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   1 /* uaccess.h: userspace accessor functions
   2  *
   3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #ifndef _ASM_UACCESS_H
  13 #define _ASM_UACCESS_H
  14
  15 /*
  16  * User space memory access functions
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/mm.h>
  20 #include <asm/segment.h>
  21 #include <asm/sections.h>
  22
  23 #define HAVE_ARCH_UNMAPPED_AREA /* we decide where to put mmaps */
  24
  25 #define __ptr(x) ((unsigned long __force *)(x))
  26
  27 #define VERIFY_READ     0
  28 #define VERIFY_WRITE    1
  29
  30 #define __addr_ok(addr) ((unsigned long)(addr) < get_addr_limit())
  31
  32 /*
  33  * check that a range of addresses falls within the current address limit
  34  */
  35 static inline int ___range_ok(unsigned long addr, unsigned long size)
  36 {
  37 #ifdef CONFIG_MMU
  38         int flag = -EFAULT, tmp;
  39
  40         asm volatile (
  41                 "       addcc   %3,%2,%1,icc0   \n"     /* set C-flag if addr+size>4GB */
  42                 "       subcc.p %1,%4,gr0,icc1  \n"     /* jump if addr+size>limit */
  43                 "       bc      icc0,#0,0f      \n"
  44                 "       bhi     icc1,#0,0f      \n"
  45                 "       setlos  #0,%0           \n"     /* mark okay */
  46                 "0:                             \n"
  47                 : "=r"(flag), "=&r"(tmp)
  48                 : "r"(addr), "r"(size), "r"(get_addr_limit()), "0"(flag)
  49                 );
  50
  51         return flag;
  52
  53 #else
  54
  55         if (addr < memory_start ||
  56             addr > memory_end ||
  57             size > memory_end - memory_start ||
  58             addr + size > memory_end)
  59                 return -EFAULT;
  60
  61         return 0;
  62 #endif
  63 }
  64
  65 #define __range_ok(addr,size) ___range_ok((unsigned long) (addr), (unsigned long) (size))
  66
  67 #define access_ok(type,addr,size) (__range_ok((void __user *)(addr), (size)) == 0)
  68 #define __access_ok(addr,size) (__range_ok((addr), (size)) == 0)
  69
  70 /*
  71  * The exception table consists of pairs of addresses: the first is the
  72  * address of an instruction that is allowed to fault, and the second is
  73  * the address at which the program should continue.  No registers are
  74  * modified, so it is entirely up to the continuation code to figure out
  75  * what to do.
  76  *
  77  * All the routines below use bits of fixup code that are out of line
  78  * with the main instruction path.  This means when everything is well,
  79  * we don't even have to jump over them.  Further, they do not intrude
  80  * on our cache or tlb entries.
  81  */
  82 struct exception_table_entry
  83 {
  84         unsigned long insn, fixup;
  85 };
  86
  87 /* Returns 0 if exception not found and fixup otherwise.  */
  88 extern unsigned long search_exception_table(unsigned long);
  89
  90
  91 /*
  92  * These are the main single-value transfer routines.  They automatically
  93  * use the right size if we just have the right pointer type.
  94  */
  95 #define __put_user(x, ptr)                                              \
  96 ({                                                                      \
  97         int __pu_err = 0;                                               \
  98                                                                         \
  99         typeof(*(ptr)) __pu_val = (x);                                  \
 100         __chk_user_ptr(ptr);                                            \
 101                                                                         \
 102         switch (sizeof (*(ptr))) {                                      \
 103         case 1:                                                         \
 104                 __put_user_asm(__pu_err, __pu_val, ptr, "b", "r");      \
 105                 break;                                                  \
 106         case 2:                                                         \
 107                 __put_user_asm(__pu_err, __pu_val, ptr, "h", "r");      \
 108                 break;                                                  \
 109         case 4:                                                         \
 110                 __put_user_asm(__pu_err, __pu_val, ptr, "",  "r");      \
 111                 break;                                                  \
 112         case 8:                                                         \
 113                 __put_user_asm(__pu_err, __pu_val, ptr, "d", "e");      \
 114                 break;                                                  \
 115         default:                                                        \
 116                 __pu_err = __put_user_bad();                            \
 117                 break;                                                  \
 118         }                                                               \
 119         __pu_err;                                                       \
 120 })
 121
 122 #define put_user(x, ptr)                        \
 123 ({                                              \
 124         typeof(*(ptr)) __user *_p = (ptr);      \
 125         int _e;                                 \
 126                                                 \
 127         _e = __range_ok(_p, sizeof(*_p));       \
 128         if (_e == 0)                            \
 129                 _e = __put_user((x), _p);       \
 130         _e;                                     \
 131 })
 132
 133 extern int __put_user_bad(void);
 134
 135 /*
 136  * Tell gcc we read from memory instead of writing: this is because
 137  * we do not write to any memory gcc knows about, so there are no
 138  * aliasing issues.
 139  */
 140
 141 #ifdef CONFIG_MMU
 142
 143 #define __put_user_asm(err,x,ptr,dsize,constraint)                                      \
 144 do {                                                                                    \
 145         asm volatile("1:        st"dsize"%I1    %2,%M1  \n"                             \
 146                      "2:                                \n"                             \
 147                      ".subsection 2                     \n"                             \
 148                      "3:        setlos          %3,%0   \n"                             \
 149                      "          bra             2b      \n"                             \
 150                      ".previous                         \n"                             \
 151                      ".section __ex_table,\"a\"         \n"                             \
 152                      "          .balign         8       \n"                             \
 153                      "          .long           1b,3b   \n"                             \
 154                      ".previous"                                                        \
 155                      : "=r" (err)                                                       \
 156                      : "m" (*__ptr(ptr)), constraint (x), "i"(-EFAULT), "0"(err)        \
 157                      : "memory");                                                       \
 158 } while (0)
 159
 160 #else
 161
 162 #define __put_user_asm(err,x,ptr,bwl,con)       \
 163 do {                                            \
 164         asm("   st"bwl"%I0      %1,%M0  \n"     \
 165             "   membar                  \n"     \
 166             :                                   \
 167             : "m" (*__ptr(ptr)), con (x)        \
 168             : "memory");                        \
 169 } while (0)
 170
 171 #endif
 172
 173 /*****************************************************************************/
 174 /*
 175  *
 176  */
 177 #define __get_user(x, ptr)                                              \
 178 ({                                                                      \
 179         int __gu_err = 0;                                               \
 180         __chk_user_ptr(ptr);                                            \
 181                                                                         \
 182         switch (sizeof(*(ptr))) {                                       \
 183         case 1: {                                                       \
 184                 unsigned char __gu_val;                                 \
 185                 __get_user_asm(__gu_err, __gu_val, ptr, "ub", "=r");    \
 186                 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val;        \
 187                 break;                                                  \
 188         }                                                               \
 189         case 2: {                                                       \
 190                 unsigned short __gu_val;                                \
 191                 __get_user_asm(__gu_err, __gu_val, ptr, "uh", "=r");    \
 192                 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val;        \
 193                 break;                                                  \
 194         }                                                               \
 195         case 4: {                                                       \
 196                 unsigned int __gu_val;                                  \
 197                 __get_user_asm(__gu_err, __gu_val, ptr, "", "=r");      \
 198                 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val;        \
 199                 break;                                                  \
 200         }                                                               \
 201         case 8: {                                                       \
 202                 unsigned long long __gu_val;                            \
 203                 __get_user_asm(__gu_err, __gu_val, ptr, "d", "=e");     \
 204                 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val;        \
 205                 break;                                                  \
 206         }                                                               \
 207         default:                                                        \
 208                 __gu_err = __get_user_bad();                            \
 209                 break;                                                  \
 210         }                                                               \
 211         __gu_err;                                                       \
 212 })
 213
 214 #define get_user(x, ptr)                        \
 215 ({                                              \
 216         const typeof(*(ptr)) __user *_p = (ptr);\
 217         int _e;                                 \
 218                                                 \
 219         _e = __range_ok(_p, sizeof(*_p));       \
 220         if (likely(_e == 0))                    \
 221                 _e = __get_user((x), _p);       \
 222         else                                    \
 223                 (x) = (typeof(x)) 0;            \
 224         _e;                                     \
 225 })
 226
 227 extern int __get_user_bad(void);
 228
 229 #ifdef CONFIG_MMU
 230
 231 #define __get_user_asm(err,x,ptr,dtype,constraint)      \
 232 do {                                                    \
 233         asm("1:         ld"dtype"%I2    %M2,%1  \n"     \
 234             "2:                                 \n"     \
 235             ".subsection 2                      \n"     \
 236             "3:         setlos          %3,%0   \n"     \
 237             "           setlos          #0,%1   \n"     \
 238             "           bra             2b      \n"     \
 239             ".previous                          \n"     \
 240             ".section __ex_table,\"a\"          \n"     \
 241             "           .balign         8       \n"     \
 242             "           .long           1b,3b   \n"     \
 243             ".previous"                                 \
 244             : "=r" (err), constraint (x)                \
 245             : "m" (*__ptr(ptr)), "i"(-EFAULT), "0"(err) \
 246             );                                          \
 247 } while(0)
 248
 249 #else
 250
 251 #define __get_user_asm(err,x,ptr,bwl,con)       \
 252         asm("   ld"bwl"%I1      %M1,%0  \n"     \
 253             "   membar                  \n"     \
 254             : con(x)                            \
 255             : "m" (*__ptr(ptr)))
 256
 257 #endif
 258
 259 /*****************************************************************************/
 260 /*
 261  *
 262  */
 263 #define ____force(x) (__force void *)(void __user *)(x)
 264 #ifdef CONFIG_MMU
 265 extern long __memset_user(void *dst, unsigned long count);
 266 extern long __memcpy_user(void *dst, const void *src, unsigned long count);
 267
 268 #define clear_user(dst,count)                   __memset_user(____force(dst), (count))
 269 #define __copy_from_user_inatomic(to, from, n)  __memcpy_user((to), ____force(from), (n))
 270 #define __copy_to_user_inatomic(to, from, n)    __memcpy_user(____force(to), (from), (n))
 271
 272 #else
 273
 274 #define clear_user(dst,count)                   (memset(____force(dst), 0, (count)), 0)
 275 #define __copy_from_user_inatomic(to, from, n)  (memcpy((to), ____force(from), (n)), 0)
 276 #define __copy_to_user_inatomic(to, from, n)    (memcpy(____force(to), (from), (n)), 0)
 277
 278 #endif
 279
 280 static inline unsigned long __must_check
 281 __copy_to_user(void __user *to, const void *from, unsigned long n)
 282 {
 283        might_sleep();
 284        return __copy_to_user_inatomic(to, from, n);
 285 }
 286
 287 static inline unsigned long
 288 __copy_from_user(void *to, const void __user *from, unsigned long n)
 289 {
 290        might_sleep();
 291        return __copy_from_user_inatomic(to, from, n);
 292 }
 293
 294 static inline long copy_from_user(void *to, const void __user *from, unsigned long n)
 295 {
 296         unsigned long ret = n;
 297
 298         if (likely(__access_ok(from, n)))
 299                 ret = __copy_from_user(to, from, n);
 300
 301         if (unlikely(ret != 0))
 302                 memset(to + (n - ret), 0, ret);
 303
 304         return ret;
 305 }
 306
 307 static inline long copy_to_user(void __user *to, const void *from, unsigned long n)
 308 {
 309         return likely(__access_ok(to, n)) ? __copy_to_user(to, from, n) : n;
 310 }
 311
 312 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 313 extern long strnlen_user(const char __user *src, long count);
 314
 315 #define strlen_user(str) strnlen_user(str, 32767)
 316
 317 extern unsigned long search_exception_table(unsigned long addr);
 318
 319 #endif /* _ASM_UACCESS_H */