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 /* this function will go away soon - use access_ok() instead */
  53 extern inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size)
  54 {
  55         return access_ok(type,addr,size) ? 0 : -EFAULT;
  56 }
  57
  58
  59 /*
  60  * The exception table consists of pairs of addresses: the first is the
  61  * address of an instruction that is allowed to fault, and the second is
  62  * the address at which the program should continue.  No registers are
  63  * modified, so it is entirely up to the continuation code to figure out
  64  * what to do.
  65  *
  66  * All the routines below use bits of fixup code that are out of line
  67  * with the main instruction path.  This means when everything is well,
  68  * we don't even have to jump over them.  Further, they do not intrude
  69  * on our cache or tlb entries.
  70  */
  71
  72 struct exception_table_entry
  73 {
  74         unsigned long insn, fixup;
  75 };
  76
  77 #define ARCH_HAS_SEARCH_EXTABLE
  78
  79 /*
  80  * These are the main single-value transfer routines.  They automatically
  81  * use the right size if we just have the right pointer type.
  82  *
  83  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  84  * and yet we don't want to do any pointers, because that is too much
  85  * of a performance impact. Thus we have a few rather ugly macros here,
  86  * and hide all the ugliness from the user.
  87  *
  88  * The "__xxx" versions of the user access functions are versions that
  89  * do not verify the address space, that must have been done previously
  90  * with a separate "access_ok()" call (this is used when we do multiple
  91  * accesses to the same area of user memory).
  92  */
  93
  94 #define __get_user_x(size,ret,x,ptr) \
  95         __asm__ __volatile__("call __get_user_" #size \
  96                 :"=a" (ret),"=d" (x) \
  97                 :"c" (ptr) \
  98                 :"r8")
  99
 100 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
 101 #define get_user(x,ptr)                                                 \
 102 ({      unsigned long __val_gu;                                         \
 103         int __ret_gu;                                                   \
 104         __chk_user_ptr(ptr);                                            \
 105         switch(sizeof (*(ptr))) {                                       \
 106         case 1:  __get_user_x(1,__ret_gu,__val_gu,ptr); break;          \
 107         case 2:  __get_user_x(2,__ret_gu,__val_gu,ptr); break;          \
 108         case 4:  __get_user_x(4,__ret_gu,__val_gu,ptr); break;          \
 109         case 8:  __get_user_x(8,__ret_gu,__val_gu,ptr); break;          \
 110         default: __get_user_bad(); break;                               \
 111         }                                                               \
 112         (x) = (__typeof__(*(ptr)))__val_gu;                             \
 113         __ret_gu;                                                       \
 114 })
 115
 116 extern void __put_user_1(void);
 117 extern void __put_user_2(void);
 118 extern void __put_user_4(void);
 119 extern void __put_user_8(void);
 120 extern void __put_user_bad(void);
 121
 122 #define __put_user_x(size,ret,x,ptr)                                    \
 123         __asm__ __volatile__("call __put_user_" #size                   \
 124                 :"=a" (ret)                                             \
 125                 :"c" (ptr),"d" (x)                                      \
 126                 :"r8")
 127
 128 #define put_user(x,ptr)                                                 \
 129   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 130
 131 #define __get_user(x,ptr) \
 132   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
 133 #define __put_user(x,ptr) \
 134   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 135
 136 #define __get_user_unaligned __get_user
 137 #define __put_user_unaligned __put_user
 138
 139 #define __put_user_nocheck(x,ptr,size)                  \
 140 ({                                                      \
 141         int __pu_err;                                   \
 142         __put_user_size((x),(ptr),(size),__pu_err);     \
 143         __pu_err;                                       \
 144 })
 145
 146
 147 #define __put_user_check(x,ptr,size)                    \
 148 ({                                                      \
 149         int __pu_err;                                   \
 150         __typeof__(*(ptr)) __user *__pu_addr = (ptr);   \
 151         switch (size) {                                 \
 152         case 1: __put_user_x(1,__pu_err,x,__pu_addr); break;    \
 153         case 2: __put_user_x(2,__pu_err,x,__pu_addr); break;    \
 154         case 4: __put_user_x(4,__pu_err,x,__pu_addr); break;    \
 155         case 8: __put_user_x(8,__pu_err,x,__pu_addr); break;    \
 156         default: __put_user_bad();                      \
 157         }                                               \
 158         __pu_err;                                       \
 159 })
 160
 161 #define __put_user_size(x,ptr,size,retval)                              \
 162 do {                                                                    \
 163         retval = 0;                                                     \
 164         __chk_user_ptr(ptr);                                            \
 165         switch (size) {                                                 \
 166           case 1: __put_user_asm(x,ptr,retval,"b","b","iq",-EFAULT); break;\
 167           case 2: __put_user_asm(x,ptr,retval,"w","w","ir",-EFAULT); break;\
 168           case 4: __put_user_asm(x,ptr,retval,"l","k","ir",-EFAULT); break;\
 169           case 8: __put_user_asm(x,ptr,retval,"q","","ir",-EFAULT); break;\
 170           default: __put_user_bad();                                    \
 171         }                                                               \
 172 } while (0)
 173
 174 /* FIXME: this hack is definitely wrong -AK */
 175 struct __large_struct { unsigned long buf[100]; };
 176 #define __m(x) (*(struct __large_struct __user *)(x))
 177
 178 /*
 179  * Tell gcc we read from memory instead of writing: this is because
 180  * we do not write to any memory gcc knows about, so there are no
 181  * aliasing issues.
 182  */
 183 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
 184         __asm__ __volatile__(                                   \
 185                 "1:     mov"itype" %"rtype"1,%2\n"              \
 186                 "2:\n"                                          \
 187                 ".section .fixup,\"ax\"\n"                      \
 188                 "3:     mov %3,%0\n"                            \
 189                 "       jmp 2b\n"                               \
 190                 ".previous\n"                                   \
 191                 ".section __ex_table,\"a\"\n"                   \
 192                 "       .align 8\n"                             \
 193                 "       .quad 1b,3b\n"                          \
 194                 ".previous"                                     \
 195                 : "=r"(err)                                     \
 196                 : ltype (x), "m"(__m(addr)), "i"(errno), "0"(err))
 197
 198
 199 #define __get_user_nocheck(x,ptr,size)                          \
 200 ({                                                              \
 201         int __gu_err;                                           \
 202         unsigned long __gu_val;                                 \
 203         __get_user_size(__gu_val,(ptr),(size),__gu_err);        \
 204         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 205         __gu_err;                                               \
 206 })
 207
 208 extern int __get_user_1(void);
 209 extern int __get_user_2(void);
 210 extern int __get_user_4(void);
 211 extern int __get_user_8(void);
 212 extern int __get_user_bad(void);
 213
 214 #define __get_user_size(x,ptr,size,retval)                              \
 215 do {                                                                    \
 216         retval = 0;                                                     \
 217         __chk_user_ptr(ptr);                                            \
 218         switch (size) {                                                 \
 219           case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
 220           case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
 221           case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
 222           case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
 223           default: (x) = __get_user_bad();                              \
 224         }                                                               \
 225 } while (0)
 226
 227 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
 228         __asm__ __volatile__(                                   \
 229                 "1:     mov"itype" %2,%"rtype"1\n"              \
 230                 "2:\n"                                          \
 231                 ".section .fixup,\"ax\"\n"                      \
 232                 "3:     mov %3,%0\n"                            \
 233                 "       xor"itype" %"rtype"1,%"rtype"1\n"       \
 234                 "       jmp 2b\n"                               \
 235                 ".previous\n"                                   \
 236                 ".section __ex_table,\"a\"\n"                   \
 237                 "       .align 8\n"                             \
 238                 "       .quad 1b,3b\n"                          \
 239                 ".previous"                                     \
 240                 : "=r"(err), ltype (x)                          \
 241                 : "m"(__m(addr)), "i"(errno), "0"(err))
 242
 243 /*
 244  * Copy To/From Userspace
 245  */
 246
 247 /* Handles exceptions in both to and from, but doesn't do access_ok */
 248 extern unsigned long copy_user_generic(void *to, const void *from, unsigned len);
 249
 250 extern unsigned long copy_to_user(void __user *to, const void *from, unsigned len);
 251 extern unsigned long copy_from_user(void *to, const void __user *from, unsigned len);
 252 extern unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len);
 253
 254 static inline int __copy_from_user(void *dst, const void __user *src, unsigned size)
 255 {
 256        int ret = 0;
 257         if (!__builtin_constant_p(size))
 258                 return copy_user_generic(dst,(__force void *)src,size);
 259         switch (size) {
 260         case 1:__get_user_asm(*(u8*)dst,(u8 __user *)src,ret,"b","b","=q",1);
 261                 return ret;
 262         case 2:__get_user_asm(*(u16*)dst,(u16 __user *)src,ret,"w","w","=r",2);
 263                 return ret;
 264         case 4:__get_user_asm(*(u32*)dst,(u32 __user *)src,ret,"l","k","=r",4);
 265                 return ret;
 266         case 8:__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",8);
 267                 return ret;
 268         case 10:
 269                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
 270                 if (unlikely(ret)) return ret;
 271                 __get_user_asm(*(u16*)(8+(char*)dst),(u16 __user *)(8+(char __user *)src),ret,"w","w","=r",2);
 272                 return ret;
 273         case 16:
 274                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
 275                 if (unlikely(ret)) return ret;
 276                 __get_user_asm(*(u64*)(8+(char*)dst),(u64 __user *)(8+(char __user *)src),ret,"q","","=r",8);
 277                 return ret;
 278         default:
 279                 return copy_user_generic(dst,(__force void *)src,size);
 280         }
 281 }
 282
 283 static inline int __copy_to_user(void __user *dst, const void *src, unsigned size)
 284 {
 285        int ret = 0;
 286         if (!__builtin_constant_p(size))
 287                 return copy_user_generic((__force void *)dst,src,size);
 288         switch (size) {
 289         case 1:__put_user_asm(*(u8*)src,(u8 __user *)dst,ret,"b","b","iq",1);
 290                 return ret;
 291         case 2:__put_user_asm(*(u16*)src,(u16 __user *)dst,ret,"w","w","ir",2);
 292                 return ret;
 293         case 4:__put_user_asm(*(u32*)src,(u32 __user *)dst,ret,"l","k","ir",4);
 294                 return ret;
 295         case 8:__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",8);
 296                 return ret;
 297         case 10:
 298                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",10);
 299                 if (unlikely(ret)) return ret;
 300                 asm("":::"memory");
 301                 __put_user_asm(4[(u16*)src],4+(u16 __user *)dst,ret,"w","w","ir",2);
 302                 return ret;
 303         case 16:
 304                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",16);
 305                 if (unlikely(ret)) return ret;
 306                 asm("":::"memory");
 307                 __put_user_asm(1[(u64*)src],1+(u64 __user *)dst,ret,"q","","ir",8);
 308                 return ret;
 309         default:
 310                 return copy_user_generic((__force void *)dst,src,size);
 311         }
 312 }
 313
 314
 315 static inline int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 316 {
 317        int ret = 0;
 318         if (!__builtin_constant_p(size))
 319                 return copy_user_generic((__force void *)dst,(__force void *)src,size);
 320         switch (size) {
 321         case 1: {
 322                 u8 tmp;
 323                 __get_user_asm(tmp,(u8 __user *)src,ret,"b","b","=q",1);
 324                 if (likely(!ret))
 325                         __put_user_asm(tmp,(u8 __user *)dst,ret,"b","b","iq",1);
 326                 return ret;
 327         }
 328         case 2: {
 329                 u16 tmp;
 330                 __get_user_asm(tmp,(u16 __user *)src,ret,"w","w","=r",2);
 331                 if (likely(!ret))
 332                         __put_user_asm(tmp,(u16 __user *)dst,ret,"w","w","ir",2);
 333                 return ret;
 334         }
 335
 336         case 4: {
 337                 u32 tmp;
 338                 __get_user_asm(tmp,(u32 __user *)src,ret,"l","k","=r",4);
 339                 if (likely(!ret))
 340                         __put_user_asm(tmp,(u32 __user *)dst,ret,"l","k","ir",4);
 341                 return ret;
 342         }
 343         case 8: {
 344                 u64 tmp;
 345                 __get_user_asm(tmp,(u64 __user *)src,ret,"q","","=r",8);
 346                 if (likely(!ret))
 347                         __put_user_asm(tmp,(u64 __user *)dst,ret,"q","","ir",8);
 348                 return ret;
 349         }
 350         default:
 351                 return copy_user_generic((__force void *)dst,(__force void *)src,size);
 352         }
 353 }
 354
 355 long strncpy_from_user(char *dst, const char __user *src, long count);
 356 long __strncpy_from_user(char *dst, const char __user *src, long count);
 357 long strnlen_user(const char __user *str, long n);
 358 long strlen_user(const char __user *str);
 359 unsigned long clear_user(void __user *mem, unsigned long len);
 360 unsigned long __clear_user(void __user *mem, unsigned long len);
 361
 362 #define __copy_to_user_inatomic __copy_to_user
 363 #define __copy_from_user_inatomic __copy_from_user
 364
 365 #endif /* __X86_64_UACCESS_H */