arch/powerpc/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ARCH_POWERPC_UACCESS_H
   3 #define _ARCH_POWERPC_UACCESS_H
   4
   5 #include <asm/processor.h>
   6 #include <asm/page.h>
   7 #include <asm/extable.h>
   8 #include <asm/kup.h>
   9
  10 #ifdef __powerpc64__
  11 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  12 #define TASK_SIZE_MAX           TASK_SIZE_USER64
  13 #endif
  14
  15 #include <asm-generic/access_ok.h>
  16
  17 /*
  18  * These are the main single-value transfer routines.  They automatically
  19  * use the right size if we just have the right pointer type.
  20  *
  21  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  22  * and yet we don't want to do any pointers, because that is too much
  23  * of a performance impact. Thus we have a few rather ugly macros here,
  24  * and hide all the ugliness from the user.
  25  *
  26  * The "__xxx" versions of the user access functions are versions that
  27  * do not verify the address space, that must have been done previously
  28  * with a separate "access_ok()" call (this is used when we do multiple
  29  * accesses to the same area of user memory).
  30  *
  31  * As we use the same address space for kernel and user data on the
  32  * PowerPC, we can just do these as direct assignments.  (Of course, the
  33  * exception handling means that it's no longer "just"...)
  34  *
  35  */
  36 #define __put_user(x, ptr)                                      \
  37 ({                                                              \
  38         long __pu_err;                                          \
  39         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
  40         __typeof__(*(ptr)) __pu_val = (__typeof__(*(ptr)))(x);  \
  41         __typeof__(sizeof(*(ptr))) __pu_size = sizeof(*(ptr));  \
  42                                                                 \
  43         might_fault();                                          \
  44         do {                                                    \
  45                 __label__ __pu_failed;                          \
  46                                                                 \
  47                 allow_write_to_user(__pu_addr, __pu_size);      \
  48                 __put_user_size_goto(__pu_val, __pu_addr, __pu_size, __pu_failed);      \
  49                 prevent_write_to_user(__pu_addr, __pu_size);    \
  50                 __pu_err = 0;                                   \
  51                 break;                                          \
  52                                                                 \
  53 __pu_failed:                                                    \
  54                 prevent_write_to_user(__pu_addr, __pu_size);    \
  55                 __pu_err = -EFAULT;                             \
  56         } while (0);                                            \
  57                                                                 \
  58         __pu_err;                                               \
  59 })
  60
  61 #define put_user(x, ptr)                                                \
  62 ({                                                                      \
  63         __typeof__(*(ptr)) __user *_pu_addr = (ptr);                    \
  64                                                                         \
  65         access_ok(_pu_addr, sizeof(*(ptr))) ?                           \
  66                   __put_user(x, _pu_addr) : -EFAULT;                    \
  67 })
  68
  69 /*
  70  * We don't tell gcc that we are accessing memory, but this is OK
  71  * because we do not write to any memory gcc knows about, so there
  72  * are no aliasing issues.
  73  */
  74 /* -mprefixed can generate offsets beyond range, fall back hack */
  75 #ifdef CONFIG_PPC_KERNEL_PREFIXED
  76 #define __put_user_asm_goto(x, addr, label, op)                 \
  77         asm goto(                                       \
  78                 "1:     " op " %0,0(%1) # put_user\n"           \
  79                 EX_TABLE(1b, %l2)                               \
  80                 :                                               \
  81                 : "r" (x), "b" (addr)                           \
  82                 :                                               \
  83                 : label)
  84 #else
  85 #define __put_user_asm_goto(x, addr, label, op)                 \
  86         asm goto(                                       \
  87                 "1:     " op "%U1%X1 %0,%1      # put_user\n"   \
  88                 EX_TABLE(1b, %l2)                               \
  89                 :                                               \
  90                 : "r" (x), "m<>" (*addr)                        \
  91                 :                                               \
  92                 : label)
  93 #endif
  94
  95 #ifdef CONFIG_CC_IS_CLANG
  96 #define DS_FORM_CONSTRAINT "Z<>"
  97 #else
  98 #define DS_FORM_CONSTRAINT "YZ<>"
  99 #endif
 100
 101 #ifdef __powerpc64__
 102 #ifdef CONFIG_PPC_KERNEL_PREFIXED
 103 #define __put_user_asm2_goto(x, ptr, label)                     \
 104         __put_user_asm_goto(x, ptr, label, "std")
 105 #else
 106 #define __put_user_asm2_goto(x, addr, label)                    \
 107         asm goto ("1: std%U1%X1 %0,%1   # put_user\n"           \
 108                 EX_TABLE(1b, %l2)                               \
 109                 :                                               \
 110                 : "r" (x), DS_FORM_CONSTRAINT (*addr)           \
 111                 :                                               \
 112                 : label)
 113 #endif // CONFIG_PPC_KERNEL_PREFIXED
 114 #else /* __powerpc64__ */
 115 #define __put_user_asm2_goto(x, addr, label)                    \
 116         asm goto(                                       \
 117                 "1:     stw%X1 %0, %1\n"                        \
 118                 "2:     stw%X1 %L0, %L1\n"                      \
 119                 EX_TABLE(1b, %l2)                               \
 120                 EX_TABLE(2b, %l2)                               \
 121                 :                                               \
 122                 : "r" (x), "m" (*addr)                          \
 123                 :                                               \
 124                 : label)
 125 #endif /* __powerpc64__ */
 126
 127 #define __put_user_size_goto(x, ptr, size, label)               \
 128 do {                                                            \
 129         __typeof__(*(ptr)) __user *__pus_addr = (ptr);          \
 130                                                                 \
 131         switch (size) {                                         \
 132         case 1: __put_user_asm_goto(x, __pus_addr, label, "stb"); break;        \
 133         case 2: __put_user_asm_goto(x, __pus_addr, label, "sth"); break;        \
 134         case 4: __put_user_asm_goto(x, __pus_addr, label, "stw"); break;        \
 135         case 8: __put_user_asm2_goto(x, __pus_addr, label); break;              \
 136         default: BUILD_BUG();                                   \
 137         }                                                       \
 138 } while (0)
 139
 140 /*
 141  * This does an atomic 128 byte aligned load from userspace.
 142  * Upto caller to do enable_kernel_vmx() before calling!
 143  */
 144 #define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
 145         __asm__ __volatile__(                           \
 146                 ".machine push\n"                       \
 147                 ".machine altivec\n"                    \
 148                 "1:     lvx  0,0,%1     # get user\n"   \
 149                 "       stvx 0,0,%2     # put kernel\n" \
 150                 ".machine pop\n"                        \
 151                 "2:\n"                                  \
 152                 ".section .fixup,\"ax\"\n"              \
 153                 "3:     li %0,%3\n"                     \
 154                 "       b 2b\n"                         \
 155                 ".previous\n"                           \
 156                 EX_TABLE(1b, 3b)                        \
 157                 : "=r" (err)                    \
 158                 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
 159
 160 #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
 161
 162 /* -mprefixed can generate offsets beyond range, fall back hack */
 163 #ifdef CONFIG_PPC_KERNEL_PREFIXED
 164 #define __get_user_asm_goto(x, addr, label, op)                 \
 165         asm_goto_output(                                        \
 166                 "1:     "op" %0,0(%1)   # get_user\n"           \
 167                 EX_TABLE(1b, %l2)                               \
 168                 : "=r" (x)                                      \
 169                 : "b" (addr)                                    \
 170                 :                                               \
 171                 : label)
 172 #else
 173 #define __get_user_asm_goto(x, addr, label, op)                 \
 174         asm_goto_output(                                        \
 175                 "1:     "op"%U1%X1 %0, %1       # get_user\n"   \
 176                 EX_TABLE(1b, %l2)                               \
 177                 : "=r" (x)                                      \
 178                 : "m<>" (*addr)                                 \
 179                 :                                               \
 180                 : label)
 181 #endif
 182
 183 #ifdef __powerpc64__
 184 #ifdef CONFIG_PPC_KERNEL_PREFIXED
 185 #define __get_user_asm2_goto(x, addr, label)                    \
 186         __get_user_asm_goto(x, addr, label, "ld")
 187 #else
 188 #define __get_user_asm2_goto(x, addr, label)                    \
 189         asm_goto_output(                                        \
 190                 "1:     ld%U1%X1 %0, %1 # get_user\n"           \
 191                 EX_TABLE(1b, %l2)                               \
 192                 : "=r" (x)                                      \
 193                 : DS_FORM_CONSTRAINT (*addr)                    \
 194                 :                                               \
 195                 : label)
 196 #endif // CONFIG_PPC_KERNEL_PREFIXED
 197 #else /* __powerpc64__ */
 198 #define __get_user_asm2_goto(x, addr, label)                    \
 199         asm_goto_output(                                        \
 200                 "1:     lwz%X1 %0, %1\n"                        \
 201                 "2:     lwz%X1 %L0, %L1\n"                      \
 202                 EX_TABLE(1b, %l2)                               \
 203                 EX_TABLE(2b, %l2)                               \
 204                 : "=&r" (x)                                     \
 205                 : "m" (*addr)                                   \
 206                 :                                               \
 207                 : label)
 208 #endif /* __powerpc64__ */
 209
 210 #define __get_user_size_goto(x, ptr, size, label)                               \
 211 do {                                                                            \
 212         BUILD_BUG_ON(size > sizeof(x));                                         \
 213         switch (size) {                                                         \
 214         case 1: __get_user_asm_goto(x, (u8 __user *)ptr, label, "lbz"); break;  \
 215         case 2: __get_user_asm_goto(x, (u16 __user *)ptr, label, "lhz"); break; \
 216         case 4: __get_user_asm_goto(x, (u32 __user *)ptr, label, "lwz"); break; \
 217         case 8: __get_user_asm2_goto(x, (u64 __user *)ptr, label);  break;      \
 218         default: x = 0; BUILD_BUG();                                            \
 219         }                                                                       \
 220 } while (0)
 221
 222 #define __get_user_size_allowed(x, ptr, size, retval)                   \
 223 do {                                                                    \
 224                 __label__ __gus_failed;                                 \
 225                                                                         \
 226                 __get_user_size_goto(x, ptr, size, __gus_failed);       \
 227                 retval = 0;                                             \
 228                 break;                                                  \
 229 __gus_failed:                                                           \
 230                 x = 0;                                                  \
 231                 retval = -EFAULT;                                       \
 232 } while (0)
 233
 234 #else /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
 235
 236 #define __get_user_asm(x, addr, err, op)                \
 237         __asm__ __volatile__(                           \
 238                 "1:     "op"%U2%X2 %1, %2       # get_user\n"   \
 239                 "2:\n"                                  \
 240                 ".section .fixup,\"ax\"\n"              \
 241                 "3:     li %0,%3\n"                     \
 242                 "       li %1,0\n"                      \
 243                 "       b 2b\n"                         \
 244                 ".previous\n"                           \
 245                 EX_TABLE(1b, 3b)                        \
 246                 : "=r" (err), "=r" (x)                  \
 247                 : "m<>" (*addr), "i" (-EFAULT), "0" (err))
 248
 249 #ifdef __powerpc64__
 250 #define __get_user_asm2(x, addr, err)                   \
 251         __get_user_asm(x, addr, err, "ld")
 252 #else /* __powerpc64__ */
 253 #define __get_user_asm2(x, addr, err)                   \
 254         __asm__ __volatile__(                           \
 255                 "1:     lwz%X2 %1, %2\n"                        \
 256                 "2:     lwz%X2 %L1, %L2\n"              \
 257                 "3:\n"                                  \
 258                 ".section .fixup,\"ax\"\n"              \
 259                 "4:     li %0,%3\n"                     \
 260                 "       li %1,0\n"                      \
 261                 "       li %1+1,0\n"                    \
 262                 "       b 3b\n"                         \
 263                 ".previous\n"                           \
 264                 EX_TABLE(1b, 4b)                        \
 265                 EX_TABLE(2b, 4b)                        \
 266                 : "=r" (err), "=&r" (x)                 \
 267                 : "m" (*addr), "i" (-EFAULT), "0" (err))
 268 #endif /* __powerpc64__ */
 269
 270 #define __get_user_size_allowed(x, ptr, size, retval)           \
 271 do {                                                            \
 272         retval = 0;                                             \
 273         BUILD_BUG_ON(size > sizeof(x));                         \
 274         switch (size) {                                         \
 275         case 1: __get_user_asm(x, (u8 __user *)ptr, retval, "lbz"); break;      \
 276         case 2: __get_user_asm(x, (u16 __user *)ptr, retval, "lhz"); break;     \
 277         case 4: __get_user_asm(x, (u32 __user *)ptr, retval, "lwz"); break;     \
 278         case 8: __get_user_asm2(x, (u64 __user *)ptr, retval);  break;  \
 279         default: x = 0; BUILD_BUG();                            \
 280         }                                                       \
 281 } while (0)
 282
 283 #define __get_user_size_goto(x, ptr, size, label)               \
 284 do {                                                            \
 285         long __gus_retval;                                      \
 286                                                                 \
 287         __get_user_size_allowed(x, ptr, size, __gus_retval);    \
 288         if (__gus_retval)                                       \
 289                 goto label;                                     \
 290 } while (0)
 291
 292 #endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
 293
 294 /*
 295  * This is a type: either unsigned long, if the argument fits into
 296  * that type, or otherwise unsigned long long.
 297  */
 298 #define __long_type(x) \
 299         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 300
 301 #define __get_user(x, ptr)                                      \
 302 ({                                                              \
 303         long __gu_err;                                          \
 304         __long_type(*(ptr)) __gu_val;                           \
 305         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 306         __typeof__(sizeof(*(ptr))) __gu_size = sizeof(*(ptr));  \
 307                                                                 \
 308         might_fault();                                  \
 309         allow_read_from_user(__gu_addr, __gu_size);             \
 310         __get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err);      \
 311         prevent_read_from_user(__gu_addr, __gu_size);           \
 312         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 313                                                                 \
 314         __gu_err;                                               \
 315 })
 316
 317 #define get_user(x, ptr)                                                \
 318 ({                                                                      \
 319         __typeof__(*(ptr)) __user *_gu_addr = (ptr);                    \
 320                                                                         \
 321         access_ok(_gu_addr, sizeof(*(ptr))) ?                           \
 322                   __get_user(x, _gu_addr) :                             \
 323                   ((x) = (__force __typeof__(*(ptr)))0, -EFAULT);       \
 324 })
 325
 326 /* more complex routines */
 327
 328 extern unsigned long __copy_tofrom_user(void __user *to,
 329                 const void __user *from, unsigned long size);
 330
 331 #ifdef __powerpc64__
 332 static inline unsigned long
 333 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 334 {
 335         unsigned long ret;
 336
 337         allow_read_write_user(to, from, n);
 338         ret = __copy_tofrom_user(to, from, n);
 339         prevent_read_write_user(to, from, n);
 340         return ret;
 341 }
 342 #endif /* __powerpc64__ */
 343
 344 static inline unsigned long raw_copy_from_user(void *to,
 345                 const void __user *from, unsigned long n)
 346 {
 347         unsigned long ret;
 348
 349         allow_read_from_user(from, n);
 350         ret = __copy_tofrom_user((__force void __user *)to, from, n);
 351         prevent_read_from_user(from, n);
 352         return ret;
 353 }
 354
 355 static inline unsigned long
 356 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 357 {
 358         unsigned long ret;
 359
 360         allow_write_to_user(to, n);
 361         ret = __copy_tofrom_user(to, (__force const void __user *)from, n);
 362         prevent_write_to_user(to, n);
 363         return ret;
 364 }
 365
 366 unsigned long __arch_clear_user(void __user *addr, unsigned long size);
 367
 368 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 369 {
 370         unsigned long ret;
 371
 372         might_fault();
 373         allow_write_to_user(addr, size);
 374         ret = __arch_clear_user(addr, size);
 375         prevent_write_to_user(addr, size);
 376         return ret;
 377 }
 378
 379 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 380 {
 381         return likely(access_ok(addr, size)) ? __clear_user(addr, size) : size;
 382 }
 383
 384 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 385 extern __must_check long strnlen_user(const char __user *str, long n);
 386
 387 #ifdef CONFIG_ARCH_HAS_COPY_MC
 388 unsigned long __must_check
 389 copy_mc_generic(void *to, const void *from, unsigned long size);
 390
 391 static inline unsigned long __must_check
 392 copy_mc_to_kernel(void *to, const void *from, unsigned long size)
 393 {
 394         return copy_mc_generic(to, from, size);
 395 }
 396 #define copy_mc_to_kernel copy_mc_to_kernel
 397
 398 static inline unsigned long __must_check
 399 copy_mc_to_user(void __user *to, const void *from, unsigned long n)
 400 {
 401         if (check_copy_size(from, n, true)) {
 402                 if (access_ok(to, n)) {
 403                         allow_write_to_user(to, n);
 404                         n = copy_mc_generic((void __force *)to, from, n);
 405                         prevent_write_to_user(to, n);
 406                 }
 407         }
 408
 409         return n;
 410 }
 411 #endif
 412
 413 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 414                 unsigned size);
 415
 416 static __must_check __always_inline bool user_access_begin(const void __user *ptr, size_t len)
 417 {
 418         if (unlikely(!access_ok(ptr, len)))
 419                 return false;
 420
 421         might_fault();
 422
 423         allow_read_write_user((void __user *)ptr, ptr, len);
 424         return true;
 425 }
 426 #define user_access_begin       user_access_begin
 427 #define user_access_end         prevent_current_access_user
 428 #define user_access_save        prevent_user_access_return
 429 #define user_access_restore     restore_user_access
 430
 431 static __must_check __always_inline bool
 432 user_read_access_begin(const void __user *ptr, size_t len)
 433 {
 434         if (unlikely(!access_ok(ptr, len)))
 435                 return false;
 436
 437         might_fault();
 438
 439         allow_read_from_user(ptr, len);
 440         return true;
 441 }
 442 #define user_read_access_begin  user_read_access_begin
 443 #define user_read_access_end            prevent_current_read_from_user
 444
 445 static __must_check __always_inline bool
 446 user_write_access_begin(const void __user *ptr, size_t len)
 447 {
 448         if (unlikely(!access_ok(ptr, len)))
 449                 return false;
 450
 451         might_fault();
 452
 453         allow_write_to_user((void __user *)ptr, len);
 454         return true;
 455 }
 456 #define user_write_access_begin user_write_access_begin
 457 #define user_write_access_end           prevent_current_write_to_user
 458
 459 #define unsafe_get_user(x, p, e) do {                                   \
 460         __long_type(*(p)) __gu_val;                             \
 461         __typeof__(*(p)) __user *__gu_addr = (p);               \
 462                                                                 \
 463         __get_user_size_goto(__gu_val, __gu_addr, sizeof(*(p)), e); \
 464         (x) = (__typeof__(*(p)))__gu_val;                       \
 465 } while (0)
 466
 467 #define unsafe_put_user(x, p, e) \
 468         __put_user_size_goto((__typeof__(*(p)))(x), (p), sizeof(*(p)), e)
 469
 470 #define unsafe_copy_from_user(d, s, l, e) \
 471 do {                                                                                    \
 472         u8 *_dst = (u8 *)(d);                                                           \
 473         const u8 __user *_src = (const u8 __user *)(s);                                 \
 474         size_t _len = (l);                                                              \
 475         int _i;                                                                         \
 476                                                                                         \
 477         for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64))               \
 478                 unsafe_get_user(*(u64 *)(_dst + _i), (u64 __user *)(_src + _i), e);     \
 479         if (_len & 4) {                                                                 \
 480                 unsafe_get_user(*(u32 *)(_dst + _i), (u32 __user *)(_src + _i), e);     \
 481                 _i += 4;                                                                \
 482         }                                                                               \
 483         if (_len & 2) {                                                                 \
 484                 unsafe_get_user(*(u16 *)(_dst + _i), (u16 __user *)(_src + _i), e);     \
 485                 _i += 2;                                                                \
 486         }                                                                               \
 487         if (_len & 1)                                                                   \
 488                 unsafe_get_user(*(u8 *)(_dst + _i), (u8 __user *)(_src + _i), e);       \
 489 } while (0)
 490
 491 #define unsafe_copy_to_user(d, s, l, e) \
 492 do {                                                                    \
 493         u8 __user *_dst = (u8 __user *)(d);                             \
 494         const u8 *_src = (const u8 *)(s);                               \
 495         size_t _len = (l);                                              \
 496         int _i;                                                         \
 497                                                                         \
 498         for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64))       \
 499                 unsafe_put_user(*(u64 *)(_src + _i), (u64 __user *)(_dst + _i), e); \
 500         if (_len & 4) {                                                 \
 501                 unsafe_put_user(*(u32*)(_src + _i), (u32 __user *)(_dst + _i), e); \
 502                 _i += 4;                                                \
 503         }                                                               \
 504         if (_len & 2) {                                                 \
 505                 unsafe_put_user(*(u16*)(_src + _i), (u16 __user *)(_dst + _i), e); \
 506                 _i += 2;                                                \
 507         }                                                               \
 508         if (_len & 1) \
 509                 unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \
 510 } while (0)
 511
 512 #define __get_kernel_nofault(dst, src, type, err_label)                 \
 513         __get_user_size_goto(*((type *)(dst)),                          \
 514                 (__force type __user *)(src), sizeof(type), err_label)
 515
 516 #define __put_kernel_nofault(dst, src, type, err_label)                 \
 517         __put_user_size_goto(*((type *)(src)),                          \
 518                 (__force type __user *)(dst), sizeof(type), err_label)
 519
 520 #endif  /* _ARCH_POWERPC_UACCESS_H */