arch/arm/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *  arch/arm/include/asm/uaccess.h
   4  */
   5 #ifndef _ASMARM_UACCESS_H
   6 #define _ASMARM_UACCESS_H
   7
   8 /*
   9  * User space memory access functions
  10  */
  11 #include <linux/string.h>
  12 #include <asm/page.h>
  13 #include <asm/domain.h>
  14 #include <asm/unaligned.h>
  15 #include <asm/unified.h>
  16 #include <asm/compiler.h>
  17
  18 #include <asm/extable.h>
  19
  20 /*
  21  * These two functions allow hooking accesses to userspace to increase
  22  * system integrity by ensuring that the kernel can not inadvertantly
  23  * perform such accesses (eg, via list poison values) which could then
  24  * be exploited for priviledge escalation.
  25  */
  26 static __always_inline unsigned int uaccess_save_and_enable(void)
  27 {
  28 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
  29         unsigned int old_domain = get_domain();
  30
  31         /* Set the current domain access to permit user accesses */
  32         set_domain((old_domain & ~domain_mask(DOMAIN_USER)) |
  33                    domain_val(DOMAIN_USER, DOMAIN_CLIENT));
  34
  35         return old_domain;
  36 #else
  37         return 0;
  38 #endif
  39 }
  40
  41 static __always_inline void uaccess_restore(unsigned int flags)
  42 {
  43 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
  44         /* Restore the user access mask */
  45         set_domain(flags);
  46 #endif
  47 }
  48
  49 /*
  50  * These two are intentionally not defined anywhere - if the kernel
  51  * code generates any references to them, that's a bug.
  52  */
  53 extern int __get_user_bad(void);
  54 extern int __put_user_bad(void);
  55
  56 #ifdef CONFIG_MMU
  57
  58 /*
  59  * This is a type: either unsigned long, if the argument fits into
  60  * that type, or otherwise unsigned long long.
  61  */
  62 #define __inttype(x) \
  63         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
  64
  65 /*
  66  * Sanitise a uaccess pointer such that it becomes NULL if addr+size
  67  * is above the current addr_limit.
  68  */
  69 #define uaccess_mask_range_ptr(ptr, size)                       \
  70         ((__typeof__(ptr))__uaccess_mask_range_ptr(ptr, size))
  71 static inline void __user *__uaccess_mask_range_ptr(const void __user *ptr,
  72                                                     size_t size)
  73 {
  74         void __user *safe_ptr = (void __user *)ptr;
  75         unsigned long tmp;
  76
  77         asm volatile(
  78         "       .syntax unified\n"
  79         "       sub     %1, %3, #1\n"
  80         "       subs    %1, %1, %0\n"
  81         "       addhs   %1, %1, #1\n"
  82         "       subshs  %1, %1, %2\n"
  83         "       movlo   %0, #0\n"
  84         : "+r" (safe_ptr), "=&r" (tmp)
  85         : "r" (size), "r" (TASK_SIZE)
  86         : "cc");
  87
  88         csdb();
  89         return safe_ptr;
  90 }
  91
  92 /*
  93  * Single-value transfer routines.  They automatically use the right
  94  * size if we just have the right pointer type.  Note that the functions
  95  * which read from user space (*get_*) need to take care not to leak
  96  * kernel data even if the calling code is buggy and fails to check
  97  * the return value.  This means zeroing out the destination variable
  98  * or buffer on error.  Normally this is done out of line by the
  99  * fixup code, but there are a few places where it intrudes on the
 100  * main code path.  When we only write to user space, there is no
 101  * problem.
 102  */
 103 extern int __get_user_1(void *);
 104 extern int __get_user_2(void *);
 105 extern int __get_user_4(void *);
 106 extern int __get_user_32t_8(void *);
 107 extern int __get_user_8(void *);
 108 extern int __get_user_64t_1(void *);
 109 extern int __get_user_64t_2(void *);
 110 extern int __get_user_64t_4(void *);
 111
 112 #define __GUP_CLOBBER_1 "lr", "cc"
 113 #ifdef CONFIG_CPU_USE_DOMAINS
 114 #define __GUP_CLOBBER_2 "ip", "lr", "cc"
 115 #else
 116 #define __GUP_CLOBBER_2 "lr", "cc"
 117 #endif
 118 #define __GUP_CLOBBER_4 "lr", "cc"
 119 #define __GUP_CLOBBER_32t_8 "lr", "cc"
 120 #define __GUP_CLOBBER_8 "lr", "cc"
 121
 122 #define __get_user_x(__r2, __p, __e, __l, __s)                          \
 123            __asm__ __volatile__ (                                       \
 124                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 125                 __asmeq("%3", "r1")                                     \
 126                 "bl     __get_user_" #__s                               \
 127                 : "=&r" (__e), "=r" (__r2)                              \
 128                 : "0" (__p), "r" (__l)                                  \
 129                 : __GUP_CLOBBER_##__s)
 130
 131 /* narrowing a double-word get into a single 32bit word register: */
 132 #ifdef __ARMEB__
 133 #define __get_user_x_32t(__r2, __p, __e, __l, __s)                      \
 134         __get_user_x(__r2, __p, __e, __l, 32t_8)
 135 #else
 136 #define __get_user_x_32t __get_user_x
 137 #endif
 138
 139 /*
 140  * storing result into proper least significant word of 64bit target var,
 141  * different only for big endian case where 64 bit __r2 lsw is r3:
 142  */
 143 #ifdef __ARMEB__
 144 #define __get_user_x_64t(__r2, __p, __e, __l, __s)                      \
 145            __asm__ __volatile__ (                                       \
 146                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 147                 __asmeq("%3", "r1")                                     \
 148                 "bl     __get_user_64t_" #__s                           \
 149                 : "=&r" (__e), "=r" (__r2)                              \
 150                 : "0" (__p), "r" (__l)                                  \
 151                 : __GUP_CLOBBER_##__s)
 152 #else
 153 #define __get_user_x_64t __get_user_x
 154 #endif
 155
 156
 157 #define __get_user_check(x, p)                                          \
 158         ({                                                              \
 159                 unsigned long __limit = TASK_SIZE - 1; \
 160                 register typeof(*(p)) __user *__p asm("r0") = (p);      \
 161                 register __inttype(x) __r2 asm("r2");                   \
 162                 register unsigned long __l asm("r1") = __limit;         \
 163                 register int __e asm("r0");                             \
 164                 unsigned int __ua_flags = uaccess_save_and_enable();    \
 165                 int __tmp_e;                                            \
 166                 switch (sizeof(*(__p))) {                               \
 167                 case 1:                                                 \
 168                         if (sizeof((x)) >= 8)                           \
 169                                 __get_user_x_64t(__r2, __p, __e, __l, 1); \
 170                         else                                            \
 171                                 __get_user_x(__r2, __p, __e, __l, 1);   \
 172                         break;                                          \
 173                 case 2:                                                 \
 174                         if (sizeof((x)) >= 8)                           \
 175                                 __get_user_x_64t(__r2, __p, __e, __l, 2); \
 176                         else                                            \
 177                                 __get_user_x(__r2, __p, __e, __l, 2);   \
 178                         break;                                          \
 179                 case 4:                                                 \
 180                         if (sizeof((x)) >= 8)                           \
 181                                 __get_user_x_64t(__r2, __p, __e, __l, 4); \
 182                         else                                            \
 183                                 __get_user_x(__r2, __p, __e, __l, 4);   \
 184                         break;                                          \
 185                 case 8:                                                 \
 186                         if (sizeof((x)) < 8)                            \
 187                                 __get_user_x_32t(__r2, __p, __e, __l, 4); \
 188                         else                                            \
 189                                 __get_user_x(__r2, __p, __e, __l, 8);   \
 190                         break;                                          \
 191                 default: __e = __get_user_bad(); break;                 \
 192                 }                                                       \
 193                 __tmp_e = __e;                                          \
 194                 uaccess_restore(__ua_flags);                            \
 195                 x = (typeof(*(p))) __r2;                                \
 196                 __tmp_e;                                                \
 197         })
 198
 199 #define get_user(x, p)                                                  \
 200         ({                                                              \
 201                 might_fault();                                          \
 202                 __get_user_check(x, p);                                 \
 203          })
 204
 205 extern int __put_user_1(void *, unsigned int);
 206 extern int __put_user_2(void *, unsigned int);
 207 extern int __put_user_4(void *, unsigned int);
 208 extern int __put_user_8(void *, unsigned long long);
 209
 210 #define __put_user_check(__pu_val, __ptr, __err, __s)                   \
 211         ({                                                              \
 212                 unsigned long __limit = TASK_SIZE - 1; \
 213                 register typeof(__pu_val) __r2 asm("r2") = __pu_val;    \
 214                 register const void __user *__p asm("r0") = __ptr;      \
 215                 register unsigned long __l asm("r1") = __limit;         \
 216                 register int __e asm("r0");                             \
 217                 __asm__ __volatile__ (                                  \
 218                         __asmeq("%0", "r0") __asmeq("%2", "r2")         \
 219                         __asmeq("%3", "r1")                             \
 220                         "bl     __put_user_" #__s                       \
 221                         : "=&r" (__e)                                   \
 222                         : "0" (__p), "r" (__r2), "r" (__l)              \
 223                         : "ip", "lr", "cc");                            \
 224                 __err = __e;                                            \
 225         })
 226
 227 #else /* CONFIG_MMU */
 228
 229 #define get_user(x, p)  __get_user(x, p)
 230 #define __put_user_check __put_user_nocheck
 231
 232 #endif /* CONFIG_MMU */
 233
 234 #include <asm-generic/access_ok.h>
 235
 236 #ifdef CONFIG_CPU_SPECTRE
 237 /*
 238  * When mitigating Spectre variant 1, it is not worth fixing the non-
 239  * verifying accessors, because we need to add verification of the
 240  * address space there.  Force these to use the standard get_user()
 241  * version instead.
 242  */
 243 #define __get_user(x, ptr) get_user(x, ptr)
 244 #else
 245
 246 /*
 247  * The "__xxx" versions of the user access functions do not verify the
 248  * address space - it must have been done previously with a separate
 249  * "access_ok()" call.
 250  *
 251  * The "xxx_error" versions set the third argument to EFAULT if an
 252  * error occurs, and leave it unchanged on success.  Note that these
 253  * versions are void (ie, don't return a value as such).
 254  */
 255 #define __get_user(x, ptr)                                              \
 256 ({                                                                      \
 257         long __gu_err = 0;                                              \
 258         __get_user_err((x), (ptr), __gu_err, TUSER());                  \
 259         __gu_err;                                                       \
 260 })
 261
 262 #define __get_user_err(x, ptr, err, __t)                                \
 263 do {                                                                    \
 264         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 265         unsigned long __gu_val;                                         \
 266         unsigned int __ua_flags;                                        \
 267         __chk_user_ptr(ptr);                                            \
 268         might_fault();                                                  \
 269         __ua_flags = uaccess_save_and_enable();                         \
 270         switch (sizeof(*(ptr))) {                                       \
 271         case 1: __get_user_asm_byte(__gu_val, __gu_addr, err, __t); break;      \
 272         case 2: __get_user_asm_half(__gu_val, __gu_addr, err, __t); break;      \
 273         case 4: __get_user_asm_word(__gu_val, __gu_addr, err, __t); break;      \
 274         default: (__gu_val) = __get_user_bad();                         \
 275         }                                                               \
 276         uaccess_restore(__ua_flags);                                    \
 277         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 278 } while (0)
 279 #endif
 280
 281 #define __get_user_asm(x, addr, err, instr)                     \
 282         __asm__ __volatile__(                                   \
 283         "1:     " instr " %1, [%2], #0\n"                       \
 284         "2:\n"                                                  \
 285         "       .pushsection .text.fixup,\"ax\"\n"              \
 286         "       .align  2\n"                                    \
 287         "3:     mov     %0, %3\n"                               \
 288         "       mov     %1, #0\n"                               \
 289         "       b       2b\n"                                   \
 290         "       .popsection\n"                                  \
 291         "       .pushsection __ex_table,\"a\"\n"                \
 292         "       .align  3\n"                                    \
 293         "       .long   1b, 3b\n"                               \
 294         "       .popsection"                                    \
 295         : "+r" (err), "=&r" (x)                                 \
 296         : "r" (addr), "i" (-EFAULT)                             \
 297         : "cc")
 298
 299 #define __get_user_asm_byte(x, addr, err, __t)                  \
 300         __get_user_asm(x, addr, err, "ldrb" __t)
 301
 302 #if __LINUX_ARM_ARCH__ >= 6
 303
 304 #define __get_user_asm_half(x, addr, err, __t)                  \
 305         __get_user_asm(x, addr, err, "ldrh" __t)
 306
 307 #else
 308
 309 #ifndef __ARMEB__
 310 #define __get_user_asm_half(x, __gu_addr, err, __t)             \
 311 ({                                                              \
 312         unsigned long __b1, __b2;                               \
 313         __get_user_asm_byte(__b1, __gu_addr, err, __t);         \
 314         __get_user_asm_byte(__b2, __gu_addr + 1, err, __t);     \
 315         (x) = __b1 | (__b2 << 8);                               \
 316 })
 317 #else
 318 #define __get_user_asm_half(x, __gu_addr, err, __t)             \
 319 ({                                                              \
 320         unsigned long __b1, __b2;                               \
 321         __get_user_asm_byte(__b1, __gu_addr, err, __t);         \
 322         __get_user_asm_byte(__b2, __gu_addr + 1, err, __t);     \
 323         (x) = (__b1 << 8) | __b2;                               \
 324 })
 325 #endif
 326
 327 #endif /* __LINUX_ARM_ARCH__ >= 6 */
 328
 329 #define __get_user_asm_word(x, addr, err, __t)                  \
 330         __get_user_asm(x, addr, err, "ldr" __t)
 331
 332 #define __put_user_switch(x, ptr, __err, __fn)                          \
 333         do {                                                            \
 334                 const __typeof__(*(ptr)) __user *__pu_ptr = (ptr);      \
 335                 __typeof__(*(ptr)) __pu_val = (x);                      \
 336                 unsigned int __ua_flags;                                \
 337                 might_fault();                                          \
 338                 __ua_flags = uaccess_save_and_enable();                 \
 339                 switch (sizeof(*(ptr))) {                               \
 340                 case 1: __fn(__pu_val, __pu_ptr, __err, 1); break;      \
 341                 case 2: __fn(__pu_val, __pu_ptr, __err, 2); break;      \
 342                 case 4: __fn(__pu_val, __pu_ptr, __err, 4); break;      \
 343                 case 8: __fn(__pu_val, __pu_ptr, __err, 8); break;      \
 344                 default: __err = __put_user_bad(); break;               \
 345                 }                                                       \
 346                 uaccess_restore(__ua_flags);                            \
 347         } while (0)
 348
 349 #define put_user(x, ptr)                                                \
 350 ({                                                                      \
 351         int __pu_err = 0;                                               \
 352         __put_user_switch((x), (ptr), __pu_err, __put_user_check);      \
 353         __pu_err;                                                       \
 354 })
 355
 356 #ifdef CONFIG_CPU_SPECTRE
 357 /*
 358  * When mitigating Spectre variant 1.1, all accessors need to include
 359  * verification of the address space.
 360  */
 361 #define __put_user(x, ptr) put_user(x, ptr)
 362
 363 #else
 364 #define __put_user(x, ptr)                                              \
 365 ({                                                                      \
 366         long __pu_err = 0;                                              \
 367         __put_user_switch((x), (ptr), __pu_err, __put_user_nocheck);    \
 368         __pu_err;                                                       \
 369 })
 370
 371 #define __put_user_nocheck(x, __pu_ptr, __err, __size)                  \
 372         do {                                                            \
 373                 unsigned long __pu_addr = (unsigned long)__pu_ptr;      \
 374                 __put_user_nocheck_##__size(x, __pu_addr, __err, TUSER());\
 375         } while (0)
 376
 377 #define __put_user_nocheck_1 __put_user_asm_byte
 378 #define __put_user_nocheck_2 __put_user_asm_half
 379 #define __put_user_nocheck_4 __put_user_asm_word
 380 #define __put_user_nocheck_8 __put_user_asm_dword
 381
 382 #endif /* !CONFIG_CPU_SPECTRE */
 383
 384 #define __put_user_asm(x, __pu_addr, err, instr)                \
 385         __asm__ __volatile__(                                   \
 386         "1:     " instr " %1, [%2], #0\n"               \
 387         "2:\n"                                                  \
 388         "       .pushsection .text.fixup,\"ax\"\n"              \
 389         "       .align  2\n"                                    \
 390         "3:     mov     %0, %3\n"                               \
 391         "       b       2b\n"                                   \
 392         "       .popsection\n"                                  \
 393         "       .pushsection __ex_table,\"a\"\n"                \
 394         "       .align  3\n"                                    \
 395         "       .long   1b, 3b\n"                               \
 396         "       .popsection"                                    \
 397         : "+r" (err)                                            \
 398         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 399         : "cc")
 400
 401 #define __put_user_asm_byte(x, __pu_addr, err, __t)             \
 402         __put_user_asm(x, __pu_addr, err, "strb" __t)
 403
 404 #if __LINUX_ARM_ARCH__ >= 6
 405
 406 #define __put_user_asm_half(x, __pu_addr, err, __t)             \
 407         __put_user_asm(x, __pu_addr, err, "strh" __t)
 408
 409 #else
 410
 411 #ifndef __ARMEB__
 412 #define __put_user_asm_half(x, __pu_addr, err, __t)             \
 413 ({                                                              \
 414         unsigned long __temp = (__force unsigned long)(x);      \
 415         __put_user_asm_byte(__temp, __pu_addr, err, __t);       \
 416         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err, __t);\
 417 })
 418 #else
 419 #define __put_user_asm_half(x, __pu_addr, err, __t)             \
 420 ({                                                              \
 421         unsigned long __temp = (__force unsigned long)(x);      \
 422         __put_user_asm_byte(__temp >> 8, __pu_addr, err, __t);  \
 423         __put_user_asm_byte(__temp, __pu_addr + 1, err, __t);   \
 424 })
 425 #endif
 426
 427 #endif /* __LINUX_ARM_ARCH__ >= 6 */
 428
 429 #define __put_user_asm_word(x, __pu_addr, err, __t)             \
 430         __put_user_asm(x, __pu_addr, err, "str" __t)
 431
 432 #ifndef __ARMEB__
 433 #define __reg_oper0     "%R2"
 434 #define __reg_oper1     "%Q2"
 435 #else
 436 #define __reg_oper0     "%Q2"
 437 #define __reg_oper1     "%R2"
 438 #endif
 439
 440 #define __put_user_asm_dword(x, __pu_addr, err, __t)            \
 441         __asm__ __volatile__(                                   \
 442  ARM(   "1:     str" __t "      " __reg_oper1 ", [%1], #4\n"  ) \
 443  ARM(   "2:     str" __t "      " __reg_oper0 ", [%1]\n"      ) \
 444  THUMB( "1:     str" __t "      " __reg_oper1 ", [%1]\n"      ) \
 445  THUMB( "2:     str" __t "      " __reg_oper0 ", [%1, #4]\n"  ) \
 446         "3:\n"                                                  \
 447         "       .pushsection .text.fixup,\"ax\"\n"              \
 448         "       .align  2\n"                                    \
 449         "4:     mov     %0, %3\n"                               \
 450         "       b       3b\n"                                   \
 451         "       .popsection\n"                                  \
 452         "       .pushsection __ex_table,\"a\"\n"                \
 453         "       .align  3\n"                                    \
 454         "       .long   1b, 4b\n"                               \
 455         "       .long   2b, 4b\n"                               \
 456         "       .popsection"                                    \
 457         : "+r" (err), "+r" (__pu_addr)                          \
 458         : "r" (x), "i" (-EFAULT)                                \
 459         : "cc")
 460
 461 #define __get_kernel_nofault(dst, src, type, err_label)                 \
 462 do {                                                                    \
 463         const type *__pk_ptr = (src);                                   \
 464         unsigned long __src = (unsigned long)(__pk_ptr);                \
 465         type __val;                                                     \
 466         int __err = 0;                                                  \
 467         switch (sizeof(type)) {                                         \
 468         case 1: __get_user_asm_byte(__val, __src, __err, ""); break;    \
 469         case 2: __get_user_asm_half(__val, __src, __err, ""); break;    \
 470         case 4: __get_user_asm_word(__val, __src, __err, ""); break;    \
 471         case 8: {                                                       \
 472                 u32 *__v32 = (u32*)&__val;                              \
 473                 __get_user_asm_word(__v32[0], __src, __err, "");        \
 474                 if (__err)                                              \
 475                         break;                                          \
 476                 __get_user_asm_word(__v32[1], __src+4, __err, "");      \
 477                 break;                                                  \
 478         }                                                               \
 479         default: __err = __get_user_bad(); break;                       \
 480         }                                                               \
 481         if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))         \
 482                 put_unaligned(__val, (type *)(dst));                    \
 483         else                                                            \
 484                 *(type *)(dst) = __val; /* aligned by caller */         \
 485         if (__err)                                                      \
 486                 goto err_label;                                         \
 487 } while (0)
 488
 489 #define __put_kernel_nofault(dst, src, type, err_label)                 \
 490 do {                                                                    \
 491         const type *__pk_ptr = (dst);                                   \
 492         unsigned long __dst = (unsigned long)__pk_ptr;                  \
 493         int __err = 0;                                                  \
 494         type __val = IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) \
 495                      ? get_unaligned((type *)(src))                     \
 496                      : *(type *)(src);  /* aligned by caller */         \
 497         switch (sizeof(type)) {                                         \
 498         case 1: __put_user_asm_byte(__val, __dst, __err, ""); break;    \
 499         case 2: __put_user_asm_half(__val, __dst, __err, ""); break;    \
 500         case 4: __put_user_asm_word(__val, __dst, __err, ""); break;    \
 501         case 8: __put_user_asm_dword(__val, __dst, __err, ""); break;   \
 502         default: __err = __put_user_bad(); break;                       \
 503         }                                                               \
 504         if (__err)                                                      \
 505                 goto err_label;                                         \
 506 } while (0)
 507
 508 #ifdef CONFIG_MMU
 509 extern unsigned long __must_check
 510 arm_copy_from_user(void *to, const void __user *from, unsigned long n);
 511
 512 extern unsigned long __must_check
 513 __copy_from_user_std(void *to, const void __user *from, unsigned long n);
 514
 515 static inline unsigned long __must_check
 516 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 517 {
 518         unsigned int __ua_flags;
 519
 520         __ua_flags = uaccess_save_and_enable();
 521         n = arm_copy_from_user(to, from, n);
 522         uaccess_restore(__ua_flags);
 523         return n;
 524 }
 525
 526 extern unsigned long __must_check
 527 arm_copy_to_user(void __user *to, const void *from, unsigned long n);
 528 extern unsigned long __must_check
 529 __copy_to_user_std(void __user *to, const void *from, unsigned long n);
 530
 531 static inline unsigned long __must_check
 532 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 533 {
 534 #ifndef CONFIG_UACCESS_WITH_MEMCPY
 535         unsigned int __ua_flags;
 536         __ua_flags = uaccess_save_and_enable();
 537         n = arm_copy_to_user(to, from, n);
 538         uaccess_restore(__ua_flags);
 539         return n;
 540 #else
 541         return arm_copy_to_user(to, from, n);
 542 #endif
 543 }
 544
 545 extern unsigned long __must_check
 546 arm_clear_user(void __user *addr, unsigned long n);
 547 extern unsigned long __must_check
 548 __clear_user_std(void __user *addr, unsigned long n);
 549
 550 static inline unsigned long __must_check
 551 __clear_user(void __user *addr, unsigned long n)
 552 {
 553         unsigned int __ua_flags = uaccess_save_and_enable();
 554         n = arm_clear_user(addr, n);
 555         uaccess_restore(__ua_flags);
 556         return n;
 557 }
 558
 559 #else
 560 static inline unsigned long
 561 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 562 {
 563         memcpy(to, (const void __force *)from, n);
 564         return 0;
 565 }
 566 static inline unsigned long
 567 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 568 {
 569         memcpy((void __force *)to, from, n);
 570         return 0;
 571 }
 572 #define __clear_user(addr, n)           (memset((void __force *)addr, 0, n), 0)
 573 #endif
 574 #define INLINE_COPY_TO_USER
 575 #define INLINE_COPY_FROM_USER
 576
 577 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
 578 {
 579         if (access_ok(to, n))
 580                 n = __clear_user(to, n);
 581         return n;
 582 }
 583
 584 /* These are from lib/ code, and use __get_user() and friends */
 585 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 586
 587 extern __must_check long strnlen_user(const char __user *str, long n);
 588
 589 #endif /* _ASMARM_UACCESS_H */