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/asm-compat.h>
   6 #include <asm/ppc_asm.h>
   7 #include <asm/processor.h>
   8 #include <asm/page.h>
   9 #include <asm/extable.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),                  \
  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)))
  96 #define __put_user(x, ptr) \
  97         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  98
  99 #define __get_user_inatomic(x, ptr) \
 100         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
 101 #define __put_user_inatomic(x, ptr) \
 102         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 103
 104 extern long __put_user_bad(void);
 105
 106 /*
 107  * We don't tell gcc that we are accessing memory, but this is OK
 108  * because we do not write to any memory gcc knows about, so there
 109  * are no aliasing issues.
 110  */
 111 #define __put_user_asm(x, addr, err, op)                        \
 112         __asm__ __volatile__(                                   \
 113                 "1:     " op " %1,0(%2) # put_user\n"           \
 114                 "2:\n"                                          \
 115                 ".section .fixup,\"ax\"\n"                      \
 116                 "3:     li %0,%3\n"                             \
 117                 "       b 2b\n"                                 \
 118                 ".previous\n"                                   \
 119                 EX_TABLE(1b, 3b)                                \
 120                 : "=r" (err)                                    \
 121                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 122
 123 #ifdef __powerpc64__
 124 #define __put_user_asm2(x, ptr, retval)                         \
 125           __put_user_asm(x, ptr, retval, "std")
 126 #else /* __powerpc64__ */
 127 #define __put_user_asm2(x, addr, err)                           \
 128         __asm__ __volatile__(                                   \
 129                 "1:     stw %1,0(%2)\n"                         \
 130                 "2:     stw %1+1,4(%2)\n"                       \
 131                 "3:\n"                                          \
 132                 ".section .fixup,\"ax\"\n"                      \
 133                 "4:     li %0,%3\n"                             \
 134                 "       b 3b\n"                                 \
 135                 ".previous\n"                                   \
 136                 EX_TABLE(1b, 4b)                                \
 137                 EX_TABLE(2b, 4b)                                \
 138                 : "=r" (err)                                    \
 139                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 140 #endif /* __powerpc64__ */
 141
 142 #define __put_user_size(x, ptr, size, retval)                   \
 143 do {                                                            \
 144         retval = 0;                                             \
 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 } while (0)
 153
 154 #define __put_user_nocheck(x, ptr, size)                        \
 155 ({                                                              \
 156         long __pu_err;                                          \
 157         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 158         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 159                 might_fault();                                  \
 160         __chk_user_ptr(ptr);                                    \
 161         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 162         __pu_err;                                               \
 163 })
 164
 165 #define __put_user_check(x, ptr, size)                                  \
 166 ({                                                                      \
 167         long __pu_err = -EFAULT;                                        \
 168         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 169         might_fault();                                                  \
 170         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 171                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 172         __pu_err;                                                       \
 173 })
 174
 175 #define __put_user_nosleep(x, ptr, size)                        \
 176 ({                                                              \
 177         long __pu_err;                                          \
 178         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 179         __chk_user_ptr(ptr);                                    \
 180         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 181         __pu_err;                                               \
 182 })
 183
 184
 185 extern long __get_user_bad(void);
 186
 187 /*
 188  * This does an atomic 128 byte aligned load from userspace.
 189  * Upto caller to do enable_kernel_vmx() before calling!
 190  */
 191 #define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
 192         __asm__ __volatile__(                           \
 193                 "1:     lvx  0,0,%1     # get user\n"   \
 194                 "       stvx 0,0,%2     # put kernel\n" \
 195                 "2:\n"                                  \
 196                 ".section .fixup,\"ax\"\n"              \
 197                 "3:     li %0,%3\n"                     \
 198                 "       b 2b\n"                         \
 199                 ".previous\n"                           \
 200                 EX_TABLE(1b, 3b)                        \
 201                 : "=r" (err)                    \
 202                 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
 203
 204 #define __get_user_asm(x, addr, err, op)                \
 205         __asm__ __volatile__(                           \
 206                 "1:     "op" %1,0(%2)   # get_user\n"   \
 207                 "2:\n"                                  \
 208                 ".section .fixup,\"ax\"\n"              \
 209                 "3:     li %0,%3\n"                     \
 210                 "       li %1,0\n"                      \
 211                 "       b 2b\n"                         \
 212                 ".previous\n"                           \
 213                 EX_TABLE(1b, 3b)                        \
 214                 : "=r" (err), "=r" (x)                  \
 215                 : "b" (addr), "i" (-EFAULT), "0" (err))
 216
 217 #ifdef __powerpc64__
 218 #define __get_user_asm2(x, addr, err)                   \
 219         __get_user_asm(x, addr, err, "ld")
 220 #else /* __powerpc64__ */
 221 #define __get_user_asm2(x, addr, err)                   \
 222         __asm__ __volatile__(                           \
 223                 "1:     lwz %1,0(%2)\n"                 \
 224                 "2:     lwz %1+1,4(%2)\n"               \
 225                 "3:\n"                                  \
 226                 ".section .fixup,\"ax\"\n"              \
 227                 "4:     li %0,%3\n"                     \
 228                 "       li %1,0\n"                      \
 229                 "       li %1+1,0\n"                    \
 230                 "       b 3b\n"                         \
 231                 ".previous\n"                           \
 232                 EX_TABLE(1b, 4b)                        \
 233                 EX_TABLE(2b, 4b)                        \
 234                 : "=r" (err), "=&r" (x)                 \
 235                 : "b" (addr), "i" (-EFAULT), "0" (err))
 236 #endif /* __powerpc64__ */
 237
 238 #define __get_user_size(x, ptr, size, retval)                   \
 239 do {                                                            \
 240         retval = 0;                                             \
 241         __chk_user_ptr(ptr);                                    \
 242         if (size > sizeof(x))                                   \
 243                 (x) = __get_user_bad();                         \
 244         switch (size) {                                         \
 245         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 246         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 247         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 248         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 249         default: (x) = __get_user_bad();                        \
 250         }                                                       \
 251 } while (0)
 252
 253 #define __get_user_nocheck(x, ptr, size)                        \
 254 ({                                                              \
 255         long __gu_err;                                          \
 256         unsigned long __gu_val;                                 \
 257         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 258         __chk_user_ptr(ptr);                                    \
 259         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 260                 might_fault();                                  \
 261         barrier_nospec();                                       \
 262         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 263         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 264         __gu_err;                                               \
 265 })
 266
 267 #define __get_user_check(x, ptr, size)                                  \
 268 ({                                                                      \
 269         long __gu_err = -EFAULT;                                        \
 270         unsigned long  __gu_val = 0;                                    \
 271         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 272         might_fault();                                                  \
 273         if (access_ok(VERIFY_READ, __gu_addr, (size))) {                \
 274                 barrier_nospec();                                       \
 275                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 276         }                                                               \
 277         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 278         __gu_err;                                                       \
 279 })
 280
 281 #define __get_user_nosleep(x, ptr, size)                        \
 282 ({                                                              \
 283         long __gu_err;                                          \
 284         unsigned long __gu_val;                                 \
 285         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 286         __chk_user_ptr(ptr);                                    \
 287         barrier_nospec();                                       \
 288         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 289         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 290         __gu_err;                                               \
 291 })
 292
 293
 294 /* more complex routines */
 295
 296 extern unsigned long __copy_tofrom_user(void __user *to,
 297                 const void __user *from, unsigned long size);
 298
 299 #ifdef __powerpc64__
 300 static inline unsigned long
 301 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 302 {
 303         return __copy_tofrom_user(to, from, n);
 304 }
 305 #endif /* __powerpc64__ */
 306
 307 static inline unsigned long raw_copy_from_user(void *to,
 308                 const void __user *from, unsigned long n)
 309 {
 310         if (__builtin_constant_p(n) && (n <= 8)) {
 311                 unsigned long ret = 1;
 312
 313                 switch (n) {
 314                 case 1:
 315                         barrier_nospec();
 316                         __get_user_size(*(u8 *)to, from, 1, ret);
 317                         break;
 318                 case 2:
 319                         barrier_nospec();
 320                         __get_user_size(*(u16 *)to, from, 2, ret);
 321                         break;
 322                 case 4:
 323                         barrier_nospec();
 324                         __get_user_size(*(u32 *)to, from, 4, ret);
 325                         break;
 326                 case 8:
 327                         barrier_nospec();
 328                         __get_user_size(*(u64 *)to, from, 8, ret);
 329                         break;
 330                 }
 331                 if (ret == 0)
 332                         return 0;
 333         }
 334
 335         barrier_nospec();
 336         return __copy_tofrom_user((__force void __user *)to, from, n);
 337 }
 338
 339 static inline unsigned long raw_copy_to_user(void __user *to,
 340                 const void *from, unsigned long n)
 341 {
 342         if (__builtin_constant_p(n) && (n <= 8)) {
 343                 unsigned long ret = 1;
 344
 345                 switch (n) {
 346                 case 1:
 347                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 348                         break;
 349                 case 2:
 350                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 351                         break;
 352                 case 4:
 353                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 354                         break;
 355                 case 8:
 356                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 357                         break;
 358                 }
 359                 if (ret == 0)
 360                         return 0;
 361         }
 362
 363         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 364 }
 365
 366 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 367
 368 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 369 {
 370         might_fault();
 371         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 372                 return __clear_user(addr, size);
 373         return size;
 374 }
 375
 376 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 377 extern __must_check long strnlen_user(const char __user *str, long n);
 378
 379 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 380                 unsigned size);
 381 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
 382                            size_t len);
 383
 384 #endif  /* _ARCH_POWERPC_UACCESS_H */