arch/arm/mm/dump.c

   1 /*
   2  * Debug helper to dump the current kernel pagetables of the system
   3  * so that we can see what the various memory ranges are set to.
   4  *
   5  * Derived from x86 implementation:
   6  * (C) Copyright 2008 Intel Corporation
   7  *
   8  * Author: Arjan van de Ven <[email protected]>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; version 2
  13  * of the License.
  14  */
  15 #include <linux/debugfs.h>
  16 #include <linux/fs.h>
  17 #include <linux/mm.h>
  18 #include <linux/seq_file.h>
  19
  20 #include <asm/domain.h>
  21 #include <asm/fixmap.h>
  22 #include <asm/memory.h>
  23 #include <asm/pgtable.h>
  24
  25 struct addr_marker {
  26         unsigned long start_address;
  27         const char *name;
  28 };
  29
  30 static struct addr_marker address_markers[] = {
  31         { MODULES_VADDR,        "Modules" },
  32         { PAGE_OFFSET,          "Kernel Mapping" },
  33         { 0,                    "vmalloc() Area" },
  34         { VMALLOC_END,          "vmalloc() End" },
  35         { FIXADDR_START,        "Fixmap Area" },
  36         { VECTORS_BASE, "Vectors" },
  37         { VECTORS_BASE + PAGE_SIZE * 2, "Vectors End" },
  38         { -1,                   NULL },
  39 };
  40
  41 struct pg_state {
  42         struct seq_file *seq;
  43         const struct addr_marker *marker;
  44         unsigned long start_address;
  45         unsigned level;
  46         u64 current_prot;
  47         const char *current_domain;
  48 };
  49
  50 struct prot_bits {
  51         u64             mask;
  52         u64             val;
  53         const char      *set;
  54         const char      *clear;
  55 };
  56
  57 static const struct prot_bits pte_bits[] = {
  58         {
  59                 .mask   = L_PTE_USER,
  60                 .val    = L_PTE_USER,
  61                 .set    = "USR",
  62                 .clear  = "   ",
  63         }, {
  64                 .mask   = L_PTE_RDONLY,
  65                 .val    = L_PTE_RDONLY,
  66                 .set    = "ro",
  67                 .clear  = "RW",
  68         }, {
  69                 .mask   = L_PTE_XN,
  70                 .val    = L_PTE_XN,
  71                 .set    = "NX",
  72                 .clear  = "x ",
  73         }, {
  74                 .mask   = L_PTE_SHARED,
  75                 .val    = L_PTE_SHARED,
  76                 .set    = "SHD",
  77                 .clear  = "   ",
  78         }, {
  79                 .mask   = L_PTE_MT_MASK,
  80                 .val    = L_PTE_MT_UNCACHED,
  81                 .set    = "SO/UNCACHED",
  82         }, {
  83                 .mask   = L_PTE_MT_MASK,
  84                 .val    = L_PTE_MT_BUFFERABLE,
  85                 .set    = "MEM/BUFFERABLE/WC",
  86         }, {
  87                 .mask   = L_PTE_MT_MASK,
  88                 .val    = L_PTE_MT_WRITETHROUGH,
  89                 .set    = "MEM/CACHED/WT",
  90         }, {
  91                 .mask   = L_PTE_MT_MASK,
  92                 .val    = L_PTE_MT_WRITEBACK,
  93                 .set    = "MEM/CACHED/WBRA",
  94 #ifndef CONFIG_ARM_LPAE
  95         }, {
  96                 .mask   = L_PTE_MT_MASK,
  97                 .val    = L_PTE_MT_MINICACHE,
  98                 .set    = "MEM/MINICACHE",
  99 #endif
 100         }, {
 101                 .mask   = L_PTE_MT_MASK,
 102                 .val    = L_PTE_MT_WRITEALLOC,
 103                 .set    = "MEM/CACHED/WBWA",
 104         }, {
 105                 .mask   = L_PTE_MT_MASK,
 106                 .val    = L_PTE_MT_DEV_SHARED,
 107                 .set    = "DEV/SHARED",
 108 #ifndef CONFIG_ARM_LPAE
 109         }, {
 110                 .mask   = L_PTE_MT_MASK,
 111                 .val    = L_PTE_MT_DEV_NONSHARED,
 112                 .set    = "DEV/NONSHARED",
 113 #endif
 114         }, {
 115                 .mask   = L_PTE_MT_MASK,
 116                 .val    = L_PTE_MT_DEV_WC,
 117                 .set    = "DEV/WC",
 118         }, {
 119                 .mask   = L_PTE_MT_MASK,
 120                 .val    = L_PTE_MT_DEV_CACHED,
 121                 .set    = "DEV/CACHED",
 122         },
 123 };
 124
 125 static const struct prot_bits section_bits[] = {
 126 #ifdef CONFIG_ARM_LPAE
 127         {
 128                 .mask   = PMD_SECT_USER,
 129                 .val    = PMD_SECT_USER,
 130                 .set    = "USR",
 131         }, {
 132                 .mask   = L_PMD_SECT_RDONLY,
 133                 .val    = L_PMD_SECT_RDONLY,
 134                 .set    = "ro",
 135                 .clear  = "RW",
 136 #elif __LINUX_ARM_ARCH__ >= 6
 137         {
 138                 .mask   = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
 139                 .val    = PMD_SECT_APX | PMD_SECT_AP_WRITE,
 140                 .set    = "    ro",
 141         }, {
 142                 .mask   = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
 143                 .val    = PMD_SECT_AP_WRITE,
 144                 .set    = "    RW",
 145         }, {
 146                 .mask   = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
 147                 .val    = PMD_SECT_AP_READ,
 148                 .set    = "USR ro",
 149         }, {
 150                 .mask   = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
 151                 .val    = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
 152                 .set    = "USR RW",
 153 #else /* ARMv4/ARMv5  */
 154         /* These are approximate */
 155         {
 156                 .mask   = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
 157                 .val    = 0,
 158                 .set    = "    ro",
 159         }, {
 160                 .mask   = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
 161                 .val    = PMD_SECT_AP_WRITE,
 162                 .set    = "    RW",
 163         }, {
 164                 .mask   = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
 165                 .val    = PMD_SECT_AP_READ,
 166                 .set    = "USR ro",
 167         }, {
 168                 .mask   = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
 169                 .val    = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
 170                 .set    = "USR RW",
 171 #endif
 172         }, {
 173                 .mask   = PMD_SECT_XN,
 174                 .val    = PMD_SECT_XN,
 175                 .set    = "NX",
 176                 .clear  = "x ",
 177         }, {
 178                 .mask   = PMD_SECT_S,
 179                 .val    = PMD_SECT_S,
 180                 .set    = "SHD",
 181                 .clear  = "   ",
 182         },
 183 };
 184
 185 struct pg_level {
 186         const struct prot_bits *bits;
 187         size_t num;
 188         u64 mask;
 189 };
 190
 191 static struct pg_level pg_level[] = {
 192         {
 193         }, { /* pgd */
 194         }, { /* pud */
 195         }, { /* pmd */
 196                 .bits   = section_bits,
 197                 .num    = ARRAY_SIZE(section_bits),
 198         }, { /* pte */
 199                 .bits   = pte_bits,
 200                 .num    = ARRAY_SIZE(pte_bits),
 201         },
 202 };
 203
 204 static void dump_prot(struct pg_state *st, const struct prot_bits *bits, size_t num)
 205 {
 206         unsigned i;
 207
 208         for (i = 0; i < num; i++, bits++) {
 209                 const char *s;
 210
 211                 if ((st->current_prot & bits->mask) == bits->val)
 212                         s = bits->set;
 213                 else
 214                         s = bits->clear;
 215
 216                 if (s)
 217                         seq_printf(st->seq, " %s", s);
 218         }
 219 }
 220
 221 static void note_page(struct pg_state *st, unsigned long addr,
 222                       unsigned int level, u64 val, const char *domain)
 223 {
 224         static const char units[] = "KMGTPE";
 225         u64 prot = val & pg_level[level].mask;
 226
 227         if (!st->level) {
 228                 st->level = level;
 229                 st->current_prot = prot;
 230                 st->current_domain = domain;
 231                 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 232         } else if (prot != st->current_prot || level != st->level ||
 233                    domain != st->current_domain ||
 234                    addr >= st->marker[1].start_address) {
 235                 const char *unit = units;
 236                 unsigned long delta;
 237
 238                 if (st->current_prot) {
 239                         seq_printf(st->seq, "0x%08lx-0x%08lx   ",
 240                                    st->start_address, addr);
 241
 242                         delta = (addr - st->start_address) >> 10;
 243                         while (!(delta & 1023) && unit[1]) {
 244                                 delta >>= 10;
 245                                 unit++;
 246                         }
 247                         seq_printf(st->seq, "%9lu%c", delta, *unit);
 248                         if (st->current_domain)
 249                                 seq_printf(st->seq, " %s", st->current_domain);
 250                         if (pg_level[st->level].bits)
 251                                 dump_prot(st, pg_level[st->level].bits, pg_level[st->level].num);
 252                         seq_printf(st->seq, "\n");
 253                 }
 254
 255                 if (addr >= st->marker[1].start_address) {
 256                         st->marker++;
 257                         seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 258                 }
 259                 st->start_address = addr;
 260                 st->current_prot = prot;
 261                 st->current_domain = domain;
 262                 st->level = level;
 263         }
 264 }
 265
 266 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start,
 267                      const char *domain)
 268 {
 269         pte_t *pte = pte_offset_kernel(pmd, 0);
 270         unsigned long addr;
 271         unsigned i;
 272
 273         for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
 274                 addr = start + i * PAGE_SIZE;
 275                 note_page(st, addr, 4, pte_val(*pte), domain);
 276         }
 277 }
 278
 279 static const char *get_domain_name(pmd_t *pmd)
 280 {
 281 #ifndef CONFIG_ARM_LPAE
 282         switch (pmd_val(*pmd) & PMD_DOMAIN_MASK) {
 283         case PMD_DOMAIN(DOMAIN_KERNEL):
 284                 return "KERNEL ";
 285         case PMD_DOMAIN(DOMAIN_USER):
 286                 return "USER   ";
 287         case PMD_DOMAIN(DOMAIN_IO):
 288                 return "IO     ";
 289         case PMD_DOMAIN(DOMAIN_VECTORS):
 290                 return "VECTORS";
 291         default:
 292                 return "unknown";
 293         }
 294 #endif
 295         return NULL;
 296 }
 297
 298 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
 299 {
 300         pmd_t *pmd = pmd_offset(pud, 0);
 301         unsigned long addr;
 302         unsigned i;
 303         const char *domain;
 304
 305         for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
 306                 addr = start + i * PMD_SIZE;
 307                 domain = get_domain_name(pmd);
 308                 if (pmd_none(*pmd) || pmd_large(*pmd) || !pmd_present(*pmd))
 309                         note_page(st, addr, 3, pmd_val(*pmd), domain);
 310                 else
 311                         walk_pte(st, pmd, addr, domain);
 312
 313                 if (SECTION_SIZE < PMD_SIZE && pmd_large(pmd[1])) {
 314                         addr += SECTION_SIZE;
 315                         pmd++;
 316                         domain = get_domain_name(pmd);
 317                         note_page(st, addr, 3, pmd_val(*pmd), domain);
 318                 }
 319         }
 320 }
 321
 322 static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
 323 {
 324         pud_t *pud = pud_offset(pgd, 0);
 325         unsigned long addr;
 326         unsigned i;
 327
 328         for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
 329                 addr = start + i * PUD_SIZE;
 330                 if (!pud_none(*pud)) {
 331                         walk_pmd(st, pud, addr);
 332                 } else {
 333                         note_page(st, addr, 2, pud_val(*pud), NULL);
 334                 }
 335         }
 336 }
 337
 338 static void walk_pgd(struct seq_file *m)
 339 {
 340         pgd_t *pgd = swapper_pg_dir;
 341         struct pg_state st;
 342         unsigned long addr;
 343         unsigned i;
 344
 345         memset(&st, 0, sizeof(st));
 346         st.seq = m;
 347         st.marker = address_markers;
 348
 349         for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
 350                 addr = i * PGDIR_SIZE;
 351                 if (!pgd_none(*pgd)) {
 352                         walk_pud(&st, pgd, addr);
 353                 } else {
 354                         note_page(&st, addr, 1, pgd_val(*pgd), NULL);
 355                 }
 356         }
 357
 358         note_page(&st, 0, 0, 0, NULL);
 359 }
 360
 361 static int ptdump_show(struct seq_file *m, void *v)
 362 {
 363         walk_pgd(m);
 364         return 0;
 365 }
 366
 367 static int ptdump_open(struct inode *inode, struct file *file)
 368 {
 369         return single_open(file, ptdump_show, NULL);
 370 }
 371
 372 static const struct file_operations ptdump_fops = {
 373         .open           = ptdump_open,
 374         .read           = seq_read,
 375         .llseek         = seq_lseek,
 376         .release        = single_release,
 377 };
 378
 379 static int ptdump_init(void)
 380 {
 381         struct dentry *pe;
 382         unsigned i, j;
 383
 384         for (i = 0; i < ARRAY_SIZE(pg_level); i++)
 385                 if (pg_level[i].bits)
 386                         for (j = 0; j < pg_level[i].num; j++)
 387                                 pg_level[i].mask |= pg_level[i].bits[j].mask;
 388
 389         address_markers[2].start_address = VMALLOC_START;
 390
 391         pe = debugfs_create_file("kernel_page_tables", 0400, NULL, NULL,
 392                                  &ptdump_fops);
 393         return pe ? 0 : -ENOMEM;
 394 }
 395 __initcall(ptdump_init);