charmask)) {
2772                         /*
2773                          * In legacy mode use the glyph we get by a 1:1
2774                          * mapping.
2775                          * This would make absolutely no sense with Unicode in
2776                          * mind, but do this for ASCII characters since a font
2777                          * may lack Unicode mapping info and we don't want to
2778                          * end up with having question marks only.
2779                          */
2780                         tc = c;
2781                 } else {
2782                         /*
2783                          * Display U+FFFD. If it's not found, display an inverse
2784                          * question mark.
2785                          */
2786                         tc = conv_uni_to_pc(vc, 0xfffd);
2787                         if (tc < 0) {
2788                                 inverse = true;
2789                                 tc = conv_uni_to_pc(vc, '?');
2790                                 if (tc < 0)
2791                                         tc = '?';
2792
2793                                 vc_attr = vc_invert_attr(vc);
2794                                 con_flush(vc, draw);
2795                         }
2796                 }
2797         }
2798
2799         next_c = c;
2800         while (1) {
2801                 if (vc->vc_need_wrap || vc->vc_decim)
2802                         con_flush(vc, draw);
2803                 if (vc->vc_need_wrap) {
2804                         cr(vc);
2805                         lf(vc);
2806                 }
2807                 if (vc->vc_decim)
2808                         insert_char(vc, 1);
2809                 vc_uniscr_putc(vc, next_c);
2810
2811                 if (himask)
2812                         tc = ((tc & 0x100) ? himask : 0) |
2813                               (tc &  0xff);
2814                 tc |= (vc_attr << 8) & ~himask;
2815
2816                 scr_writew(tc, (u16 *)vc->vc_pos);
2817
2818                 if (con_should_update(vc) && draw->x < 0) {
2819                         draw->x = vc->state.x;
2820                         draw->from = vc->vc_pos;
2821                 }
2822                 if (vc->state.x == vc->vc_cols - 1) {
2823                         vc->vc_need_wrap = vc->vc_decawm;
2824                         draw->to = vc->vc_pos + 2;
2825                 } else {
2826                         vc->state.x++;
2827                         draw->to = (vc->vc_pos += 2);
2828                 }
2829
2830                 if (!--width)
2831                         break;
2832
2833                 /* A space is printed in the second column */
2834                 tc = conv_uni_to_pc(vc, ' ');
2835                 if (tc < 0)
2836                         tc = ' ';
2837                 next_c = ' ';
2838         }
2839         notify_write(vc, c);
2840
2841         if (inverse)
2842                 con_flush(vc, draw);
2843
2844         return 0;
2845 }
2846
2847 /* acquires console_lock */
2848 static int do_con_write(struct tty_struct *tty, const u8 *buf, int count)
2849 {
2850         struct vc_draw_region draw = {
2851                 .x = -1,
2852         };
2853         int c, tc, n = 0;
2854         unsigned int currcons;
2855         struct vc_data *vc;
2856         struct vt_notifier_param param;
2857         bool rescan;
2858
2859         if (in_interrupt())
2860                 return count;
2861
2862         console_lock();
2863         vc = tty->driver_data;
2864         if (vc == NULL) {
2865                 pr_err("vt: argh, driver_data is NULL !\n");
2866                 console_unlock();
2867                 return 0;
2868         }
2869
2870         currcons = vc->vc_num;
2871         if (!vc_cons_allocated(currcons)) {
2872                 /* could this happen? */
2873                 pr_warn_once("con_write: tty %d not allocated\n", currcons+1);
2874                 console_unlock();
2875                 return 0;
2876         }
2877
2878
2879         /* undraw cursor first */
2880         if (con_is_fg(vc))
2881                 hide_cursor(vc);
2882
2883         param.vc = vc;
2884
2885         while (!tty->flow.stopped && count) {
2886                 int orig = *buf;
2887                 buf++;
2888                 n++;
2889                 count--;
2890 rescan_last_byte:
2891                 c = orig;
2892                 rescan = false;
2893
2894                 tc = vc_translate(vc, &c, &rescan);
2895                 if (tc == -1)
2896                         continue;
2897
2898                 param.c = tc;
2899                 if (atomic_notifier_call_chain(&vt_notifier_list, VT_PREWRITE,
2900                                         &param) == NOTIFY_STOP)
2901                         continue;
2902
2903                 if (vc_is_control(vc, tc, c)) {
2904                         con_flush(vc, &draw);
2905                         do_con_trol(tty, vc, orig);
2906                         continue;
2907                 }
2908
2909                 if (vc_con_write_normal(vc, tc, c, &draw) < 0)
2910                         continue;
2911
2912                 if (rescan)
2913                         goto rescan_last_byte;
2914         }
2915         con_flush(vc, &draw);
2916         console_conditional_schedule();
2917         notify_update(vc);
2918         console_unlock();
2919         return n;
2920 }
2921
2922 /*
2923  * This is the console switching callback.
2924  *
2925  * Doing console switching in a process context allows
2926  * us to do the switches asynchronously (needed when we want
2927  * to switch due to a keyboard interrupt).  Synchronization
2928  * with other console code and prevention of re-entrancy is
2929  * ensured with console_lock.
2930  */
2931 static void console_callback(struct work_struct *ignored)
2932 {
2933         console_lock();
2934
2935         if (want_console >= 0) {
2936                 if (want_console != fg_console &&
2937                     vc_cons_allocated(want_console)) {
2938                         hide_cursor(vc_cons[fg_console].d);
2939                         change_console(vc_cons[want_console].d);
2940                         /* we only changed when the console had already
2941                            been allocated - a new console is not created
2942                            in an interrupt routine */
2943                 }
2944                 want_console = -1;
2945         }
2946         if (do_poke_blanked_console) { /* do not unblank for a LED change */
2947                 do_poke_blanked_console = 0;
2948                 poke_blanked_console();
2949         }
2950         if (scrollback_delta) {
2951                 struct vc_data *vc = vc_cons[fg_console].d;
2952                 clear_selection();
2953                 if (vc->vc_mode == KD_TEXT && vc->vc_sw->con_scrolldelta)
2954                         vc->vc_sw->con_scrolldelta(vc, scrollback_delta);
2955                 scrollback_delta = 0;
2956         }
2957         if (blank_timer_expired) {
2958                 do_blank_screen(0);
2959                 blank_timer_expired = 0;
2960         }
2961         notify_update(vc_cons[fg_console].d);
2962
2963         console_unlock();
2964 }
2965
2966 int set_console(int nr)
2967 {
2968         struct vc_data *vc = vc_cons[fg_console].d;
2969
2970         if (!vc_cons_allocated(nr) || vt_dont_switch ||
2971                 (vc->vt_mode.mode == VT_AUTO && vc->vc_mode == KD_GRAPHICS)) {
2972
2973                 /*
2974                  * Console switch will fail in console_callback() or
2975                  * change_console() so there is no point scheduling
2976                  * the callback
2977                  *
2978                  * Existing set_console() users don't check the return
2979                  * value so this shouldn't break anything
2980                  */
2981                 return -EINVAL;
2982         }
2983
2984         want_console = nr;
2985         schedule_console_callback();
2986
2987         return 0;
2988 }
2989
2990 struct tty_driver *console_driver;
2991
2992 #ifdef CONFIG_VT_CONSOLE
2993
2994 /**
2995  * vt_kmsg_redirect() - Sets/gets the kernel message console
2996  * @new:        The new virtual terminal number or -1 if the console should stay
2997  *              unchanged
2998  *
2999  * By default, the kernel messages are always printed on the current virtual
3000  * console. However, the user may modify that default with the
3001  * TIOCL_SETKMSGREDIRECT ioctl call.
3002  *
3003  * This function sets the kernel message console to be @new. It returns the old
3004  * virtual console number. The virtual terminal number 0 (both as parameter and
3005  * return value) means no redirection (i.e. always printed on the currently
3006  * active console).
3007  *
3008  * The parameter -1 means that only the current console is returned, but the
3009  * value is not modified. You may use the macro vt_get_kmsg_redirect() in that
3010  * case to make the code more understandable.
3011  *
3012  * When the kernel is compiled without CONFIG_VT_CONSOLE, this function ignores
3013  * the parameter and always returns 0.
3014  */
3015 int vt_kmsg_redirect(int new)
3016 {
3017         static int kmsg_con;
3018
3019         if (new != -1)
3020                 return xchg(&kmsg_con, new);
3021         else
3022                 return kmsg_con;
3023 }
3024
3025 /*
3026  *      Console on virtual terminal
3027  *
3028  * The console must be locked when we get here.
3029  */
3030
3031 static void vt_console_print(struct console *co, const char *b, unsigned count)
3032 {
3033         struct vc_data *vc = vc_cons[fg_console].d;
3034         unsigned char c;
3035         static DEFINE_SPINLOCK(printing_lock);
3036         const ushort *start;
3037         ushort start_x, cnt;
3038         int kmsg_console;
3039
3040         WARN_CONSOLE_UNLOCKED();
3041
3042         /* this protects against concurrent oops only */
3043         if (!spin_trylock(&printing_lock))
3044                 return;
3045
3046         kmsg_console = vt_get_kmsg_redirect();
3047         if (kmsg_console && vc_cons_allocated(kmsg_console - 1))
3048                 vc = vc_cons[kmsg_console - 1].d;
3049
3050         if (!vc_cons_allocated(fg_console)) {
3051                 /* impossible */
3052                 /* printk("vt_console_print: tty %d not allocated ??\n", currcons+1); */
3053                 goto quit;
3054         }
3055
3056         if (vc->vc_mode != KD_TEXT)
3057                 goto quit;
3058
3059         /* undraw cursor first */
3060         if (con_is_fg(vc))
3061                 hide_cursor(vc);
3062
3063         start = (ushort *)vc->vc_pos;
3064         start_x = vc->state.x;
3065         cnt = 0;
3066         while (count--) {
3067                 c = *b++;
3068                 if (c == 10 || c == 13 || c == 8 || vc->vc_need_wrap) {
3069                         if (cnt && con_is_visible(vc))
3070                                 vc->vc_sw->con_putcs(vc, start, cnt, vc->state.y, start_x);
3071                         cnt = 0;
3072                         if (c == 8) {           /* backspace */
3073                                 bs(vc);
3074                                 start = (ushort *)vc->vc_pos;
3075                                 start_x = vc->state.x;
3076                                 continue;
3077                         }
3078                         if (c != 13)
3079                                 lf(vc);
3080                         cr(vc);
3081                         start = (ushort *)vc->vc_pos;
3082                         start_x = vc->state.x;
3083                         if (c == 10 || c == 13)
3084                                 continue;
3085                 }
3086                 vc_uniscr_putc(vc, c);
3087                 scr_writew((vc->vc_attr << 8) + c, (unsigned short *)vc->vc_pos);
3088                 notify_write(vc, c);
3089                 cnt++;
3090                 if (vc->state.x == vc->vc_cols - 1) {
3091                         vc->vc_need_wrap = 1;
3092                 } else {
3093                         vc->vc_pos += 2;
3094                         vc->state.x++;
3095                 }
3096         }
3097         if (cnt && con_is_visible(vc))
3098                 vc->vc_sw->con_putcs(vc, start, cnt, vc->state.y, start_x);
3099         set_cursor(vc);
3100         notify_update(vc);
3101
3102 quit:
3103         spin_unlock(&printing_lock);
3104 }
3105
3106 static struct tty_driver *vt_console_device(struct console *c, int *index)
3107 {
3108         *index = c->index ? c->index-1 : fg_console;
3109         return console_driver;
3110 }
3111
3112 static int vt_console_setup(struct console *co, char *options)
3113 {
3114         return co->index >= MAX_NR_CONSOLES ? -EINVAL : 0;
3115 }
3116
3117 static struct console vt_console_driver = {
3118         .name           = "tty",
3119         .setup          = vt_console_setup,
3120         .write          = vt_console_print,
3121         .device         = vt_console_device,
3122         .unblank        = unblank_screen,
3123         .flags          = CON_PRINTBUFFER,
3124         .index          = -1,
3125 };
3126 #endif
3127
3128 /*
3129  *      Handling of Linux-specific VC ioctls
3130  */
3131
3132 /*
3133  * Generally a bit racy with respect to console_lock();.
3134  *
3135  * There are some functions which don't need it.
3136  *
3137  * There are some functions which can sleep for arbitrary periods
3138  * (paste_selection) but we don't need the lock there anyway.
3139  *
3140  * set_selection_user has locking, and definitely needs it
3141  */
3142
3143 int tioclinux(struct tty_struct *tty, unsigned long arg)
3144 {
3145         char type, data;
3146         char __user *p = (char __user *)arg;
3147         int lines;
3148         int ret;
3149
3150         if (current->signal->tty != tty && !capable(CAP_SYS_ADMIN))
3151                 return -EPERM;
3152         if (get_user(type, p))
3153                 return -EFAULT;
3154         ret = 0;
3155
3156         switch (type) {
3157         case TIOCL_SETSEL:
3158                 if (!capable(CAP_SYS_ADMIN))
3159                         return -EPERM;
3160                 return set_selection_user((struct tiocl_selection
3161                                          __user *)(p+1), tty);
3162         case TIOCL_PASTESEL:
3163                 if (!capable(CAP_SYS_ADMIN))
3164                         return -EPERM;
3165                 return paste_selection(tty);
3166         case TIOCL_UNBLANKSCREEN:
3167                 console_lock();
3168                 unblank_screen();
3169                 console_unlock();
3170                 break;
3171         case TIOCL_SELLOADLUT:
3172                 if (!capable(CAP_SYS_ADMIN))
3173                         return -EPERM;
3174                 console_lock();
3175                 ret = sel_loadlut(p);
3176                 console_unlock();
3177                 break;
3178         case TIOCL_GETSHIFTSTATE:
3179                 /*
3180                  * Make it possible to react to Shift+Mousebutton. Note that
3181                  * 'shift_state' is an undocumented kernel-internal variable;
3182                  * programs not closely related to the kernel should not use
3183                  * this.
3184                  */
3185                 data = vt_get_shift_state();
3186                 return put_user(data, p);
3187         case TIOCL_GETMOUSEREPORTING:
3188                 console_lock(); /* May be overkill */
3189                 data = mouse_reporting();
3190                 console_unlock();
3191                 return put_user(data, p);
3192         case TIOCL_SETVESABLANK:
3193                 console_lock();
3194                 ret = set_vesa_blanking(p);
3195                 console_unlock();
3196                 break;
3197         case TIOCL_GETKMSGREDIRECT:
3198                 data = vt_get_kmsg_redirect();
3199                 return put_user(data, p);
3200         case TIOCL_SETKMSGREDIRECT:
3201                 if (!capable(CAP_SYS_ADMIN))
3202                         return -EPERM;
3203
3204                 if (get_user(data, p+1))
3205                         return -EFAULT;
3206
3207                 vt_kmsg_redirect(data);
3208
3209                 break;
3210         case TIOCL_GETFGCONSOLE:
3211                 /*
3212                  * No locking needed as this is a transiently correct return
3213                  * anyway if the caller hasn't disabled switching.
3214                  */
3215                 return fg_console;
3216         case TIOCL_SCROLLCONSOLE:
3217                 if (get_user(lines, (s32 __user *)(p+4)))
3218                         return -EFAULT;
3219
3220                 /*
3221                  * Needs the console lock here. Note that lots of other calls
3222                  * need fixing before the lock is actually useful!
3223                  */
3224                 console_lock();
3225                 scrollfront(vc_cons[fg_console].d, lines);
3226                 console_unlock();
3227                 break;
3228         case TIOCL_BLANKSCREEN: /* until explicitly unblanked, not only poked */
3229                 console_lock();
3230                 ignore_poke = 1;
3231                 do_blank_screen(0);
3232                 console_unlock();
3233                 break;
3234         case TIOCL_BLANKEDSCREEN:
3235                 return console_blanked;
3236         default:
3237                 return -EINVAL;
3238         }
3239
3240         return ret;
3241 }
3242
3243 /*
3244  * /dev/ttyN handling
3245  */
3246
3247 static ssize_t con_write(struct tty_struct *tty, const u8 *buf, size_t count)
3248 {
3249         int     retval;
3250
3251         retval = do_con_write(tty, buf, count);
3252         con_flush_chars(tty);
3253
3254         return retval;
3255 }
3256
3257 static int con_put_char(struct tty_struct *tty, u8 ch)
3258 {
3259         return do_con_write(tty, &ch, 1);
3260 }
3261
3262 static unsigned int con_write_room(struct tty_struct *tty)
3263 {
3264         if (tty->flow.stopped)
3265                 return 0;
3266         return 32768;           /* No limit, really; we're not buffering */
3267 }
3268
3269 /*
3270  * con_throttle and con_unthrottle are only used for
3271  * paste_selection(), which has to stuff in a large number of
3272  * characters...
3273  */
3274 static void con_throttle(struct tty_struct *tty)
3275 {
3276 }
3277
3278 static void con_unthrottle(struct tty_struct *tty)
3279 {
3280         struct vc_data *vc = tty->driver_data;
3281
3282         wake_up_interruptible(&vc->paste_wait);
3283 }
3284
3285 /*
3286  * Turn the Scroll-Lock LED on when the tty is stopped
3287  */
3288 static void con_stop(struct tty_struct *tty)
3289 {
3290         int console_num;
3291         if (!tty)
3292                 return;
3293         console_num = tty->index;
3294         if (!vc_cons_allocated(console_num))
3295                 return;
3296         vt_kbd_con_stop(console_num);
3297 }
3298
3299 /*
3300  * Turn the Scroll-Lock LED off when the console is started
3301  */
3302 static void con_start(struct tty_struct *tty)
3303 {
3304         int console_num;
3305         if (!tty)
3306                 return;
3307         console_num = tty->index;
3308         if (!vc_cons_allocated(console_num))
3309                 return;
3310         vt_kbd_con_start(console_num);
3311 }
3312
3313 static void con_flush_chars(struct tty_struct *tty)
3314 {
3315         struct vc_data *vc;
3316
3317         if (in_interrupt())     /* from flush_to_ldisc */
3318                 return;
3319
3320         /* if we race with con_close(), vt may be null */
3321         console_lock();
3322         vc = tty->driver_data;
3323         if (vc)
3324                 set_cursor(vc);
3325         console_unlock();
3326 }
3327
3328 /*
3329  * Allocate the console screen memory.
3330  */
3331 static int con_install(struct tty_driver *driver, struct tty_struct *tty)
3332 {
3333         unsigned int currcons = tty->index;
3334         struct vc_data *vc;
3335         int ret;
3336
3337         console_lock();
3338         ret = vc_allocate(currcons);
3339         if (ret)
3340                 goto unlock;
3341
3342         vc = vc_cons[currcons].d;
3343
3344         /* Still being freed */
3345         if (vc->port.tty) {
3346                 ret = -ERESTARTSYS;
3347                 goto unlock;
3348         }
3349
3350         ret = tty_port_install(&vc->port, driver, tty);
3351         if (ret)
3352                 goto unlock;
3353
3354         tty->driver_data = vc;
3355         vc->port.tty = tty;
3356         tty_port_get(&vc->port);
3357
3358         if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
3359                 tty->winsize.ws_row = vc_cons[currcons].d->vc_rows;
3360                 tty->winsize.ws_col = vc_cons[currcons].d->vc_cols;
3361         }
3362         if (vc->vc_utf)
3363                 tty->termios.c_iflag |= IUTF8;
3364         else
3365                 tty->termios.c_iflag &= ~IUTF8;
3366 unlock:
3367         console_unlock();
3368         return ret;
3369 }
3370
3371 static int con_open(struct tty_struct *tty, struct file *filp)
3372 {
3373         /* everything done in install */
3374         return 0;
3375 }
3376
3377
3378 static void con_close(struct tty_struct *tty, struct file *filp)
3379 {
3380         /* Nothing to do - we defer to shutdown */
3381 }
3382
3383 static void con_shutdown(struct tty_struct *tty)
3384 {
3385         struct vc_data *vc = tty->driver_data;
3386         BUG_ON(vc == NULL);
3387         console_lock();
3388         vc->port.tty = NULL;
3389         console_unlock();
3390 }
3391
3392 static void con_cleanup(struct tty_struct *tty)
3393 {
3394         struct vc_data *vc = tty->driver_data;
3395
3396         tty_port_put(&vc->port);
3397 }
3398
3399 static int default_color           = 7; /* white */
3400 static int default_italic_color    = 2; // green (ASCII)
3401 static int default_underline_color = 3; // cyan (ASCII)
3402 module_param_named(color, default_color, int, S_IRUGO | S_IWUSR);
3403 module_param_named(italic, default_italic_color, int, S_IRUGO | S_IWUSR);
3404 module_param_named(underline, default_underline_color, int, S_IRUGO | S_IWUSR);
3405
3406 static void vc_init(struct vc_data *vc, int do_clear)
3407 {
3408         int j, k ;
3409
3410         set_origin(vc);
3411         vc->vc_pos = vc->vc_origin;
3412         reset_vc(vc);
3413         for (j=k=0; j<16; j++) {
3414                 vc->vc_palette[k++] = default_red[j] ;
3415                 vc->vc_palette[k++] = default_grn[j] ;
3416                 vc->vc_palette[k++] = default_blu[j] ;
3417         }
3418         vc->vc_def_color       = default_color;
3419         vc->vc_ulcolor         = default_underline_color;
3420         vc->vc_itcolor         = default_italic_color;
3421         vc->vc_halfcolor       = 0x08;   /* grey */
3422         init_waitqueue_head(&vc->paste_wait);
3423         reset_terminal(vc, do_clear);
3424 }
3425
3426 /*
3427  * This routine initializes console interrupts, and does nothing
3428  * else. If you want the screen to clear, call tty_write with
3429  * the appropriate escape-sequence.
3430  */
3431
3432 static int __init con_init(void)
3433 {
3434         const char *display_desc = NULL;
3435         struct vc_data *vc;
3436         unsigned int currcons = 0, i;
3437
3438         console_lock();
3439
3440         if (!conswitchp)
3441                 conswitchp = &dummy_con;
3442         display_desc = conswitchp->con_startup();
3443         if (!display_desc) {
3444                 fg_console = 0;
3445                 console_unlock();
3446                 return 0;
3447         }
3448
3449         for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
3450                 struct con_driver *con_driver = &registered_con_driver[i];
3451
3452                 if (con_driver->con == NULL) {
3453                         con_driver->con = conswitchp;
3454                         con_driver->desc = display_desc;
3455                         con_driver->flag = CON_DRIVER_FLAG_INIT;
3456                         con_driver->first = 0;
3457                         con_driver->last = MAX_NR_CONSOLES - 1;
3458                         break;
3459                 }
3460         }
3461
3462         for (i = 0; i < MAX_NR_CONSOLES; i++)
3463                 con_driver_map[i] = conswitchp;
3464
3465         if (blankinterval) {
3466                 blank_state = blank_normal_wait;
3467                 mod_timer(&console_timer, jiffies + (blankinterval * HZ));
3468         }
3469
3470         for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) {
3471                 vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data), GFP_NOWAIT);
3472                 INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
3473                 tty_port_init(&vc->port);
3474                 visual_init(vc, currcons, 1);
3475                 /* Assuming vc->vc_{cols,rows,screenbuf_size} are sane here. */
3476                 vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_NOWAIT);
3477                 vc_init(vc, currcons || !vc->vc_sw->con_save_screen);
3478         }
3479         currcons = fg_console = 0;
3480         master_display_fg = vc = vc_cons[currcons].d;
3481         set_origin(vc);
3482         save_screen(vc);
3483         gotoxy(vc, vc->state.x, vc->state.y);
3484         csi_J(vc, 0);
3485         update_screen(vc);
3486         pr_info("Console: %s %s %dx%d\n",
3487                 vc->vc_can_do_color ? "colour" : "mono",
3488                 display_desc, vc->vc_cols, vc->vc_rows);
3489
3490         console_unlock();
3491
3492 #ifdef CONFIG_VT_CONSOLE
3493         register_console(&vt_console_driver);
3494 #endif
3495         return 0;
3496 }
3497 console_initcall(con_init);
3498
3499 static const struct tty_operations con_ops = {
3500         .install = con_install,
3501         .open = con_open,
3502         .close = con_close,
3503         .write = con_write,
3504         .write_room = con_write_room,
3505         .put_char = con_put_char,
3506         .flush_chars = con_flush_chars,
3507         .ioctl = vt_ioctl,
3508 #ifdef CONFIG_COMPAT
3509         .compat_ioctl = vt_compat_ioctl,
3510 #endif
3511         .stop = con_stop,
3512         .start = con_start,
3513         .throttle = con_throttle,
3514         .unthrottle = con_unthrottle,
3515         .resize = vt_resize,
3516         .shutdown = con_shutdown,
3517         .cleanup = con_cleanup,
3518 };
3519
3520 static struct cdev vc0_cdev;
3521
3522 static ssize_t show_tty_active(struct device *dev,
3523                                 struct device_attribute *attr, char *buf)
3524 {
3525         return sprintf(buf, "tty%d\n", fg_console + 1);
3526 }
3527 static DEVICE_ATTR(active, S_IRUGO, show_tty_active, NULL);
3528
3529 static struct attribute *vt_dev_attrs[] = {
3530         &dev_attr_active.attr,
3531         NULL
3532 };
3533
3534 ATTRIBUTE_GROUPS(vt_dev);
3535
3536 int __init vty_init(const struct file_operations *console_fops)
3537 {
3538         cdev_init(&vc0_cdev, console_fops);
3539         if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||
3540             register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)
3541                 panic("Couldn't register /dev/tty0 driver\n");
3542         tty0dev = device_create_with_groups(&tty_class, NULL,
3543                                             MKDEV(TTY_MAJOR, 0), NULL,
3544                                             vt_dev_groups, "tty0");
3545         if (IS_ERR(tty0dev))
3546                 tty0dev = NULL;
3547
3548         vcs_init();
3549
3550         console_driver = tty_alloc_driver(MAX_NR_CONSOLES, TTY_DRIVER_REAL_RAW |
3551                         TTY_DRIVER_RESET_TERMIOS);
3552         if (IS_ERR(console_driver))
3553                 panic("Couldn't allocate console driver\n");
3554
3555         console_driver->name = "tty";
3556         console_driver->name_base = 1;
3557         console_driver->major = TTY_MAJOR;
3558         console_driver->minor_start = 1;
3559         console_driver->type = TTY_DRIVER_TYPE_CONSOLE;
3560         console_driver->init_termios = tty_std_termios;
3561         if (default_utf8)
3562                 console_driver->init_termios.c_iflag |= IUTF8;
3563         tty_set_operations(console_driver, &con_ops);
3564         if (tty_register_driver(console_driver))
3565                 panic("Couldn't register console driver\n");
3566         kbd_init();
3567         console_map_init();
3568 #ifdef CONFIG_MDA_CONSOLE
3569         mda_console_init();
3570 #endif
3571         return 0;
3572 }
3573
3574 static const struct class vtconsole_class = {
3575         .name = "vtconsole",
3576 };
3577
3578 static int do_bind_con_driver(const struct consw *csw, int first, int last,
3579                            int deflt)
3580 {
3581         struct module *owner = csw->owner;
3582         const char *desc = NULL;
3583         struct con_driver *con_driver;
3584         int i, j = -1, k = -1, retval = -ENODEV;
3585
3586         if (!try_module_get(owner))
3587                 return -ENODEV;
3588
3589         WARN_CONSOLE_UNLOCKED();
3590
3591         /* check if driver is registered */
3592         for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
3593                 con_driver = &registered_con_driver[i];
3594
3595                 if (con_driver->con == csw) {
3596                         desc = con_driver->desc;
3597                         retval = 0;
3598                         break;
3599                 }
3600         }
3601
3602         if (retval)
3603                 goto err;
3604
3605         if (!(con_driver->flag & CON_DRIVER_FLAG_INIT)) {
3606                 csw->con_startup();
3607                 con_driver->flag |= CON_DRIVER_FLAG_INIT;
3608         }
3609
3610         if (deflt) {
3611                 if (conswitchp)
3612                         module_put(conswitchp->owner);
3613
3614                 __module_get(owner);
3615                 conswitchp = csw;
3616         }
3617
3618         first = max(first, con_driver->first);
3619         last = min(last, con_driver->last);
3620
3621         for (i = first; i <= last; i++) {
3622                 int old_was_color;
3623                 struct vc_data *vc = vc_cons[i].d;
3624
3625                 if (con_driver_map[i])
3626                         module_put(con_driver_map[i]->owner);
3627                 __module_get(owner);
3628                 con_driver_map[i] = csw;
3629
3630                 if (!vc || !vc->vc_sw)
3631                         continue;
3632
3633                 j = i;
3634
3635                 if (con_is_visible(vc)) {
3636                         k = i;
3637                         save_screen(vc);
3638                 }
3639
3640                 old_was_color = vc->vc_can_do_color;
3641                 vc->vc_sw->con_deinit(vc);
3642                 vc->vc_origin = (unsigned long)vc->vc_screenbuf;
3643                 visual_init(vc, i, 0);
3644                 set_origin(vc);
3645                 update_attr(vc);
3646
3647                 /* If the console changed between mono <-> color, then
3648                  * the attributes in the screenbuf will be wrong.  The
3649                  * following resets all attributes to something sane.
3650                  */
3651                 if (old_was_color != vc->vc_can_do_color)
3652                         clear_buffer_attributes(vc);
3653         }
3654
3655         pr_info("Console: switching ");
3656         if (!deflt)
3657                 pr_cont("consoles %d-%d ", first + 1, last + 1);
3658         if (j >= 0) {
3659                 struct vc_data *vc = vc_cons[j].d;
3660
3661                 pr_cont("to %s %s %dx%d\n",
3662                         vc->vc_can_do_color ? "colour" : "mono",
3663                         desc, vc->vc_cols, vc->vc_rows);
3664
3665                 if (k >= 0) {
3666                         vc = vc_cons[k].d;
3667                         update_screen(vc);
3668                 }
3669         } else {
3670                 pr_cont("to %s\n", desc);
3671         }
3672
3673         retval = 0;
3674 err:
3675         module_put(owner);
3676         return retval;
3677 };
3678
3679
3680 #ifdef CONFIG_VT_HW_CONSOLE_BINDING
3681 int do_unbind_con_driver(const struct consw *csw, int first, int last, int deflt)
3682 {
3683         struct module *owner = csw->owner;
3684         const struct consw *defcsw = NULL;
3685         struct con_driver *con_driver = NULL, *con_back = NULL;
3686         int i, retval = -ENODEV;
3687
3688         if (!try_module_get(owner))
3689                 return -ENODEV;
3690
3691         WARN_CONSOLE_UNLOCKED();
3692
3693         /* check if driver is registered and if it is unbindable */
3694         for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
3695                 con_driver = &registered_con_driver[i];
3696
3697                 if (con_driver->con == csw &&
3698                     con_driver->flag & CON_DRIVER_FLAG_MODULE) {
3699                         retval = 0;
3700                         break;
3701                 }
3702         }
3703
3704         if (retval)
3705                 goto err;
3706
3707         retval = -ENODEV;
3708
3709         /* check if backup driver exists */
3710         for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
3711                 con_back = &registered_con_driver[i];
3712
3713                 if (con_back->con && con_back->con != csw) {
3714                         defcsw = con_back->con;
3715                         retval = 0;
3716                         break;
3717                 }
3718         }
3719
3720         if (retval)
3721                 goto err;
3722
3723         if (!con_is_bound(csw))
3724                 goto err;
3725
3726         first = max(first, con_driver->first);
3727         last = min(last, con_driver->last);
3728
3729         for (i = first; i <= last; i++) {
3730                 if (con_driver_map[i] == csw) {
3731                         module_put(csw->owner);
3732                         con_driver_map[i] = NULL;
3733                 }
3734         }
3735
3736         if (!con_is_bound(defcsw)) {
3737                 const struct consw *defconsw = conswitchp;
3738
3739                 defcsw->con_startup();
3740                 con_back->flag |= CON_DRIVER_FLAG_INIT;
3741                 /*
3742                  * vgacon may change the default driver to point
3743                  * to dummycon, we restore it here...
3744                  */
3745                 conswitchp = defconsw;
3746         }
3747
3748         if (!con_is_bound(csw))
3749                 con_driver->flag &= ~CON_DRIVER_FLAG_INIT;
3750
3751         /* ignore return value, binding should not fail */
3752         do_bind_con_driver(defcsw, first, last, deflt);
3753 err:
3754         module_put(owner);
3755         return retval;
3756
3757 }
3758 EXPORT_SYMBOL_GPL(do_unbind_con_driver);
3759
3760 static int vt_bind(struct con_driver *con)
3761 {
3762         const struct consw *defcsw = NULL, *csw = NULL;
3763         int i, more = 1, first = -1, last = -1, deflt = 0;
3764
3765         if (!con->con || !(con->flag & CON_DRIVER_FLAG_MODULE))
3766                 goto err;
3767
3768         csw = con->con;
3769
3770         for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
3771                 struct con_driver *con = &registered_con_driver[i];
3772
3773                 if (con->con && !(con->flag & CON_DRIVER_FLAG_MODULE)) {
3774                         defcsw = con->con;
3775                         break;
3776                 }
3777         }
3778
3779         if (!defcsw)
3780                 goto err;
3781
3782         while (more) {
3783                 more = 0;
3784
3785                 for (i = con->first; i <= con->last; i++) {
3786                         if (con_driver_map[i] == defcsw) {
3787                                 if (first == -1)
3788                                         first = i;
3789                                 last = i;
3790                                 more = 1;
3791                         } else if (first != -1)
3792                                 break;
3793                 }
3794
3795                 if (first == 0 && last == MAX_NR_CONSOLES -1)
3796                         deflt = 1;
3797
3798                 if (first != -1)
3799                         do_bind_con_driver(csw, first, last, deflt);
3800
3801                 first = -1;
3802                 last = -1;
3803                 deflt = 0;
3804         }
3805
3806 err:
3807         return 0;
3808 }
3809
3810 static int vt_unbind(struct con_driver *con)
3811 {
3812         const struct consw *csw = NULL;
3813         int i, more = 1, first = -1, last = -1, deflt = 0;
3814         int ret;
3815
3816         if (!con->con || !(con->flag & CON_DRIVER_FLAG_MODULE))
3817                 goto err;
3818
3819         csw = con->con;
3820
3821         while (more) {
3822                 more = 0;
3823
3824                 for (i = con->first; i <= con->last; i++) {
3825                         if (con_driver_map[i] == csw) {
3826                                 if (first == -1)
3827                                         first = i;
3828                                 last = i;
3829                                 more = 1;
3830                         } else if (first != -1)
3831                                 break;
3832                 }
3833
3834                 if (first == 0 && last == MAX_NR_CONSOLES -1)
3835                         deflt = 1;
3836
3837                 if (first != -1) {
3838                         ret = do_unbind_con_driver(csw, first, last, deflt);
3839                         if (ret != 0)
3840                                 return ret;
3841                 }
3842
3843                 first = -1;
3844                 last = -1;
3845                 deflt = 0;
3846         }
3847
3848 err:
3849         return 0;
3850 }
3851 #else
3852 static inline int vt_bind(struct con_driver *con)
3853 {
3854         return 0;
3855 }
3856 static inline int vt_unbind(struct con_driver *con)
3857 {
3858         return 0;
3859 }
3860 #endif /* CONFIG_VT_HW_CONSOLE_BINDING */
3861
3862 static ssize_t store_bind(struct device *dev, struct device_attribute *attr,
3863                           const char *buf, size_t count)
3864 {
3865         struct con_driver *con = dev_get_drvdata(dev);
3866         int bind = simple_strtoul(buf, NULL, 0);
3867
3868         console_lock();
3869
3870         if (bind)
3871                 vt_bind(con);
3872         else
3873                 vt_unbind(con);
3874
3875         console_unlock();
3876
3877         return count;
3878 }
3879
3880 static ssize_t show_bind(struct device *dev, struct device_attribute *attr,
3881                          char *buf)
3882 {
3883         struct con_driver *con = dev_get_drvdata(dev);
3884         int bind;
3885
3886         console_lock();
3887         bind = con_is_bound(con->con);
3888         console_unlock();
3889
3890         return sysfs_emit(buf, "%i\n", bind);
3891 }
3892
3893 static ssize_t show_name(struct device *dev, struct device_attribute *attr,
3894                          char *buf)
3895 {
3896         struct con_driver *con = dev_get_drvdata(dev);
3897
3898         return sysfs_emit(buf, "%s %s\n",
3899                         (con->flag & CON_DRIVER_FLAG_MODULE) ? "(M)" : "(S)",
3900                          con->desc);
3901
3902 }
3903
3904 static DEVICE_ATTR(bind, S_IRUGO|S_IWUSR, show_bind, store_bind);
3905 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
3906
3907 static struct attribute *con_dev_attrs[] = {
3908         &dev_attr_bind.attr,
3909         &dev_attr_name.attr,
3910         NULL
3911 };
3912
3913 ATTRIBUTE_GROUPS(con_dev);
3914
3915 static int vtconsole_init_device(struct con_driver *con)
3916 {
3917         con->flag |= CON_DRIVER_FLAG_ATTR;
3918         return 0;
3919 }
3920
3921 static void vtconsole_deinit_device(struct con_driver *con)
3922 {
3923         con->flag &= ~CON_DRIVER_FLAG_ATTR;
3924 }
3925
3926 /**
3927  * con_is_bound - checks if driver is bound to the console
3928  * @csw: console driver
3929  *
3930  * RETURNS: zero if unbound, nonzero if bound
3931  *
3932  * Drivers can call this and if zero, they should release
3933  * all resources allocated on con_startup()
3934  */
3935 int con_is_bound(const struct consw *csw)
3936 {
3937         int i, bound = 0;
3938
3939         WARN_CONSOLE_UNLOCKED();
3940
3941         for (i = 0; i < MAX_NR_CONSOLES; i++) {
3942                 if (con_driver_map[i] == csw) {
3943                         bound = 1;
3944                         break;
3945                 }
3946         }
3947
3948         return bound;
3949 }
3950 EXPORT_SYMBOL(con_is_bound);
3951
3952 /**
3953  * con_is_visible - checks whether the current console is visible
3954  * @vc: virtual console
3955  *
3956  * RETURNS: zero if not visible, nonzero if visible
3957  */
3958 bool con_is_visible(const struct vc_data *vc)
3959 {
3960         WARN_CONSOLE_UNLOCKED();
3961
3962         return *vc->vc_display_fg == vc;
3963 }
3964 EXPORT_SYMBOL(con_is_visible);
3965
3966 /**
3967  * con_debug_enter - prepare the console for the kernel debugger
3968  * @vc: virtual console
3969  *
3970  * Called when the console is taken over by the kernel debugger, this
3971  * function needs to save the current console state, then put the console
3972  * into a state suitable for the kernel debugger.
3973  *
3974  * RETURNS:
3975  * Zero on success, nonzero if a failure occurred when trying to prepare
3976  * the console for the debugger.
3977  */
3978 int con_debug_enter(struct vc_data *vc)
3979 {
3980         int ret = 0;
3981
3982         saved_fg_console = fg_console;
3983         saved_last_console = last_console;
3984         saved_want_console = want_console;
3985         saved_vc_mode = vc->vc_mode;
3986         saved_console_blanked = console_blanked;
3987         vc->vc_mode = KD_TEXT;
3988         console_blanked = 0;
3989         if (vc->vc_sw->con_debug_enter)
3990                 ret = vc->vc_sw->con_debug_enter(vc);
3991 #ifdef CONFIG_KGDB_KDB
3992         /* Set the initial LINES variable if it is not already set */
3993         if (vc->vc_rows < 999) {
3994                 int linecount;
3995                 char lns[4];
3996                 const char *setargs[3] = {
3997                         "set",
3998                         "LINES",
3999                         lns,
4000                 };
4001                 if (kdbgetintenv(setargs[0], &linecount)) {
4002                         snprintf(lns, 4, "%i", vc->vc_rows);
4003                         kdb_set(2, setargs);
4004                 }
4005         }
4006         if (vc->vc_cols < 999) {
4007                 int colcount;
4008                 char cols[4];
4009                 const char *setargs[3] = {
4010                         "set",
4011                         "COLUMNS",
4012                         cols,
4013                 };
4014                 if (kdbgetintenv(setargs[0], &colcount)) {
4015                         snprintf(cols, 4, "%i", vc->vc_cols);
4016                         kdb_set(2, setargs);
4017                 }
4018         }
4019 #endif /* CONFIG_KGDB_KDB */
4020         return ret;
4021 }
4022 EXPORT_SYMBOL_GPL(con_debug_enter);
4023
4024 /**
4025  * con_debug_leave - restore console state
4026  *
4027  * Restore the console state to what it was before the kernel debugger
4028  * was invoked.
4029  *
4030  * RETURNS:
4031  * Zero on success, nonzero if a failure occurred when trying to restore
4032  * the console.
4033  */
4034 int con_debug_leave(void)
4035 {
4036         struct vc_data *vc;
4037         int ret = 0;
4038
4039         fg_console = saved_fg_console;
4040         last_console = saved_last_console;
4041         want_console = saved_want_console;
4042         console_blanked = saved_console_blanked;
4043         vc_cons[fg_console].d->vc_mode = saved_vc_mode;
4044
4045         vc = vc_cons[fg_console].d;
4046         if (vc->vc_sw->con_debug_leave)
4047                 ret = vc->vc_sw->con_debug_leave(vc);
4048         return ret;
4049 }
4050 EXPORT_SYMBOL_GPL(con_debug_leave);
4051
4052 static int do_register_con_driver(const struct consw *csw, int first, int last)
4053 {
4054         struct module *owner = csw->owner;
4055         struct con_driver *con_driver;
4056         const char *desc;
4057         int i, retval;
4058
4059         WARN_CONSOLE_UNLOCKED();
4060
4061         if (!try_module_get(owner))
4062                 return -ENODEV;
4063
4064         for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
4065                 con_driver = &registered_con_driver[i];
4066
4067                 /* already registered */
4068                 if (con_driver->con == csw) {
4069                         retval = -EBUSY;
4070                         goto err;
4071                 }
4072         }
4073
4074         desc = csw->con_startup();
4075         if (!desc) {
4076                 retval = -ENODEV;
4077                 goto err;
4078         }
4079
4080         retval = -EINVAL;
4081
4082         for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
4083                 con_driver = &registered_con_driver[i];
4084
4085                 if (con_driver->con == NULL &&
4086                     !(con_driver->flag & CON_DRIVER_FLAG_ZOMBIE)) {
4087                         con_driver->con = csw;
4088                         con_driver->desc = desc;
4089                         con_driver->node = i;
4090                         con_driver->flag = CON_DRIVER_FLAG_MODULE |
4091                                            CON_DRIVER_FLAG_INIT;
4092                         con_driver->first = first;
4093                         con_driver->last = last;
4094                         retval = 0;
4095                         break;
4096                 }
4097         }
4098
4099         if (retval)
4100                 goto err;
4101
4102         con_driver->dev =
4103                 device_create_with_groups(&vtconsole_class, NULL,
4104                                           MKDEV(0, con_driver->node),
4105                                           con_driver, con_dev_groups,
4106                                           "vtcon%i", con_driver->node);
4107         if (IS_ERR(con_driver->dev)) {
4108                 pr_warn("Unable to create device for %s; errno = %ld\n",
4109                         con_driver->desc, PTR_ERR(con_driver->dev));
4110                 con_driver->dev = NULL;
4111         } else {
4112                 vtconsole_init_device(con_driver);
4113         }
4114
4115 err:
4116         module_put(owner);
4117         return retval;
4118 }
4119
4120
4121 /**
4122  * do_unregister_con_driver - unregister console driver from console layer
4123  * @csw: console driver
4124  *
4125  * DESCRIPTION: All drivers that registers to the console layer must
4126  * call this function upon exit, or if the console driver is in a state
4127  * where it won't be able to handle console services, such as the
4128  * framebuffer console without loaded framebuffer drivers.
4129  *
4130  * The driver must unbind first prior to unregistration.
4131  */
4132 int do_unregister_con_driver(const struct consw *csw)
4133 {
4134         int i;
4135
4136         /* cannot unregister a bound driver */
4137         if (con_is_bound(csw))
4138                 return -EBUSY;
4139
4140         if (csw == conswitchp)
4141                 return -EINVAL;
4142
4143         for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
4144                 struct con_driver *con_driver = &registered_con_driver[i];
4145
4146                 if (con_driver->con == csw) {
4147                         /*
4148                          * Defer the removal of the sysfs entries since that
4149                          * will acquire the kernfs s_active lock and we can't
4150                          * acquire this lock while holding the console lock:
4151                          * the unbind sysfs entry imposes already the opposite
4152                          * order. Reset con already here to prevent any later
4153                          * lookup to succeed and mark this slot as zombie, so
4154                          * it won't get reused until we complete the removal
4155                          * in the deferred work.
4156                          */
4157                         con_driver->con = NULL;
4158                         con_driver->flag = CON_DRIVER_FLAG_ZOMBIE;
4159                         schedule_work(&con_driver_unregister_work);
4160
4161                         return 0;
4162                 }
4163         }
4164
4165         return -ENODEV;
4166 }
4167 EXPORT_SYMBOL_GPL(do_unregister_con_driver);
4168
4169 static void con_driver_unregister_callback(struct work_struct *ignored)
4170 {
4171         int i;
4172
4173         console_lock();
4174
4175         for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
4176                 struct con_driver *con_driver = &registered_con_driver[i];
4177
4178                 if (!(con_driver->flag & CON_DRIVER_FLAG_ZOMBIE))
4179                         continue;
4180
4181                 console_unlock();
4182
4183                 vtconsole_deinit_device(con_driver);
4184                 device_destroy(&vtconsole_class, MKDEV(0, con_driver->node));
4185
4186                 console_lock();
4187
4188                 if (WARN_ON_ONCE(con_driver->con))
4189                         con_driver->con = NULL;
4190                 con_driver->desc = NULL;
4191                 con_driver->dev = NULL;
4192                 con_driver->node = 0;
4193                 WARN_ON_ONCE(con_driver->flag != CON_DRIVER_FLAG_ZOMBIE);
4194                 con_driver->flag = 0;
4195                 con_driver->first = 0;
4196                 con_driver->last = 0;
4197         }
4198
4199         console_unlock();
4200 }
4201
4202 /*
4203  *      If we support more console drivers, this function is used
4204  *      when a driver wants to take over some existing consoles
4205  *      and become default driver for newly opened ones.
4206  *
4207  *      do_take_over_console is basically a register followed by bind
4208  */
4209 int do_take_over_console(const struct consw *csw, int first, int last, int deflt)
4210 {
4211         int err;
4212
4213         err = do_register_con_driver(csw, first, last);
4214         /*
4215          * If we get an busy error we still want to bind the console driver
4216          * and return success, as we may have unbound the console driver
4217          * but not unregistered it.
4218          */
4219         if (err == -EBUSY)
4220                 err = 0;
4221         if (!err)
4222                 do_bind_con_driver(csw, first, last, deflt);
4223
4224         return err;
4225 }
4226 EXPORT_SYMBOL_GPL(do_take_over_console);
4227
4228
4229 /*
4230  * give_up_console is a wrapper to unregister_con_driver. It will only
4231  * work if driver is fully unbound.
4232  */
4233 void give_up_console(const struct consw *csw)
4234 {
4235         console_lock();
4236         do_unregister_con_driver(csw);
4237         console_unlock();
4238 }
4239 EXPORT_SYMBOL(give_up_console);
4240
4241 static int __init vtconsole_class_init(void)
4242 {
4243         int i;
4244
4245         i = class_register(&vtconsole_class);
4246         if (i)
4247                 pr_warn("Unable to create vt console class; errno = %d\n", i);
4248
4249         /* Add system drivers to sysfs */
4250         for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
4251                 struct con_driver *con = &registered_con_driver[i];
4252
4253                 if (con->con && !con->dev) {
4254                         con->dev =
4255                                 device_create_with_groups(&vtconsole_class, NULL,
4256                                                           MKDEV(0, con->node),
4257                                                           con, con_dev_groups,
4258                                                           "vtcon%i", con->node);
4259
4260                         if (IS_ERR(con->dev)) {
4261                                 pr_warn("Unable to create device for %s; errno = %ld\n",
4262                                         con->desc, PTR_ERR(con->dev));
4263                                 con->dev = NULL;
4264                         } else {
4265                                 vtconsole_init_device(con);
4266                         }
4267                 }
4268         }
4269
4270         return 0;
4271 }
4272 postcore_initcall(vtconsole_class_init);
4273
4274 /*
4275  *      Screen blanking
4276  */
4277
4278 static int set_vesa_blanking(char __user *p)
4279 {
4280         unsigned int mode;
4281
4282         if (get_user(mode, p + 1))
4283                 return -EFAULT;
4284
4285         vesa_blank_mode = (mode < 4) ? mode : 0;
4286         return 0;
4287 }
4288
4289 void do_blank_screen(int entering_gfx)
4290 {
4291         struct vc_data *vc = vc_cons[fg_console].d;
4292         int i;
4293
4294         might_sleep();
4295
4296         WARN_CONSOLE_UNLOCKED();
4297
4298         if (console_blanked) {
4299                 if (blank_state == blank_vesa_wait) {
4300                         blank_state = blank_off;
4301                         vc->vc_sw->con_blank(vc, vesa_blank_mode + 1, 0);
4302                 }
4303                 return;
4304         }
4305
4306         /* entering graphics mode? */
4307         if (entering_gfx) {
4308                 hide_cursor(vc);
4309                 save_screen(vc);
4310                 vc->vc_sw->con_blank(vc, -1, 1);
4311                 console_blanked = fg_console + 1;
4312                 blank_state = blank_off;
4313                 set_origin(vc);
4314                 return;
4315         }
4316
4317         blank_state = blank_off;
4318
4319         /* don't blank graphics */
4320         if (vc->vc_mode != KD_TEXT) {
4321                 console_blanked = fg_console + 1;
4322                 return;
4323         }
4324
4325         hide_cursor(vc);
4326         del_timer_sync(&console_timer);
4327         blank_timer_expired = 0;
4328
4329         save_screen(vc);
4330         /* In case we need to reset origin, blanking hook returns 1 */
4331         i = vc->vc_sw->con_blank(vc, vesa_off_interval ? 1 : (vesa_blank_mode + 1), 0);
4332         console_blanked = fg_console + 1;
4333         if (i)
4334                 set_origin(vc);
4335
4336         if (console_blank_hook && console_blank_hook(1))
4337                 return;
4338
4339         if (vesa_off_interval && vesa_blank_mode) {
4340                 blank_state = blank_vesa_wait;
4341                 mod_timer(&console_timer, jiffies + vesa_off_interval);
4342         }
4343         vt_event_post(VT_EVENT_BLANK, vc->vc_num, vc->vc_num);
4344 }
4345 EXPORT_SYMBOL(do_blank_screen);
4346
4347 /*
4348  * Called by timer as well as from vt_console_driver
4349  */
4350 void do_unblank_screen(int leaving_gfx)
4351 {
4352         struct vc_data *vc;
4353
4354         /* This should now always be called from a "sane" (read: can schedule)
4355          * context for the sake of the low level drivers, except in the special
4356          * case of oops_in_progress
4357          */
4358         if (!oops_in_progress)
4359                 might_sleep();
4360
4361         WARN_CONSOLE_UNLOCKED();
4362
4363         ignore_poke = 0;
4364         if (!console_blanked)
4365                 return;
4366         if (!vc_cons_allocated(fg_console)) {
4367                 /* impossible */
4368                 pr_warn("unblank_screen: tty %d not allocated ??\n",
4369                         fg_console + 1);
4370                 return;
4371         }
4372         vc = vc_cons[fg_console].d;
4373         if (vc->vc_mode != KD_TEXT)
4374                 return; /* but leave console_blanked != 0 */
4375
4376         if (blankinterval) {
4377                 mod_timer(&console_timer, jiffies + (blankinterval * HZ));
4378                 blank_state = blank_normal_wait;
4379         }
4380
4381         console_blanked = 0;
4382         if (vc->vc_sw->con_blank(vc, 0, leaving_gfx))
4383                 /* Low-level driver cannot restore -> do it ourselves */
4384                 update_screen(vc);
4385         if (console_blank_hook)
4386                 console_blank_hook(0);
4387         set_palette(vc);
4388         set_cursor(vc);
4389         vt_event_post(VT_EVENT_UNBLANK, vc->vc_num, vc->vc_num);
4390 }
4391 EXPORT_SYMBOL(do_unblank_screen);
4392
4393 /*
4394  * This is called by the outside world to cause a forced unblank, mostly for
4395  * oopses. Currently, I just call do_unblank_screen(0), but we could eventually
4396  * call it with 1 as an argument and so force a mode restore... that may kill
4397  * X or at least garbage the screen but would also make the Oops visible...
4398  */
4399 static void unblank_screen(void)
4400 {
4401         do_unblank_screen(0);
4402 }
4403
4404 /*
4405  * We defer the timer blanking to work queue so it can take the console mutex
4406  * (console operations can still happen at irq time, but only from printk which
4407  * has the console mutex. Not perfect yet, but better than no locking
4408  */
4409 static void blank_screen_t(struct timer_list *unused)
4410 {
4411         blank_timer_expired = 1;
4412         schedule_work(&console_work);
4413 }
4414
4415 void poke_blanked_console(void)
4416 {
4417         WARN_CONSOLE_UNLOCKED();
4418
4419         /* Add this so we quickly catch whoever might call us in a non
4420          * safe context. Nowadays, unblank_screen() isn't to be called in
4421          * atomic contexts and is allowed to schedule (with the special case
4422          * of oops_in_progress, but that isn't of any concern for this
4423          * function. --BenH.
4424          */
4425         might_sleep();
4426
4427         /* This isn't perfectly race free, but a race here would be mostly harmless,
4428          * at worst, we'll do a spurious blank and it's unlikely
4429          */
4430         del_timer(&console_timer);
4431         blank_timer_expired = 0;
4432
4433         if (ignore_poke || !vc_cons[fg_console].d || vc_cons[fg_console].d->vc_mode == KD_GRAPHICS)
4434                 return;
4435         if (console_blanked)
4436                 unblank_screen();
4437         else if (blankinterval) {
4438                 mod_timer(&console_timer, jiffies + (blankinterval * HZ));
4439                 blank_state = blank_normal_wait;
4440         }
4441 }
4442
4443 /*
4444  *      Palettes
4445  */
4446
4447 static void set_palette(struct vc_data *vc)
4448 {
4449         WARN_CONSOLE_UNLOCKED();
4450
4451         if (vc->vc_mode != KD_GRAPHICS && vc->vc_sw->con_set_palette)
4452                 vc->vc_sw->con_set_palette(vc, color_table);
4453 }
4454
4455 /*
4456  * Load palette into the DAC registers. arg points to a colour
4457  * map, 3 bytes per colour, 16 colours, range from 0 to 255.
4458  */
4459
4460 int con_set_cmap(unsigned char __user *arg)
4461 {
4462         int i, j, k;
4463         unsigned char colormap[3*16];
4464
4465         if (copy_from_user(colormap, arg, sizeof(colormap)))
4466                 return -EFAULT;
4467
4468         console_lock();
4469         for (i = k = 0; i < 16; i++) {
4470                 default_red[i] = colormap[k++];
4471                 default_grn[i] = colormap[k++];
4472                 default_blu[i] = colormap[k++];
4473         }
4474         for (i = 0; i < MAX_NR_CONSOLES; i++) {
4475                 if (!vc_cons_allocated(i))
4476                         continue;
4477                 for (j = k = 0; j < 16; j++) {
4478                         vc_cons[i].d->vc_palette[k++] = default_red[j];
4479                         vc_cons[i].d->vc_palette[k++] = default_grn[j];
4480                         vc_cons[i].d->vc_palette[k++] = default_blu[j];
4481                 }
4482                 set_palette(vc_cons[i].d);
4483         }
4484         console_unlock();
4485
4486         return 0;
4487 }
4488
4489 int con_get_cmap(unsigned char __user *arg)
4490 {
4491         int i, k;
4492         unsigned char colormap[3*16];
4493
4494         console_lock();
4495         for (i = k = 0; i < 16; i++) {
4496                 colormap[k++] = default_red[i];
4497                 colormap[k++] = default_grn[i];
4498                 colormap[k++] = default_blu[i];
4499         }
4500         console_unlock();
4501
4502         if (copy_to_user(arg, colormap, sizeof(colormap)))
4503                 return -EFAULT;
4504
4505         return 0;
4506 }
4507
4508 void reset_palette(struct vc_data *vc)
4509 {
4510         int j, k;
4511         for (j=k=0; j<16; j++) {
4512                 vc->vc_palette[k++] = default_red[j];
4513                 vc->vc_palette[k++] = default_grn[j];
4514                 vc->vc_palette[k++] = default_blu[j];
4515         }
4516         set_palette(vc);
4517 }
4518
4519 /*
4520  *  Font switching
4521  *
4522  *  Currently we only support fonts up to 128 pixels wide, at a maximum height
4523  *  of 128 pixels. Userspace fontdata may have to be stored with 32 bytes
4524  *  (shorts/ints, depending on width) reserved for each character which is
4525  *  kinda wasty, but this is done in order to maintain compatibility with the
4526  *  EGA/VGA fonts. It is up to the actual low-level console-driver convert data
4527  *  into its favorite format (maybe we should add a `fontoffset' field to the
4528  *  `display' structure so we won't have to convert the fontdata all the time.
4529  *  /Jes
4530  */
4531
4532 #define max_font_width  64
4533 #define max_font_height 128
4534 #define max_font_glyphs 512
4535 #define max_font_size   (max_font_glyphs*max_font_width*max_font_height)
4536
4537 static int con_font_get(struct vc_data *vc, struct console_font_op *op)
4538 {
4539         struct console_font font;
4540         int rc = -EINVAL;
4541         int c;
4542         unsigned int vpitch = op->op == KD_FONT_OP_GET_TALL ? op->height : 32;
4543
4544         if (vpitch > max_font_height)
4545                 return -EINVAL;
4546
4547         if (op->data) {
4548                 font.data = kvmalloc(max_font_size, GFP_KERNEL);
4549                 if (!font.data)
4550                         return -ENOMEM;
4551         } else
4552                 font.data = NULL;
4553
4554         console_lock();
4555         if (vc->vc_mode != KD_TEXT)
4556                 rc = -EINVAL;
4557         else if (vc->vc_sw->con_font_get)
4558                 rc = vc->vc_sw->con_font_get(vc, &font, vpitch);
4559         else
4560                 rc = -ENOSYS;
4561         console_unlock();
4562
4563         if (rc)
4564                 goto out;
4565
4566         c = (font.width+7)/8 * vpitch * font.charcount;
4567
4568         if (op->data && font.charcount > op->charcount)
4569                 rc = -ENOSPC;
4570         if (font.width > op->width || font.height > op->height)
4571                 rc = -ENOSPC;
4572         if (rc)
4573                 goto out;
4574
4575         op->height = font.height;
4576         op->width = font.width;
4577         op->charcount = font.charcount;
4578
4579         if (op->data && copy_to_user(op->data, font.data, c))
4580                 rc = -EFAULT;
4581
4582 out:
4583         kvfree(font.data);
4584         return rc;
4585 }
4586
4587 static int con_font_set(struct vc_data *vc, struct console_font_op *op)
4588 {
4589         struct console_font font;
4590         int rc = -EINVAL;
4591         int size;
4592         unsigned int vpitch = op->op == KD_FONT_OP_SET_TALL ? op->height : 32;
4593
4594         if (vc->vc_mode != KD_TEXT)
4595                 return -EINVAL;
4596         if (!op->data)
4597                 return -EINVAL;
4598         if (op->charcount > max_font_glyphs)
4599                 return -EINVAL;
4600         if (op->width <= 0 || op->width > max_font_width || !op->height ||
4601             op->height > max_font_height)
4602                 return -EINVAL;
4603         if (vpitch < op->height)
4604                 return -EINVAL;
4605         size = (op->width+7)/8 * vpitch * op->charcount;
4606         if (size > max_font_size)
4607                 return -ENOSPC;
4608
4609         font.data = memdup_user(op->data, size);
4610         if (IS_ERR(font.data))
4611                 return PTR_ERR(font.data);
4612
4613         font.charcount = op->charcount;
4614         font.width = op->width;
4615         font.height = op->height;
4616
4617         console_lock();
4618         if (vc->vc_mode != KD_TEXT)
4619                 rc = -EINVAL;
4620         else if (vc->vc_sw->con_font_set) {
4621                 if (vc_is_sel(vc))
4622                         clear_selection();
4623                 rc = vc->vc_sw->con_font_set(vc, &font, vpitch, op->flags);
4624         } else
4625                 rc = -ENOSYS;
4626         console_unlock();
4627         kfree(font.data);
4628         return rc;
4629 }
4630
4631 static int con_font_default(struct vc_data *vc, struct console_font_op *op)
4632 {
4633         struct console_font font = {.width = op->width, .height = op->height};
4634         char name[MAX_FONT_NAME];
4635         char *s = name;
4636         int rc;
4637
4638
4639         if (!op->data)
4640                 s = NULL;
4641         else if (strncpy_from_user(name, op->data, MAX_FONT_NAME - 1) < 0)
4642                 return -EFAULT;
4643         else
4644                 name[MAX_FONT_NAME - 1] = 0;
4645
4646         console_lock();
4647         if (vc->vc_mode != KD_TEXT) {
4648                 console_unlock();
4649                 return -EINVAL;
4650         }
4651         if (vc->vc_sw->con_font_default) {
4652                 if (vc_is_sel(vc))
4653                         clear_selection();
4654                 rc = vc->vc_sw->con_font_default(vc, &font, s);
4655         } else
4656                 rc = -ENOSYS;
4657         console_unlock();
4658         if (!rc) {
4659                 op->width = font.width;
4660                 op->height = font.height;
4661         }
4662         return rc;
4663 }
4664
4665 int con_font_op(struct vc_data *vc, struct console_font_op *op)
4666 {
4667         switch (op->op) {
4668         case KD_FONT_OP_SET:
4669         case KD_FONT_OP_SET_TALL:
4670                 return con_font_set(vc, op);
4671         case KD_FONT_OP_GET:
4672         case KD_FONT_OP_GET_TALL:
4673                 return con_font_get(vc, op);
4674         case KD_FONT_OP_SET_DEFAULT:
4675                 return con_font_default(vc, op);
4676         case KD_FONT_OP_COPY:
4677                 /* was buggy and never really used */
4678                 return -EINVAL;
4679         }
4680         return -ENOSYS;
4681 }
4682
4683 /*
4684  *      Interface exported to selection and vcs.
4685  */
4686
4687 /* used by selection */
4688 u16 screen_glyph(const struct vc_data *vc, int offset)
4689 {
4690         u16 w = scr_readw(screenpos(vc, offset, true));
4691         u16 c = w & 0xff;
4692
4693         if (w & vc->vc_hi_font_mask)
4694                 c |= 0x100;
4695         return c;
4696 }
4697 EXPORT_SYMBOL_GPL(screen_glyph);
4698
4699 u32 screen_glyph_unicode(const struct vc_data *vc, int n)
4700 {
4701         u32 **uni_lines = vc->vc_uni_lines;
4702
4703         if (uni_lines)
4704                 return uni_lines[n / vc->vc_cols][n % vc->vc_cols];
4705
4706         return inverse_translate(vc, screen_glyph(vc, n * 2), true);
4707 }
4708 EXPORT_SYMBOL_GPL(screen_glyph_unicode);
4709
4710 /* used by vcs - note the word offset */
4711 unsigned short *screen_pos(const struct vc_data *vc, int w_offset, bool viewed)
4712 {
4713         return screenpos(vc, 2 * w_offset, viewed);
4714 }
4715 EXPORT_SYMBOL_GPL(screen_pos);
4716
4717 void getconsxy(const struct vc_data *vc, unsigned char xy[static 2])
4718 {
4719         /* clamp values if they don't fit */
4720         xy[0] = min(vc->state.x, 0xFFu);
4721         xy[1] = min(vc->state.y, 0xFFu);
4722 }
4723
4724 void putconsxy(struct vc_data *vc, unsigned char xy[static const 2])
4725 {
4726         hide_cursor(vc);
4727         gotoxy(vc, xy[0], xy[1]);
4728         set_cursor(vc);
4729 }
4730
4731 u16 vcs_scr_readw(const struct vc_data *vc, const u16 *org)
4732 {
4733         if ((unsigned long)org == vc->vc_pos && softcursor_original != -1)
4734                 return softcursor_original;
4735         return scr_readw(org);
4736 }
4737
4738 void vcs_scr_writew(struct vc_data *vc, u16 val, u16 *org)
4739 {
4740         scr_writew(val, org);
4741         if ((unsigned long)org == vc->vc_pos) {
4742                 softcursor_original = -1;
4743                 add_softcursor(vc);
4744         }
4745 }
4746
4747 void vcs_scr_updated(struct vc_data *vc)
4748 {
4749         notify_update(vc);
4750 }
4751
4752 void vc_scrolldelta_helper(struct vc_data *c, int lines,
4753                 unsigned int rolled_over, void *base, unsigned int size)
4754 {
4755         unsigned long ubase = (unsigned long)base;
4756         ptrdiff_t scr_end = (void *)c->vc_scr_end - base;
4757         ptrdiff_t vorigin = (void *)c->vc_visible_origin - base;
4758         ptrdiff_t origin = (void *)c->vc_origin - base;
4759         int margin = c->vc_size_row * 4;
4760         int from, wrap, from_off, avail;
4761
4762         /* Turn scrollback off */
4763         if (!lines) {
4764                 c->vc_visible_origin = c->vc_origin;
4765                 return;
4766         }
4767
4768         /* Do we have already enough to allow jumping from 0 to the end? */
4769         if (rolled_over > scr_end + margin) {
4770                 from = scr_end;
4771                 wrap = rolled_over + c->vc_size_row;
4772         } else {
4773                 from = 0;
4774                 wrap = size;
4775         }
4776
4777         from_off = (vorigin - from + wrap) % wrap + lines * c->vc_size_row;
4778         avail = (origin - from + wrap) % wrap;
4779
4780         /* Only a little piece would be left? Show all incl. the piece! */
4781         if (avail < 2 * margin)
4782                 margin = 0;
4783         if (from_off < margin)
4784                 from_off = 0;
4785         if (from_off > avail - margin)
4786                 from_off = avail;
4787
4788         c->vc_visible_origin = ubase + (from + from_off) % wrap;
4789 }
4790 EXPORT_SYMBOL_GPL(vc_scrolldelta_helper);