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