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 #define __put_user_asm_goto(x, addr, label, op)                 \
  75         asm_volatile_goto(                                      \
  76                 "1:     " op "%U1%X1 %0,%1      # put_user\n"   \
  77                 EX_TABLE(1b, %l2)                               \
  78                 :                                               \
  79                 : "r" (x), "m<>" (*addr)                \
  80                 :                                               \
  81                 : label)
  82
  83 #ifdef __powerpc64__
  84 #define __put_user_asm2_goto(x, ptr, label)                     \
  85         __put_user_asm_goto(x, ptr, label, "std")
  86 #else /* __powerpc64__ */
  87 #define __put_user_asm2_goto(x, addr, label)                    \
  88         asm_volatile_goto(                                      \
  89                 "1:     stw%X1 %0, %1\n"                        \
  90                 "2:     stw%X1 %L0, %L1\n"                      \
  91                 EX_TABLE(1b, %l2)                               \
  92                 EX_TABLE(2b, %l2)                               \
  93                 :                                               \
  94                 : "r" (x), "m" (*addr)                          \
  95                 :                                               \
  96                 : label)
  97 #endif /* __powerpc64__ */
  98
  99 #define __put_user_size_goto(x, ptr, size, label)               \
 100 do {                                                            \
 101         __typeof__(*(ptr)) __user *__pus_addr = (ptr);          \
 102                                                                 \
 103         switch (size) {                                         \
 104         case 1: __put_user_asm_goto(x, __pus_addr, label, "stb"); break;        \
 105         case 2: __put_user_asm_goto(x, __pus_addr, label, "sth"); break;        \
 106         case 4: __put_user_asm_goto(x, __pus_addr, label, "stw"); break;        \
 107         case 8: __put_user_asm2_goto(x, __pus_addr, label); break;              \
 108         default: BUILD_BUG();                                   \
 109         }                                                       \
 110 } while (0)
 111
 112 /*
 113  * This does an atomic 128 byte aligned load from userspace.
 114  * Upto caller to do enable_kernel_vmx() before calling!
 115  */
 116 #define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
 117         __asm__ __volatile__(                           \
 118                 ".machine push\n"                       \
 119                 ".machine altivec\n"                    \
 120                 "1:     lvx  0,0,%1     # get user\n"   \
 121                 "       stvx 0,0,%2     # put kernel\n" \
 122                 ".machine pop\n"                        \
 123                 "2:\n"                                  \
 124                 ".section .fixup,\"ax\"\n"              \
 125                 "3:     li %0,%3\n"                     \
 126                 "       b 2b\n"                         \
 127                 ".previous\n"                           \
 128                 EX_TABLE(1b, 3b)                        \
 129                 : "=r" (err)                    \
 130                 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
 131
 132 #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
 133
 134 #define __get_user_asm_goto(x, addr, label, op)                 \
 135         asm_volatile_goto(                                      \
 136                 "1:     "op"%U1%X1 %0, %1       # get_user\n"   \
 137                 EX_TABLE(1b, %l2)                               \
 138                 : "=r" (x)                                      \
 139                 : "m<>" (*addr)                         \
 140                 :                                               \
 141                 : label)
 142
 143 #ifdef __powerpc64__
 144 #define __get_user_asm2_goto(x, addr, label)                    \
 145         __get_user_asm_goto(x, addr, label, "ld")
 146 #else /* __powerpc64__ */
 147 #define __get_user_asm2_goto(x, addr, label)                    \
 148         asm_volatile_goto(                                      \
 149                 "1:     lwz%X1 %0, %1\n"                        \
 150                 "2:     lwz%X1 %L0, %L1\n"                      \
 151                 EX_TABLE(1b, %l2)                               \
 152                 EX_TABLE(2b, %l2)                               \
 153                 : "=&r" (x)                                     \
 154                 : "m" (*addr)                                   \
 155                 :                                               \
 156                 : label)
 157 #endif /* __powerpc64__ */
 158
 159 #define __get_user_size_goto(x, ptr, size, label)                               \
 160 do {                                                                            \
 161         BUILD_BUG_ON(size > sizeof(x));                                         \
 162         switch (size) {                                                         \
 163         case 1: __get_user_asm_goto(x, (u8 __user *)ptr, label, "lbz"); break;  \
 164         case 2: __get_user_asm_goto(x, (u16 __user *)ptr, label, "lhz"); break; \
 165         case 4: __get_user_asm_goto(x, (u32 __user *)ptr, label, "lwz"); break; \
 166         case 8: __get_user_asm2_goto(x, (u64 __user *)ptr, label);  break;      \
 167         default: x = 0; BUILD_BUG();                                            \
 168         }                                                                       \
 169 } while (0)
 170
 171 #define __get_user_size_allowed(x, ptr, size, retval)                   \
 172 do {                                                                    \
 173                 __label__ __gus_failed;                                 \
 174                                                                         \
 175                 __get_user_size_goto(x, ptr, size, __gus_failed);       \
 176                 retval = 0;                                             \
 177                 break;                                                  \
 178 __gus_failed:                                                           \
 179                 x = 0;                                                  \
 180                 retval = -EFAULT;                                       \
 181 } while (0)
 182
 183 #else /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
 184
 185 #define __get_user_asm(x, addr, err, op)                \
 186         __asm__ __volatile__(                           \
 187                 "1:     "op"%U2%X2 %1, %2       # get_user\n"   \
 188                 "2:\n"                                  \
 189                 ".section .fixup,\"ax\"\n"              \
 190                 "3:     li %0,%3\n"                     \
 191                 "       li %1,0\n"                      \
 192                 "       b 2b\n"                         \
 193                 ".previous\n"                           \
 194                 EX_TABLE(1b, 3b)                        \
 195                 : "=r" (err), "=r" (x)                  \
 196                 : "m<>" (*addr), "i" (-EFAULT), "0" (err))
 197
 198 #ifdef __powerpc64__
 199 #define __get_user_asm2(x, addr, err)                   \
 200         __get_user_asm(x, addr, err, "ld")
 201 #else /* __powerpc64__ */
 202 #define __get_user_asm2(x, addr, err)                   \
 203         __asm__ __volatile__(                           \
 204                 "1:     lwz%X2 %1, %2\n"                        \
 205                 "2:     lwz%X2 %L1, %L2\n"              \
 206                 "3:\n"                                  \
 207                 ".section .fixup,\"ax\"\n"              \
 208                 "4:     li %0,%3\n"                     \
 209                 "       li %1,0\n"                      \
 210                 "       li %1+1,0\n"                    \
 211                 "       b 3b\n"                         \
 212                 ".previous\n"                           \
 213                 EX_TABLE(1b, 4b)                        \
 214                 EX_TABLE(2b, 4b)                        \
 215                 : "=r" (err), "=&r" (x)                 \
 216                 : "m" (*addr), "i" (-EFAULT), "0" (err))
 217 #endif /* __powerpc64__ */
 218
 219 #define __get_user_size_allowed(x, ptr, size, retval)           \
 220 do {                                                            \
 221         retval = 0;                                             \
 222         BUILD_BUG_ON(size > sizeof(x));                         \
 223         switch (size) {                                         \
 224         case 1: __get_user_asm(x, (u8 __user *)ptr, retval, "lbz"); break;      \
 225         case 2: __get_user_asm(x, (u16 __user *)ptr, retval, "lhz"); break;     \
 226         case 4: __get_user_asm(x, (u32 __user *)ptr, retval, "lwz"); break;     \
 227         case 8: __get_user_asm2(x, (u64 __user *)ptr, retval);  break;  \
 228         default: x = 0; BUILD_BUG();                            \
 229         }                                                       \
 230 } while (0)
 231
 232 #define __get_user_size_goto(x, ptr, size, label)               \
 233 do {                                                            \
 234         long __gus_retval;                                      \
 235                                                                 \
 236         __get_user_size_allowed(x, ptr, size, __gus_retval);    \
 237         if (__gus_retval)                                       \
 238                 goto label;                                     \
 239 } while (0)
 240
 241 #endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
 242
 243 /*
 244  * This is a type: either unsigned long, if the argument fits into
 245  * that type, or otherwise unsigned long long.
 246  */
 247 #define __long_type(x) \
 248         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 249
 250 #define __get_user(x, ptr)                                      \
 251 ({                                                              \
 252         long __gu_err;                                          \
 253         __long_type(*(ptr)) __gu_val;                           \
 254         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 255         __typeof__(sizeof(*(ptr))) __gu_size = sizeof(*(ptr));  \
 256                                                                 \
 257         might_fault();                                  \
 258         allow_read_from_user(__gu_addr, __gu_size);             \
 259         __get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err);      \
 260         prevent_read_from_user(__gu_addr, __gu_size);           \
 261         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 262                                                                 \
 263         __gu_err;                                               \
 264 })
 265
 266 #define get_user(x, ptr)                                                \
 267 ({                                                                      \
 268         __typeof__(*(ptr)) __user *_gu_addr = (ptr);                    \
 269                                                                         \
 270         access_ok(_gu_addr, sizeof(*(ptr))) ?                           \
 271                   __get_user(x, _gu_addr) :                             \
 272                   ((x) = (__force __typeof__(*(ptr)))0, -EFAULT);       \
 273 })
 274
 275 /* more complex routines */
 276
 277 extern unsigned long __copy_tofrom_user(void __user *to,
 278                 const void __user *from, unsigned long size);
 279
 280 #ifdef __powerpc64__
 281 static inline unsigned long
 282 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 283 {
 284         unsigned long ret;
 285
 286         allow_read_write_user(to, from, n);
 287         ret = __copy_tofrom_user(to, from, n);
 288         prevent_read_write_user(to, from, n);
 289         return ret;
 290 }
 291 #endif /* __powerpc64__ */
 292
 293 static inline unsigned long raw_copy_from_user(void *to,
 294                 const void __user *from, unsigned long n)
 295 {
 296         unsigned long ret;
 297
 298         allow_read_from_user(from, n);
 299         ret = __copy_tofrom_user((__force void __user *)to, from, n);
 300         prevent_read_from_user(from, n);
 301         return ret;
 302 }
 303
 304 static inline unsigned long
 305 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 306 {
 307         unsigned long ret;
 308
 309         allow_write_to_user(to, n);
 310         ret = __copy_tofrom_user(to, (__force const void __user *)from, n);
 311         prevent_write_to_user(to, n);
 312         return ret;
 313 }
 314
 315 unsigned long __arch_clear_user(void __user *addr, unsigned long size);
 316
 317 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 318 {
 319         unsigned long ret;
 320
 321         might_fault();
 322         allow_write_to_user(addr, size);
 323         ret = __arch_clear_user(addr, size);
 324         prevent_write_to_user(addr, size);
 325         return ret;
 326 }
 327
 328 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 329 {
 330         return likely(access_ok(addr, size)) ? __clear_user(addr, size) : size;
 331 }
 332
 333 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 334 extern __must_check long strnlen_user(const char __user *str, long n);
 335
 336 #ifdef CONFIG_ARCH_HAS_COPY_MC
 337 unsigned long __must_check
 338 copy_mc_generic(void *to, const void *from, unsigned long size);
 339
 340 static inline unsigned long __must_check
 341 copy_mc_to_kernel(void *to, const void *from, unsigned long size)
 342 {
 343         return copy_mc_generic(to, from, size);
 344 }
 345 #define copy_mc_to_kernel copy_mc_to_kernel
 346
 347 static inline unsigned long __must_check
 348 copy_mc_to_user(void __user *to, const void *from, unsigned long n)
 349 {
 350         if (check_copy_size(from, n, true)) {
 351                 if (access_ok(to, n)) {
 352                         allow_write_to_user(to, n);
 353                         n = copy_mc_generic((void *)to, from, n);
 354                         prevent_write_to_user(to, n);
 355                 }
 356         }
 357
 358         return n;
 359 }
 360 #endif
 361
 362 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 363                 unsigned size);
 364 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
 365                            size_t len);
 366
 367 static __must_check inline bool user_access_begin(const void __user *ptr, size_t len)
 368 {
 369         if (unlikely(!access_ok(ptr, len)))
 370                 return false;
 371
 372         might_fault();
 373
 374         allow_read_write_user((void __user *)ptr, ptr, len);
 375         return true;
 376 }
 377 #define user_access_begin       user_access_begin
 378 #define user_access_end         prevent_current_access_user
 379 #define user_access_save        prevent_user_access_return
 380 #define user_access_restore     restore_user_access
 381
 382 static __must_check inline bool
 383 user_read_access_begin(const void __user *ptr, size_t len)
 384 {
 385         if (unlikely(!access_ok(ptr, len)))
 386                 return false;
 387
 388         might_fault();
 389
 390         allow_read_from_user(ptr, len);
 391         return true;
 392 }
 393 #define user_read_access_begin  user_read_access_begin
 394 #define user_read_access_end            prevent_current_read_from_user
 395
 396 static __must_check inline bool
 397 user_write_access_begin(const void __user *ptr, size_t len)
 398 {
 399         if (unlikely(!access_ok(ptr, len)))
 400                 return false;
 401
 402         might_fault();
 403
 404         allow_write_to_user((void __user *)ptr, len);
 405         return true;
 406 }
 407 #define user_write_access_begin user_write_access_begin
 408 #define user_write_access_end           prevent_current_write_to_user
 409
 410 #define unsafe_get_user(x, p, e) do {                                   \
 411         __long_type(*(p)) __gu_val;                             \
 412         __typeof__(*(p)) __user *__gu_addr = (p);               \
 413                                                                 \
 414         __get_user_size_goto(__gu_val, __gu_addr, sizeof(*(p)), e); \
 415         (x) = (__typeof__(*(p)))__gu_val;                       \
 416 } while (0)
 417
 418 #define unsafe_put_user(x, p, e) \
 419         __put_user_size_goto((__typeof__(*(p)))(x), (p), sizeof(*(p)), e)
 420
 421 #define unsafe_copy_from_user(d, s, l, e) \
 422 do {                                                                                    \
 423         u8 *_dst = (u8 *)(d);                                                           \
 424         const u8 __user *_src = (const u8 __user *)(s);                                 \
 425         size_t _len = (l);                                                              \
 426         int _i;                                                                         \
 427                                                                                         \
 428         for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64))               \
 429                 unsafe_get_user(*(u64 *)(_dst + _i), (u64 __user *)(_src + _i), e);     \
 430         if (_len & 4) {                                                                 \
 431                 unsafe_get_user(*(u32 *)(_dst + _i), (u32 __user *)(_src + _i), e);     \
 432                 _i += 4;                                                                \
 433         }                                                                               \
 434         if (_len & 2) {                                                                 \
 435                 unsafe_get_user(*(u16 *)(_dst + _i), (u16 __user *)(_src + _i), e);     \
 436                 _i += 2;                                                                \
 437         }                                                                               \
 438         if (_len & 1)                                                                   \
 439                 unsafe_get_user(*(u8 *)(_dst + _i), (u8 __user *)(_src + _i), e);       \
 440 } while (0)
 441
 442 #define unsafe_copy_to_user(d, s, l, e) \
 443 do {                                                                    \
 444         u8 __user *_dst = (u8 __user *)(d);                             \
 445         const u8 *_src = (const u8 *)(s);                               \
 446         size_t _len = (l);                                              \
 447         int _i;                                                         \
 448                                                                         \
 449         for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64))       \
 450                 unsafe_put_user(*(u64 *)(_src + _i), (u64 __user *)(_dst + _i), e); \
 451         if (_len & 4) {                                                 \
 452                 unsafe_put_user(*(u32*)(_src + _i), (u32 __user *)(_dst + _i), e); \
 453                 _i += 4;                                                \
 454         }                                                               \
 455         if (_len & 2) {                                                 \
 456                 unsafe_put_user(*(u16*)(_src + _i), (u16 __user *)(_dst + _i), e); \
 457                 _i += 2;                                                \
 458         }                                                               \
 459         if (_len & 1) \
 460                 unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \
 461 } while (0)
 462
 463 #define __get_kernel_nofault(dst, src, type, err_label)                 \
 464         __get_user_size_goto(*((type *)(dst)),                          \
 465                 (__force type __user *)(src), sizeof(type), err_label)
 466
 467 #define __put_kernel_nofault(dst, src, type, err_label)                 \
 468         __put_user_size_goto(*((type *)(src)),                          \
 469                 (__force type __user *)(dst), sizeof(type), err_label)
 470
 471 #endif  /* _ARCH_POWERPC_UACCESS_H */