LXR linux/arch/metag/include/asm/uaccess.h

   1#ifndef __METAG_UACCESS_H
   2#define __METAG_UACCESS_H
   3
   4/*
   5 * User space memory access functions
   6 */
   7
   8/*
   9 * The fs value determines whether argument validity checking should be
  10 * performed or not.  If get_fs() == USER_DS, checking is performed, with
  11 * get_fs() == KERNEL_DS, checking is bypassed.
  12 *
  13 * For historical reasons, these macros are grossly misnamed.
  14 */
  15
  16#define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  17
  18#define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
  19#define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
  20
  21#define get_ds()        (KERNEL_DS)
  22#define get_fs()        (current_thread_info()->addr_limit)
  23#define set_fs(x)       (current_thread_info()->addr_limit = (x))
  24
  25#define segment_eq(a, b)        ((a).seg == (b).seg)
  26
  27static inline int __access_ok(unsigned long addr, unsigned long size)
  28{
  29        /*
  30         * Allow access to the user mapped memory area, but not the system area
  31         * before it. The check extends to the top of the address space when
  32         * kernel access is allowed (there's no real reason to user copy to the
  33         * system area in any case).
  34         */
  35        if (likely(addr >= META_MEMORY_BASE && addr < get_fs().seg &&
  36                   size <= get_fs().seg - addr))
  37                return true;
  38        /*
  39         * Explicitly allow NULL pointers here. Parts of the kernel such
  40         * as readv/writev use access_ok to validate pointers, but want
  41         * to allow NULL pointers for various reasons. NULL pointers are
  42         * safe to allow through because the first page is not mappable on
  43         * Meta.
  44         */
  45        if (!addr)
  46                return true;
  47        /* Allow access to core code memory area... */
  48        if (addr >= LINCORE_CODE_BASE && addr <= LINCORE_CODE_LIMIT &&
  49            size <= LINCORE_CODE_LIMIT + 1 - addr)
  50                return true;
  51        /* ... but no other areas. */
  52        return false;
  53}
  54
  55#define access_ok(type, addr, size) __access_ok((unsigned long)(addr),  \
  56                                                (unsigned long)(size))
  57
  58#include <asm/extable.h>
  59
  60/*
  61 * These are the main single-value transfer routines.  They automatically
  62 * use the right size if we just have the right pointer type.
  63 */
  64
  65#define put_user(x, ptr) \
  66        __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  67#define __put_user(x, ptr) \
  68        __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  69
  70extern void __put_user_bad(void);
  71
  72#define __put_user_nocheck(x, ptr, size)                \
  73({                                                      \
  74        long __pu_err;                                  \
  75        __put_user_size((x), (ptr), (size), __pu_err);  \
  76        __pu_err;                                       \
  77})
  78
  79#define __put_user_check(x, ptr, size)                          \
  80({                                                              \
  81        long __pu_err = -EFAULT;                                \
  82        __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
  83        if (access_ok(VERIFY_WRITE, __pu_addr, size))           \
  84                __put_user_size((x), __pu_addr, (size), __pu_err);      \
  85        __pu_err;                                               \
  86})
  87
  88extern long __put_user_asm_b(unsigned int x, void __user *addr);
  89extern long __put_user_asm_w(unsigned int x, void __user *addr);
  90extern long __put_user_asm_d(unsigned int x, void __user *addr);
  91extern long __put_user_asm_l(unsigned long long x, void __user *addr);
  92
  93#define __put_user_size(x, ptr, size, retval)                           \
  94do {                                                                    \
  95        retval = 0;                                                     \
  96        switch (size) {                                                 \
  97        case 1:                                                         \
  98                retval = __put_user_asm_b((__force unsigned int)x, ptr);\
  99                break;                                                  \
 100        case 2:                                                         \
 101                retval = __put_user_asm_w((__force unsigned int)x, ptr);\
 102                break;                                                  \
 103        case 4:                                                         \
 104                retval = __put_user_asm_d((__force unsigned int)x, ptr);\
 105                break;                                                  \
 106        case 8:                                                         \
 107                retval = __put_user_asm_l((__force unsigned long long)x,\
 108                                          ptr);                         \
 109                break;                                                  \
 110        default:                                                        \
 111                __put_user_bad();                                       \
 112        }                                                               \
 113} while (0)
 114
 115#define get_user(x, ptr) \
 116        __get_user_check((x), (ptr), sizeof(*(ptr)))
 117#define __get_user(x, ptr) \
 118        __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 119
 120extern long __get_user_bad(void);
 121
 122#define __get_user_nocheck(x, ptr, size)                        \
 123({                                                              \
 124        long __gu_err;                                          \
 125        long long __gu_val;                                     \
 126        __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 127        (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 128        __gu_err;                                               \
 129})
 130
 131#define __get_user_check(x, ptr, size)                                  \
 132({                                                                      \
 133        long __gu_err = -EFAULT;                                        \
 134        long long __gu_val = 0;                                         \
 135        const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 136        if (access_ok(VERIFY_READ, __gu_addr, size))                    \
 137                __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 138        (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 139        __gu_err;                                                       \
 140})
 141
 142extern unsigned char __get_user_asm_b(const void __user *addr, long *err);
 143extern unsigned short __get_user_asm_w(const void __user *addr, long *err);
 144extern unsigned int __get_user_asm_d(const void __user *addr, long *err);
 145extern unsigned long long __get_user_asm_l(const void __user *addr, long *err);
 146
 147#define __get_user_size(x, ptr, size, retval)                   \
 148do {                                                            \
 149        retval = 0;                                             \
 150        switch (size) {                                         \
 151        case 1:                                                 \
 152                x = __get_user_asm_b(ptr, &retval); break;      \
 153        case 2:                                                 \
 154                x = __get_user_asm_w(ptr, &retval); break;      \
 155        case 4:                                                 \
 156                x = __get_user_asm_d(ptr, &retval); break;      \
 157        case 8:                                                 \
 158                x = __get_user_asm_l(ptr, &retval); break;      \
 159        default:                                                \
 160                (x) = __get_user_bad();                         \
 161        }                                                       \
 162} while (0)
 163
 164/*
 165 * Copy a null terminated string from userspace.
 166 *
 167 * Must return:
 168 * -EFAULT              for an exception
 169 * count                if we hit the buffer limit
 170 * bytes copied         if we hit a null byte
 171 * (without the null byte)
 172 */
 173
 174extern long __must_check __strncpy_from_user(char *dst, const char __user *src,
 175                                             long count);
 176
 177static inline long
 178strncpy_from_user(char *dst, const char __user *src, long count)
 179{
 180        if (!access_ok(VERIFY_READ, src, 1))
 181                return -EFAULT;
 182        return __strncpy_from_user(dst, src, count);
 183}
 184/*
 185 * Return the size of a string (including the ending 0)
 186 *
 187 * Return 0 on exception, a value greater than N if too long
 188 */
 189extern long __must_check strnlen_user(const char __user *src, long count);
 190
 191extern unsigned long raw_copy_from_user(void *to, const void __user *from,
 192                                        unsigned long n);
 193extern unsigned long raw_copy_to_user(void __user *to, const void *from,
 194                                      unsigned long n);
 195
 196/*
 197 * Zero Userspace
 198 */
 199
 200extern unsigned long __must_check __do_clear_user(void __user *to,
 201                                                  unsigned long n);
 202
 203static inline unsigned long clear_user(void __user *to, unsigned long n)
 204{
 205        if (access_ok(VERIFY_WRITE, to, n))
 206                return __do_clear_user(to, n);
 207        return n;
 208}
 209
 210#define __clear_user(to, n)            __do_clear_user(to, n)
 211
 212#endif /* _METAG_UACCESS_H */
 213