include/asm-x86_64/uaccess.h

   1 #ifndef __X86_64_UACCESS_H
   2 #define __X86_64_UACCESS_H
   3
   4 /*
   5  * User space memory access functions
   6  */
   7 #include <linux/config.h>
   8 #include <linux/compiler.h>
   9 #include <linux/errno.h>
  10 #include <linux/sched.h>
  11 #include <linux/prefetch.h>
  12 #include <asm/page.h>
  13
  14 #define VERIFY_READ 0
  15 #define VERIFY_WRITE 1
  16
  17 /*
  18  * The fs value determines whether argument validity checking should be
  19  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  20  * get_fs() == KERNEL_DS, checking is bypassed.
  21  *
  22  * For historical reasons, these macros are grossly misnamed.
  23  */
  24
  25 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  26
  27 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFFFFFFFFFFUL)
  28 #define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
  29
  30 #define get_ds()        (KERNEL_DS)
  31 #define get_fs()        (current_thread_info()->addr_limit)
  32 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  33
  34 #define segment_eq(a,b) ((a).seg == (b).seg)
  35
  36 #define __addr_ok(addr) (!((unsigned long)(addr) & (current_thread_info()->addr_limit.seg)))
  37
  38 /*
  39  * Uhhuh, this needs 65-bit arithmetic. We have a carry..
  40  */
  41 #define __range_not_ok(addr,size) ({ \
  42         unsigned long flag,sum; \
  43         __chk_user_ptr(addr); \
  44         asm("# range_ok\n\r" \
  45                 "addq %3,%1 ; sbbq %0,%0 ; cmpq %1,%4 ; sbbq $0,%0"  \
  46                 :"=&r" (flag), "=r" (sum) \
  47                 :"1" (addr),"g" ((long)(size)),"g" (current_thread_info()->addr_limit.seg)); \
  48         flag; })
  49
  50 #define access_ok(type, addr, size) (__range_not_ok(addr,size) == 0)
  51
  52 /*
  53  * The exception table consists of pairs of addresses: the first is the
  54  * address of an instruction that is allowed to fault, and the second is
  55  * the address at which the program should continue.  No registers are
  56  * modified, so it is entirely up to the continuation code to figure out
  57  * what to do.
  58  *
  59  * All the routines below use bits of fixup code that are out of line
  60  * with the main instruction path.  This means when everything is well,
  61  * we don't even have to jump over them.  Further, they do not intrude
  62  * on our cache or tlb entries.
  63  */
  64
  65 struct exception_table_entry
  66 {
  67         unsigned long insn, fixup;
  68 };
  69
  70 #define ARCH_HAS_SEARCH_EXTABLE
  71
  72 /*
  73  * These are the main single-value transfer routines.  They automatically
  74  * use the right size if we just have the right pointer type.
  75  *
  76  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  77  * and yet we don't want to do any pointers, because that is too much
  78  * of a performance impact. Thus we have a few rather ugly macros here,
  79  * and hide all the ugliness from the user.
  80  *
  81  * The "__xxx" versions of the user access functions are versions that
  82  * do not verify the address space, that must have been done previously
  83  * with a separate "access_ok()" call (this is used when we do multiple
  84  * accesses to the same area of user memory).
  85  */
  86
  87 #define __get_user_x(size,ret,x,ptr) \
  88         __asm__ __volatile__("call __get_user_" #size \
  89                 :"=a" (ret),"=d" (x) \
  90                 :"c" (ptr) \
  91                 :"r8")
  92
  93 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
  94 #define get_user(x,ptr)                                                 \
  95 ({      unsigned long __val_gu;                                         \
  96         int __ret_gu;                                                   \
  97         __chk_user_ptr(ptr);                                            \
  98         switch(sizeof (*(ptr))) {                                       \
  99         case 1:  __get_user_x(1,__ret_gu,__val_gu,ptr); break;          \
 100         case 2:  __get_user_x(2,__ret_gu,__val_gu,ptr); break;          \
 101         case 4:  __get_user_x(4,__ret_gu,__val_gu,ptr); break;          \
 102         case 8:  __get_user_x(8,__ret_gu,__val_gu,ptr); break;          \
 103         default: __get_user_bad(); break;                               \
 104         }                                                               \
 105         (x) = (__typeof__(*(ptr)))__val_gu;                             \
 106         __ret_gu;                                                       \
 107 })
 108
 109 extern void __put_user_1(void);
 110 extern void __put_user_2(void);
 111 extern void __put_user_4(void);
 112 extern void __put_user_8(void);
 113 extern void __put_user_bad(void);
 114
 115 #define __put_user_x(size,ret,x,ptr)                                    \
 116         __asm__ __volatile__("call __put_user_" #size                   \
 117                 :"=a" (ret)                                             \
 118                 :"c" (ptr),"d" (x)                                      \
 119                 :"r8")
 120
 121 #define put_user(x,ptr)                                                 \
 122   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 123
 124 #define __get_user(x,ptr) \
 125   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
 126 #define __put_user(x,ptr) \
 127   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 128
 129 #define __get_user_unaligned __get_user
 130 #define __put_user_unaligned __put_user
 131
 132 #define __put_user_nocheck(x,ptr,size)                  \
 133 ({                                                      \
 134         int __pu_err;                                   \
 135         __put_user_size((x),(ptr),(size),__pu_err);     \
 136         __pu_err;                                       \
 137 })
 138
 139
 140 #define __put_user_check(x,ptr,size)                    \
 141 ({                                                      \
 142         int __pu_err;                                   \
 143         __typeof__(*(ptr)) __user *__pu_addr = (ptr);   \
 144         switch (size) {                                 \
 145         case 1: __put_user_x(1,__pu_err,x,__pu_addr); break;    \
 146         case 2: __put_user_x(2,__pu_err,x,__pu_addr); break;    \
 147         case 4: __put_user_x(4,__pu_err,x,__pu_addr); break;    \
 148         case 8: __put_user_x(8,__pu_err,x,__pu_addr); break;    \
 149         default: __put_user_bad();                      \
 150         }                                               \
 151         __pu_err;                                       \
 152 })
 153
 154 #define __put_user_size(x,ptr,size,retval)                              \
 155 do {                                                                    \
 156         retval = 0;                                                     \
 157         __chk_user_ptr(ptr);                                            \
 158         switch (size) {                                                 \
 159           case 1: __put_user_asm(x,ptr,retval,"b","b","iq",-EFAULT); break;\
 160           case 2: __put_user_asm(x,ptr,retval,"w","w","ir",-EFAULT); break;\
 161           case 4: __put_user_asm(x,ptr,retval,"l","k","ir",-EFAULT); break;\
 162           case 8: __put_user_asm(x,ptr,retval,"q","","ir",-EFAULT); break;\
 163           default: __put_user_bad();                                    \
 164         }                                                               \
 165 } while (0)
 166
 167 /* FIXME: this hack is definitely wrong -AK */
 168 struct __large_struct { unsigned long buf[100]; };
 169 #define __m(x) (*(struct __large_struct __user *)(x))
 170
 171 /*
 172  * Tell gcc we read from memory instead of writing: this is because
 173  * we do not write to any memory gcc knows about, so there are no
 174  * aliasing issues.
 175  */
 176 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
 177         __asm__ __volatile__(                                   \
 178                 "1:     mov"itype" %"rtype"1,%2\n"              \
 179                 "2:\n"                                          \
 180                 ".section .fixup,\"ax\"\n"                      \
 181                 "3:     mov %3,%0\n"                            \
 182                 "       jmp 2b\n"                               \
 183                 ".previous\n"                                   \
 184                 ".section __ex_table,\"a\"\n"                   \
 185                 "       .align 8\n"                             \
 186                 "       .quad 1b,3b\n"                          \
 187                 ".previous"                                     \
 188                 : "=r"(err)                                     \
 189                 : ltype (x), "m"(__m(addr)), "i"(errno), "0"(err))
 190
 191
 192 #define __get_user_nocheck(x,ptr,size)                          \
 193 ({                                                              \
 194         int __gu_err;                                           \
 195         unsigned long __gu_val;                                 \
 196         __get_user_size(__gu_val,(ptr),(size),__gu_err);        \
 197         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 198         __gu_err;                                               \
 199 })
 200
 201 extern int __get_user_1(void);
 202 extern int __get_user_2(void);
 203 extern int __get_user_4(void);
 204 extern int __get_user_8(void);
 205 extern int __get_user_bad(void);
 206
 207 #define __get_user_size(x,ptr,size,retval)                              \
 208 do {                                                                    \
 209         retval = 0;                                                     \
 210         __chk_user_ptr(ptr);                                            \
 211         switch (size) {                                                 \
 212           case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
 213           case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
 214           case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
 215           case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
 216           default: (x) = __get_user_bad();                              \
 217         }                                                               \
 218 } while (0)
 219
 220 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
 221         __asm__ __volatile__(                                   \
 222                 "1:     mov"itype" %2,%"rtype"1\n"              \
 223                 "2:\n"                                          \
 224                 ".section .fixup,\"ax\"\n"                      \
 225                 "3:     mov %3,%0\n"                            \
 226                 "       xor"itype" %"rtype"1,%"rtype"1\n"       \
 227                 "       jmp 2b\n"                               \
 228                 ".previous\n"                                   \
 229                 ".section __ex_table,\"a\"\n"                   \
 230                 "       .align 8\n"                             \
 231                 "       .quad 1b,3b\n"                          \
 232                 ".previous"                                     \
 233                 : "=r"(err), ltype (x)                          \
 234                 : "m"(__m(addr)), "i"(errno), "0"(err))
 235
 236 /*
 237  * Copy To/From Userspace
 238  */
 239
 240 /* Handles exceptions in both to and from, but doesn't do access_ok */
 241 extern unsigned long copy_user_generic(void *to, const void *from, unsigned len);
 242
 243 extern unsigned long copy_to_user(void __user *to, const void *from, unsigned len);
 244 extern unsigned long copy_from_user(void *to, const void __user *from, unsigned len);
 245 extern unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len);
 246
 247 static inline int __copy_from_user(void *dst, const void __user *src, unsigned size)
 248 {
 249        int ret = 0;
 250         if (!__builtin_constant_p(size))
 251                 return copy_user_generic(dst,(__force void *)src,size);
 252         switch (size) {
 253         case 1:__get_user_asm(*(u8*)dst,(u8 __user *)src,ret,"b","b","=q",1);
 254                 return ret;
 255         case 2:__get_user_asm(*(u16*)dst,(u16 __user *)src,ret,"w","w","=r",2);
 256                 return ret;
 257         case 4:__get_user_asm(*(u32*)dst,(u32 __user *)src,ret,"l","k","=r",4);
 258                 return ret;
 259         case 8:__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",8);
 260                 return ret;
 261         case 10:
 262                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
 263                 if (unlikely(ret)) return ret;
 264                 __get_user_asm(*(u16*)(8+(char*)dst),(u16 __user *)(8+(char __user *)src),ret,"w","w","=r",2);
 265                 return ret;
 266         case 16:
 267                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
 268                 if (unlikely(ret)) return ret;
 269                 __get_user_asm(*(u64*)(8+(char*)dst),(u64 __user *)(8+(char __user *)src),ret,"q","","=r",8);
 270                 return ret;
 271         default:
 272                 return copy_user_generic(dst,(__force void *)src,size);
 273         }
 274 }
 275
 276 static inline int __copy_to_user(void __user *dst, const void *src, unsigned size)
 277 {
 278        int ret = 0;
 279         if (!__builtin_constant_p(size))
 280                 return copy_user_generic((__force void *)dst,src,size);
 281         switch (size) {
 282         case 1:__put_user_asm(*(u8*)src,(u8 __user *)dst,ret,"b","b","iq",1);
 283                 return ret;
 284         case 2:__put_user_asm(*(u16*)src,(u16 __user *)dst,ret,"w","w","ir",2);
 285                 return ret;
 286         case 4:__put_user_asm(*(u32*)src,(u32 __user *)dst,ret,"l","k","ir",4);
 287                 return ret;
 288         case 8:__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",8);
 289                 return ret;
 290         case 10:
 291                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",10);
 292                 if (unlikely(ret)) return ret;
 293                 asm("":::"memory");
 294                 __put_user_asm(4[(u16*)src],4+(u16 __user *)dst,ret,"w","w","ir",2);
 295                 return ret;
 296         case 16:
 297                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",16);
 298                 if (unlikely(ret)) return ret;
 299                 asm("":::"memory");
 300                 __put_user_asm(1[(u64*)src],1+(u64 __user *)dst,ret,"q","","ir",8);
 301                 return ret;
 302         default:
 303                 return copy_user_generic((__force void *)dst,src,size);
 304         }
 305 }
 306
 307
 308 static inline int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 309 {
 310        int ret = 0;
 311         if (!__builtin_constant_p(size))
 312                 return copy_user_generic((__force void *)dst,(__force void *)src,size);
 313         switch (size) {
 314         case 1: {
 315                 u8 tmp;
 316                 __get_user_asm(tmp,(u8 __user *)src,ret,"b","b","=q",1);
 317                 if (likely(!ret))
 318                         __put_user_asm(tmp,(u8 __user *)dst,ret,"b","b","iq",1);
 319                 return ret;
 320         }
 321         case 2: {
 322                 u16 tmp;
 323                 __get_user_asm(tmp,(u16 __user *)src,ret,"w","w","=r",2);
 324                 if (likely(!ret))
 325                         __put_user_asm(tmp,(u16 __user *)dst,ret,"w","w","ir",2);
 326                 return ret;
 327         }
 328
 329         case 4: {
 330                 u32 tmp;
 331                 __get_user_asm(tmp,(u32 __user *)src,ret,"l","k","=r",4);
 332                 if (likely(!ret))
 333                         __put_user_asm(tmp,(u32 __user *)dst,ret,"l","k","ir",4);
 334                 return ret;
 335         }
 336         case 8: {
 337                 u64 tmp;
 338                 __get_user_asm(tmp,(u64 __user *)src,ret,"q","","=r",8);
 339                 if (likely(!ret))
 340                         __put_user_asm(tmp,(u64 __user *)dst,ret,"q","","ir",8);
 341                 return ret;
 342         }
 343         default:
 344                 return copy_user_generic((__force void *)dst,(__force void *)src,size);
 345         }
 346 }
 347
 348 long strncpy_from_user(char *dst, const char __user *src, long count);
 349 long __strncpy_from_user(char *dst, const char __user *src, long count);
 350 long strnlen_user(const char __user *str, long n);
 351 long strlen_user(const char __user *str);
 352 unsigned long clear_user(void __user *mem, unsigned long len);
 353 unsigned long __clear_user(void __user *mem, unsigned long len);
 354
 355 #define __copy_to_user_inatomic __copy_to_user
 356 #define __copy_from_user_inatomic __copy_from_user
 357
 358 #endif /* __X86_64_UACCESS_H */