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/unified.h>
  15 #include <asm/compiler.h>
  16
  17 #include <asm/extable.h>
  18
  19 /*
  20  * These two functions allow hooking accesses to userspace to increase
  21  * system integrity by ensuring that the kernel can not inadvertantly
  22  * perform such accesses (eg, via list poison values) which could then
  23  * be exploited for priviledge escalation.
  24  */
  25 static inline unsigned int uaccess_save_and_enable(void)
  26 {
  27 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
  28         unsigned int old_domain = get_domain();
  29
  30         /* Set the current domain access to permit user accesses */
  31         set_domain((old_domain & ~domain_mask(DOMAIN_USER)) |
  32                    domain_val(DOMAIN_USER, DOMAIN_CLIENT));
  33
  34         return old_domain;
  35 #else
  36         return 0;
  37 #endif
  38 }
  39
  40 static inline void uaccess_restore(unsigned int flags)
  41 {
  42 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
  43         /* Restore the user access mask */
  44         set_domain(flags);
  45 #endif
  46 }
  47
  48 /*
  49  * These two are intentionally not defined anywhere - if the kernel
  50  * code generates any references to them, that's a bug.
  51  */
  52 extern int __get_user_bad(void);
  53 extern int __put_user_bad(void);
  54
  55 /*
  56  * Note that this is actually 0x1,0000,0000
  57  */
  58 #define KERNEL_DS       0x00000000
  59
  60 #ifdef CONFIG_MMU
  61
  62 #define USER_DS         TASK_SIZE
  63 #define get_fs()        (current_thread_info()->addr_limit)
  64
  65 static inline void set_fs(mm_segment_t fs)
  66 {
  67         current_thread_info()->addr_limit = fs;
  68
  69         /*
  70          * Prevent a mispredicted conditional call to set_fs from forwarding
  71          * the wrong address limit to access_ok under speculation.
  72          */
  73         dsb(nsh);
  74         isb();
  75
  76         modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
  77 }
  78
  79 #define segment_eq(a, b)        ((a) == (b))
  80
  81 /* We use 33-bit arithmetic here... */
  82 #define __range_ok(addr, size) ({ \
  83         unsigned long flag, roksum; \
  84         __chk_user_ptr(addr);   \
  85         __asm__(".syntax unified\n" \
  86                 "adds %1, %2, %3; sbcscc %1, %1, %0; movcc %0, #0" \
  87                 : "=&r" (flag), "=&r" (roksum) \
  88                 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
  89                 : "cc"); \
  90         flag; })
  91
  92 /*
  93  * This is a type: either unsigned long, if the argument fits into
  94  * that type, or otherwise unsigned long long.
  95  */
  96 #define __inttype(x) \
  97         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
  98
  99 /*
 100  * Sanitise a uaccess pointer such that it becomes NULL if addr+size
 101  * is above the current addr_limit.
 102  */
 103 #define uaccess_mask_range_ptr(ptr, size)                       \
 104         ((__typeof__(ptr))__uaccess_mask_range_ptr(ptr, size))
 105 static inline void __user *__uaccess_mask_range_ptr(const void __user *ptr,
 106                                                     size_t size)
 107 {
 108         void __user *safe_ptr = (void __user *)ptr;
 109         unsigned long tmp;
 110
 111         asm volatile(
 112         "       .syntax unified\n"
 113         "       sub     %1, %3, #1\n"
 114         "       subs    %1, %1, %0\n"
 115         "       addhs   %1, %1, #1\n"
 116         "       subshs  %1, %1, %2\n"
 117         "       movlo   %0, #0\n"
 118         : "+r" (safe_ptr), "=&r" (tmp)
 119         : "r" (size), "r" (current_thread_info()->addr_limit)
 120         : "cc");
 121
 122         csdb();
 123         return safe_ptr;
 124 }
 125
 126 /*
 127  * Single-value transfer routines.  They automatically use the right
 128  * size if we just have the right pointer type.  Note that the functions
 129  * which read from user space (*get_*) need to take care not to leak
 130  * kernel data even if the calling code is buggy and fails to check
 131  * the return value.  This means zeroing out the destination variable
 132  * or buffer on error.  Normally this is done out of line by the
 133  * fixup code, but there are a few places where it intrudes on the
 134  * main code path.  When we only write to user space, there is no
 135  * problem.
 136  */
 137 extern int __get_user_1(void *);
 138 extern int __get_user_2(void *);
 139 extern int __get_user_4(void *);
 140 extern int __get_user_32t_8(void *);
 141 extern int __get_user_8(void *);
 142 extern int __get_user_64t_1(void *);
 143 extern int __get_user_64t_2(void *);
 144 extern int __get_user_64t_4(void *);
 145
 146 #define __GUP_CLOBBER_1 "lr", "cc"
 147 #ifdef CONFIG_CPU_USE_DOMAINS
 148 #define __GUP_CLOBBER_2 "ip", "lr", "cc"
 149 #else
 150 #define __GUP_CLOBBER_2 "lr", "cc"
 151 #endif
 152 #define __GUP_CLOBBER_4 "lr", "cc"
 153 #define __GUP_CLOBBER_32t_8 "lr", "cc"
 154 #define __GUP_CLOBBER_8 "lr", "cc"
 155
 156 #define __get_user_x(__r2, __p, __e, __l, __s)                          \
 157            __asm__ __volatile__ (                                       \
 158                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 159                 __asmeq("%3", "r1")                                     \
 160                 "bl     __get_user_" #__s                               \
 161                 : "=&r" (__e), "=r" (__r2)                              \
 162                 : "0" (__p), "r" (__l)                                  \
 163                 : __GUP_CLOBBER_##__s)
 164
 165 /* narrowing a double-word get into a single 32bit word register: */
 166 #ifdef __ARMEB__
 167 #define __get_user_x_32t(__r2, __p, __e, __l, __s)                      \
 168         __get_user_x(__r2, __p, __e, __l, 32t_8)
 169 #else
 170 #define __get_user_x_32t __get_user_x
 171 #endif
 172
 173 /*
 174  * storing result into proper least significant word of 64bit target var,
 175  * different only for big endian case where 64 bit __r2 lsw is r3:
 176  */
 177 #ifdef __ARMEB__
 178 #define __get_user_x_64t(__r2, __p, __e, __l, __s)                      \
 179            __asm__ __volatile__ (                                       \
 180                 __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
 181                 __asmeq("%3", "r1")                                     \
 182                 "bl     __get_user_64t_" #__s                           \
 183                 : "=&r" (__e), "=r" (__r2)                              \
 184                 : "0" (__p), "r" (__l)                                  \
 185                 : __GUP_CLOBBER_##__s)
 186 #else
 187 #define __get_user_x_64t __get_user_x
 188 #endif
 189
 190
 191 #define __get_user_check(x, p)                                          \
 192         ({                                                              \
 193                 unsigned long __limit = current_thread_info()->addr_limit - 1; \
 194                 register typeof(*(p)) __user *__p asm("r0") = (p);      \
 195                 register __inttype(x) __r2 asm("r2");                   \
 196                 register unsigned long __l asm("r1") = __limit;         \
 197                 register int __e asm("r0");                             \
 198                 unsigned int __ua_flags = uaccess_save_and_enable();    \
 199                 switch (sizeof(*(__p))) {                               \
 200                 case 1:                                                 \
 201                         if (sizeof((x)) >= 8)                           \
 202                                 __get_user_x_64t(__r2, __p, __e, __l, 1); \
 203                         else                                            \
 204                                 __get_user_x(__r2, __p, __e, __l, 1);   \
 205                         break;                                          \
 206                 case 2:                                                 \
 207                         if (sizeof((x)) >= 8)                           \
 208                                 __get_user_x_64t(__r2, __p, __e, __l, 2); \
 209                         else                                            \
 210                                 __get_user_x(__r2, __p, __e, __l, 2);   \
 211                         break;                                          \
 212                 case 4:                                                 \
 213                         if (sizeof((x)) >= 8)                           \
 214                                 __get_user_x_64t(__r2, __p, __e, __l, 4); \
 215                         else                                            \
 216                                 __get_user_x(__r2, __p, __e, __l, 4);   \
 217                         break;                                          \
 218                 case 8:                                                 \
 219                         if (sizeof((x)) < 8)                            \
 220                                 __get_user_x_32t(__r2, __p, __e, __l, 4); \
 221                         else                                            \
 222                                 __get_user_x(__r2, __p, __e, __l, 8);   \
 223                         break;                                          \
 224                 default: __e = __get_user_bad(); break;                 \
 225                 }                                                       \
 226                 uaccess_restore(__ua_flags);                            \
 227                 x = (typeof(*(p))) __r2;                                \
 228                 __e;                                                    \
 229         })
 230
 231 #define get_user(x, p)                                                  \
 232         ({                                                              \
 233                 might_fault();                                          \
 234                 __get_user_check(x, p);                                 \
 235          })
 236
 237 extern int __put_user_1(void *, unsigned int);
 238 extern int __put_user_2(void *, unsigned int);
 239 extern int __put_user_4(void *, unsigned int);
 240 extern int __put_user_8(void *, unsigned long long);
 241
 242 #define __put_user_check(__pu_val, __ptr, __err, __s)                   \
 243         ({                                                              \
 244                 unsigned long __limit = current_thread_info()->addr_limit - 1; \
 245                 register typeof(__pu_val) __r2 asm("r2") = __pu_val;    \
 246                 register const void __user *__p asm("r0") = __ptr;      \
 247                 register unsigned long __l asm("r1") = __limit;         \
 248                 register int __e asm("r0");                             \
 249                 __asm__ __volatile__ (                                  \
 250                         __asmeq("%0", "r0") __asmeq("%2", "r2")         \
 251                         __asmeq("%3", "r1")                             \
 252                         "bl     __put_user_" #__s                       \
 253                         : "=&r" (__e)                                   \
 254                         : "0" (__p), "r" (__r2), "r" (__l)              \
 255                         : "ip", "lr", "cc");                            \
 256                 __err = __e;                                            \
 257         })
 258
 259 #else /* CONFIG_MMU */
 260
 261 /*
 262  * uClinux has only one addr space, so has simplified address limits.
 263  */
 264 #define USER_DS                 KERNEL_DS
 265
 266 #define segment_eq(a, b)                (1)
 267 #define __addr_ok(addr)         ((void)(addr), 1)
 268 #define __range_ok(addr, size)  ((void)(addr), 0)
 269 #define get_fs()                (KERNEL_DS)
 270
 271 static inline void set_fs(mm_segment_t fs)
 272 {
 273 }
 274
 275 #define get_user(x, p)  __get_user(x, p)
 276 #define __put_user_check __put_user_nocheck
 277
 278 #endif /* CONFIG_MMU */
 279
 280 #define access_ok(addr, size)   (__range_ok(addr, size) == 0)
 281
 282 #define user_addr_max() \
 283         (uaccess_kernel() ? ~0UL : get_fs())
 284
 285 #ifdef CONFIG_CPU_SPECTRE
 286 /*
 287  * When mitigating Spectre variant 1, it is not worth fixing the non-
 288  * verifying accessors, because we need to add verification of the
 289  * address space there.  Force these to use the standard get_user()
 290  * version instead.
 291  */
 292 #define __get_user(x, ptr) get_user(x, ptr)
 293 #else
 294
 295 /*
 296  * The "__xxx" versions of the user access functions do not verify the
 297  * address space - it must have been done previously with a separate
 298  * "access_ok()" call.
 299  *
 300  * The "xxx_error" versions set the third argument to EFAULT if an
 301  * error occurs, and leave it unchanged on success.  Note that these
 302  * versions are void (ie, don't return a value as such).
 303  */
 304 #define __get_user(x, ptr)                                              \
 305 ({                                                                      \
 306         long __gu_err = 0;                                              \
 307         __get_user_err((x), (ptr), __gu_err);                           \
 308         __gu_err;                                                       \
 309 })
 310
 311 #define __get_user_err(x, ptr, err)                                     \
 312 do {                                                                    \
 313         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 314         unsigned long __gu_val;                                         \
 315         unsigned int __ua_flags;                                        \
 316         __chk_user_ptr(ptr);                                            \
 317         might_fault();                                                  \
 318         __ua_flags = uaccess_save_and_enable();                         \
 319         switch (sizeof(*(ptr))) {                                       \
 320         case 1: __get_user_asm_byte(__gu_val, __gu_addr, err);  break;  \
 321         case 2: __get_user_asm_half(__gu_val, __gu_addr, err);  break;  \
 322         case 4: __get_user_asm_word(__gu_val, __gu_addr, err);  break;  \
 323         default: (__gu_val) = __get_user_bad();                         \
 324         }                                                               \
 325         uaccess_restore(__ua_flags);                                    \
 326         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 327 } while (0)
 328
 329 #define __get_user_asm(x, addr, err, instr)                     \
 330         __asm__ __volatile__(                                   \
 331         "1:     " TUSER(instr) " %1, [%2], #0\n"                \
 332         "2:\n"                                                  \
 333         "       .pushsection .text.fixup,\"ax\"\n"              \
 334         "       .align  2\n"                                    \
 335         "3:     mov     %0, %3\n"                               \
 336         "       mov     %1, #0\n"                               \
 337         "       b       2b\n"                                   \
 338         "       .popsection\n"                                  \
 339         "       .pushsection __ex_table,\"a\"\n"                \
 340         "       .align  3\n"                                    \
 341         "       .long   1b, 3b\n"                               \
 342         "       .popsection"                                    \
 343         : "+r" (err), "=&r" (x)                                 \
 344         : "r" (addr), "i" (-EFAULT)                             \
 345         : "cc")
 346
 347 #define __get_user_asm_byte(x, addr, err)                       \
 348         __get_user_asm(x, addr, err, ldrb)
 349
 350 #if __LINUX_ARM_ARCH__ >= 6
 351
 352 #define __get_user_asm_half(x, addr, err)                       \
 353         __get_user_asm(x, addr, err, ldrh)
 354
 355 #else
 356
 357 #ifndef __ARMEB__
 358 #define __get_user_asm_half(x, __gu_addr, err)                  \
 359 ({                                                              \
 360         unsigned long __b1, __b2;                               \
 361         __get_user_asm_byte(__b1, __gu_addr, err);              \
 362         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 363         (x) = __b1 | (__b2 << 8);                               \
 364 })
 365 #else
 366 #define __get_user_asm_half(x, __gu_addr, err)                  \
 367 ({                                                              \
 368         unsigned long __b1, __b2;                               \
 369         __get_user_asm_byte(__b1, __gu_addr, err);              \
 370         __get_user_asm_byte(__b2, __gu_addr + 1, err);          \
 371         (x) = (__b1 << 8) | __b2;                               \
 372 })
 373 #endif
 374
 375 #endif /* __LINUX_ARM_ARCH__ >= 6 */
 376
 377 #define __get_user_asm_word(x, addr, err)                       \
 378         __get_user_asm(x, addr, err, ldr)
 379 #endif
 380
 381
 382 #define __put_user_switch(x, ptr, __err, __fn)                          \
 383         do {                                                            \
 384                 const __typeof__(*(ptr)) __user *__pu_ptr = (ptr);      \
 385                 __typeof__(*(ptr)) __pu_val = (x);                      \
 386                 unsigned int __ua_flags;                                \
 387                 might_fault();                                          \
 388                 __ua_flags = uaccess_save_and_enable();                 \
 389                 switch (sizeof(*(ptr))) {                               \
 390                 case 1: __fn(__pu_val, __pu_ptr, __err, 1); break;      \
 391                 case 2: __fn(__pu_val, __pu_ptr, __err, 2); break;      \
 392                 case 4: __fn(__pu_val, __pu_ptr, __err, 4); break;      \
 393                 case 8: __fn(__pu_val, __pu_ptr, __err, 8); break;      \
 394                 default: __err = __put_user_bad(); break;               \
 395                 }                                                       \
 396                 uaccess_restore(__ua_flags);                            \
 397         } while (0)
 398
 399 #define put_user(x, ptr)                                                \
 400 ({                                                                      \
 401         int __pu_err = 0;                                               \
 402         __put_user_switch((x), (ptr), __pu_err, __put_user_check);      \
 403         __pu_err;                                                       \
 404 })
 405
 406 #ifdef CONFIG_CPU_SPECTRE
 407 /*
 408  * When mitigating Spectre variant 1.1, all accessors need to include
 409  * verification of the address space.
 410  */
 411 #define __put_user(x, ptr) put_user(x, ptr)
 412
 413 #else
 414 #define __put_user(x, ptr)                                              \
 415 ({                                                                      \
 416         long __pu_err = 0;                                              \
 417         __put_user_switch((x), (ptr), __pu_err, __put_user_nocheck);    \
 418         __pu_err;                                                       \
 419 })
 420
 421 #define __put_user_nocheck(x, __pu_ptr, __err, __size)                  \
 422         do {                                                            \
 423                 unsigned long __pu_addr = (unsigned long)__pu_ptr;      \
 424                 __put_user_nocheck_##__size(x, __pu_addr, __err);       \
 425         } while (0)
 426
 427 #define __put_user_nocheck_1 __put_user_asm_byte
 428 #define __put_user_nocheck_2 __put_user_asm_half
 429 #define __put_user_nocheck_4 __put_user_asm_word
 430 #define __put_user_nocheck_8 __put_user_asm_dword
 431
 432 #define __put_user_asm(x, __pu_addr, err, instr)                \
 433         __asm__ __volatile__(                                   \
 434         "1:     " TUSER(instr) " %1, [%2], #0\n"                \
 435         "2:\n"                                                  \
 436         "       .pushsection .text.fixup,\"ax\"\n"              \
 437         "       .align  2\n"                                    \
 438         "3:     mov     %0, %3\n"                               \
 439         "       b       2b\n"                                   \
 440         "       .popsection\n"                                  \
 441         "       .pushsection __ex_table,\"a\"\n"                \
 442         "       .align  3\n"                                    \
 443         "       .long   1b, 3b\n"                               \
 444         "       .popsection"                                    \
 445         : "+r" (err)                                            \
 446         : "r" (x), "r" (__pu_addr), "i" (-EFAULT)               \
 447         : "cc")
 448
 449 #define __put_user_asm_byte(x, __pu_addr, err)                  \
 450         __put_user_asm(x, __pu_addr, err, strb)
 451
 452 #if __LINUX_ARM_ARCH__ >= 6
 453
 454 #define __put_user_asm_half(x, __pu_addr, err)                  \
 455         __put_user_asm(x, __pu_addr, err, strh)
 456
 457 #else
 458
 459 #ifndef __ARMEB__
 460 #define __put_user_asm_half(x, __pu_addr, err)                  \
 461 ({                                                              \
 462         unsigned long __temp = (__force unsigned long)(x);      \
 463         __put_user_asm_byte(__temp, __pu_addr, err);            \
 464         __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
 465 })
 466 #else
 467 #define __put_user_asm_half(x, __pu_addr, err)                  \
 468 ({                                                              \
 469         unsigned long __temp = (__force unsigned long)(x);      \
 470         __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
 471         __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
 472 })
 473 #endif
 474
 475 #endif /* __LINUX_ARM_ARCH__ >= 6 */
 476
 477 #define __put_user_asm_word(x, __pu_addr, err)                  \
 478         __put_user_asm(x, __pu_addr, err, str)
 479
 480 #ifndef __ARMEB__
 481 #define __reg_oper0     "%R2"
 482 #define __reg_oper1     "%Q2"
 483 #else
 484 #define __reg_oper0     "%Q2"
 485 #define __reg_oper1     "%R2"
 486 #endif
 487
 488 #define __put_user_asm_dword(x, __pu_addr, err)                 \
 489         __asm__ __volatile__(                                   \
 490  ARM(   "1:     " TUSER(str) "  " __reg_oper1 ", [%1], #4\n"    ) \
 491  ARM(   "2:     " TUSER(str) "  " __reg_oper0 ", [%1]\n"        ) \
 492  THUMB( "1:     " TUSER(str) "  " __reg_oper1 ", [%1]\n"        ) \
 493  THUMB( "2:     " TUSER(str) "  " __reg_oper0 ", [%1, #4]\n"    ) \
 494         "3:\n"                                                  \
 495         "       .pushsection .text.fixup,\"ax\"\n"              \
 496         "       .align  2\n"                                    \
 497         "4:     mov     %0, %3\n"                               \
 498         "       b       3b\n"                                   \
 499         "       .popsection\n"                                  \
 500         "       .pushsection __ex_table,\"a\"\n"                \
 501         "       .align  3\n"                                    \
 502         "       .long   1b, 4b\n"                               \
 503         "       .long   2b, 4b\n"                               \
 504         "       .popsection"                                    \
 505         : "+r" (err), "+r" (__pu_addr)                          \
 506         : "r" (x), "i" (-EFAULT)                                \
 507         : "cc")
 508
 509 #endif /* !CONFIG_CPU_SPECTRE */
 510
 511 #ifdef CONFIG_MMU
 512 extern unsigned long __must_check
 513 arm_copy_from_user(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 */