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