LXR linux/arch/m68k/include/asm/uaccess

   1#ifndef __M68KNOMMU_UACCESS_H
   2#define __M68KNOMMU_UACCESS_H
   3
   4/*
   5 * User space memory access functions
   6 */
   7#include <linux/sched.h>
   8#include <linux/mm.h>
   9#include <linux/string.h>
  10
  11#include <asm/segment.h>
  12
  13#define VERIFY_READ     0
  14#define VERIFY_WRITE    1
  15
  16#define access_ok(type,addr,size)       _access_ok((unsigned long)(addr),(size))
  17
  18/*
  19 * It is not enough to just have access_ok check for a real RAM address.
  20 * This would disallow the case of code/ro-data running XIP in flash/rom.
  21 * Ideally we would check the possible flash ranges too, but that is
  22 * currently not so easy.
  23 */
  24static inline int _access_ok(unsigned long addr, unsigned long size)
  25{
  26        return 1;
  27}
  28
  29/*
  30 * The exception table consists of pairs of addresses: the first is the
  31 * address of an instruction that is allowed to fault, and the second is
  32 * the address at which the program should continue.  No registers are
  33 * modified, so it is entirely up to the continuation code to figure out
  34 * what to do.
  35 *
  36 * All the routines below use bits of fixup code that are out of line
  37 * with the main instruction path.  This means when everything is well,
  38 * we don't even have to jump over them.  Further, they do not intrude
  39 * on our cache or tlb entries.
  40 */
  41
  42struct exception_table_entry
  43{
  44        unsigned long insn, fixup;
  45};
  46
  47/* Returns 0 if exception not found and fixup otherwise.  */
  48extern unsigned long search_exception_table(unsigned long);
  49
  50
  51/*
  52 * These are the main single-value transfer routines.  They automatically
  53 * use the right size if we just have the right pointer type.
  54 */
  55
  56#define put_user(x, ptr)                                \
  57({                                                      \
  58    int __pu_err = 0;                                   \
  59    typeof(*(ptr)) __pu_val = (x);                      \
  60    switch (sizeof (*(ptr))) {                          \
  61    case 1:                                             \
  62        __put_user_asm(__pu_err, __pu_val, ptr, b);     \
  63        break;                                          \
  64    case 2:                                             \
  65        __put_user_asm(__pu_err, __pu_val, ptr, w);     \
  66        break;                                          \
  67    case 4:                                             \
  68        __put_user_asm(__pu_err, __pu_val, ptr, l);     \
  69        break;                                          \
  70    case 8:                                             \
  71        memcpy(ptr, &__pu_val, sizeof (*(ptr))); \
  72        break;                                          \
  73    default:                                            \
  74        __pu_err = __put_user_bad();                    \
  75        break;                                          \
  76    }                                                   \
  77    __pu_err;                                           \
  78})
  79#define __put_user(x, ptr) put_user(x, ptr)
  80
  81extern int __put_user_bad(void);
  82
  83/*
  84 * Tell gcc we read from memory instead of writing: this is because
  85 * we do not write to any memory gcc knows about, so there are no
  86 * aliasing issues.
  87 */
  88
  89#define __ptr(x) ((unsigned long *)(x))
  90
  91#define __put_user_asm(err,x,ptr,bwl)                           \
  92        __asm__ ("move" #bwl " %0,%1"                           \
  93                : /* no outputs */                                              \
  94                :"d" (x),"m" (*__ptr(ptr)) : "memory")
  95
  96#define get_user(x, ptr)                                        \
  97({                                                              \
  98    int __gu_err = 0;                                           \
  99    typeof(x) __gu_val = 0;                                     \
 100    switch (sizeof(*(ptr))) {                                   \
 101    case 1:                                                     \
 102        __get_user_asm(__gu_err, __gu_val, ptr, b, "=d");       \
 103        break;                                                  \
 104    case 2:                                                     \
 105        __get_user_asm(__gu_err, __gu_val, ptr, w, "=r");       \
 106        break;                                                  \
 107    case 4:                                                     \
 108        __get_user_asm(__gu_err, __gu_val, ptr, l, "=r");       \
 109        break;                                                  \
 110    case 8:                                                     \
 111        memcpy((void *) &__gu_val, ptr, sizeof (*(ptr)));       \
 112        break;                                                  \
 113    default:                                                    \
 114        __gu_val = 0;                                           \
 115        __gu_err = __get_user_bad();                            \
 116        break;                                                  \
 117    }                                                           \
 118    (x) = (typeof(*(ptr))) __gu_val;                            \
 119    __gu_err;                                                   \
 120})
 121#define __get_user(x, ptr) get_user(x, ptr)
 122
 123extern int __get_user_bad(void);
 124
 125#define __get_user_asm(err,x,ptr,bwl,reg)                       \
 126        __asm__ ("move" #bwl " %1,%0"                           \
 127                 : "=d" (x)                                     \
 128                 : "m" (*__ptr(ptr)))
 129
 130#define copy_from_user(to, from, n)             (memcpy(to, from, n), 0)
 131#define copy_to_user(to, from, n)               (memcpy(to, from, n), 0)
 132
 133#define __copy_from_user(to, from, n) copy_from_user(to, from, n)
 134#define __copy_to_user(to, from, n) copy_to_user(to, from, n)
 135#define __copy_to_user_inatomic __copy_to_user
 136#define __copy_from_user_inatomic __copy_from_user
 137
 138#define copy_to_user_ret(to,from,n,retval) ({ if (copy_to_user(to,from,n)) return retval; })
 139
 140#define copy_from_user_ret(to,from,n,retval) ({ if (copy_from_user(to,from,n)) return retval; })
 141
 142/*
 143 * Copy a null terminated string from userspace.
 144 */
 145
 146static inline long
 147strncpy_from_user(char *dst, const char *src, long count)
 148{
 149        char *tmp;
 150        strncpy(dst, src, count);
 151        for (tmp = dst; *tmp && count > 0; tmp++, count--)
 152                ;
 153        return(tmp - dst); /* DAVIDM should we count a NUL ?  check getname */
 154}
 155
 156/*
 157 * Return the size of a string (including the ending 0)
 158 *
 159 * Return 0 on exception, a value greater than N if too long
 160 */
 161static inline long strnlen_user(const char *src, long n)
 162{
 163        return(strlen(src) + 1); /* DAVIDM make safer */
 164}
 165
 166#define strlen_user(str) strnlen_user(str, 32767)
 167
 168/*
 169 * Zero Userspace
 170 */
 171
 172static inline unsigned long
 173__clear_user(void *to, unsigned long n)
 174{
 175        memset(to, 0, n);
 176        return 0;
 177}
 178
 179#define clear_user(to,n)        __clear_user(to,n)
 180
 181#endif /* _M68KNOMMU_UACCESS_H */
 182