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