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 /*
  12  * The fs value determines whether argument validity checking should be
  13  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  14  * get_fs() == KERNEL_DS, checking is bypassed.
  15  *
  16  * For historical reasons, these macros are grossly misnamed.
  17  *
  18  * The fs/ds values are now the highest legal address in the "segment".
  19  * This simplifies the checking in the routines below.
  20  */
  21
  22 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  23
  24 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
  25 #ifdef __powerpc64__
  26 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  27 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
  28 #else
  29 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  30 #endif
  31
  32 #define get_ds()        (KERNEL_DS)
  33 #define get_fs()        (current->thread.addr_limit)
  34
  35 static inline void set_fs(mm_segment_t fs)
  36 {
  37         current->thread.addr_limit = fs;
  38         /* On user-mode return check addr_limit (fs) is correct */
  39         set_thread_flag(TIF_FSCHECK);
  40 }
  41
  42 #define segment_eq(a, b)        ((a).seg == (b).seg)
  43
  44 #define user_addr_max() (get_fs().seg)
  45
  46 #ifdef __powerpc64__
  47 /*
  48  * This check is sufficient because there is a large enough
  49  * gap between user addresses and the kernel addresses
  50  */
  51 #define __access_ok(addr, size, segment)        \
  52         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  53
  54 #else
  55
  56 static inline int __access_ok(unsigned long addr, unsigned long size,
  57                         mm_segment_t seg)
  58 {
  59         if (addr > seg.seg)
  60                 return 0;
  61         return (size == 0 || size - 1 <= seg.seg - addr);
  62 }
  63
  64 #endif
  65
  66 #define access_ok(type, addr, size)             \
  67         (__chk_user_ptr(addr), (void)(type),            \
  68          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  69
  70 /*
  71  * These are the main single-value transfer routines.  They automatically
  72  * use the right size if we just have the right pointer type.
  73  *
  74  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  75  * and yet we don't want to do any pointers, because that is too much
  76  * of a performance impact. Thus we have a few rather ugly macros here,
  77  * and hide all the ugliness from the user.
  78  *
  79  * The "__xxx" versions of the user access functions are versions that
  80  * do not verify the address space, that must have been done previously
  81  * with a separate "access_ok()" call (this is used when we do multiple
  82  * accesses to the same area of user memory).
  83  *
  84  * As we use the same address space for kernel and user data on the
  85  * PowerPC, we can just do these as direct assignments.  (Of course, the
  86  * exception handling means that it's no longer "just"...)
  87  *
  88  */
  89 #define get_user(x, ptr) \
  90         __get_user_check((x), (ptr), sizeof(*(ptr)))
  91 #define put_user(x, ptr) \
  92         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  93
  94 #define __get_user(x, ptr) \
  95         __get_user_nocheck((x), (ptr), sizeof(*(ptr)), true)
  96 #define __put_user(x, ptr) \
  97         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)), true)
  98
  99 #define __get_user_allowed(x, ptr) \
 100         __get_user_nocheck((x), (ptr), sizeof(*(ptr)), false)
 101 #define __put_user_allowed(x, ptr) \
 102         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)), false)
 103
 104 #define __get_user_inatomic(x, ptr) \
 105         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
 106 #define __put_user_inatomic(x, ptr) \
 107         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 108
 109 extern long __put_user_bad(void);
 110
 111 /*
 112  * We don't tell gcc that we are accessing memory, but this is OK
 113  * because we do not write to any memory gcc knows about, so there
 114  * are no aliasing issues.
 115  */
 116 #define __put_user_asm(x, addr, err, op)                        \
 117         __asm__ __volatile__(                                   \
 118                 "1:     " op " %1,0(%2) # put_user\n"           \
 119                 "2:\n"                                          \
 120                 ".section .fixup,\"ax\"\n"                      \
 121                 "3:     li %0,%3\n"                             \
 122                 "       b 2b\n"                                 \
 123                 ".previous\n"                                   \
 124                 EX_TABLE(1b, 3b)                                \
 125                 : "=r" (err)                                    \
 126                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 127
 128 #ifdef __powerpc64__
 129 #define __put_user_asm2(x, ptr, retval)                         \
 130           __put_user_asm(x, ptr, retval, "std")
 131 #else /* __powerpc64__ */
 132 #define __put_user_asm2(x, addr, err)                           \
 133         __asm__ __volatile__(                                   \
 134                 "1:     stw %1,0(%2)\n"                         \
 135                 "2:     stw %1+1,4(%2)\n"                       \
 136                 "3:\n"                                          \
 137                 ".section .fixup,\"ax\"\n"                      \
 138                 "4:     li %0,%3\n"                             \
 139                 "       b 3b\n"                                 \
 140                 ".previous\n"                                   \
 141                 EX_TABLE(1b, 4b)                                \
 142                 EX_TABLE(2b, 4b)                                \
 143                 : "=r" (err)                                    \
 144                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 145 #endif /* __powerpc64__ */
 146
 147 #define __put_user_size_allowed(x, ptr, size, retval)           \
 148 do {                                                            \
 149         retval = 0;                                             \
 150         switch (size) {                                         \
 151           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 152           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 153           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 154           case 8: __put_user_asm2(x, ptr, retval); break;       \
 155           default: __put_user_bad();                            \
 156         }                                                       \
 157 } while (0)
 158
 159 #define __put_user_size(x, ptr, size, retval)                   \
 160 do {                                                            \
 161         allow_write_to_user(ptr, size);                         \
 162         __put_user_size_allowed(x, ptr, size, retval);          \
 163         prevent_write_to_user(ptr, size);                       \
 164 } while (0)
 165
 166 #define __put_user_nocheck(x, ptr, size, do_allow)                      \
 167 ({                                                              \
 168         long __pu_err;                                          \
 169         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 170         __typeof__(*(ptr)) __pu_val = (x);                      \
 171         __typeof__(size) __pu_size = (size);                    \
 172                                                                 \
 173         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 174                 might_fault();                                  \
 175         __chk_user_ptr(__pu_addr);                              \
 176         if (do_allow)                                                           \
 177                 __put_user_size(__pu_val, __pu_addr, __pu_size, __pu_err);      \
 178         else                                                                    \
 179                 __put_user_size_allowed(__pu_val, __pu_addr, __pu_size, __pu_err); \
 180                                                                 \
 181         __pu_err;                                               \
 182 })
 183
 184 #define __put_user_check(x, ptr, size)                                  \
 185 ({                                                                      \
 186         long __pu_err = -EFAULT;                                        \
 187         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 188         __typeof__(*(ptr)) __pu_val = (x);                              \
 189         __typeof__(size) __pu_size = (size);                            \
 190                                                                         \
 191         might_fault();                                                  \
 192         if (access_ok(VERIFY_WRITE, __pu_addr, __pu_size))                      \
 193                 __put_user_size(__pu_val, __pu_addr, __pu_size, __pu_err); \
 194                                                                         \
 195         __pu_err;                                                       \
 196 })
 197
 198 #define __put_user_nosleep(x, ptr, size)                        \
 199 ({                                                              \
 200         long __pu_err;                                          \
 201         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 202         __typeof__(*(ptr)) __pu_val = (x);                      \
 203         __typeof__(size) __pu_size = (size);                    \
 204                                                                 \
 205         __chk_user_ptr(__pu_addr);                              \
 206         __put_user_size(__pu_val, __pu_addr, __pu_size, __pu_err); \
 207                                                                 \
 208         __pu_err;                                               \
 209 })
 210
 211
 212 extern long __get_user_bad(void);
 213
 214 /*
 215  * This does an atomic 128 byte aligned load from userspace.
 216  * Upto caller to do enable_kernel_vmx() before calling!
 217  */
 218 #define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
 219         __asm__ __volatile__(                           \
 220                 ".machine push\n"                       \
 221                 ".machine altivec\n"                    \
 222                 "1:     lvx  0,0,%1     # get user\n"   \
 223                 "       stvx 0,0,%2     # put kernel\n" \
 224                 ".machine pop\n"                        \
 225                 "2:\n"                                  \
 226                 ".section .fixup,\"ax\"\n"              \
 227                 "3:     li %0,%3\n"                     \
 228                 "       b 2b\n"                         \
 229                 ".previous\n"                           \
 230                 EX_TABLE(1b, 3b)                        \
 231                 : "=r" (err)                    \
 232                 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
 233
 234 #define __get_user_asm(x, addr, err, op)                \
 235         __asm__ __volatile__(                           \
 236                 "1:     "op" %1,0(%2)   # get_user\n"   \
 237                 "2:\n"                                  \
 238                 ".section .fixup,\"ax\"\n"              \
 239                 "3:     li %0,%3\n"                     \
 240                 "       li %1,0\n"                      \
 241                 "       b 2b\n"                         \
 242                 ".previous\n"                           \
 243                 EX_TABLE(1b, 3b)                        \
 244                 : "=r" (err), "=r" (x)                  \
 245                 : "b" (addr), "i" (-EFAULT), "0" (err))
 246
 247 #ifdef __powerpc64__
 248 #define __get_user_asm2(x, addr, err)                   \
 249         __get_user_asm(x, addr, err, "ld")
 250 #else /* __powerpc64__ */
 251 #define __get_user_asm2(x, addr, err)                   \
 252         __asm__ __volatile__(                           \
 253                 "1:     lwz %1,0(%2)\n"                 \
 254                 "2:     lwz %1+1,4(%2)\n"               \
 255                 "3:\n"                                  \
 256                 ".section .fixup,\"ax\"\n"              \
 257                 "4:     li %0,%3\n"                     \
 258                 "       li %1,0\n"                      \
 259                 "       li %1+1,0\n"                    \
 260                 "       b 3b\n"                         \
 261                 ".previous\n"                           \
 262                 EX_TABLE(1b, 4b)                        \
 263                 EX_TABLE(2b, 4b)                        \
 264                 : "=r" (err), "=&r" (x)                 \
 265                 : "b" (addr), "i" (-EFAULT), "0" (err))
 266 #endif /* __powerpc64__ */
 267
 268 #define __get_user_size_allowed(x, ptr, size, retval)           \
 269 do {                                                            \
 270         retval = 0;                                             \
 271         __chk_user_ptr(ptr);                                    \
 272         if (size > sizeof(x))                                   \
 273                 (x) = __get_user_bad();                         \
 274         switch (size) {                                         \
 275         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 276         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 277         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 278         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 279         default: (x) = __get_user_bad();                        \
 280         }                                                       \
 281 } while (0)
 282
 283 #define __get_user_size(x, ptr, size, retval)                   \
 284 do {                                                            \
 285         allow_read_from_user(ptr, size);                        \
 286         __get_user_size_allowed(x, ptr, size, retval);          \
 287         prevent_read_from_user(ptr, size);                      \
 288 } while (0)
 289
 290 /*
 291  * This is a type: either unsigned long, if the argument fits into
 292  * that type, or otherwise unsigned long long.
 293  */
 294 #define __long_type(x) \
 295         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 296
 297 #define __get_user_nocheck(x, ptr, size, do_allow)                      \
 298 ({                                                              \
 299         long __gu_err;                                          \
 300         __long_type(*(ptr)) __gu_val;                           \
 301         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 302         __typeof__(size) __gu_size = (size);                    \
 303                                                                 \
 304         __chk_user_ptr(__gu_addr);                              \
 305         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 306                 might_fault();                                  \
 307         barrier_nospec();                                       \
 308         if (do_allow)                                                           \
 309                 __get_user_size(__gu_val, __gu_addr, __gu_size, __gu_err);      \
 310         else                                                                    \
 311                 __get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err); \
 312         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 313                                                                 \
 314         __gu_err;                                               \
 315 })
 316
 317 #define __get_user_check(x, ptr, size)                                  \
 318 ({                                                                      \
 319         long __gu_err = -EFAULT;                                        \
 320         __long_type(*(ptr)) __gu_val = 0;                               \
 321         __typeof__(*(ptr)) __user *__gu_addr = (ptr);           \
 322         __typeof__(size) __gu_size = (size);                            \
 323                                                                         \
 324         might_fault();                                                  \
 325         if (access_ok(VERIFY_READ, __gu_addr, __gu_size)) {             \
 326                 barrier_nospec();                                       \
 327                 __get_user_size(__gu_val, __gu_addr, __gu_size, __gu_err); \
 328         }                                                               \
 329         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 330                                                                         \
 331         __gu_err;                                                       \
 332 })
 333
 334 #define __get_user_nosleep(x, ptr, size)                        \
 335 ({                                                              \
 336         long __gu_err;                                          \
 337         __long_type(*(ptr)) __gu_val;                           \
 338         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 339         __typeof__(size) __gu_size = (size);                    \
 340                                                                 \
 341         __chk_user_ptr(__gu_addr);                              \
 342         barrier_nospec();                                       \
 343         __get_user_size(__gu_val, __gu_addr, __gu_size, __gu_err); \
 344         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 345                                                                 \
 346         __gu_err;                                               \
 347 })
 348
 349
 350 /* more complex routines */
 351
 352 extern unsigned long __copy_tofrom_user(void __user *to,
 353                 const void __user *from, unsigned long size);
 354
 355 #ifdef __powerpc64__
 356 static inline unsigned long
 357 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 358 {
 359         unsigned long ret;
 360
 361         barrier_nospec();
 362         allow_user_access(to, from, n);
 363         ret = __copy_tofrom_user(to, from, n);
 364         prevent_user_access(to, from, n);
 365         return ret;
 366 }
 367 #endif /* __powerpc64__ */
 368
 369 static inline unsigned long raw_copy_from_user(void *to,
 370                 const void __user *from, unsigned long n)
 371 {
 372         unsigned long ret;
 373         if (__builtin_constant_p(n) && (n <= 8)) {
 374                 ret = 1;
 375
 376                 switch (n) {
 377                 case 1:
 378                         barrier_nospec();
 379                         __get_user_size(*(u8 *)to, from, 1, ret);
 380                         break;
 381                 case 2:
 382                         barrier_nospec();
 383                         __get_user_size(*(u16 *)to, from, 2, ret);
 384                         break;
 385                 case 4:
 386                         barrier_nospec();
 387                         __get_user_size(*(u32 *)to, from, 4, ret);
 388                         break;
 389                 case 8:
 390                         barrier_nospec();
 391                         __get_user_size(*(u64 *)to, from, 8, ret);
 392                         break;
 393                 }
 394                 if (ret == 0)
 395                         return 0;
 396         }
 397
 398         barrier_nospec();
 399         allow_read_from_user(from, n);
 400         ret = __copy_tofrom_user((__force void __user *)to, from, n);
 401         prevent_read_from_user(from, n);
 402         return ret;
 403 }
 404
 405 static inline unsigned long
 406 raw_copy_to_user_allowed(void __user *to, const void *from, unsigned long n)
 407 {
 408         if (__builtin_constant_p(n) && (n <= 8)) {
 409                 unsigned long ret = 1;
 410
 411                 switch (n) {
 412                 case 1:
 413                         __put_user_size_allowed(*(u8 *)from, (u8 __user *)to, 1, ret);
 414                         break;
 415                 case 2:
 416                         __put_user_size_allowed(*(u16 *)from, (u16 __user *)to, 2, ret);
 417                         break;
 418                 case 4:
 419                         __put_user_size_allowed(*(u32 *)from, (u32 __user *)to, 4, ret);
 420                         break;
 421                 case 8:
 422                         __put_user_size_allowed(*(u64 *)from, (u64 __user *)to, 8, ret);
 423                         break;
 424                 }
 425                 if (ret == 0)
 426                         return 0;
 427         }
 428
 429         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 430 }
 431
 432 static inline unsigned long
 433 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 434 {
 435         unsigned long ret;
 436
 437         allow_write_to_user(to, n);
 438         ret = raw_copy_to_user_allowed(to, from, n);
 439         prevent_write_to_user(to, n);
 440         return ret;
 441 }
 442
 443 unsigned long __arch_clear_user(void __user *addr, unsigned long size);
 444
 445 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 446 {
 447         unsigned long ret = size;
 448         might_fault();
 449         if (likely(access_ok(VERIFY_WRITE, addr, size))) {
 450                 allow_write_to_user(addr, size);
 451                 ret = __arch_clear_user(addr, size);
 452                 prevent_write_to_user(addr, size);
 453         }
 454         return ret;
 455 }
 456
 457 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 458 {
 459         return clear_user(addr, size);
 460 }
 461
 462 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 463 extern __must_check long strnlen_user(const char __user *str, long n);
 464
 465 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 466                 unsigned size);
 467 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
 468                            size_t len);
 469
 470 #define user_access_begin(type, ptr, len) access_ok(type, ptr, len)
 471 #define user_access_end()                 prevent_user_access(NULL, NULL, ~0ul)
 472
 473 #define unsafe_op_wrap(op, err) do { if (unlikely(op)) goto err; } while (0)
 474 #define unsafe_get_user(x, p, e) unsafe_op_wrap(__get_user_allowed(x, p), e)
 475 #define unsafe_put_user(x, p, e) unsafe_op_wrap(__put_user_allowed(x, p), e)
 476 #define unsafe_copy_to_user(d, s, l, e) \
 477         unsafe_op_wrap(raw_copy_to_user_allowed(d, s, l), e)
 478
 479 #endif  /* _ARCH_POWERPC_UACCESS_H */