arch/powerpc/include/asm/uaccess.h

   1 #ifndef _ARCH_POWERPC_UACCESS_H
   2 #define _ARCH_POWERPC_UACCESS_H
   3
   4 #include <asm/asm-compat.h>
   5 #include <asm/ppc_asm.h>
   6 #include <asm/processor.h>
   7 #include <asm/page.h>
   8 #include <asm/extable.h>
   9
  10 /*
  11  * The fs value determines whether argument validity checking should be
  12  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  13  * get_fs() == KERNEL_DS, checking is bypassed.
  14  *
  15  * For historical reasons, these macros are grossly misnamed.
  16  *
  17  * The fs/ds values are now the highest legal address in the "segment".
  18  * This simplifies the checking in the routines below.
  19  */
  20
  21 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  22
  23 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
  24 #ifdef __powerpc64__
  25 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  26 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
  27 #else
  28 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  29 #endif
  30
  31 #define get_ds()        (KERNEL_DS)
  32 #define get_fs()        (current->thread.fs)
  33 #define set_fs(val)     (current->thread.fs = (val))
  34
  35 #define segment_eq(a, b)        ((a).seg == (b).seg)
  36
  37 #define user_addr_max() (get_fs().seg)
  38
  39 #ifdef __powerpc64__
  40 /*
  41  * This check is sufficient because there is a large enough
  42  * gap between user addresses and the kernel addresses
  43  */
  44 #define __access_ok(addr, size, segment)        \
  45         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  46
  47 #else
  48
  49 #define __access_ok(addr, size, segment)        \
  50         (((addr) <= (segment).seg) &&           \
  51          (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
  52
  53 #endif
  54
  55 #define access_ok(type, addr, size)             \
  56         (__chk_user_ptr(addr),                  \
  57          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  58
  59 /*
  60  * These are the main single-value transfer routines.  They automatically
  61  * use the right size if we just have the right pointer type.
  62  *
  63  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  64  * and yet we don't want to do any pointers, because that is too much
  65  * of a performance impact. Thus we have a few rather ugly macros here,
  66  * and hide all the ugliness from the user.
  67  *
  68  * The "__xxx" versions of the user access functions are versions that
  69  * do not verify the address space, that must have been done previously
  70  * with a separate "access_ok()" call (this is used when we do multiple
  71  * accesses to the same area of user memory).
  72  *
  73  * As we use the same address space for kernel and user data on the
  74  * PowerPC, we can just do these as direct assignments.  (Of course, the
  75  * exception handling means that it's no longer "just"...)
  76  *
  77  */
  78 #define get_user(x, ptr) \
  79         __get_user_check((x), (ptr), sizeof(*(ptr)))
  80 #define put_user(x, ptr) \
  81         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  82
  83 #define __get_user(x, ptr) \
  84         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  85 #define __put_user(x, ptr) \
  86         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  87
  88 #define __get_user_inatomic(x, ptr) \
  89         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
  90 #define __put_user_inatomic(x, ptr) \
  91         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  92
  93 #define __get_user_unaligned __get_user
  94 #define __put_user_unaligned __put_user
  95
  96 extern long __put_user_bad(void);
  97
  98 /*
  99  * We don't tell gcc that we are accessing memory, but this is OK
 100  * because we do not write to any memory gcc knows about, so there
 101  * are no aliasing issues.
 102  */
 103 #define __put_user_asm(x, addr, err, op)                        \
 104         __asm__ __volatile__(                                   \
 105                 "1:     " op " %1,0(%2) # put_user\n"           \
 106                 "2:\n"                                          \
 107                 ".section .fixup,\"ax\"\n"                      \
 108                 "3:     li %0,%3\n"                             \
 109                 "       b 2b\n"                                 \
 110                 ".previous\n"                                   \
 111                 EX_TABLE(1b, 3b)                                \
 112                 : "=r" (err)                                    \
 113                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 114
 115 #ifdef __powerpc64__
 116 #define __put_user_asm2(x, ptr, retval)                         \
 117           __put_user_asm(x, ptr, retval, "std")
 118 #else /* __powerpc64__ */
 119 #define __put_user_asm2(x, addr, err)                           \
 120         __asm__ __volatile__(                                   \
 121                 "1:     stw %1,0(%2)\n"                         \
 122                 "2:     stw %1+1,4(%2)\n"                       \
 123                 "3:\n"                                          \
 124                 ".section .fixup,\"ax\"\n"                      \
 125                 "4:     li %0,%3\n"                             \
 126                 "       b 3b\n"                                 \
 127                 ".previous\n"                                   \
 128                 EX_TABLE(1b, 4b)                                \
 129                 EX_TABLE(2b, 4b)                                \
 130                 : "=r" (err)                                    \
 131                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 132 #endif /* __powerpc64__ */
 133
 134 #define __put_user_size(x, ptr, size, retval)                   \
 135 do {                                                            \
 136         retval = 0;                                             \
 137         switch (size) {                                         \
 138           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 139           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 140           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 141           case 8: __put_user_asm2(x, ptr, retval); break;       \
 142           default: __put_user_bad();                            \
 143         }                                                       \
 144 } while (0)
 145
 146 #define __put_user_nocheck(x, ptr, size)                        \
 147 ({                                                              \
 148         long __pu_err;                                          \
 149         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 150         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 151                 might_fault();                                  \
 152         __chk_user_ptr(ptr);                                    \
 153         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 154         __pu_err;                                               \
 155 })
 156
 157 #define __put_user_check(x, ptr, size)                                  \
 158 ({                                                                      \
 159         long __pu_err = -EFAULT;                                        \
 160         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 161         might_fault();                                                  \
 162         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 163                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 164         __pu_err;                                                       \
 165 })
 166
 167 #define __put_user_nosleep(x, ptr, size)                        \
 168 ({                                                              \
 169         long __pu_err;                                          \
 170         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 171         __chk_user_ptr(ptr);                                    \
 172         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 173         __pu_err;                                               \
 174 })
 175
 176
 177 extern long __get_user_bad(void);
 178
 179 #define __get_user_asm(x, addr, err, op)                \
 180         __asm__ __volatile__(                           \
 181                 "1:     "op" %1,0(%2)   # get_user\n"   \
 182                 "2:\n"                                  \
 183                 ".section .fixup,\"ax\"\n"              \
 184                 "3:     li %0,%3\n"                     \
 185                 "       li %1,0\n"                      \
 186                 "       b 2b\n"                         \
 187                 ".previous\n"                           \
 188                 EX_TABLE(1b, 3b)                        \
 189                 : "=r" (err), "=r" (x)                  \
 190                 : "b" (addr), "i" (-EFAULT), "0" (err))
 191
 192 #ifdef __powerpc64__
 193 #define __get_user_asm2(x, addr, err)                   \
 194         __get_user_asm(x, addr, err, "ld")
 195 #else /* __powerpc64__ */
 196 #define __get_user_asm2(x, addr, err)                   \
 197         __asm__ __volatile__(                           \
 198                 "1:     lwz %1,0(%2)\n"                 \
 199                 "2:     lwz %1+1,4(%2)\n"               \
 200                 "3:\n"                                  \
 201                 ".section .fixup,\"ax\"\n"              \
 202                 "4:     li %0,%3\n"                     \
 203                 "       li %1,0\n"                      \
 204                 "       li %1+1,0\n"                    \
 205                 "       b 3b\n"                         \
 206                 ".previous\n"                           \
 207                 EX_TABLE(1b, 4b)                        \
 208                 EX_TABLE(2b, 4b)                        \
 209                 : "=r" (err), "=&r" (x)                 \
 210                 : "b" (addr), "i" (-EFAULT), "0" (err))
 211 #endif /* __powerpc64__ */
 212
 213 #define __get_user_size(x, ptr, size, retval)                   \
 214 do {                                                            \
 215         retval = 0;                                             \
 216         __chk_user_ptr(ptr);                                    \
 217         if (size > sizeof(x))                                   \
 218                 (x) = __get_user_bad();                         \
 219         switch (size) {                                         \
 220         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 221         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 222         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 223         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 224         default: (x) = __get_user_bad();                        \
 225         }                                                       \
 226 } while (0)
 227
 228 #define __get_user_nocheck(x, ptr, size)                        \
 229 ({                                                              \
 230         long __gu_err;                                          \
 231         unsigned long __gu_val;                                 \
 232         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 233         __chk_user_ptr(ptr);                                    \
 234         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 235                 might_fault();                                  \
 236         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 237         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 238         __gu_err;                                               \
 239 })
 240
 241 #define __get_user_check(x, ptr, size)                                  \
 242 ({                                                                      \
 243         long __gu_err = -EFAULT;                                        \
 244         unsigned long  __gu_val = 0;                                    \
 245         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 246         might_fault();                                                  \
 247         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 248                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 249         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 250         __gu_err;                                                       \
 251 })
 252
 253 #define __get_user_nosleep(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         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 260         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 261         __gu_err;                                               \
 262 })
 263
 264
 265 /* more complex routines */
 266
 267 extern unsigned long __copy_tofrom_user(void __user *to,
 268                 const void __user *from, unsigned long size);
 269
 270 #ifndef __powerpc64__
 271
 272 #define INLINE_COPY_FROM_USER
 273 #define INLINE_COPY_TO_USER
 274
 275 #else /* __powerpc64__ */
 276
 277 static inline unsigned long
 278 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 279 {
 280         return __copy_tofrom_user(to, from, n);
 281 }
 282 #endif /* __powerpc64__ */
 283
 284 static inline unsigned long raw_copy_from_user(void *to,
 285                 const void __user *from, unsigned long n)
 286 {
 287         if (__builtin_constant_p(n) && (n <= 8)) {
 288                 unsigned long ret = 1;
 289
 290                 switch (n) {
 291                 case 1:
 292                         __get_user_size(*(u8 *)to, from, 1, ret);
 293                         break;
 294                 case 2:
 295                         __get_user_size(*(u16 *)to, from, 2, ret);
 296                         break;
 297                 case 4:
 298                         __get_user_size(*(u32 *)to, from, 4, ret);
 299                         break;
 300                 case 8:
 301                         __get_user_size(*(u64 *)to, from, 8, ret);
 302                         break;
 303                 }
 304                 if (ret == 0)
 305                         return 0;
 306         }
 307
 308         return __copy_tofrom_user((__force void __user *)to, from, n);
 309 }
 310
 311 static inline unsigned long raw_copy_to_user(void __user *to,
 312                 const void *from, unsigned long n)
 313 {
 314         if (__builtin_constant_p(n) && (n <= 8)) {
 315                 unsigned long ret = 1;
 316
 317                 switch (n) {
 318                 case 1:
 319                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 320                         break;
 321                 case 2:
 322                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 323                         break;
 324                 case 4:
 325                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 326                         break;
 327                 case 8:
 328                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 329                         break;
 330                 }
 331                 if (ret == 0)
 332                         return 0;
 333         }
 334
 335         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 336 }
 337
 338 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 339
 340 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 341 {
 342         might_fault();
 343         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 344                 return __clear_user(addr, size);
 345         return size;
 346 }
 347
 348 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 349 extern __must_check long strlen_user(const char __user *str);
 350 extern __must_check long strnlen_user(const char __user *str, long n);
 351
 352 #endif  /* _ARCH_POWERPC_UACCESS_H */