linux/include/asm-arm/uaccess.h
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   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
  36struct exception_table_entry
  37{
  38        unsigned long insn, fixup;
  39};
  40
  41extern 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
  52static 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
  80static inline int verify_area(int type, const void __user *addr, unsigned long size)
  81{
  82        return access_ok(type, addr, size) ? 0 : -EFAULT;
  83}
  84
  85/*
  86 * Single-value transfer routines.  They automatically use the right
  87 * size if we just have the right pointer type.  Note that the functions
  88 * which read from user space (*get_*) need to take care not to leak
  89 * kernel data even if the calling code is buggy and fails to check
  90 * the return value.  This means zeroing out the destination variable
  91 * or buffer on error.  Normally this is done out of line by the
  92 * fixup code, but there are a few places where it intrudes on the
  93 * main code path.  When we only write to user space, there is no
  94 * problem.
  95 *
  96 * The "__xxx" versions of the user access functions do not verify the
  97 * address space - it must have been done previously with a separate
  98 * "access_ok()" call.
  99 *
 100 * The "xxx_error" versions set the third argument to EFAULT if an
 101 * error occurs, and leave it unchanged on success.  Note that these
 102 * versions are void (ie, don't return a value as such).
 103 */
 104
 105extern int __get_user_1(void *);
 106extern int __get_user_2(void *);
 107extern int __get_user_4(void *);
 108extern int __get_user_8(void *);
 109extern int __get_user_bad(void);
 110
 111#define __get_user_x(__r2,__p,__e,__s,__i...)                           \
 112           __asm__ __volatile__ (                                       \
 113                __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 114                "bl     __get_user_" #__s                               \
 115                : "=&r" (__e), "=r" (__r2)                              \
 116                : "0" (__p)                                             \
 117                : __i, "cc")
 118
 119#define get_user(x,p)                                                   \
 120        ({                                                              \
 121                const register typeof(*(p)) __user *__p asm("r0") = (p);\
 122                register typeof(*(p)) __r2 asm("r2");                   \
 123                register int __e asm("r0");                             \
 124                switch (sizeof(*(__p))) {                               \
 125                case 1:                                                 \
 126                        __get_user_x(__r2, __p, __e, 1, "lr");          \
 127                        break;                                          \
 128                case 2:                                                 \
 129                        __get_user_x(__r2, __p, __e, 2, "r3", "lr");    \
 130                        break;                                          \
 131                case 4:                                                 \
 132                        __get_user_x(__r2, __p, __e, 4, "lr");          \
 133                        break;                                          \
 134                case 8:                                                 \
 135                        __get_user_x(__r2, __p, __e, 8, "lr");          \
 136                        break;                                          \
 137                default: __e = __get_user_bad(); break;                 \
 138                }                                                       \
 139                x = __r2;                                               \
 140                __e;                                                    \
 141        })
 142
 143#define __get_user(x,ptr)                                               \
 144({                                                                      \
 145        long __gu_err = 0;                                              \
 146        __get_user_err((x),(ptr),__gu_err);                             \
 147        __gu_err;                                                       \
 148})
 149
 150#define __get_user_error(x,ptr,err)                                     \
 151({                                                                      \
 152        __get_user_err((x),(ptr),err);                                  \
 153        (void) 0;                                                       \
 154})
 155
 156#define __get_user_err(x,ptr,err)                                       \
 157do {                                                                    \
 158        unsigned long __gu_addr = (unsigned long)(ptr);                 \
 159        unsigned long __gu_val;                                         \
 160        __chk_user_ptr(ptr);                                            \
 161        switch (sizeof(*(ptr))) {                                       \
 162        case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
 163        case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
 164        case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
 165        default: (__gu_val) = __get_user_bad();                         \
 166        }                                                               \
 167        (x) = (__typeof__(*(ptr)))__gu_val;                             \
 168} while (0)
 169
 170#define __get_user_asm_byte(x,addr,err)                         \
 171        __asm__ __volatile__(                                   \
 172        "1:     ldrbt   %1,[%2],#0\n"                           \
 173        "2:\n"                                                  \
 174        "       .section .fixup,\"ax\"\n"                       \
 175        "       .align  2\n"                                    \
 176        "3:     mov     %0, %3\n"                               \
 177        "       mov     %1, #0\n"                               \
 178        "       b       2b\n"                                   \
 179        "       .previous\n"                                    \
 180        "       .section __ex_table,\"a\"\n"                    \
 181        "       .align  3\n"                                    \
 182        "       .long   1b, 3b\n"                               \
 183        "       .previous"                                      \
 184        : "+r" (err), "=&r" (x)                                 \
 185        : "r" (addr), "i" (-EFAULT)                             \
 186        : "cc")
 187
 188#ifndef __ARMEB__
 189#define __get_user_asm_half(x,__gu_addr,err)                    \
 190({                                                              \
 191        unsigned long __b1, __b2;                               \
 192        __get_user_asm_byte(__b1, __gu_addr, err);              \
 193        __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 194        (x) = __b1 | (__b2 << 8);                               \
 195})
 196#else
 197#define __get_user_asm_half(x,__gu_addr,err)                    \
 198({                                                              \
 199        unsigned long __b1, __b2;                               \
 200        __get_user_asm_byte(__b1, __gu_addr, err);              \
 201        __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 202        (x) = (__b1 << 8) | __b2;                               \
 203})
 204#endif
 205
 206#define __get_user_asm_word(x,addr,err)                         \
 207        __asm__ __volatile__(                                   \
 208        "1:     ldrt    %1,[%2],#0\n"                           \
 209        "2:\n"                                                  \
 210        "       .section .fixup,\"ax\"\n"                       \
 211        "       .align  2\n"                                    \
 212        "3:     mov     %0, %3\n"                               \
 213        "       mov     %1, #0\n"                               \
 214        "       b       2b\n"                                   \
 215        "       .previous\n"                                    \
 216        "       .section __ex_table,\"a\"\n"                    \
 217        "       .align  3\n"                                    \
 218        "       .long   1b, 3b\n"                               \
 219        "       .previous"                                      \
 220        : "+r" (err), "=&r" (x)                                 \
 221        : "r" (addr), "i" (-EFAULT)                             \
 222        : "cc")
 223
 224extern int __put_user_1(void *, unsigned int);
 225extern int __put_user_2(void *, unsigned int);
 226extern int __put_user_4(void *, unsigned int);
 227extern int __put_user_8(void *, unsigned long long);
 228extern int __put_user_bad(void);
 229
 230#define __put_user_x(__r2,__p,__e,__s)                                  \
 231           __asm__ __volatile__ (                                       \
 232                __asmeq("%0", "r0") __asmeq("%2", "r2")                 \
 233                "bl     __put_user_" #__s                               \
 234                : "=&r" (__e)                                           \
 235                : "0" (__p), "r" (__r2)                                 \
 236                : "ip", "lr", "cc")
 237
 238#define put_user(x,p)                                                   \
 239        ({                                                              \
 240                const register typeof(*(p)) __r2 asm("r2") = (x);       \
 241                const register typeof(*(p)) __user *__p asm("r0") = (p);\
 242                register int __e asm("r0");                             \
 243                switch (sizeof(*(__p))) {                               \
 244                case 1:                                                 \
 245                        __put_user_x(__r2, __p, __e, 1);                \
 246                        break;                                          \
 247                case 2:                                                 \
 248                        __put_user_x(__r2, __p, __e, 2);                \
 249                        break;                                          \
 250                case 4:                                                 \
 251                        __put_user_x(__r2, __p, __e, 4);                \
 252                        break;                                          \
 253                case 8:                                                 \
 254                        __put_user_x(__r2, __p, __e, 8);                \
 255                        break;                                          \
 256                default: __e = __put_user_bad(); break;                 \
 257                }                                                       \
 258                __e;                                                    \
 259        })
 260
 261#define __put_user(x,ptr)                                               \
 262({                                                                      \
 263        long __pu_err = 0;                                              \
 264        __put_user_err((x),(ptr),__pu_err);                             \
 265        __pu_err;                                                       \
 266})
 267
 268#define __put_user_error(x,ptr,err)                                     \
 269({                                                                      \
 270        __put_user_err((x),(ptr),err);                                  \
 271        (void) 0;                                                       \
 272})
 273
 274#define __put_user_err(x,ptr,err)                                       \
 275do {                                                                    \
 276        unsigned long __pu_addr = (unsigned long)(ptr);                 \
 277        __typeof__(*(ptr)) __pu_val = (x);                              \
 278        __chk_user_ptr(ptr);                                            \
 279        switch (sizeof(*(ptr))) {                                       \
 280        case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
 281        case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
 282        case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
 283        case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
 284        default: __put_user_bad();                                      \
 285        }                                                               \
 286} while (0)
 287
 288#define __put_user_asm_byte(x,__pu_addr,err)                    \
 289        __asm__ __volatile__(                                   \
 290        "1:     strbt   %1,[%2],#0\n"                           \
 291        "2:\n"                                                  \
 292        "       .section .fixup,\"ax\"\n"                       \
 293        "       .align  2\n"                                    \
 294        "3:     mov     %0, %3\n"                               \
 295        "       b       2b\n"                                   \
 296        "       .previous\n"                                    \
 297        "       .section __ex_table,\"a\"\n"                    \
 298        "       .align  3\n"                                    \
 299        "       .long   1b, 3b\n"                               \
 300        "       .previous"                                      \
 301        : "+r" (err)                                            \
 302        : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 303        : "cc")
 304
 305#ifndef __ARMEB__
 306#define __put_user_asm_half(x,__pu_addr,err)                    \
 307({                                                              \
 308        unsigned long __temp = (unsigned long)(x);              \
 309        __put_user_asm_byte(__temp, __pu_addr, err);            \
 310        __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
 311})
 312#else
 313#define __put_user_asm_half(x,__pu_addr,err)                    \
 314({                                                              \
 315        unsigned long __temp = (unsigned long)(x);              \
 316        __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
 317        __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
 318})
 319#endif
 320
 321#define __put_user_asm_word(x,__pu_addr,err)                    \
 322        __asm__ __volatile__(                                   \
 323        "1:     strt    %1,[%2],#0\n"                           \
 324        "2:\n"                                                  \
 325        "       .section .fixup,\"ax\"\n"                       \
 326        "       .align  2\n"                                    \
 327        "3:     mov     %0, %3\n"                               \
 328        "       b       2b\n"                                   \
 329        "       .previous\n"                                    \
 330        "       .section __ex_table,\"a\"\n"                    \
 331        "       .align  3\n"                                    \
 332        "       .long   1b, 3b\n"                               \
 333        "       .previous"                                      \
 334        : "+r" (err)                                            \
 335        : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 336        : "cc")
 337
 338#ifndef __ARMEB__
 339#define __reg_oper0     "%R2"
 340#define __reg_oper1     "%Q2"
 341#else
 342#define __reg_oper0     "%Q2"
 343#define __reg_oper1     "%R2"
 344#endif
 345
 346#define __put_user_asm_dword(x,__pu_addr,err)                   \
 347        __asm__ __volatile__(                                   \
 348        "1:     strt    " __reg_oper1 ", [%1], #4\n"            \
 349        "2:     strt    " __reg_oper0 ", [%1], #0\n"            \
 350        "3:\n"                                                  \
 351        "       .section .fixup,\"ax\"\n"                       \
 352        "       .align  2\n"                                    \
 353        "4:     mov     %0, %3\n"                               \
 354        "       b       3b\n"                                   \
 355        "       .previous\n"                                    \
 356        "       .section __ex_table,\"a\"\n"                    \
 357        "       .align  3\n"                                    \
 358        "       .long   1b, 4b\n"                               \
 359        "       .long   2b, 4b\n"                               \
 360        "       .previous"                                      \
 361        : "+r" (err), "+r" (__pu_addr)                          \
 362        : "r" (x), "i" (-EFAULT)                                \
 363        : "cc")
 364
 365extern unsigned long __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
 366extern unsigned long __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
 367extern unsigned long __arch_clear_user(void __user *addr, unsigned long n);
 368extern unsigned long __arch_strncpy_from_user(char *to, const char __user *from, unsigned long count);
 369extern unsigned long __arch_strnlen_user(const char __user *s, long n);
 370
 371static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 372{
 373        if (access_ok(VERIFY_READ, from, n))
 374                n = __arch_copy_from_user(to, from, n);
 375        else /* security hole - plug it */
 376                memzero(to, n);
 377        return n;
 378}
 379
 380static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 381{
 382        return __arch_copy_from_user(to, from, n);
 383}
 384
 385static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 386{
 387        if (access_ok(VERIFY_WRITE, to, n))
 388                n = __arch_copy_to_user(to, from, n);
 389        return n;
 390}
 391
 392static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 393{
 394        return __arch_copy_to_user(to, from, n);
 395}
 396
 397#define __copy_to_user_inatomic __copy_to_user
 398#define __copy_from_user_inatomic __copy_from_user
 399
 400static inline unsigned long clear_user (void __user *to, unsigned long n)
 401{
 402        if (access_ok(VERIFY_WRITE, to, n))
 403                n = __arch_clear_user(to, n);
 404        return n;
 405}
 406
 407static inline unsigned long __clear_user (void __user *to, unsigned long n)
 408{
 409        return __arch_clear_user(to, n);
 410}
 411
 412static inline long strncpy_from_user (char *dst, const char __user *src, long count)
 413{
 414        long res = -EFAULT;
 415        if (access_ok(VERIFY_READ, src, 1))
 416                res = __arch_strncpy_from_user(dst, src, count);
 417        return res;
 418}
 419
 420static inline long __strncpy_from_user (char *dst, const char __user *src, long count)
 421{
 422        return __arch_strncpy_from_user(dst, src, count);
 423}
 424
 425#define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
 426
 427static inline long strnlen_user(const char __user *s, long n)
 428{
 429        unsigned long res = 0;
 430
 431        if (__addr_ok(s))
 432                res = __arch_strnlen_user(s, n);
 433
 434        return res;
 435}
 436
 437#endif /* _ASMARM_UACCESS_H */
 438
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