include/asm-arm/uaccess.h

   1 /*
   2  *  linux/include/asm-arm/uaccess.h
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8 #ifndef _ASMARM_UACCESS_H
   9 #define _ASMARM_UACCESS_H
  10
  11 /*
  12  * User space memory access functions
  13  */
  14 #include <linux/sched.h>
  15 #include <asm/errno.h>
  16 #include <asm/memory.h>
  17 #include <asm/domain.h>
  18 #include <asm/system.h>
  19
  20 #define VERIFY_READ 0
  21 #define VERIFY_WRITE 1
  22
  23 /*
  24  * The exception table consists of pairs of addresses: the first is the
  25  * address of an instruction that is allowed to fault, and the second is
  26  * the address at which the program should continue.  No registers are
  27  * modified, so it is entirely up to the continuation code to figure out
  28  * what to do.
  29  *
  30  * All the routines below use bits of fixup code that are out of line
  31  * with the main instruction path.  This means when everything is well,
  32  * we don't even have to jump over them.  Further, they do not intrude
  33  * on our cache or tlb entries.
  34  */
  35
  36 struct exception_table_entry
  37 {
  38         unsigned long insn, fixup;
  39 };
  40
  41 extern int fixup_exception(struct pt_regs *regs);
  42
  43 /*
  44  * Note that this is actually 0x1,0000,0000
  45  */
  46 #define KERNEL_DS       0x00000000
  47 #define USER_DS         TASK_SIZE
  48
  49 #define get_ds()        (KERNEL_DS)
  50 #define get_fs()        (current_thread_info()->addr_limit)
  51
  52 static inline void set_fs (mm_segment_t fs)
  53 {
  54         current_thread_info()->addr_limit = fs;
  55         modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
  56 }
  57
  58 #define segment_eq(a,b) ((a) == (b))
  59
  60 #define __addr_ok(addr) ({ \
  61         unsigned long flag; \
  62         __asm__("cmp %2, %0; movlo %0, #0" \
  63                 : "=&r" (flag) \
  64                 : "0" (current_thread_info()->addr_limit), "r" (addr) \
  65                 : "cc"); \
  66         (flag == 0); })
  67
  68 /* We use 33-bit arithmetic here... */
  69 #define __range_ok(addr,size) ({ \
  70         unsigned long flag, sum; \
  71         __chk_user_ptr(addr);   \
  72         __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
  73                 : "=&r" (flag), "=&r" (sum) \
  74                 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
  75                 : "cc"); \
  76         flag; })
  77
  78 #define access_ok(type,addr,size)       (__range_ok(addr,size) == 0)
  79
  80 /* this function will go away soon - use access_ok() instead */
  81 static inline int __deprecated verify_area(int type, const void __user *addr, unsigned long size)
  82 {
  83         return access_ok(type, addr, size) ? 0 : -EFAULT;
  84 }
  85
  86 /*
  87  * Single-value transfer routines.  They automatically use the right
  88  * size if we just have the right pointer type.  Note that the functions
  89  * which read from user space (*get_*) need to take care not to leak
  90  * kernel data even if the calling code is buggy and fails to check
  91  * the return value.  This means zeroing out the destination variable
  92  * or buffer on error.  Normally this is done out of line by the
  93  * fixup code, but there are a few places where it intrudes on the
  94  * main code path.  When we only write to user space, there is no
  95  * problem.
  96  *
  97  * The "__xxx" versions of the user access functions do not verify the
  98  * address space - it must have been done previously with a separate
  99  * "access_ok()" call.
 100  *
 101  * The "xxx_error" versions set the third argument to EFAULT if an
 102  * error occurs, and leave it unchanged on success.  Note that these
 103  * versions are void (ie, don't return a value as such).
 104  */
 105
 106 extern int __get_user_1(void *);
 107 extern int __get_user_2(void *);
 108 extern int __get_user_4(void *);
 109 extern int __get_user_8(void *);
 110 extern int __get_user_bad(void);
 111
 112 #define __get_user_x(__r2,__p,__e,__s,__i...)                           \
 113            __asm__ __volatile__ (                                       \
 114                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 115                 "bl     __get_user_" #__s                               \
 116                 : "=&r" (__e), "=r" (__r2)                              \
 117                 : "0" (__p)                                             \
 118                 : __i, "cc")
 119
 120 #define get_user(x,p)                                                   \
 121         ({                                                              \
 122                 const register typeof(*(p)) __user *__p asm("r0") = (p);\
 123                 register typeof(*(p)) __r2 asm("r2");                   \
 124                 register int __e asm("r0");                             \
 125                 switch (sizeof(*(__p))) {                               \
 126                 case 1:                                                 \
 127                         __get_user_x(__r2, __p, __e, 1, "lr");          \
 128                         break;                                          \
 129                 case 2:                                                 \
 130                         __get_user_x(__r2, __p, __e, 2, "r3", "lr");    \
 131                         break;                                          \
 132                 case 4:                                                 \
 133                         __get_user_x(__r2, __p, __e, 4, "lr");          \
 134                         break;                                          \
 135                 case 8:                                                 \
 136                         __get_user_x(__r2, __p, __e, 8, "lr");          \
 137                         break;                                          \
 138                 default: __e = __get_user_bad(); break;                 \
 139                 }                                                       \
 140                 x = __r2;                                               \
 141                 __e;                                                    \
 142         })
 143
 144 #define __get_user(x,ptr)                                               \
 145 ({                                                                      \
 146         long __gu_err = 0;                                              \
 147         __get_user_err((x),(ptr),__gu_err);                             \
 148         __gu_err;                                                       \
 149 })
 150
 151 #define __get_user_error(x,ptr,err)                                     \
 152 ({                                                                      \
 153         __get_user_err((x),(ptr),err);                                  \
 154         (void) 0;                                                       \
 155 })
 156
 157 #define __get_user_err(x,ptr,err)                                       \
 158 do {                                                                    \
 159         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 160         unsigned long __gu_val;                                         \
 161         __chk_user_ptr(ptr);                                            \
 162         switch (sizeof(*(ptr))) {                                       \
 163         case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
 164         case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
 165         case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
 166         default: (__gu_val) = __get_user_bad();                         \
 167         }                                                               \
 168         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 169 } while (0)
 170
 171 #define __get_user_asm_byte(x,addr,err)                         \
 172         __asm__ __volatile__(                                   \
 173         "1:     ldrbt   %1,[%2],#0\n"                           \
 174         "2:\n"                                                  \
 175         "       .section .fixup,\"ax\"\n"                       \
 176         "       .align  2\n"                                    \
 177         "3:     mov     %0, %3\n"                               \
 178         "       mov     %1, #0\n"                               \
 179         "       b       2b\n"                                   \
 180         "       .previous\n"                                    \
 181         "       .section __ex_table,\"a\"\n"                    \
 182         "       .align  3\n"                                    \
 183         "       .long   1b, 3b\n"                               \
 184         "       .previous"                                      \
 185         : "+r" (err), "=&r" (x)                                 \
 186         : "r" (addr), "i" (-EFAULT)                             \
 187         : "cc")
 188
 189 #ifndef __ARMEB__
 190 #define __get_user_asm_half(x,__gu_addr,err)                    \
 191 ({                                                              \
 192         unsigned long __b1, __b2;                               \
 193         __get_user_asm_byte(__b1, __gu_addr, err);              \
 194         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 195         (x) = __b1 | (__b2 << 8);                               \
 196 })
 197 #else
 198 #define __get_user_asm_half(x,__gu_addr,err)                    \
 199 ({                                                              \
 200         unsigned long __b1, __b2;                               \
 201         __get_user_asm_byte(__b1, __gu_addr, err);              \
 202         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 203         (x) = (__b1 << 8) | __b2;                               \
 204 })
 205 #endif
 206
 207 #define __get_user_asm_word(x,addr,err)                         \
 208         __asm__ __volatile__(                                   \
 209         "1:     ldrt    %1,[%2],#0\n"                           \
 210         "2:\n"                                                  \
 211         "       .section .fixup,\"ax\"\n"                       \
 212         "       .align  2\n"                                    \
 213         "3:     mov     %0, %3\n"                               \
 214         "       mov     %1, #0\n"                               \
 215         "       b       2b\n"                                   \
 216         "       .previous\n"                                    \
 217         "       .section __ex_table,\"a\"\n"                    \
 218         "       .align  3\n"                                    \
 219         "       .long   1b, 3b\n"                               \
 220         "       .previous"                                      \
 221         : "+r" (err), "=&r" (x)                                 \
 222         : "r" (addr), "i" (-EFAULT)                             \
 223         : "cc")
 224
 225 extern int __put_user_1(void *, unsigned int);
 226 extern int __put_user_2(void *, unsigned int);
 227 extern int __put_user_4(void *, unsigned int);
 228 extern int __put_user_8(void *, unsigned long long);
 229 extern int __put_user_bad(void);
 230
 231 #define __put_user_x(__r2,__p,__e,__s)                                  \
 232            __asm__ __volatile__ (                                       \
 233                 __asmeq("%0", "r0") __asmeq("%2", "r2")                 \
 234                 "bl     __put_user_" #__s                               \
 235                 : "=&r" (__e)                                           \
 236                 : "0" (__p), "r" (__r2)                                 \
 237                 : "ip", "lr", "cc")
 238
 239 #define put_user(x,p)                                                   \
 240         ({                                                              \
 241                 const register typeof(*(p)) __r2 asm("r2") = (x);       \
 242                 const register typeof(*(p)) __user *__p asm("r0") = (p);\
 243                 register int __e asm("r0");                             \
 244                 switch (sizeof(*(__p))) {                               \
 245                 case 1:                                                 \
 246                         __put_user_x(__r2, __p, __e, 1);                \
 247                         break;                                          \
 248                 case 2:                                                 \
 249                         __put_user_x(__r2, __p, __e, 2);                \
 250                         break;                                          \
 251                 case 4:                                                 \
 252                         __put_user_x(__r2, __p, __e, 4);                \
 253                         break;                                          \
 254                 case 8:                                                 \
 255                         __put_user_x(__r2, __p, __e, 8);                \
 256                         break;                                          \
 257                 default: __e = __put_user_bad(); break;                 \
 258                 }                                                       \
 259                 __e;                                                    \
 260         })
 261
 262 #define __put_user(x,ptr)                                               \
 263 ({                                                                      \
 264         long __pu_err = 0;                                              \
 265         __put_user_err((x),(ptr),__pu_err);                             \
 266         __pu_err;                                                       \
 267 })
 268
 269 #define __put_user_error(x,ptr,err)                                     \
 270 ({                                                                      \
 271         __put_user_err((x),(ptr),err);                                  \
 272         (void) 0;                                                       \
 273 })
 274
 275 #define __put_user_err(x,ptr,err)                                       \
 276 do {                                                                    \
 277         unsigned long __pu_addr = (unsigned long)(ptr);                 \
 278         __typeof__(*(ptr)) __pu_val = (x);                              \
 279         __chk_user_ptr(ptr);                                            \
 280         switch (sizeof(*(ptr))) {                                       \
 281         case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
 282         case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
 283         case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
 284         case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
 285         default: __put_user_bad();                                      \
 286         }                                                               \
 287 } while (0)
 288
 289 #define __put_user_asm_byte(x,__pu_addr,err)                    \
 290         __asm__ __volatile__(                                   \
 291         "1:     strbt   %1,[%2],#0\n"                           \
 292         "2:\n"                                                  \
 293         "       .section .fixup,\"ax\"\n"                       \
 294         "       .align  2\n"                                    \
 295         "3:     mov     %0, %3\n"                               \
 296         "       b       2b\n"                                   \
 297         "       .previous\n"                                    \
 298         "       .section __ex_table,\"a\"\n"                    \
 299         "       .align  3\n"                                    \
 300         "       .long   1b, 3b\n"                               \
 301         "       .previous"                                      \
 302         : "+r" (err)                                            \
 303         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 304         : "cc")
 305
 306 #ifndef __ARMEB__
 307 #define __put_user_asm_half(x,__pu_addr,err)                    \
 308 ({                                                              \
 309         unsigned long __temp = (unsigned long)(x);              \
 310         __put_user_asm_byte(__temp, __pu_addr, err);            \
 311         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
 312 })
 313 #else
 314 #define __put_user_asm_half(x,__pu_addr,err)                    \
 315 ({                                                              \
 316         unsigned long __temp = (unsigned long)(x);              \
 317         __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
 318         __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
 319 })
 320 #endif
 321
 322 #define __put_user_asm_word(x,__pu_addr,err)                    \
 323         __asm__ __volatile__(                                   \
 324         "1:     strt    %1,[%2],#0\n"                           \
 325         "2:\n"                                                  \
 326         "       .section .fixup,\"ax\"\n"                       \
 327         "       .align  2\n"                                    \
 328         "3:     mov     %0, %3\n"                               \
 329         "       b       2b\n"                                   \
 330         "       .previous\n"                                    \
 331         "       .section __ex_table,\"a\"\n"                    \
 332         "       .align  3\n"                                    \
 333         "       .long   1b, 3b\n"                               \
 334         "       .previous"                                      \
 335         : "+r" (err)                                            \
 336         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 337         : "cc")
 338
 339 #ifndef __ARMEB__
 340 #define __reg_oper0     "%R2"
 341 #define __reg_oper1     "%Q2"
 342 #else
 343 #define __reg_oper0     "%Q2"
 344 #define __reg_oper1     "%R2"
 345 #endif
 346
 347 #define __put_user_asm_dword(x,__pu_addr,err)                   \
 348         __asm__ __volatile__(                                   \
 349         "1:     strt    " __reg_oper1 ", [%1], #4\n"            \
 350         "2:     strt    " __reg_oper0 ", [%1], #0\n"            \
 351         "3:\n"                                                  \
 352         "       .section .fixup,\"ax\"\n"                       \
 353         "       .align  2\n"                                    \
 354         "4:     mov     %0, %3\n"                               \
 355         "       b       3b\n"                                   \
 356         "       .previous\n"                                    \
 357         "       .section __ex_table,\"a\"\n"                    \
 358         "       .align  3\n"                                    \
 359         "       .long   1b, 4b\n"                               \
 360         "       .long   2b, 4b\n"                               \
 361         "       .previous"                                      \
 362         : "+r" (err), "+r" (__pu_addr)                          \
 363         : "r" (x), "i" (-EFAULT)                                \
 364         : "cc")
 365
 366 extern unsigned long __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
 367 extern unsigned long __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
 368 extern unsigned long __arch_clear_user(void __user *addr, unsigned long n);
 369 extern unsigned long __arch_strncpy_from_user(char *to, const char __user *from, unsigned long count);
 370 extern unsigned long __arch_strnlen_user(const char __user *s, long n);
 371
 372 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 373 {
 374         if (access_ok(VERIFY_READ, from, n))
 375                 n = __arch_copy_from_user(to, from, n);
 376         else /* security hole - plug it */
 377                 memzero(to, n);
 378         return n;
 379 }
 380
 381 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 382 {
 383         return __arch_copy_from_user(to, from, n);
 384 }
 385
 386 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 387 {
 388         if (access_ok(VERIFY_WRITE, to, n))
 389                 n = __arch_copy_to_user(to, from, n);
 390         return n;
 391 }
 392
 393 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 394 {
 395         return __arch_copy_to_user(to, from, n);
 396 }
 397
 398 #define __copy_to_user_inatomic __copy_to_user
 399 #define __copy_from_user_inatomic __copy_from_user
 400
 401 static inline unsigned long clear_user (void __user *to, unsigned long n)
 402 {
 403         if (access_ok(VERIFY_WRITE, to, n))
 404                 n = __arch_clear_user(to, n);
 405         return n;
 406 }
 407
 408 static inline unsigned long __clear_user (void __user *to, unsigned long n)
 409 {
 410         return __arch_clear_user(to, n);
 411 }
 412
 413 static inline long strncpy_from_user (char *dst, const char __user *src, long count)
 414 {
 415         long res = -EFAULT;
 416         if (access_ok(VERIFY_READ, src, 1))
 417                 res = __arch_strncpy_from_user(dst, src, count);
 418         return res;
 419 }
 420
 421 static inline long __strncpy_from_user (char *dst, const char __user *src, long count)
 422 {
 423         return __arch_strncpy_from_user(dst, src, count);
 424 }
 425
 426 #define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
 427
 428 static inline long strnlen_user(const char __user *s, long n)
 429 {
 430         unsigned long res = 0;
 431
 432         if (__addr_ok(s))
 433                 res = __arch_strnlen_user(s, n);
 434
 435         return res;
 436 }
 437
 438 #endif /* _ASMARM_UACCESS_H */