LXR linux/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
  96extern 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)                   \
 135do {                                                            \
 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
 177extern 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)                   \
 214do {                                                            \
 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
 267extern unsigned long __copy_tofrom_user(void __user *to,
 268                const void __user *from, unsigned long size);
 269
 270#ifdef __powerpc64__
 271static inline unsigned long
 272raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 273{
 274        return __copy_tofrom_user(to, from, n);
 275}
 276#endif /* __powerpc64__ */
 277
 278static inline unsigned long raw_copy_from_user(void *to,
 279                const void __user *from, unsigned long n)
 280{
 281        if (__builtin_constant_p(n) && (n <= 8)) {
 282                unsigned long ret = 1;
 283
 284                switch (n) {
 285                case 1:
 286                        __get_user_size(*(u8 *)to, from, 1, ret);
 287                        break;
 288                case 2:
 289                        __get_user_size(*(u16 *)to, from, 2, ret);
 290                        break;
 291                case 4:
 292                        __get_user_size(*(u32 *)to, from, 4, ret);
 293                        break;
 294                case 8:
 295                        __get_user_size(*(u64 *)to, from, 8, ret);
 296                        break;
 297                }
 298                if (ret == 0)
 299                        return 0;
 300        }
 301
 302        return __copy_tofrom_user((__force void __user *)to, from, n);
 303}
 304
 305static inline unsigned long raw_copy_to_user(void __user *to,
 306                const void *from, unsigned long n)
 307{
 308        if (__builtin_constant_p(n) && (n <= 8)) {
 309                unsigned long ret = 1;
 310
 311                switch (n) {
 312                case 1:
 313                        __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 314                        break;
 315                case 2:
 316                        __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 317                        break;
 318                case 4:
 319                        __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 320                        break;
 321                case 8:
 322                        __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 323                        break;
 324                }
 325                if (ret == 0)
 326                        return 0;
 327        }
 328
 329        return __copy_tofrom_user(to, (__force const void __user *)from, n);
 330}
 331
 332extern unsigned long __clear_user(void __user *addr, unsigned long size);
 333
 334static inline unsigned long clear_user(void __user *addr, unsigned long size)
 335{
 336        might_fault();
 337        if (likely(access_ok(VERIFY_WRITE, addr, size)))
 338                return __clear_user(addr, size);
 339        return size;
 340}
 341
 342extern long strncpy_from_user(char *dst, const char __user *src, long count);
 343extern __must_check long strlen_user(const char __user *str);
 344extern __must_check long strnlen_user(const char __user *str, long n);
 345
 346#endif  /* _ARCH_POWERPC_UACCESS_H */
 347