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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 *)(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((addr), (size)) == 0)
  68 #define __access_ok(addr,size) (__range_ok((addr), (size)) == 0)
  69
  70 /* this function will go away soon - use access_ok() / __range_ok() instead */
  71 static inline int __deprecated verify_area(int type, const void * addr, unsigned long size)
  72 {
  73         return __range_ok(addr, size);
  74 }
  75
  76 /*
  77  * The exception table consists of pairs of addresses: the first is the
  78  * address of an instruction that is allowed to fault, and the second is
  79  * the address at which the program should continue.  No registers are
  80  * modified, so it is entirely up to the continuation code to figure out
  81  * what to do.
  82  *
  83  * All the routines below use bits of fixup code that are out of line
  84  * with the main instruction path.  This means when everything is well,
  85  * we don't even have to jump over them.  Further, they do not intrude
  86  * on our cache or tlb entries.
  87  */
  88 struct exception_table_entry
  89 {
  90         unsigned long insn, fixup;
  91 };
  92
  93 /* Returns 0 if exception not found and fixup otherwise.  */
  94 extern unsigned long search_exception_table(unsigned long);
  95
  96
  97 /*
  98  * These are the main single-value transfer routines.  They automatically
  99  * use the right size if we just have the right pointer type.
 100  */
 101 #define __put_user(x, ptr)                                              \
 102 ({                                                                      \
 103         int __pu_err = 0;                                               \
 104                                                                         \
 105         typeof(*(ptr)) __pu_val = (x);                                  \
 106                                                                         \
 107         switch (sizeof (*(ptr))) {                                      \
 108         case 1:                                                         \
 109                 __put_user_asm(__pu_err, __pu_val, ptr, "b", "r");      \
 110                 break;                                                  \
 111         case 2:                                                         \
 112                 __put_user_asm(__pu_err, __pu_val, ptr, "h", "r");      \
 113                 break;                                                  \
 114         case 4:                                                         \
 115                 __put_user_asm(__pu_err, __pu_val, ptr, "",  "r");      \
 116                 break;                                                  \
 117         case 8:                                                         \
 118                 __put_user_asm(__pu_err, __pu_val, ptr, "d", "e");      \
 119                 break;                                                  \
 120         default:                                                        \
 121                 __pu_err = __put_user_bad();                            \
 122                 break;                                                  \
 123         }                                                               \
 124         __pu_err;                                                       \
 125 })
 126
 127 #define put_user(x, ptr)                        \
 128 ({                                              \
 129         typeof(&*ptr) _p = (ptr);               \
 130         int _e;                                 \
 131                                                 \
 132         _e = __range_ok(_p, sizeof(*_p));       \
 133         if (_e == 0)                            \
 134                 _e = __put_user((x), _p);       \
 135         _e;                                     \
 136 })
 137
 138 extern int __put_user_bad(void);
 139
 140 /*
 141  * Tell gcc we read from memory instead of writing: this is because
 142  * we do not write to any memory gcc knows about, so there are no
 143  * aliasing issues.
 144  */
 145
 146 #ifdef CONFIG_MMU
 147
 148 #define __put_user_asm(err,x,ptr,dsize,constraint)                                      \
 149 do {                                                                                    \
 150         asm volatile("1:        st"dsize"%I1    %2,%M1  \n"                             \
 151                      "2:                                \n"                             \
 152                      ".subsection 2                     \n"                             \
 153                      "3:        setlos          %3,%0   \n"                             \
 154                      "          bra             2b      \n"                             \
 155                      ".previous                         \n"                             \
 156                      ".section __ex_table,\"a\"         \n"                             \
 157                      "          .balign         8       \n"                             \
 158                      "          .long           1b,3b   \n"                             \
 159                      ".previous"                                                        \
 160                      : "=r" (err)                                                       \
 161                      : "m" (*__ptr(ptr)), constraint (x), "i"(-EFAULT), "0"(err)        \
 162                      : "memory");                                                       \
 163 } while (0)
 164
 165 #else
 166
 167 #define __put_user_asm(err,x,ptr,bwl,con)       \
 168 do {                                            \
 169         asm("   st"bwl"%I0      %1,%M0  \n"     \
 170             "   membar                  \n"     \
 171             :                                   \
 172             : "m" (*__ptr(ptr)), con (x)        \
 173             : "memory");                        \
 174 } while (0)
 175
 176 #endif
 177
 178 /*****************************************************************************/
 179 /*
 180  *
 181  */
 182 #define __get_user(x, ptr)                                              \
 183 ({                                                                      \
 184         typeof(*(ptr)) __gu_val = 0;                                    \
 185         int __gu_err = 0;                                               \
 186                                                                         \
 187         switch (sizeof(*(ptr))) {                                       \
 188         case 1:                                                         \
 189                 __get_user_asm(__gu_err, __gu_val, ptr, "ub", "=r");    \
 190                 break;                                                  \
 191         case 2:                                                         \
 192                 __get_user_asm(__gu_err, __gu_val, ptr, "uh", "=r");    \
 193                 break;                                                  \
 194         case 4:                                                         \
 195                 __get_user_asm(__gu_err, __gu_val, ptr, "", "=r");      \
 196                 break;                                                  \
 197         case 8:                                                         \
 198                 __get_user_asm(__gu_err, __gu_val, ptr, "d", "=e");     \
 199                 break;                                                  \
 200         default:                                                        \
 201                 __gu_err = __get_user_bad();                            \
 202                 break;                                                  \
 203         }                                                               \
 204         (x) = __gu_val;                                                 \
 205         __gu_err;                                                       \
 206 })
 207
 208 #define get_user(x, ptr)                        \
 209 ({                                              \
 210         typeof(&*ptr) _p = (ptr);               \
 211         int _e;                                 \
 212                                                 \
 213         _e = __range_ok(_p, sizeof(*_p));       \
 214         if (likely(_e == 0))                    \
 215                 _e = __get_user((x), _p);       \
 216         else                                    \
 217                 (x) = (typeof(x)) 0;            \
 218         _e;                                     \
 219 })
 220
 221 extern int __get_user_bad(void);
 222
 223 #ifdef CONFIG_MMU
 224
 225 #define __get_user_asm(err,x,ptr,dtype,constraint)      \
 226 do {                                                    \
 227         asm("1:         ld"dtype"%I2    %M2,%1  \n"     \
 228             "2:                                 \n"     \
 229             ".subsection 2                      \n"     \
 230             "3:         setlos          %3,%0   \n"     \
 231             "           setlos          #0,%1   \n"     \
 232             "           bra             2b      \n"     \
 233             ".previous                          \n"     \
 234             ".section __ex_table,\"a\"          \n"     \
 235             "           .balign         8       \n"     \
 236             "           .long           1b,3b   \n"     \
 237             ".previous"                                 \
 238             : "=r" (err), constraint (x)                \
 239             : "m" (*__ptr(ptr)), "i"(-EFAULT), "0"(err) \
 240             );                                          \
 241 } while(0)
 242
 243 #else
 244
 245 #define __get_user_asm(err,x,ptr,bwl,con)       \
 246         asm("   ld"bwl"%I1      %M1,%0  \n"     \
 247             "   membar                  \n"     \
 248             : con(x)                            \
 249             : "m" (*__ptr(ptr)))
 250
 251 #endif
 252
 253 /*****************************************************************************/
 254 /*
 255  *
 256  */
 257 #ifdef CONFIG_MMU
 258 extern long __memset_user(void *dst, unsigned long count);
 259 extern long __memcpy_user(void *dst, const void *src, unsigned long count);
 260
 261 #define clear_user(dst,count)                   __memset_user((dst), (count))
 262 #define __copy_from_user_inatomic(to, from, n)  __memcpy_user((to), (from), (n))
 263 #define __copy_to_user_inatomic(to, from, n)    __memcpy_user((to), (from), (n))
 264
 265 #else
 266
 267 #define clear_user(dst,count)                   (memset((dst), 0, (count)), 0)
 268 #define __copy_from_user_inatomic(to, from, n)  (memcpy((to), (from), (n)), 0)
 269 #define __copy_to_user_inatomic(to, from, n)    (memcpy((to), (from), (n)), 0)
 270
 271 #endif
 272
 273 static inline unsigned long __must_check
 274 __copy_to_user(void __user *to, const void *from, unsigned long n)
 275 {
 276        might_sleep();
 277        return __copy_to_user_inatomic(to, from, n);
 278 }
 279
 280 static inline unsigned long
 281 __copy_from_user(void *to, const void __user *from, unsigned long n)
 282 {
 283        might_sleep();
 284        return __copy_from_user_inatomic(to, from, n);
 285 }
 286
 287 static inline long copy_from_user(void *to, const void *from, unsigned long n)
 288 {
 289         unsigned long ret = n;
 290
 291         if (likely(__access_ok(from, n)))
 292                 ret = __copy_from_user(to, from, n);
 293
 294         if (unlikely(ret != 0))
 295                 memset(to + (n - ret), 0, ret);
 296
 297         return ret;
 298 }
 299
 300 static inline long copy_to_user(void *to, const void *from, unsigned long n)
 301 {
 302         return likely(__access_ok(to, n)) ? __copy_to_user(to, from, n) : n;
 303 }
 304
 305 #define copy_to_user_ret(to,from,n,retval)      ({ if (copy_to_user(to,from,n)) return retval; })
 306 #define copy_from_user_ret(to,from,n,retval)    ({ if (copy_from_user(to,from,n)) return retval; })
 307
 308 extern long strncpy_from_user(char *dst, const char *src, long count);
 309 extern long strnlen_user(const char *src, long count);
 310
 311 #define strlen_user(str) strnlen_user(str, 32767)
 312
 313 extern unsigned long search_exception_table(unsigned long addr);
 314
 315 #define copy_to_user_page(vma, page, vaddr, dst, src, len)      memcpy(dst, src, len)
 316 #define copy_from_user_page(vma, page, vaddr, dst, src, len)    memcpy(dst, src, len)
 317
 318 #endif /* _ASM_UACCESS_H */