| 1 | |
| 2 | * This file is subject to the terms and conditions of the GNU General Public
|
| 3 | * License. See the file "COPYING" in the main directory of this archive
|
| 4 | * for more details.
|
| 5 | *
|
| 6 | * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
|
| 7 | * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
|
| 8 | * Copyright (C) 2007 Maciej W. Rozycki
|
| 9 | * Copyright (C) 2014, Imagination Technologies Ltd.
|
| 10 |
|
| 11 | #ifndef _ASM_UACCESS_H
|
| 12 | #define _ASM_UACCESS_H
|
| 13 |
|
| 14 | #include <linux/kernel.h>
|
| 15 | #include <linux/string.h>
|
| 16 | #include <asm/asm-eva.h>
|
| 17 | #include <asm/extable.h>
|
| 18 |
|
| 19 | #ifdef CONFIG_32BIT
|
| 20 |
|
| 21 | #define __UA_LIMIT 0x80000000UL
|
| 22 | #define TASK_SIZE_MAX KSEG0
|
| 23 |
|
| 24 | #define __UA_ADDR ".word"
|
| 25 | #define __UA_LA "la"
|
| 26 | #define __UA_ADDU "addu"
|
| 27 | #define __UA_t0 "$8"
|
| 28 | #define __UA_t1 "$9"
|
| 29 |
|
| 30 | #endif
|
| 31 |
|
| 32 | #ifdef CONFIG_64BIT
|
| 33 |
|
| 34 | extern u64 __ua_limit;
|
| 35 |
|
| 36 | #define __UA_LIMIT __ua_limit
|
| 37 | #define TASK_SIZE_MAX XKSSEG
|
| 38 |
|
| 39 | #define __UA_ADDR ".dword"
|
| 40 | #define __UA_LA "dla"
|
| 41 | #define __UA_ADDU "daddu"
|
| 42 | #define __UA_t0 "$12"
|
| 43 | #define __UA_t1 "$13"
|
| 44 |
|
| 45 | #endif
|
| 46 |
|
| 47 | #include <asm-generic/access_ok.h>
|
| 48 |
|
| 49 | |
| 50 | * put_user: - Write a simple value into user space.
|
| 51 | * @x: Value to copy to user space.
|
| 52 | * @ptr: Destination address, in user space.
|
| 53 | *
|
| 54 | * Context: User context only. This function may sleep if pagefaults are
|
| 55 | * enabled.
|
| 56 | *
|
| 57 | * This macro copies a single simple value from kernel space to user
|
| 58 | * space. It supports simple types like char and int, but not larger
|
| 59 | * data types like structures or arrays.
|
| 60 | *
|
| 61 | * @ptr must have pointer-to-simple-variable type, and @x must be assignable
|
| 62 | * to the result of dereferencing @ptr.
|
| 63 | *
|
| 64 | * Returns zero on success, or -EFAULT on error.
|
| 65 |
|
| 66 | #define put_user(x, ptr) \
|
| 67 | ({ \
|
| 68 | __typeof__(*(ptr)) __user *__p = (ptr); \
|
| 69 | \
|
| 70 | might_fault(); \
|
| 71 | access_ok(__p, sizeof(*__p)) ? __put_user((x), __p) : -EFAULT; \
|
| 72 | })
|
| 73 |
|
| 74 | |
| 75 | * get_user: - Get a simple variable from user space.
|
| 76 | * @x: Variable to store result.
|
| 77 | * @ptr: Source address, in user space.
|
| 78 | *
|
| 79 | * Context: User context only. This function may sleep if pagefaults are
|
| 80 | * enabled.
|
| 81 | *
|
| 82 | * This macro copies a single simple variable from user space to kernel
|
| 83 | * space. It supports simple types like char and int, but not larger
|
| 84 | * data types like structures or arrays.
|
| 85 | *
|
| 86 | * @ptr must have pointer-to-simple-variable type, and the result of
|
| 87 | * dereferencing @ptr must be assignable to @x without a cast.
|
| 88 | *
|
| 89 | * Returns zero on success, or -EFAULT on error.
|
| 90 | * On error, the variable @x is set to zero.
|
| 91 |
|
| 92 | #define get_user(x, ptr) \
|
| 93 | ({ \
|
| 94 | const __typeof__(*(ptr)) __user *__p = (ptr); \
|
| 95 | \
|
| 96 | might_fault(); \
|
| 97 | access_ok(__p, sizeof(*__p)) ? __get_user((x), __p) : \
|
| 98 | ((x) = 0, -EFAULT); \
|
| 99 | })
|
| 100 |
|
| 101 | |
| 102 | * __put_user: - Write a simple value into user space, with less checking.
|
| 103 | * @x: Value to copy to user space.
|
| 104 | * @ptr: Destination address, in user space.
|
| 105 | *
|
| 106 | * Context: User context only. This function may sleep if pagefaults are
|
| 107 | * enabled.
|
| 108 | *
|
| 109 | * This macro copies a single simple value from kernel space to user
|
| 110 | * space. It supports simple types like char and int, but not larger
|
| 111 | * data types like structures or arrays.
|
| 112 | *
|
| 113 | * @ptr must have pointer-to-simple-variable type, and @x must be assignable
|
| 114 | * to the result of dereferencing @ptr.
|
| 115 | *
|
| 116 | * Caller must check the pointer with access_ok() before calling this
|
| 117 | * function.
|
| 118 | *
|
| 119 | * Returns zero on success, or -EFAULT on error.
|
| 120 |
|
| 121 | #define __put_user(x, ptr) \
|
| 122 | ({ \
|
| 123 | __typeof__(*(ptr)) __user *__pu_ptr = (ptr); \
|
| 124 | __typeof__(*(ptr)) __pu_val = (x); \
|
| 125 | int __pu_err = 0; \
|
| 126 | \
|
| 127 | __chk_user_ptr(__pu_ptr); \
|
| 128 | switch (sizeof(*__pu_ptr)) { \
|
| 129 | case 1: \
|
| 130 | __put_data_asm(user_sb, __pu_ptr); \
|
| 131 | break; \
|
| 132 | case 2: \
|
| 133 | __put_data_asm(user_sh, __pu_ptr); \
|
| 134 | break; \
|
| 135 | case 4: \
|
| 136 | __put_data_asm(user_sw, __pu_ptr); \
|
| 137 | break; \
|
| 138 | case 8: \
|
| 139 | __PUT_DW(user_sd, __pu_ptr); \
|
| 140 | break; \
|
| 141 | default: \
|
| 142 | BUILD_BUG(); \
|
| 143 | } \
|
| 144 | \
|
| 145 | __pu_err; \
|
| 146 | })
|
| 147 |
|
| 148 | |
| 149 | * __get_user: - Get a simple variable from user space, with less checking.
|
| 150 | * @x: Variable to store result.
|
| 151 | * @ptr: Source address, in user space.
|
| 152 | *
|
| 153 | * Context: User context only. This function may sleep if pagefaults are
|
| 154 | * enabled.
|
| 155 | *
|
| 156 | * This macro copies a single simple variable from user space to kernel
|
| 157 | * space. It supports simple types like char and int, but not larger
|
| 158 | * data types like structures or arrays.
|
| 159 | *
|
| 160 | * @ptr must have pointer-to-simple-variable type, and the result of
|
| 161 | * dereferencing @ptr must be assignable to @x without a cast.
|
| 162 | *
|
| 163 | * Caller must check the pointer with access_ok() before calling this
|
| 164 | * function.
|
| 165 | *
|
| 166 | * Returns zero on success, or -EFAULT on error.
|
| 167 | * On error, the variable @x is set to zero.
|
| 168 |
|
| 169 | #define __get_user(x, ptr) \
|
| 170 | ({ \
|
| 171 | const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
|
| 172 | int __gu_err = 0; \
|
| 173 | \
|
| 174 | __chk_user_ptr(__gu_ptr); \
|
| 175 | switch (sizeof(*__gu_ptr)) { \
|
| 176 | case 1: \
|
| 177 | __get_data_asm((x), user_lb, __gu_ptr); \
|
| 178 | break; \
|
| 179 | case 2: \
|
| 180 | __get_data_asm((x), user_lh, __gu_ptr); \
|
| 181 | break; \
|
| 182 | case 4: \
|
| 183 | __get_data_asm((x), user_lw, __gu_ptr); \
|
| 184 | break; \
|
| 185 | case 8: \
|
| 186 | __GET_DW((x), user_ld, __gu_ptr); \
|
| 187 | break; \
|
| 188 | default: \
|
| 189 | BUILD_BUG(); \
|
| 190 | } \
|
| 191 | \
|
| 192 | __gu_err; \
|
| 193 | })
|
| 194 |
|
| 195 | struct __large_struct { unsigned long buf[100]; };
|
| 196 | #define __m(x) (*(struct __large_struct __user *)(x))
|
| 197 |
|
| 198 | #ifdef CONFIG_32BIT
|
| 199 | #define __GET_DW(val, insn, ptr) __get_data_asm_ll32(val, insn, ptr)
|
| 200 | #endif
|
| 201 | #ifdef CONFIG_64BIT
|
| 202 | #define __GET_DW(val, insn, ptr) __get_data_asm(val, insn, ptr)
|
| 203 | #endif
|
| 204 |
|
| 205 | #define __get_data_asm(val, insn, addr) \
|
| 206 | { \
|
| 207 | long __gu_tmp; \
|
| 208 | \
|
| 209 | __asm__ __volatile__( \
|
| 210 | "1: "insn("%1", "%3")" \n" \
|
| 211 | "2: \n" \
|
| 212 | " .insn \n" \
|
| 213 | " .section .fixup,\"ax\" \n" \
|
| 214 | "3: li %0, %4 \n" \
|
| 215 | " move %1, $0 \n" \
|
| 216 | " j 2b \n" \
|
| 217 | " .previous \n" \
|
| 218 | " .section __ex_table,\"a\" \n" \
|
| 219 | " "__UA_ADDR "\t1b, 3b \n" \
|
| 220 | " .previous \n" \
|
| 221 | : "=r" (__gu_err), "=r" (__gu_tmp) \
|
| 222 | : "0" (0), "o" (__m(addr)), "i" (-EFAULT)); \
|
| 223 | \
|
| 224 | (val) = (__typeof__(*(addr))) __gu_tmp; \
|
| 225 | }
|
| 226 |
|
| 227 | |
| 228 | * Get a long long 64 using 32 bit registers.
|
| 229 |
|
| 230 | #define __get_data_asm_ll32(val, insn, addr) \
|
| 231 | { \
|
| 232 | union { \
|
| 233 | unsigned long long l; \
|
| 234 | __typeof__(*(addr)) t; \
|
| 235 | } __gu_tmp; \
|
| 236 | \
|
| 237 | __asm__ __volatile__( \
|
| 238 | "1: " insn("%1", "(%3)")" \n" \
|
| 239 | "2: " insn("%D1", "4(%3)")" \n" \
|
| 240 | "3: \n" \
|
| 241 | " .insn \n" \
|
| 242 | " .section .fixup,\"ax\" \n" \
|
| 243 | "4: li %0, %4 \n" \
|
| 244 | " move %1, $0 \n" \
|
| 245 | " move %D1, $0 \n" \
|
| 246 | " j 3b \n" \
|
| 247 | " .previous \n" \
|
| 248 | " .section __ex_table,\"a\" \n" \
|
| 249 | " " __UA_ADDR " 1b, 4b \n" \
|
| 250 | " " __UA_ADDR " 2b, 4b \n" \
|
| 251 | " .previous \n" \
|
| 252 | : "=r" (__gu_err), "=&r" (__gu_tmp.l) \
|
| 253 | : "0" (0), "r" (addr), "i" (-EFAULT)); \
|
| 254 | \
|
| 255 | (val) = __gu_tmp.t; \
|
| 256 | }
|
| 257 |
|
| 258 | #define __get_kernel_nofault(dst, src, type, err_label) \
|
| 259 | do { \
|
| 260 | int __gu_err; \
|
| 261 | \
|
| 262 | switch (sizeof(type)) { \
|
| 263 | case 1: \
|
| 264 | __get_data_asm(*(type *)(dst), kernel_lb, \
|
| 265 | (__force type *)(src)); \
|
| 266 | break; \
|
| 267 | case 2: \
|
| 268 | __get_data_asm(*(type *)(dst), kernel_lh, \
|
| 269 | (__force type *)(src)); \
|
| 270 | break; \
|
| 271 | case 4: \
|
| 272 | __get_data_asm(*(type *)(dst), kernel_lw, \
|
| 273 | (__force type *)(src)); \
|
| 274 | break; \
|
| 275 | case 8: \
|
| 276 | __GET_DW(*(type *)(dst), kernel_ld, \
|
| 277 | (__force type *)(src)); \
|
| 278 | break; \
|
| 279 | default: \
|
| 280 | BUILD_BUG(); \
|
| 281 | break; \
|
| 282 | } \
|
| 283 | if (unlikely(__gu_err)) \
|
| 284 | goto err_label; \
|
| 285 | } while (0)
|
| 286 |
|
| 287 | |
| 288 | * Yuck. We need two variants, one for 64bit operation and one
|
| 289 | * for 32 bit mode and old iron.
|
| 290 |
|
| 291 | #ifdef CONFIG_32BIT
|
| 292 | #define __PUT_DW(insn, ptr) __put_data_asm_ll32(insn, ptr)
|
| 293 | #endif
|
| 294 | #ifdef CONFIG_64BIT
|
| 295 | #define __PUT_DW(insn, ptr) __put_data_asm(insn, ptr)
|
| 296 | #endif
|
| 297 |
|
| 298 | #define __put_data_asm(insn, ptr) \
|
| 299 | { \
|
| 300 | __asm__ __volatile__( \
|
| 301 | "1: "insn("%z2", "%3")" # __put_data_asm \n" \
|
| 302 | "2: \n" \
|
| 303 | " .insn \n" \
|
| 304 | " .section .fixup,\"ax\" \n" \
|
| 305 | "3: li %0, %4 \n" \
|
| 306 | " j 2b \n" \
|
| 307 | " .previous \n" \
|
| 308 | " .section __ex_table,\"a\" \n" \
|
| 309 | " " __UA_ADDR " 1b, 3b \n" \
|
| 310 | " .previous \n" \
|
| 311 | : "=r" (__pu_err) \
|
| 312 | : "0" (0), "Jr" (__pu_val), "o" (__m(ptr)), \
|
| 313 | "i" (-EFAULT)); \
|
| 314 | }
|
| 315 |
|
| 316 | #define __put_data_asm_ll32(insn, ptr) \
|
| 317 | { \
|
| 318 | __asm__ __volatile__( \
|
| 319 | "1: "insn("%2", "(%3)")" # __put_data_asm_ll32 \n" \
|
| 320 | "2: "insn("%D2", "4(%3)")" \n" \
|
| 321 | "3: \n" \
|
| 322 | " .insn \n" \
|
| 323 | " .section .fixup,\"ax\" \n" \
|
| 324 | "4: li %0, %4 \n" \
|
| 325 | " j 3b \n" \
|
| 326 | " .previous \n" \
|
| 327 | " .section __ex_table,\"a\" \n" \
|
| 328 | " " __UA_ADDR " 1b, 4b \n" \
|
| 329 | " " __UA_ADDR " 2b, 4b \n" \
|
| 330 | " .previous" \
|
| 331 | : "=r" (__pu_err) \
|
| 332 | : "0" (0), "r" (__pu_val), "r" (ptr), \
|
| 333 | "i" (-EFAULT)); \
|
| 334 | }
|
| 335 |
|
| 336 | #define __put_kernel_nofault(dst, src, type, err_label) \
|
| 337 | do { \
|
| 338 | type __pu_val; \
|
| 339 | int __pu_err = 0; \
|
| 340 | \
|
| 341 | __pu_val = *(__force type *)(src); \
|
| 342 | switch (sizeof(type)) { \
|
| 343 | case 1: \
|
| 344 | __put_data_asm(kernel_sb, (type *)(dst)); \
|
| 345 | break; \
|
| 346 | case 2: \
|
| 347 | __put_data_asm(kernel_sh, (type *)(dst)); \
|
| 348 | break; \
|
| 349 | case 4: \
|
| 350 | __put_data_asm(kernel_sw, (type *)(dst)) \
|
| 351 | break; \
|
| 352 | case 8: \
|
| 353 | __PUT_DW(kernel_sd, (type *)(dst)); \
|
| 354 | break; \
|
| 355 | default: \
|
| 356 | BUILD_BUG(); \
|
| 357 | break; \
|
| 358 | } \
|
| 359 | if (unlikely(__pu_err)) \
|
| 360 | goto err_label; \
|
| 361 | } while (0)
|
| 362 |
|
| 363 |
|
| 364 | |
| 365 | * We're generating jump to subroutines which will be outside the range of
|
| 366 | * jump instructions
|
| 367 |
|
| 368 | #ifdef MODULE
|
| 369 | #define __MODULE_JAL(destination) \
|
| 370 | ".set\tnoat\n\t" \
|
| 371 | __UA_LA "\t$1, " #destination "\n\t" \
|
| 372 | "jalr\t$1\n\t" \
|
| 373 | ".set\tat\n\t"
|
| 374 | #else
|
| 375 | #define __MODULE_JAL(destination) \
|
| 376 | "jal\t" #destination "\n\t"
|
| 377 | #endif
|
| 378 |
|
| 379 | #if defined(CONFIG_CPU_DADDI_WORKAROUNDS) || (defined(CONFIG_EVA) && \
|
| 380 | defined(CONFIG_CPU_HAS_PREFETCH))
|
| 381 | #define DADDI_SCRATCH "$3"
|
| 382 | #else
|
| 383 | #define DADDI_SCRATCH "$0"
|
| 384 | #endif
|
| 385 |
|
| 386 | extern size_t __raw_copy_from_user(void *__to, const void *__from, size_t __n);
|
| 387 | extern size_t __raw_copy_to_user(void *__to, const void *__from, size_t __n);
|
| 388 |
|
| 389 | static inline unsigned long
|
| 390 | raw_copy_from_user(void *to, const void __user *from, unsigned long n)
|
| 391 | {
|
| 392 | register void *__cu_to_r __asm__("$4");
|
| 393 | register const void __user *__cu_from_r __asm__("$5");
|
| 394 | register long __cu_len_r __asm__("$6");
|
| 395 |
|
| 396 | __cu_to_r = to;
|
| 397 | __cu_from_r = from;
|
| 398 | __cu_len_r = n;
|
| 399 |
|
| 400 | __asm__ __volatile__(
|
| 401 | ".set\tnoreorder\n\t"
|
| 402 | __MODULE_JAL(__raw_copy_from_user)
|
| 403 | ".set\tnoat\n\t"
|
| 404 | __UA_ADDU "\t$1, %1, %2\n\t"
|
| 405 | ".set\tat\n\t"
|
| 406 | ".set\treorder"
|
| 407 | : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)
|
| 408 | :
|
| 409 | : "$8", "$9", "$10", "$11", "$12", "$14", "$15", "$24", "$31",
|
| 410 | DADDI_SCRATCH, "memory");
|
| 411 |
|
| 412 | return __cu_len_r;
|
| 413 | }
|
| 414 |
|
| 415 | static inline unsigned long
|
| 416 | raw_copy_to_user(void __user *to, const void *from, unsigned long n)
|
| 417 | {
|
| 418 | register void __user *__cu_to_r __asm__("$4");
|
| 419 | register const void *__cu_from_r __asm__("$5");
|
| 420 | register long __cu_len_r __asm__("$6");
|
| 421 |
|
| 422 | __cu_to_r = (to);
|
| 423 | __cu_from_r = (from);
|
| 424 | __cu_len_r = (n);
|
| 425 |
|
| 426 | __asm__ __volatile__(
|
| 427 | __MODULE_JAL(__raw_copy_to_user)
|
| 428 | : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)
|
| 429 | :
|
| 430 | : "$8", "$9", "$10", "$11", "$12", "$14", "$15", "$24", "$31",
|
| 431 | DADDI_SCRATCH, "memory");
|
| 432 |
|
| 433 | return __cu_len_r;
|
| 434 | }
|
| 435 |
|
| 436 | #define INLINE_COPY_USER
|
| 437 |
|
| 438 | extern __kernel_size_t __bzero(void __user *addr, __kernel_size_t size);
|
| 439 |
|
| 440 | |
| 441 | * __clear_user: - Zero a block of memory in user space, with less checking.
|
| 442 | * @to: Destination address, in user space.
|
| 443 | * @n: Number of bytes to zero.
|
| 444 | *
|
| 445 | * Zero a block of memory in user space. Caller must check
|
| 446 | * the specified block with access_ok() before calling this function.
|
| 447 | *
|
| 448 | * Returns number of bytes that could not be cleared.
|
| 449 | * On success, this will be zero.
|
| 450 |
|
| 451 | static inline __kernel_size_t
|
| 452 | __clear_user(void __user *addr, __kernel_size_t size)
|
| 453 | {
|
| 454 | __kernel_size_t res;
|
| 455 |
|
| 456 | #ifdef CONFIG_CPU_MICROMIPS
|
| 457 |
|
| 458 | #define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$15", "$24", "$31"
|
| 459 | #else
|
| 460 | #define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$31"
|
| 461 | #endif
|
| 462 |
|
| 463 | might_fault();
|
| 464 | __asm__ __volatile__(
|
| 465 | "move\t$4, %1\n\t"
|
| 466 | "move\t$5, $0\n\t"
|
| 467 | "move\t$6, %2\n\t"
|
| 468 | __MODULE_JAL(__bzero)
|
| 469 | "move\t%0, $6"
|
| 470 | : "=r" (res)
|
| 471 | : "r" (addr), "r" (size)
|
| 472 | : bzero_clobbers);
|
| 473 |
|
| 474 | return res;
|
| 475 | }
|
| 476 |
|
| 477 | #define clear_user(addr,n) \
|
| 478 | ({ \
|
| 479 | void __user * __cl_addr = (addr); \
|
| 480 | unsigned long __cl_size = (n); \
|
| 481 | if (__cl_size && access_ok(__cl_addr, __cl_size)) \
|
| 482 | __cl_size = __clear_user(__cl_addr, __cl_size); \
|
| 483 | __cl_size; \
|
| 484 | })
|
| 485 |
|
| 486 | extern long __strncpy_from_user_asm(char *__to, const char __user *__from, long __len);
|
| 487 |
|
| 488 | |
| 489 | * strncpy_from_user: - Copy a NUL terminated string from userspace.
|
| 490 | * @dst: Destination address, in kernel space. This buffer must be at
|
| 491 | * least @count bytes long.
|
| 492 | * @src: Source address, in user space.
|
| 493 | * @count: Maximum number of bytes to copy, including the trailing NUL.
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| 494 | *
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| 495 | * Copies a NUL-terminated string from userspace to kernel space.
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| 496 | *
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| 497 | * On success, returns the length of the string (not including the trailing
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| 498 | * NUL).
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| 499 | *
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| 500 | * If access to userspace fails, returns -EFAULT (some data may have been
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| 501 | * copied).
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| 502 | *
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| 503 | * If @count is smaller than the length of the string, copies @count bytes
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| 504 | * and returns @count.
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| 505 |
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| 506 | static inline long
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| 507 | strncpy_from_user(char *__to, const char __user *__from, long __len)
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| 508 | {
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| 509 | long res;
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| 510 |
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| 511 | if (!access_ok(__from, __len))
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| 512 | return -EFAULT;
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| 513 |
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| 514 | might_fault();
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| 515 | __asm__ __volatile__(
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| 516 | "move\t$4, %1\n\t"
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| 517 | "move\t$5, %2\n\t"
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| 518 | "move\t$6, %3\n\t"
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| 519 | __MODULE_JAL(__strncpy_from_user_asm)
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| 520 | "move\t%0, $2"
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| 521 | : "=r" (res)
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| 522 | : "r" (__to), "r" (__from), "r" (__len)
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| 523 | : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
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| 524 |
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| 525 | return res;
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| 526 | }
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| 527 |
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| 528 | extern long __strnlen_user_asm(const char __user *s, long n);
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| 529 |
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| 530 | |
| 531 | * strnlen_user: - Get the size of a string in user space.
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| 532 | * @str: The string to measure.
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| 533 | *
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| 534 | * Context: User context only. This function may sleep if pagefaults are
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| 535 | * enabled.
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| 536 | *
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| 537 | * Get the size of a NUL-terminated string in user space.
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| 538 | *
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| 539 | * Returns the size of the string INCLUDING the terminating NUL.
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| 540 | * On exception, returns 0.
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| 541 | * If the string is too long, returns a value greater than @n.
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| 542 |
|
| 543 | static inline long strnlen_user(const char __user *s, long n)
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| 544 | {
|
| 545 | long res;
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| 546 |
|
| 547 | if (!access_ok(s, 1))
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| 548 | return 0;
|
| 549 |
|
| 550 | might_fault();
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| 551 | __asm__ __volatile__(
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| 552 | "move\t$4, %1\n\t"
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| 553 | "move\t$5, %2\n\t"
|
| 554 | __MODULE_JAL(__strnlen_user_asm)
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| 555 | "move\t%0, $2"
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| 556 | : "=r" (res)
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| 557 | : "r" (s), "r" (n)
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| 558 | : "$2", "$4", "$5", __UA_t0, "$31");
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| 559 |
|
| 560 | return res;
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| 561 | }
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| 562 |
|
| 563 | #endif
|