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