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/memory.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  * We use 33-bit arithmetic here.  Success returns zero, failure returns
  60  * addr_limit.  We take advantage that addr_limit will be zero for KERNEL_DS,
  61  * so this will always return success in that case.
  62  */
  63 #define __range_ok(addr, size) ({ \
  64         unsigned long flag, roksum; \
  65         __chk_user_ptr(addr);   \
  66         __asm__(".syntax unified\n" \
  67                 "adds %1, %2, %3; sbcscc %1, %1, %0; movcc %0, #0" \
  68                 : "=&r" (flag), "=&r" (roksum) \
  69                 : "r" (addr), "Ir" (size), "0" (TASK_SIZE) \
  70                 : "cc"); \
  71         flag; })
  72
  73 /*
  74  * This is a type: either unsigned long, if the argument fits into
  75  * that type, or otherwise unsigned long long.
  76  */
  77 #define __inttype(x) \
  78         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
  79
  80 /*
  81  * Sanitise a uaccess pointer such that it becomes NULL if addr+size
  82  * is above the current addr_limit.
  83  */
  84 #define uaccess_mask_range_ptr(ptr, size)                       \
  85         ((__typeof__(ptr))__uaccess_mask_range_ptr(ptr, size))
  86 static inline void __user *__uaccess_mask_range_ptr(const void __user *ptr,
  87                                                     size_t size)
  88 {
  89         void __user *safe_ptr = (void __user *)ptr;
  90         unsigned long tmp;
  91
  92         asm volatile(
  93         "       .syntax unified\n"
  94         "       sub     %1, %3, #1\n"
  95         "       subs    %1, %1, %0\n"
  96         "       addhs   %1, %1, #1\n"
  97         "       subshs  %1, %1, %2\n"
  98         "       movlo   %0, #0\n"
  99         : "+r" (safe_ptr), "=&r" (tmp)
 100         : "r" (size), "r" (TASK_SIZE)
 101         : "cc");
 102
 103         csdb();
 104         return safe_ptr;
 105 }
 106
 107 /*
 108  * Single-value transfer routines.  They automatically use the right
 109  * size if we just have the right pointer type.  Note that the functions
 110  * which read from user space (*get_*) need to take care not to leak
 111  * kernel data even if the calling code is buggy and fails to check
 112  * the return value.  This means zeroing out the destination variable
 113  * or buffer on error.  Normally this is done out of line by the
 114  * fixup code, but there are a few places where it intrudes on the
 115  * main code path.  When we only write to user space, there is no
 116  * problem.
 117  */
 118 extern int __get_user_1(void *);
 119 extern int __get_user_2(void *);
 120 extern int __get_user_4(void *);
 121 extern int __get_user_32t_8(void *);
 122 extern int __get_user_8(void *);
 123 extern int __get_user_64t_1(void *);
 124 extern int __get_user_64t_2(void *);
 125 extern int __get_user_64t_4(void *);
 126
 127 #define __GUP_CLOBBER_1 "lr", "cc"
 128 #ifdef CONFIG_CPU_USE_DOMAINS
 129 #define __GUP_CLOBBER_2 "ip", "lr", "cc"
 130 #else
 131 #define __GUP_CLOBBER_2 "lr", "cc"
 132 #endif
 133 #define __GUP_CLOBBER_4 "lr", "cc"
 134 #define __GUP_CLOBBER_32t_8 "lr", "cc"
 135 #define __GUP_CLOBBER_8 "lr", "cc"
 136
 137 #define __get_user_x(__r2, __p, __e, __l, __s)                          \
 138            __asm__ __volatile__ (                                       \
 139                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 140                 __asmeq("%3", "r1")                                     \
 141                 "bl     __get_user_" #__s                               \
 142                 : "=&r" (__e), "=r" (__r2)                              \
 143                 : "0" (__p), "r" (__l)                                  \
 144                 : __GUP_CLOBBER_##__s)
 145
 146 /* narrowing a double-word get into a single 32bit word register: */
 147 #ifdef __ARMEB__
 148 #define __get_user_x_32t(__r2, __p, __e, __l, __s)                      \
 149         __get_user_x(__r2, __p, __e, __l, 32t_8)
 150 #else
 151 #define __get_user_x_32t __get_user_x
 152 #endif
 153
 154 /*
 155  * storing result into proper least significant word of 64bit target var,
 156  * different only for big endian case where 64 bit __r2 lsw is r3:
 157  */
 158 #ifdef __ARMEB__
 159 #define __get_user_x_64t(__r2, __p, __e, __l, __s)                      \
 160            __asm__ __volatile__ (                                       \
 161                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 162                 __asmeq("%3", "r1")                                     \
 163                 "bl     __get_user_64t_" #__s                           \
 164                 : "=&r" (__e), "=r" (__r2)                              \
 165                 : "0" (__p), "r" (__l)                                  \
 166                 : __GUP_CLOBBER_##__s)
 167 #else
 168 #define __get_user_x_64t __get_user_x
 169 #endif
 170
 171
 172 #define __get_user_check(x, p)                                          \
 173         ({                                                              \
 174                 unsigned long __limit = TASK_SIZE - 1; \
 175                 register typeof(*(p)) __user *__p asm("r0") = (p);      \
 176                 register __inttype(x) __r2 asm("r2");                   \
 177                 register unsigned long __l asm("r1") = __limit;         \
 178                 register int __e asm("r0");                             \
 179                 unsigned int __ua_flags = uaccess_save_and_enable();    \
 180                 int __tmp_e;                                            \
 181                 switch (sizeof(*(__p))) {                               \
 182                 case 1:                                                 \
 183                         if (sizeof((x)) >= 8)                           \
 184                                 __get_user_x_64t(__r2, __p, __e, __l, 1); \
 185                         else                                            \
 186                                 __get_user_x(__r2, __p, __e, __l, 1);   \
 187                         break;                                          \
 188                 case 2:                                                 \
 189                         if (sizeof((x)) >= 8)                           \
 190                                 __get_user_x_64t(__r2, __p, __e, __l, 2); \
 191                         else                                            \
 192                                 __get_user_x(__r2, __p, __e, __l, 2);   \
 193                         break;                                          \
 194                 case 4:                                                 \
 195                         if (sizeof((x)) >= 8)                           \
 196                                 __get_user_x_64t(__r2, __p, __e, __l, 4); \
 197                         else                                            \
 198                                 __get_user_x(__r2, __p, __e, __l, 4);   \
 199                         break;                                          \
 200                 case 8:                                                 \
 201                         if (sizeof((x)) < 8)                            \
 202                                 __get_user_x_32t(__r2, __p, __e, __l, 4); \
 203                         else                                            \
 204                                 __get_user_x(__r2, __p, __e, __l, 8);   \
 205                         break;                                          \
 206                 default: __e = __get_user_bad(); break;                 \
 207                 }                                                       \
 208                 __tmp_e = __e;                                          \
 209                 uaccess_restore(__ua_flags);                            \
 210                 x = (typeof(*(p))) __r2;                                \
 211                 __tmp_e;                                                \
 212         })
 213
 214 #define get_user(x, p)                                                  \
 215         ({                                                              \
 216                 might_fault();                                          \
 217                 __get_user_check(x, p);                                 \
 218          })
 219
 220 extern int __put_user_1(void *, unsigned int);
 221 extern int __put_user_2(void *, unsigned int);
 222 extern int __put_user_4(void *, unsigned int);
 223 extern int __put_user_8(void *, unsigned long long);
 224
 225 #define __put_user_check(__pu_val, __ptr, __err, __s)                   \
 226         ({                                                              \
 227                 unsigned long __limit = TASK_SIZE - 1; \
 228                 register typeof(__pu_val) __r2 asm("r2") = __pu_val;    \
 229                 register const void __user *__p asm("r0") = __ptr;      \
 230                 register unsigned long __l asm("r1") = __limit;         \
 231                 register int __e asm("r0");                             \
 232                 __asm__ __volatile__ (                                  \
 233                         __asmeq("%0", "r0") __asmeq("%2", "r2")         \
 234                         __asmeq("%3", "r1")                             \
 235                         "bl     __put_user_" #__s                       \
 236                         : "=&r" (__e)                                   \
 237                         : "0" (__p), "r" (__r2), "r" (__l)              \
 238                         : "ip", "lr", "cc");                            \
 239                 __err = __e;                                            \
 240         })
 241
 242 #else /* CONFIG_MMU */
 243
 244 #define __addr_ok(addr)         ((void)(addr), 1)
 245 #define __range_ok(addr, size)  ((void)(addr), 0)
 246
 247 #define get_user(x, p)  __get_user(x, p)
 248 #define __put_user_check __put_user_nocheck
 249
 250 #endif /* CONFIG_MMU */
 251
 252 #define access_ok(addr, size)   (__range_ok(addr, size) == 0)
 253
 254 #ifdef CONFIG_CPU_SPECTRE
 255 /*
 256  * When mitigating Spectre variant 1, it is not worth fixing the non-
 257  * verifying accessors, because we need to add verification of the
 258  * address space there.  Force these to use the standard get_user()
 259  * version instead.
 260  */
 261 #define __get_user(x, ptr) get_user(x, ptr)
 262 #else
 263
 264 /*
 265  * The "__xxx" versions of the user access functions do not verify the
 266  * address space - it must have been done previously with a separate
 267  * "access_ok()" call.
 268  *
 269  * The "xxx_error" versions set the third argument to EFAULT if an
 270  * error occurs, and leave it unchanged on success.  Note that these
 271  * versions are void (ie, don't return a value as such).
 272  */
 273 #define __get_user(x, ptr)                                              \
 274 ({                                                                      \
 275         long __gu_err = 0;                                              \
 276         __get_user_err((x), (ptr), __gu_err, TUSER());                  \
 277         __gu_err;                                                       \
 278 })
 279
 280 #define __get_user_err(x, ptr, err, __t)                                \
 281 do {                                                                    \
 282         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 283         unsigned long __gu_val;                                         \
 284         unsigned int __ua_flags;                                        \
 285         __chk_user_ptr(ptr);                                            \
 286         might_fault();                                                  \
 287         __ua_flags = uaccess_save_and_enable();                         \
 288         switch (sizeof(*(ptr))) {                                       \
 289         case 1: __get_user_asm_byte(__gu_val, __gu_addr, err, __t); break;      \
 290         case 2: __get_user_asm_half(__gu_val, __gu_addr, err, __t); break;      \
 291         case 4: __get_user_asm_word(__gu_val, __gu_addr, err, __t); break;      \
 292         default: (__gu_val) = __get_user_bad();                         \
 293         }                                                               \
 294         uaccess_restore(__ua_flags);                                    \
 295         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 296 } while (0)
 297 #endif
 298
 299 #define __get_user_asm(x, addr, err, instr)                     \
 300         __asm__ __volatile__(                                   \
 301         "1:     " instr " %1, [%2], #0\n"                       \
 302         "2:\n"                                                  \
 303         "       .pushsection .text.fixup,\"ax\"\n"              \
 304         "       .align  2\n"                                    \
 305         "3:     mov     %0, %3\n"                               \
 306         "       mov     %1, #0\n"                               \
 307         "       b       2b\n"                                   \
 308         "       .popsection\n"                                  \
 309         "       .pushsection __ex_table,\"a\"\n"                \
 310         "       .align  3\n"                                    \
 311         "       .long   1b, 3b\n"                               \
 312         "       .popsection"                                    \
 313         : "+r" (err), "=&r" (x)                                 \
 314         : "r" (addr), "i" (-EFAULT)                             \
 315         : "cc")
 316
 317 #define __get_user_asm_byte(x, addr, err, __t)                  \
 318         __get_user_asm(x, addr, err, "ldrb" __t)
 319
 320 #if __LINUX_ARM_ARCH__ >= 6
 321
 322 #define __get_user_asm_half(x, addr, err, __t)                  \
 323         __get_user_asm(x, addr, err, "ldrh" __t)
 324
 325 #else
 326
 327 #ifndef __ARMEB__
 328 #define __get_user_asm_half(x, __gu_addr, err, __t)             \
 329 ({                                                              \
 330         unsigned long __b1, __b2;                               \
 331         __get_user_asm_byte(__b1, __gu_addr, err, __t);         \
 332         __get_user_asm_byte(__b2, __gu_addr + 1, err, __t);     \
 333         (x) = __b1 | (__b2 << 8);                               \
 334 })
 335 #else
 336 #define __get_user_asm_half(x, __gu_addr, err, __t)             \
 337 ({                                                              \
 338         unsigned long __b1, __b2;                               \
 339         __get_user_asm_byte(__b1, __gu_addr, err, __t);         \
 340         __get_user_asm_byte(__b2, __gu_addr + 1, err, __t);     \
 341         (x) = (__b1 << 8) | __b2;                               \
 342 })
 343 #endif
 344
 345 #endif /* __LINUX_ARM_ARCH__ >= 6 */
 346
 347 #define __get_user_asm_word(x, addr, err, __t)                  \
 348         __get_user_asm(x, addr, err, "ldr" __t)
 349
 350 #define __put_user_switch(x, ptr, __err, __fn)                          \
 351         do {                                                            \
 352                 const __typeof__(*(ptr)) __user *__pu_ptr = (ptr);      \
 353                 __typeof__(*(ptr)) __pu_val = (x);                      \
 354                 unsigned int __ua_flags;                                \
 355                 might_fault();                                          \
 356                 __ua_flags = uaccess_save_and_enable();                 \
 357                 switch (sizeof(*(ptr))) {                               \
 358                 case 1: __fn(__pu_val, __pu_ptr, __err, 1); break;      \
 359                 case 2: __fn(__pu_val, __pu_ptr, __err, 2); break;      \
 360                 case 4: __fn(__pu_val, __pu_ptr, __err, 4); break;      \
 361                 case 8: __fn(__pu_val, __pu_ptr, __err, 8); break;      \
 362                 default: __err = __put_user_bad(); break;               \
 363                 }                                                       \
 364                 uaccess_restore(__ua_flags);                            \
 365         } while (0)
 366
 367 #define put_user(x, ptr)                                                \
 368 ({                                                                      \
 369         int __pu_err = 0;                                               \
 370         __put_user_switch((x), (ptr), __pu_err, __put_user_check);      \
 371         __pu_err;                                                       \
 372 })
 373
 374 #ifdef CONFIG_CPU_SPECTRE
 375 /*
 376  * When mitigating Spectre variant 1.1, all accessors need to include
 377  * verification of the address space.
 378  */
 379 #define __put_user(x, ptr) put_user(x, ptr)
 380
 381 #else
 382 #define __put_user(x, ptr)                                              \
 383 ({                                                                      \
 384         long __pu_err = 0;                                              \
 385         __put_user_switch((x), (ptr), __pu_err, __put_user_nocheck);    \
 386         __pu_err;                                                       \
 387 })
 388
 389 #define __put_user_nocheck(x, __pu_ptr, __err, __size)                  \
 390         do {                                                            \
 391                 unsigned long __pu_addr = (unsigned long)__pu_ptr;      \
 392                 __put_user_nocheck_##__size(x, __pu_addr, __err, TUSER());\
 393         } while (0)
 394
 395 #define __put_user_nocheck_1 __put_user_asm_byte
 396 #define __put_user_nocheck_2 __put_user_asm_half
 397 #define __put_user_nocheck_4 __put_user_asm_word
 398 #define __put_user_nocheck_8 __put_user_asm_dword
 399
 400 #endif /* !CONFIG_CPU_SPECTRE */
 401
 402 #define __put_user_asm(x, __pu_addr, err, instr)                \
 403         __asm__ __volatile__(                                   \
 404         "1:     " instr " %1, [%2], #0\n"               \
 405         "2:\n"                                                  \
 406         "       .pushsection .text.fixup,\"ax\"\n"              \
 407         "       .align  2\n"                                    \
 408         "3:     mov     %0, %3\n"                               \
 409         "       b       2b\n"                                   \
 410         "       .popsection\n"                                  \
 411         "       .pushsection __ex_table,\"a\"\n"                \
 412         "       .align  3\n"                                    \
 413         "       .long   1b, 3b\n"                               \
 414         "       .popsection"                                    \
 415         : "+r" (err)                                            \
 416         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 417         : "cc")
 418
 419 #define __put_user_asm_byte(x, __pu_addr, err, __t)             \
 420         __put_user_asm(x, __pu_addr, err, "strb" __t)
 421
 422 #if __LINUX_ARM_ARCH__ >= 6
 423
 424 #define __put_user_asm_half(x, __pu_addr, err, __t)             \
 425         __put_user_asm(x, __pu_addr, err, "strh" __t)
 426
 427 #else
 428
 429 #ifndef __ARMEB__
 430 #define __put_user_asm_half(x, __pu_addr, err, __t)             \
 431 ({                                                              \
 432         unsigned long __temp = (__force unsigned long)(x);      \
 433         __put_user_asm_byte(__temp, __pu_addr, err, __t);       \
 434         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err, __t);\
 435 })
 436 #else
 437 #define __put_user_asm_half(x, __pu_addr, err, __t)             \
 438 ({                                                              \
 439         unsigned long __temp = (__force unsigned long)(x);      \
 440         __put_user_asm_byte(__temp >> 8, __pu_addr, err, __t);  \
 441         __put_user_asm_byte(__temp, __pu_addr + 1, err, __t);   \
 442 })
 443 #endif
 444
 445 #endif /* __LINUX_ARM_ARCH__ >= 6 */
 446
 447 #define __put_user_asm_word(x, __pu_addr, err, __t)             \
 448         __put_user_asm(x, __pu_addr, err, "str" __t)
 449
 450 #ifndef __ARMEB__
 451 #define __reg_oper0     "%R2"
 452 #define __reg_oper1     "%Q2"
 453 #else
 454 #define __reg_oper0     "%Q2"
 455 #define __reg_oper1     "%R2"
 456 #endif
 457
 458 #define __put_user_asm_dword(x, __pu_addr, err, __t)            \
 459         __asm__ __volatile__(                                   \
 460  ARM(   "1:     str" __t "      " __reg_oper1 ", [%1], #4\n"  ) \
 461  ARM(   "2:     str" __t "      " __reg_oper0 ", [%1]\n"      ) \
 462  THUMB( "1:     str" __t "      " __reg_oper1 ", [%1]\n"      ) \
 463  THUMB( "2:     str" __t "      " __reg_oper0 ", [%1, #4]\n"  ) \
 464         "3:\n"                                                  \
 465         "       .pushsection .text.fixup,\"ax\"\n"              \
 466         "       .align  2\n"                                    \
 467         "4:     mov     %0, %3\n"                               \
 468         "       b       3b\n"                                   \
 469         "       .popsection\n"                                  \
 470         "       .pushsection __ex_table,\"a\"\n"                \
 471         "       .align  3\n"                                    \
 472         "       .long   1b, 4b\n"                               \
 473         "       .long   2b, 4b\n"                               \
 474         "       .popsection"                                    \
 475         : "+r" (err), "+r" (__pu_addr)                          \
 476         : "r" (x), "i" (-EFAULT)                                \
 477         : "cc")
 478
 479 #define HAVE_GET_KERNEL_NOFAULT
 480
 481 #define __get_kernel_nofault(dst, src, type, err_label)                 \
 482 do {                                                                    \
 483         const type *__pk_ptr = (src);                                   \
 484         unsigned long __src = (unsigned long)(__pk_ptr);                \
 485         type __val;                                                     \
 486         int __err = 0;                                                  \
 487         switch (sizeof(type)) {                                         \
 488         case 1: __get_user_asm_byte(__val, __src, __err, ""); break;    \
 489         case 2: __get_user_asm_half(__val, __src, __err, ""); break;    \
 490         case 4: __get_user_asm_word(__val, __src, __err, ""); break;    \
 491         case 8: {                                                       \
 492                 u32 *__v32 = (u32*)&__val;                              \
 493                 __get_user_asm_word(__v32[0], __src, __err, "");        \
 494                 if (__err)                                              \
 495                         break;                                          \
 496                 __get_user_asm_word(__v32[1], __src+4, __err, "");      \
 497                 break;                                                  \
 498         }                                                               \
 499         default: __err = __get_user_bad(); break;                       \
 500         }                                                               \
 501         if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))         \
 502                 put_unaligned(__val, (type *)(dst));                    \
 503         else                                                            \
 504                 *(type *)(dst) = __val; /* aligned by caller */         \
 505         if (__err)                                                      \
 506                 goto err_label;                                         \
 507 } while (0)
 508
 509 #define __put_kernel_nofault(dst, src, type, err_label)                 \
 510 do {                                                                    \
 511         const type *__pk_ptr = (dst);                                   \
 512         unsigned long __dst = (unsigned long)__pk_ptr;                  \
 513         int __err = 0;                                                  \
 514         type __val = IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) \
 515                      ? get_unaligned((type *)(src))                     \
 516                      : *(type *)(src);  /* aligned by caller */         \
 517         switch (sizeof(type)) {                                         \
 518         case 1: __put_user_asm_byte(__val, __dst, __err, ""); break;    \
 519         case 2: __put_user_asm_half(__val, __dst, __err, ""); break;    \
 520         case 4: __put_user_asm_word(__val, __dst, __err, ""); break;    \
 521         case 8: __put_user_asm_dword(__val, __dst, __err, ""); break;   \
 522         default: __err = __put_user_bad(); break;                       \
 523         }                                                               \
 524         if (__err)                                                      \
 525                 goto err_label;                                         \
 526 } while (0)
 527
 528 #ifdef CONFIG_MMU
 529 extern unsigned long __must_check
 530 arm_copy_from_user(void *to, const void __user *from, unsigned long n);
 531
 532 static inline unsigned long __must_check
 533 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 534 {
 535         unsigned int __ua_flags;
 536
 537         __ua_flags = uaccess_save_and_enable();
 538         n = arm_copy_from_user(to, from, n);
 539         uaccess_restore(__ua_flags);
 540         return n;
 541 }
 542
 543 extern unsigned long __must_check
 544 arm_copy_to_user(void __user *to, const void *from, unsigned long n);
 545 extern unsigned long __must_check
 546 __copy_to_user_std(void __user *to, const void *from, unsigned long n);
 547
 548 static inline unsigned long __must_check
 549 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 550 {
 551 #ifndef CONFIG_UACCESS_WITH_MEMCPY
 552         unsigned int __ua_flags;
 553         __ua_flags = uaccess_save_and_enable();
 554         n = arm_copy_to_user(to, from, n);
 555         uaccess_restore(__ua_flags);
 556         return n;
 557 #else
 558         return arm_copy_to_user(to, from, n);
 559 #endif
 560 }
 561
 562 extern unsigned long __must_check
 563 arm_clear_user(void __user *addr, unsigned long n);
 564 extern unsigned long __must_check
 565 __clear_user_std(void __user *addr, unsigned long n);
 566
 567 static inline unsigned long __must_check
 568 __clear_user(void __user *addr, unsigned long n)
 569 {
 570         unsigned int __ua_flags = uaccess_save_and_enable();
 571         n = arm_clear_user(addr, n);
 572         uaccess_restore(__ua_flags);
 573         return n;
 574 }
 575
 576 #else
 577 static inline unsigned long
 578 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 579 {
 580         memcpy(to, (const void __force *)from, n);
 581         return 0;
 582 }
 583 static inline unsigned long
 584 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 585 {
 586         memcpy((void __force *)to, from, n);
 587         return 0;
 588 }
 589 #define __clear_user(addr, n)           (memset((void __force *)addr, 0, n), 0)
 590 #endif
 591 #define INLINE_COPY_TO_USER
 592 #define INLINE_COPY_FROM_USER
 593
 594 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
 595 {
 596         if (access_ok(to, n))
 597                 n = __clear_user(to, n);
 598         return n;
 599 }
 600
 601 /* These are from lib/ code, and use __get_user() and friends */
 602 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 603
 604 extern __must_check long strnlen_user(const char __user *str, long n);
 605
 606 #endif /* _ASMARM_UACCESS_H */