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 extern long __put_user_bad(void);
  94
  95 /*
  96  * We don't tell gcc that we are accessing memory, but this is OK
  97  * because we do not write to any memory gcc knows about, so there
  98  * are no aliasing issues.
  99  */
 100 #define __put_user_asm(x, addr, err, op)                        \
 101         __asm__ __volatile__(                                   \
 102                 "1:     " op " %1,0(%2) # put_user\n"           \
 103                 "2:\n"                                          \
 104                 ".section .fixup,\"ax\"\n"                      \
 105                 "3:     li %0,%3\n"                             \
 106                 "       b 2b\n"                                 \
 107                 ".previous\n"                                   \
 108                 EX_TABLE(1b, 3b)                                \
 109                 : "=r" (err)                                    \
 110                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 111
 112 #ifdef __powerpc64__
 113 #define __put_user_asm2(x, ptr, retval)                         \
 114           __put_user_asm(x, ptr, retval, "std")
 115 #else /* __powerpc64__ */
 116 #define __put_user_asm2(x, addr, err)                           \
 117         __asm__ __volatile__(                                   \
 118                 "1:     stw %1,0(%2)\n"                         \
 119                 "2:     stw %1+1,4(%2)\n"                       \
 120                 "3:\n"                                          \
 121                 ".section .fixup,\"ax\"\n"                      \
 122                 "4:     li %0,%3\n"                             \
 123                 "       b 3b\n"                                 \
 124                 ".previous\n"                                   \
 125                 EX_TABLE(1b, 4b)                                \
 126                 EX_TABLE(2b, 4b)                                \
 127                 : "=r" (err)                                    \
 128                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 129 #endif /* __powerpc64__ */
 130
 131 #define __put_user_size(x, ptr, size, retval)                   \
 132 do {                                                            \
 133         retval = 0;                                             \
 134         switch (size) {                                         \
 135           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 136           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 137           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 138           case 8: __put_user_asm2(x, ptr, retval); break;       \
 139           default: __put_user_bad();                            \
 140         }                                                       \
 141 } while (0)
 142
 143 #define __put_user_nocheck(x, ptr, size)                        \
 144 ({                                                              \
 145         long __pu_err;                                          \
 146         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 147         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 148                 might_fault();                                  \
 149         __chk_user_ptr(ptr);                                    \
 150         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 151         __pu_err;                                               \
 152 })
 153
 154 #define __put_user_check(x, ptr, size)                                  \
 155 ({                                                                      \
 156         long __pu_err = -EFAULT;                                        \
 157         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 158         might_fault();                                                  \
 159         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 160                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 161         __pu_err;                                                       \
 162 })
 163
 164 #define __put_user_nosleep(x, ptr, size)                        \
 165 ({                                                              \
 166         long __pu_err;                                          \
 167         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 168         __chk_user_ptr(ptr);                                    \
 169         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 170         __pu_err;                                               \
 171 })
 172
 173
 174 extern long __get_user_bad(void);
 175
 176 #define __get_user_asm(x, addr, err, op)                \
 177         __asm__ __volatile__(                           \
 178                 "1:     "op" %1,0(%2)   # get_user\n"   \
 179                 "2:\n"                                  \
 180                 ".section .fixup,\"ax\"\n"              \
 181                 "3:     li %0,%3\n"                     \
 182                 "       li %1,0\n"                      \
 183                 "       b 2b\n"                         \
 184                 ".previous\n"                           \
 185                 EX_TABLE(1b, 3b)                        \
 186                 : "=r" (err), "=r" (x)                  \
 187                 : "b" (addr), "i" (-EFAULT), "0" (err))
 188
 189 #ifdef __powerpc64__
 190 #define __get_user_asm2(x, addr, err)                   \
 191         __get_user_asm(x, addr, err, "ld")
 192 #else /* __powerpc64__ */
 193 #define __get_user_asm2(x, addr, err)                   \
 194         __asm__ __volatile__(                           \
 195                 "1:     lwz %1,0(%2)\n"                 \
 196                 "2:     lwz %1+1,4(%2)\n"               \
 197                 "3:\n"                                  \
 198                 ".section .fixup,\"ax\"\n"              \
 199                 "4:     li %0,%3\n"                     \
 200                 "       li %1,0\n"                      \
 201                 "       li %1+1,0\n"                    \
 202                 "       b 3b\n"                         \
 203                 ".previous\n"                           \
 204                 EX_TABLE(1b, 4b)                        \
 205                 EX_TABLE(2b, 4b)                        \
 206                 : "=r" (err), "=&r" (x)                 \
 207                 : "b" (addr), "i" (-EFAULT), "0" (err))
 208 #endif /* __powerpc64__ */
 209
 210 #define __get_user_size(x, ptr, size, retval)                   \
 211 do {                                                            \
 212         retval = 0;                                             \
 213         __chk_user_ptr(ptr);                                    \
 214         if (size > sizeof(x))                                   \
 215                 (x) = __get_user_bad();                         \
 216         switch (size) {                                         \
 217         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 218         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 219         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 220         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 221         default: (x) = __get_user_bad();                        \
 222         }                                                       \
 223 } while (0)
 224
 225 #define __get_user_nocheck(x, ptr, size)                        \
 226 ({                                                              \
 227         long __gu_err;                                          \
 228         unsigned long __gu_val;                                 \
 229         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 230         __chk_user_ptr(ptr);                                    \
 231         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 232                 might_fault();                                  \
 233         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 234         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 235         __gu_err;                                               \
 236 })
 237
 238 #define __get_user_check(x, ptr, size)                                  \
 239 ({                                                                      \
 240         long __gu_err = -EFAULT;                                        \
 241         unsigned long  __gu_val = 0;                                    \
 242         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 243         might_fault();                                                  \
 244         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 245                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 246         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 247         __gu_err;                                                       \
 248 })
 249
 250 #define __get_user_nosleep(x, ptr, size)                        \
 251 ({                                                              \
 252         long __gu_err;                                          \
 253         unsigned long __gu_val;                                 \
 254         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 255         __chk_user_ptr(ptr);                                    \
 256         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 257         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 258         __gu_err;                                               \
 259 })
 260
 261
 262 /* more complex routines */
 263
 264 extern unsigned long __copy_tofrom_user(void __user *to,
 265                 const void __user *from, unsigned long size);
 266
 267 #ifdef __powerpc64__
 268 static inline unsigned long
 269 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 270 {
 271         return __copy_tofrom_user(to, from, n);
 272 }
 273 #endif /* __powerpc64__ */
 274
 275 static inline unsigned long raw_copy_from_user(void *to,
 276                 const void __user *from, unsigned long n)
 277 {
 278         if (__builtin_constant_p(n) && (n <= 8)) {
 279                 unsigned long ret = 1;
 280
 281                 switch (n) {
 282                 case 1:
 283                         __get_user_size(*(u8 *)to, from, 1, ret);
 284                         break;
 285                 case 2:
 286                         __get_user_size(*(u16 *)to, from, 2, ret);
 287                         break;
 288                 case 4:
 289                         __get_user_size(*(u32 *)to, from, 4, ret);
 290                         break;
 291                 case 8:
 292                         __get_user_size(*(u64 *)to, from, 8, ret);
 293                         break;
 294                 }
 295                 if (ret == 0)
 296                         return 0;
 297         }
 298
 299         return __copy_tofrom_user((__force void __user *)to, from, n);
 300 }
 301
 302 static inline unsigned long raw_copy_to_user(void __user *to,
 303                 const void *from, unsigned long n)
 304 {
 305         if (__builtin_constant_p(n) && (n <= 8)) {
 306                 unsigned long ret = 1;
 307
 308                 switch (n) {
 309                 case 1:
 310                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 311                         break;
 312                 case 2:
 313                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 314                         break;
 315                 case 4:
 316                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 317                         break;
 318                 case 8:
 319                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 320                         break;
 321                 }
 322                 if (ret == 0)
 323                         return 0;
 324         }
 325
 326         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 327 }
 328
 329 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 330
 331 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 332 {
 333         might_fault();
 334         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 335                 return __clear_user(addr, size);
 336         return size;
 337 }
 338
 339 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 340 extern __must_check long strnlen_user(const char __user *str, long n);
 341
 342 #endif  /* _ARCH_POWERPC_UACCESS_H */