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 #include <asm/asm-compat.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 /* -mprefixed can generate offsets beyond range, fall back hack */
  76 #ifdef CONFIG_PPC_KERNEL_PREFIXED
  77 #define __put_user_asm_goto(x, addr, label, op)                 \
  78         asm goto(                                       \
  79                 "1:     " op " %0,0(%1) # put_user\n"           \
  80                 EX_TABLE(1b, %l2)                               \
  81                 :                                               \
  82                 : "r" (x), "b" (addr)                           \
  83                 :                                               \
  84                 : label)
  85 #else
  86 #define __put_user_asm_goto(x, addr, label, op)                 \
  87         asm goto(                                       \
  88                 "1:     " op "%U1%X1 %0,%1      # put_user\n"   \
  89                 EX_TABLE(1b, %l2)                               \
  90                 :                                               \
  91                 : "r" (x), "m<>" (*addr)                        \
  92                 :                                               \
  93                 : label)
  94 #endif
  95
  96 #ifdef __powerpc64__
  97 #ifdef CONFIG_PPC_KERNEL_PREFIXED
  98 #define __put_user_asm2_goto(x, ptr, label)                     \
  99         __put_user_asm_goto(x, ptr, label, "std")
 100 #else
 101 #define __put_user_asm2_goto(x, addr, label)                    \
 102         asm goto ("1: std%U1%X1 %0,%1   # put_user\n"           \
 103                 EX_TABLE(1b, %l2)                               \
 104                 :                                               \
 105                 : "r" (x), DS_FORM_CONSTRAINT (*addr)           \
 106                 :                                               \
 107                 : label)
 108 #endif // CONFIG_PPC_KERNEL_PREFIXED
 109 #else /* __powerpc64__ */
 110 #define __put_user_asm2_goto(x, addr, label)                    \
 111         asm goto(                                       \
 112                 "1:     stw%X1 %0, %1\n"                        \
 113                 "2:     stw%X1 %L0, %L1\n"                      \
 114                 EX_TABLE(1b, %l2)                               \
 115                 EX_TABLE(2b, %l2)                               \
 116                 :                                               \
 117                 : "r" (x), "m" (*addr)                          \
 118                 :                                               \
 119                 : label)
 120 #endif /* __powerpc64__ */
 121
 122 #define __put_user_size_goto(x, ptr, size, label)               \
 123 do {                                                            \
 124         __typeof__(*(ptr)) __user *__pus_addr = (ptr);          \
 125                                                                 \
 126         switch (size) {                                         \
 127         case 1: __put_user_asm_goto(x, __pus_addr, label, "stb"); break;        \
 128         case 2: __put_user_asm_goto(x, __pus_addr, label, "sth"); break;        \
 129         case 4: __put_user_asm_goto(x, __pus_addr, label, "stw"); break;        \
 130         case 8: __put_user_asm2_goto(x, __pus_addr, label); break;              \
 131         default: BUILD_BUG();                                   \
 132         }                                                       \
 133 } while (0)
 134
 135 /*
 136  * This does an atomic 128 byte aligned load from userspace.
 137  * Upto caller to do enable_kernel_vmx() before calling!
 138  */
 139 #define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
 140         __asm__ __volatile__(                           \
 141                 ".machine push\n"                       \
 142                 ".machine altivec\n"                    \
 143                 "1:     lvx  0,0,%1     # get user\n"   \
 144                 "       stvx 0,0,%2     # put kernel\n" \
 145                 ".machine pop\n"                        \
 146                 "2:\n"                                  \
 147                 ".section .fixup,\"ax\"\n"              \
 148                 "3:     li %0,%3\n"                     \
 149                 "       b 2b\n"                         \
 150                 ".previous\n"                           \
 151                 EX_TABLE(1b, 3b)                        \
 152                 : "=r" (err)                    \
 153                 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
 154
 155 #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
 156
 157 /* -mprefixed can generate offsets beyond range, fall back hack */
 158 #ifdef CONFIG_PPC_KERNEL_PREFIXED
 159 #define __get_user_asm_goto(x, addr, label, op)                 \
 160         asm_goto_output(                                        \
 161                 "1:     "op" %0,0(%1)   # get_user\n"           \
 162                 EX_TABLE(1b, %l2)                               \
 163                 : "=r" (x)                                      \
 164                 : "b" (addr)                                    \
 165                 :                                               \
 166                 : label)
 167 #else
 168 #define __get_user_asm_goto(x, addr, label, op)                 \
 169         asm_goto_output(                                        \
 170                 "1:     "op"%U1%X1 %0, %1       # get_user\n"   \
 171                 EX_TABLE(1b, %l2)                               \
 172                 : "=r" (x)                                      \
 173                 : "m<>" (*addr)                                 \
 174                 :                                               \
 175                 : label)
 176 #endif
 177
 178 #ifdef __powerpc64__
 179 #ifdef CONFIG_PPC_KERNEL_PREFIXED
 180 #define __get_user_asm2_goto(x, addr, label)                    \
 181         __get_user_asm_goto(x, addr, label, "ld")
 182 #else
 183 #define __get_user_asm2_goto(x, addr, label)                    \
 184         asm_goto_output(                                        \
 185                 "1:     ld%U1%X1 %0, %1 # get_user\n"           \
 186                 EX_TABLE(1b, %l2)                               \
 187                 : "=r" (x)                                      \
 188                 : DS_FORM_CONSTRAINT (*addr)                    \
 189                 :                                               \
 190                 : label)
 191 #endif // CONFIG_PPC_KERNEL_PREFIXED
 192 #else /* __powerpc64__ */
 193 #define __get_user_asm2_goto(x, addr, label)                    \
 194         asm_goto_output(                                        \
 195                 "1:     lwz%X1 %0, %1\n"                        \
 196                 "2:     lwz%X1 %L0, %L1\n"                      \
 197                 EX_TABLE(1b, %l2)                               \
 198                 EX_TABLE(2b, %l2)                               \
 199                 : "=&r" (x)                                     \
 200                 : "m" (*addr)                                   \
 201                 :                                               \
 202                 : label)
 203 #endif /* __powerpc64__ */
 204
 205 #define __get_user_size_goto(x, ptr, size, label)                               \
 206 do {                                                                            \
 207         BUILD_BUG_ON(size > sizeof(x));                                         \
 208         switch (size) {                                                         \
 209         case 1: __get_user_asm_goto(x, (u8 __user *)ptr, label, "lbz"); break;  \
 210         case 2: __get_user_asm_goto(x, (u16 __user *)ptr, label, "lhz"); break; \
 211         case 4: __get_user_asm_goto(x, (u32 __user *)ptr, label, "lwz"); break; \
 212         case 8: __get_user_asm2_goto(x, (u64 __user *)ptr, label);  break;      \
 213         default: x = 0; BUILD_BUG();                                            \
 214         }                                                                       \
 215 } while (0)
 216
 217 #define __get_user_size_allowed(x, ptr, size, retval)                   \
 218 do {                                                                    \
 219                 __label__ __gus_failed;                                 \
 220                                                                         \
 221                 __get_user_size_goto(x, ptr, size, __gus_failed);       \
 222                 retval = 0;                                             \
 223                 break;                                                  \
 224 __gus_failed:                                                           \
 225                 x = 0;                                                  \
 226                 retval = -EFAULT;                                       \
 227 } while (0)
 228
 229 #else /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
 230
 231 #define __get_user_asm(x, addr, err, op)                \
 232         __asm__ __volatile__(                           \
 233                 "1:     "op"%U2%X2 %1, %2       # get_user\n"   \
 234                 "2:\n"                                  \
 235                 ".section .fixup,\"ax\"\n"              \
 236                 "3:     li %0,%3\n"                     \
 237                 "       li %1,0\n"                      \
 238                 "       b 2b\n"                         \
 239                 ".previous\n"                           \
 240                 EX_TABLE(1b, 3b)                        \
 241                 : "=r" (err), "=r" (x)                  \
 242                 : "m<>" (*addr), "i" (-EFAULT), "0" (err))
 243
 244 #ifdef __powerpc64__
 245 #define __get_user_asm2(x, addr, err)                   \
 246         __get_user_asm(x, addr, err, "ld")
 247 #else /* __powerpc64__ */
 248 #define __get_user_asm2(x, addr, err)                   \
 249         __asm__ __volatile__(                           \
 250                 "1:     lwz%X2 %1, %2\n"                        \
 251                 "2:     lwz%X2 %L1, %L2\n"              \
 252                 "3:\n"                                  \
 253                 ".section .fixup,\"ax\"\n"              \
 254                 "4:     li %0,%3\n"                     \
 255                 "       li %1,0\n"                      \
 256                 "       li %1+1,0\n"                    \
 257                 "       b 3b\n"                         \
 258                 ".previous\n"                           \
 259                 EX_TABLE(1b, 4b)                        \
 260                 EX_TABLE(2b, 4b)                        \
 261                 : "=r" (err), "=&r" (x)                 \
 262                 : "m" (*addr), "i" (-EFAULT), "0" (err))
 263 #endif /* __powerpc64__ */
 264
 265 #define __get_user_size_allowed(x, ptr, size, retval)           \
 266 do {                                                            \
 267         retval = 0;                                             \
 268         BUILD_BUG_ON(size > sizeof(x));                         \
 269         switch (size) {                                         \
 270         case 1: __get_user_asm(x, (u8 __user *)ptr, retval, "lbz"); break;      \
 271         case 2: __get_user_asm(x, (u16 __user *)ptr, retval, "lhz"); break;     \
 272         case 4: __get_user_asm(x, (u32 __user *)ptr, retval, "lwz"); break;     \
 273         case 8: __get_user_asm2(x, (u64 __user *)ptr, retval);  break;  \
 274         default: x = 0; BUILD_BUG();                            \
 275         }                                                       \
 276 } while (0)
 277
 278 #define __get_user_size_goto(x, ptr, size, label)               \
 279 do {                                                            \
 280         long __gus_retval;                                      \
 281                                                                 \
 282         __get_user_size_allowed(x, ptr, size, __gus_retval);    \
 283         if (__gus_retval)                                       \
 284                 goto label;                                     \
 285 } while (0)
 286
 287 #endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
 288
 289 /*
 290  * This is a type: either unsigned long, if the argument fits into
 291  * that type, or otherwise unsigned long long.
 292  */
 293 #define __long_type(x) \
 294         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 295
 296 #define __get_user(x, ptr)                                      \
 297 ({                                                              \
 298         long __gu_err;                                          \
 299         __long_type(*(ptr)) __gu_val;                           \
 300         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 301         __typeof__(sizeof(*(ptr))) __gu_size = sizeof(*(ptr));  \
 302                                                                 \
 303         might_fault();                                  \
 304         allow_read_from_user(__gu_addr, __gu_size);             \
 305         __get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err);      \
 306         prevent_read_from_user(__gu_addr, __gu_size);           \
 307         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 308                                                                 \
 309         __gu_err;                                               \
 310 })
 311
 312 #define get_user(x, ptr)                                                \
 313 ({                                                                      \
 314         __typeof__(*(ptr)) __user *_gu_addr = (ptr);                    \
 315                                                                         \
 316         access_ok(_gu_addr, sizeof(*(ptr))) ?                           \
 317                   __get_user(x, _gu_addr) :                             \
 318                   ((x) = (__force __typeof__(*(ptr)))0, -EFAULT);       \
 319 })
 320
 321 /* more complex routines */
 322
 323 extern unsigned long __copy_tofrom_user(void __user *to,
 324                 const void __user *from, unsigned long size);
 325
 326 #ifdef __powerpc64__
 327 static inline unsigned long
 328 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 329 {
 330         unsigned long ret;
 331
 332         allow_read_write_user(to, from, n);
 333         ret = __copy_tofrom_user(to, from, n);
 334         prevent_read_write_user(to, from, n);
 335         return ret;
 336 }
 337 #endif /* __powerpc64__ */
 338
 339 static inline unsigned long raw_copy_from_user(void *to,
 340                 const void __user *from, unsigned long n)
 341 {
 342         unsigned long ret;
 343
 344         allow_read_from_user(from, n);
 345         ret = __copy_tofrom_user((__force void __user *)to, from, n);
 346         prevent_read_from_user(from, n);
 347         return ret;
 348 }
 349
 350 static inline unsigned long
 351 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 352 {
 353         unsigned long ret;
 354
 355         allow_write_to_user(to, n);
 356         ret = __copy_tofrom_user(to, (__force const void __user *)from, n);
 357         prevent_write_to_user(to, n);
 358         return ret;
 359 }
 360
 361 unsigned long __arch_clear_user(void __user *addr, unsigned long size);
 362
 363 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 364 {
 365         unsigned long ret;
 366
 367         might_fault();
 368         allow_write_to_user(addr, size);
 369         ret = __arch_clear_user(addr, size);
 370         prevent_write_to_user(addr, size);
 371         return ret;
 372 }
 373
 374 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 375 {
 376         return likely(access_ok(addr, size)) ? __clear_user(addr, size) : size;
 377 }
 378
 379 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 380 extern __must_check long strnlen_user(const char __user *str, long n);
 381
 382 #ifdef CONFIG_ARCH_HAS_COPY_MC
 383 unsigned long __must_check
 384 copy_mc_generic(void *to, const void *from, unsigned long size);
 385
 386 static inline unsigned long __must_check
 387 copy_mc_to_kernel(void *to, const void *from, unsigned long size)
 388 {
 389         return copy_mc_generic(to, from, size);
 390 }
 391 #define copy_mc_to_kernel copy_mc_to_kernel
 392
 393 static inline unsigned long __must_check
 394 copy_mc_to_user(void __user *to, const void *from, unsigned long n)
 395 {
 396         if (check_copy_size(from, n, true)) {
 397                 if (access_ok(to, n)) {
 398                         allow_write_to_user(to, n);
 399                         n = copy_mc_generic((void __force *)to, from, n);
 400                         prevent_write_to_user(to, n);
 401                 }
 402         }
 403
 404         return n;
 405 }
 406 #endif
 407
 408 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 409                 unsigned size);
 410
 411 static __must_check __always_inline bool user_access_begin(const void __user *ptr, size_t len)
 412 {
 413         if (unlikely(!access_ok(ptr, len)))
 414                 return false;
 415
 416         might_fault();
 417
 418         allow_read_write_user((void __user *)ptr, ptr, len);
 419         return true;
 420 }
 421 #define user_access_begin       user_access_begin
 422 #define user_access_end         prevent_current_access_user
 423 #define user_access_save        prevent_user_access_return
 424 #define user_access_restore     restore_user_access
 425
 426 static __must_check __always_inline bool
 427 user_read_access_begin(const void __user *ptr, size_t len)
 428 {
 429         if (unlikely(!access_ok(ptr, len)))
 430                 return false;
 431
 432         might_fault();
 433
 434         allow_read_from_user(ptr, len);
 435         return true;
 436 }
 437 #define user_read_access_begin  user_read_access_begin
 438 #define user_read_access_end            prevent_current_read_from_user
 439
 440 static __must_check __always_inline bool
 441 user_write_access_begin(const void __user *ptr, size_t len)
 442 {
 443         if (unlikely(!access_ok(ptr, len)))
 444                 return false;
 445
 446         might_fault();
 447
 448         allow_write_to_user((void __user *)ptr, len);
 449         return true;
 450 }
 451 #define user_write_access_begin user_write_access_begin
 452 #define user_write_access_end           prevent_current_write_to_user
 453
 454 #define unsafe_get_user(x, p, e) do {                                   \
 455         __long_type(*(p)) __gu_val;                             \
 456         __typeof__(*(p)) __user *__gu_addr = (p);               \
 457                                                                 \
 458         __get_user_size_goto(__gu_val, __gu_addr, sizeof(*(p)), e); \
 459         (x) = (__typeof__(*(p)))__gu_val;                       \
 460 } while (0)
 461
 462 #define unsafe_put_user(x, p, e) \
 463         __put_user_size_goto((__typeof__(*(p)))(x), (p), sizeof(*(p)), e)
 464
 465 #define unsafe_copy_from_user(d, s, l, e) \
 466 do {                                                                                    \
 467         u8 *_dst = (u8 *)(d);                                                           \
 468         const u8 __user *_src = (const u8 __user *)(s);                                 \
 469         size_t _len = (l);                                                              \
 470         int _i;                                                                         \
 471                                                                                         \
 472         for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64))               \
 473                 unsafe_get_user(*(u64 *)(_dst + _i), (u64 __user *)(_src + _i), e);     \
 474         if (_len & 4) {                                                                 \
 475                 unsafe_get_user(*(u32 *)(_dst + _i), (u32 __user *)(_src + _i), e);     \
 476                 _i += 4;                                                                \
 477         }                                                                               \
 478         if (_len & 2) {                                                                 \
 479                 unsafe_get_user(*(u16 *)(_dst + _i), (u16 __user *)(_src + _i), e);     \
 480                 _i += 2;                                                                \
 481         }                                                                               \
 482         if (_len & 1)                                                                   \
 483                 unsafe_get_user(*(u8 *)(_dst + _i), (u8 __user *)(_src + _i), e);       \
 484 } while (0)
 485
 486 #define unsafe_copy_to_user(d, s, l, e) \
 487 do {                                                                    \
 488         u8 __user *_dst = (u8 __user *)(d);                             \
 489         const u8 *_src = (const u8 *)(s);                               \
 490         size_t _len = (l);                                              \
 491         int _i;                                                         \
 492                                                                         \
 493         for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64))       \
 494                 unsafe_put_user(*(u64 *)(_src + _i), (u64 __user *)(_dst + _i), e); \
 495         if (_len & 4) {                                                 \
 496                 unsafe_put_user(*(u32*)(_src + _i), (u32 __user *)(_dst + _i), e); \
 497                 _i += 4;                                                \
 498         }                                                               \
 499         if (_len & 2) {                                                 \
 500                 unsafe_put_user(*(u16*)(_src + _i), (u16 __user *)(_dst + _i), e); \
 501                 _i += 2;                                                \
 502         }                                                               \
 503         if (_len & 1) \
 504                 unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \
 505 } while (0)
 506
 507 #define __get_kernel_nofault(dst, src, type, err_label)                 \
 508         __get_user_size_goto(*((type *)(dst)),                          \
 509                 (__force type __user *)(src), sizeof(type), err_label)
 510
 511 #define __put_kernel_nofault(dst, src, type, err_label)                 \
 512         __put_user_size_goto(*((type *)(src)),                          \
 513                 (__force type __user *)(dst), sizeof(type), err_label)
 514
 515 #endif  /* _ARCH_POWERPC_UACCESS_H */