kitten/include/arch-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 <lwk/compiler.h>
   8 #include <lwk/errno.h>
   9 #include <lwk/prefetch.h>
  10 #include <lwk/task.h>
  11 #include <arch/page.h>
  12
  13 #define VERIFY_READ 0
  14 #define VERIFY_WRITE 1
  15
  16 /*
  17  * The fs value determines whether argument validity checking should be
  18  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  19  * get_fs() == KERNEL_DS, checking is bypassed.
  20  *
  21  * For historical reasons, these macros are grossly misnamed.
  22  */
  23
  24 #define KERNEL_DS       0xFFFFFFFFFFFFFFFFUL
  25 #define USER_DS         PAGE_OFFSET
  26
  27 #define get_ds()        (KERNEL_DS)
  28 #define get_fs()        (current->arch.addr_limit)
  29 #define set_fs(x)       (current->arch.addr_limit = (x))
  30
  31 #define segment_eq(a,b) ((a).seg == (b).seg)
  32
  33 #define __addr_ok(addr) (!((unsigned long)(addr) & (current->arch.addr_limit)))
  34
  35 /*
  36  * Uhhuh, this needs 65-bit arithmetic. We have a carry..
  37  */
  38 #define __range_not_ok(addr,size) ({ \
  39         unsigned long flag,sum; \
  40         __chk_user_ptr(addr); \
  41         asm("# range_ok\n\r" \
  42                 "addq %3,%1 ; sbbq %0,%0 ; cmpq %1,%4 ; sbbq $0,%0"  \
  43                 :"=&r" (flag), "=r" (sum) \
  44                 :"1" (addr),"g" ((long)(size)),"g" (current->arch.addr_limit)); \
  45         flag; })
  46
  47 #define access_ok(type, addr, size) (__range_not_ok(addr,size) == 0)
  48
  49 /*
  50  * These are the main single-value transfer routines.  They automatically
  51  * use the right size if we just have the right pointer type.
  52  *
  53  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  54  * and yet we don't want to do any pointers, because that is too much
  55  * of a performance impact. Thus we have a few rather ugly macros here,
  56  * and hide all the ugliness from the user.
  57  *
  58  * The "__xxx" versions of the user access functions are versions that
  59  * do not verify the address space, that must have been done previously
  60  * with a separate "access_ok()" call (this is used when we do multiple
  61  * accesses to the same area of user memory).
  62  */
  63
  64 #define __get_user_x(size,ret,x,ptr) \
  65         asm volatile("call __get_user_" #size \
  66                 :"=a" (ret),"=d" (x) \
  67                 :"c" (ptr) \
  68                 :"r8")
  69
  70 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
  71 #define get_user(x,ptr)                                                 \
  72 ({      unsigned long __val_gu;                                         \
  73         int __ret_gu;                                                   \
  74         __chk_user_ptr(ptr);                                            \
  75         switch(sizeof (*(ptr))) {                                       \
  76         case 1:  __get_user_x(1,__ret_gu,__val_gu,ptr); break;          \
  77         case 2:  __get_user_x(2,__ret_gu,__val_gu,ptr); break;          \
  78         case 4:  __get_user_x(4,__ret_gu,__val_gu,ptr); break;          \
  79         case 8:  __get_user_x(8,__ret_gu,__val_gu,ptr); break;          \
  80         default: __get_user_bad(); break;                               \
  81         }                                                               \
  82         (x) = (typeof(*(ptr)))__val_gu;                         \
  83         __ret_gu;                                                       \
  84 })
  85
  86 extern void __put_user_1(void);
  87 extern void __put_user_2(void);
  88 extern void __put_user_4(void);
  89 extern void __put_user_8(void);
  90 extern void __put_user_bad(void);
  91
  92 #define __put_user_x(size,ret,x,ptr)                                    \
  93         asm volatile("call __put_user_" #size                   \
  94                 :"=a" (ret)                                             \
  95                 :"c" (ptr),"d" (x)                                      \
  96                 :"r8")
  97
  98 #define put_user(x,ptr)                                                 \
  99   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 100
 101 #define __get_user(x,ptr) \
 102   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
 103 #define __put_user(x,ptr) \
 104   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 105
 106 #define __get_user_unaligned __get_user
 107 #define __put_user_unaligned __put_user
 108
 109 #define __put_user_nocheck(x,ptr,size)                  \
 110 ({                                                      \
 111         int __pu_err;                                   \
 112         __put_user_size((x),(ptr),(size),__pu_err);     \
 113         __pu_err;                                       \
 114 })
 115
 116
 117 #define __put_user_check(x,ptr,size)                    \
 118 ({                                                      \
 119         int __pu_err;                                   \
 120         typeof(*(ptr)) __user *__pu_addr = (ptr);       \
 121         switch (size) {                                 \
 122         case 1: __put_user_x(1,__pu_err,x,__pu_addr); break;    \
 123         case 2: __put_user_x(2,__pu_err,x,__pu_addr); break;    \
 124         case 4: __put_user_x(4,__pu_err,x,__pu_addr); break;    \
 125         case 8: __put_user_x(8,__pu_err,x,__pu_addr); break;    \
 126         default: __put_user_bad();                      \
 127         }                                               \
 128         __pu_err;                                       \
 129 })
 130
 131 #define __put_user_size(x,ptr,size,retval)                              \
 132 do {                                                                    \
 133         retval = 0;                                                     \
 134         __chk_user_ptr(ptr);                                            \
 135         switch (size) {                                                 \
 136           case 1: __put_user_asm(x,ptr,retval,"b","b","iq",-EFAULT); break;\
 137           case 2: __put_user_asm(x,ptr,retval,"w","w","ir",-EFAULT); break;\
 138           case 4: __put_user_asm(x,ptr,retval,"l","k","ir",-EFAULT); break;\
 139           case 8: __put_user_asm(x,ptr,retval,"q","","Zr",-EFAULT); break;\
 140           default: __put_user_bad();                                    \
 141         }                                                               \
 142 } while (0)
 143
 144 /* FIXME: this hack is definitely wrong -AK */
 145 struct __large_struct { unsigned long buf[100]; };
 146 #define __m(x) (*(struct __large_struct __user *)(x))
 147
 148 /*
 149  * Tell gcc we read from memory instead of writing: this is because
 150  * we do not write to any memory gcc knows about, so there are no
 151  * aliasing issues.
 152  */
 153 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
 154         asm volatile(                                   \
 155                 "1:     mov"itype" %"rtype"1,%2\n"              \
 156                 "2:\n"                                          \
 157                 ".section .fixup,\"ax\"\n"                      \
 158                 "3:     mov %3,%0\n"                            \
 159                 "       jmp 2b\n"                               \
 160                 ".previous\n"                                   \
 161                 ".section __ex_table,\"a\"\n"                   \
 162                 "       .align 8\n"                             \
 163                 "       .quad 1b,3b\n"                          \
 164                 ".previous"                                     \
 165                 : "=r"(err)                                     \
 166                 : ltype (x), "m"(__m(addr)), "i"(errno), "0"(err))
 167
 168
 169 #define __get_user_nocheck(x,ptr,size)                          \
 170 ({                                                              \
 171         int __gu_err;                                           \
 172         unsigned long __gu_val;                                 \
 173         __get_user_size(__gu_val,(ptr),(size),__gu_err);        \
 174         (x) = (typeof(*(ptr)))__gu_val;                 \
 175         __gu_err;                                               \
 176 })
 177
 178 extern int __get_user_1(void);
 179 extern int __get_user_2(void);
 180 extern int __get_user_4(void);
 181 extern int __get_user_8(void);
 182 extern int __get_user_bad(void);
 183
 184 #define __get_user_size(x,ptr,size,retval)                              \
 185 do {                                                                    \
 186         retval = 0;                                                     \
 187         __chk_user_ptr(ptr);                                            \
 188         switch (size) {                                                 \
 189           case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
 190           case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
 191           case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
 192           case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
 193           default: (x) = __get_user_bad();                              \
 194         }                                                               \
 195 } while (0)
 196
 197 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errno)        \
 198         asm volatile(                                   \
 199                 "1:     mov"itype" %2,%"rtype"1\n"              \
 200                 "2:\n"                                          \
 201                 ".section .fixup,\"ax\"\n"                      \
 202                 "3:     mov %3,%0\n"                            \
 203                 "       xor"itype" %"rtype"1,%"rtype"1\n"       \
 204                 "       jmp 2b\n"                               \
 205                 ".previous\n"                                   \
 206                 ".section __ex_table,\"a\"\n"                   \
 207                 "       .align 8\n"                             \
 208                 "       .quad 1b,3b\n"                          \
 209                 ".previous"                                     \
 210                 : "=r"(err), ltype (x)                          \
 211                 : "m"(__m(addr)), "i"(errno), "0"(err))
 212
 213 /*
 214  * Copy To/From Userspace
 215  */
 216
 217 /* Handles exceptions in both to and from, but doesn't do access_ok */
 218 __must_check unsigned long
 219 copy_user_generic(void *to, const void *from, unsigned len);
 220
 221 __must_check unsigned long
 222 copy_to_user(void __user *to, const void *from, unsigned len);
 223 __must_check unsigned long
 224 copy_from_user(void *to, const void __user *from, unsigned len);
 225 __must_check unsigned long
 226 copy_in_user(void __user *to, const void __user *from, unsigned len);
 227
 228 static __always_inline __must_check
 229 int __copy_from_user(void *dst, const void __user *src, unsigned size)
 230 {
 231         int ret = 0;
 232         if (!__builtin_constant_p(size))
 233                 return copy_user_generic(dst,(__force void *)src,size);
 234         switch (size) {
 235         case 1:__get_user_asm(*(u8*)dst,(u8 __user *)src,ret,"b","b","=q",1);
 236                 return ret;
 237         case 2:__get_user_asm(*(u16*)dst,(u16 __user *)src,ret,"w","w","=r",2);
 238                 return ret;
 239         case 4:__get_user_asm(*(u32*)dst,(u32 __user *)src,ret,"l","k","=r",4);
 240                 return ret;
 241         case 8:__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",8);
 242                 return ret;
 243         case 10:
 244                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
 245                 if (unlikely(ret)) return ret;
 246                 __get_user_asm(*(u16*)(8+(char*)dst),(u16 __user *)(8+(char __user *)src),ret,"w","w","=r",2);
 247                 return ret;
 248         case 16:
 249                 __get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
 250                 if (unlikely(ret)) return ret;
 251                 __get_user_asm(*(u64*)(8+(char*)dst),(u64 __user *)(8+(char __user *)src),ret,"q","","=r",8);
 252                 return ret;
 253         default:
 254                 return copy_user_generic(dst,(__force void *)src,size);
 255         }
 256 }
 257
 258 static __always_inline __must_check
 259 int __copy_to_user(void __user *dst, const void *src, unsigned size)
 260 {
 261         int ret = 0;
 262         if (!__builtin_constant_p(size))
 263                 return copy_user_generic((__force void *)dst,src,size);
 264         switch (size) {
 265         case 1:__put_user_asm(*(u8*)src,(u8 __user *)dst,ret,"b","b","iq",1);
 266                 return ret;
 267         case 2:__put_user_asm(*(u16*)src,(u16 __user *)dst,ret,"w","w","ir",2);
 268                 return ret;
 269         case 4:__put_user_asm(*(u32*)src,(u32 __user *)dst,ret,"l","k","ir",4);
 270                 return ret;
 271         case 8:__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",8);
 272                 return ret;
 273         case 10:
 274                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",10);
 275                 if (unlikely(ret)) return ret;
 276                 asm("":::"memory");
 277                 __put_user_asm(4[(u16*)src],4+(u16 __user *)dst,ret,"w","w","ir",2);
 278                 return ret;
 279         case 16:
 280                 __put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",16);
 281                 if (unlikely(ret)) return ret;
 282                 asm("":::"memory");
 283                 __put_user_asm(1[(u64*)src],1+(u64 __user *)dst,ret,"q","","ir",8);
 284                 return ret;
 285         default:
 286                 return copy_user_generic((__force void *)dst,src,size);
 287         }
 288 }
 289
 290 static __always_inline __must_check
 291 int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 292 {
 293         int ret = 0;
 294         if (!__builtin_constant_p(size))
 295                 return copy_user_generic((__force void *)dst,(__force void *)src,size);
 296         switch (size) {
 297         case 1: {
 298                 u8 tmp;
 299                 __get_user_asm(tmp,(u8 __user *)src,ret,"b","b","=q",1);
 300                 if (likely(!ret))
 301                         __put_user_asm(tmp,(u8 __user *)dst,ret,"b","b","iq",1);
 302                 return ret;
 303         }
 304         case 2: {
 305                 u16 tmp;
 306                 __get_user_asm(tmp,(u16 __user *)src,ret,"w","w","=r",2);
 307                 if (likely(!ret))
 308                         __put_user_asm(tmp,(u16 __user *)dst,ret,"w","w","ir",2);
 309                 return ret;
 310         }
 311
 312         case 4: {
 313                 u32 tmp;
 314                 __get_user_asm(tmp,(u32 __user *)src,ret,"l","k","=r",4);
 315                 if (likely(!ret))
 316                         __put_user_asm(tmp,(u32 __user *)dst,ret,"l","k","ir",4);
 317                 return ret;
 318         }
 319         case 8: {
 320                 u64 tmp;
 321                 __get_user_asm(tmp,(u64 __user *)src,ret,"q","","=r",8);
 322                 if (likely(!ret))
 323                         __put_user_asm(tmp,(u64 __user *)dst,ret,"q","","ir",8);
 324                 return ret;
 325         }
 326         default:
 327                 return copy_user_generic((__force void *)dst,(__force void *)src,size);
 328         }
 329 }
 330
 331 __must_check long
 332 strncpy_from_user(char *dst, const char __user *src, long count);
 333 __must_check long
 334 __strncpy_from_user(char *dst, const char __user *src, long count);
 335 __must_check long strnlen_user(const char __user *str, long n);
 336 __must_check long __strnlen_user(const char __user *str, long n);
 337 __must_check long strlen_user(const char __user *str);
 338 __must_check unsigned long clear_user(void __user *mem, unsigned long len);
 339 __must_check unsigned long __clear_user(void __user *mem, unsigned long len);
 340
 341 __must_check long __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size);
 342
 343 static __must_check __always_inline int
 344 __copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
 345 {
 346         return copy_user_generic((__force void *)dst, src, size);
 347 }
 348
 349 #endif /* _X86_64_UACCESS_H */