1 #ifndef _ASM_X86_UACCESS_H 2 #define _ASM_X86_UACCESS_H 3 /* 4 * User space memory access functions 5 */ 6 #include <linux/errno.h> 7 #include <linux/compiler.h> 8 #include <linux/thread_info.h> 9 #include <linux/prefetch.h> 10 #include <linux/string.h> 11 #include <asm/asm.h> 12 #include <asm/page.h> 13 14 #define VERIFY_READ 0 15 #define VERIFY_WRITE 1 16 17 /* 18 * The fs value determines whether argument validity checking should be 19 * performed or not. If get_fs() == USER_DS, checking is performed, with 20 * get_fs() == KERNEL_DS, checking is bypassed. 21 * 22 * For historical reasons, these macros are grossly misnamed. 23 */ 24 25 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) 26 27 #define KERNEL_DS MAKE_MM_SEG(-1UL) 28 #define USER_DS MAKE_MM_SEG(PAGE_OFFSET) 29 30 #define get_ds() (KERNEL_DS) 31 #define get_fs() (current_thread_info()->addr_limit) 32 #define set_fs(x) (current_thread_info()->addr_limit = (x)) 33 34 #define segment_eq(a, b) ((a).seg == (b).seg) 35 36 #define __addr_ok(addr) \ 37 ((unsigned long __force)(addr) < \ 38 (current_thread_info()->addr_limit.seg)) 39 40 /* 41 * Test whether a block of memory is a valid user space address. 42 * Returns 0 if the range is valid, nonzero otherwise. 43 * 44 * This is equivalent to the following test: 45 * (u33)addr + (u33)size >= (u33)current->addr_limit.seg (u65 for x86_64) 46 * 47 * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry... 48 */ 49 50 #define __range_not_ok(addr, size) \ 51 ({ \ 52 unsigned long flag, roksum; \ 53 __chk_user_ptr(addr); \ 54 asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \ 55 : "=&r" (flag), "=r" (roksum) \ 56 : "1" (addr), "g" ((long)(size)), \ 57 "rm" (current_thread_info()->addr_limit.seg)); \ 58 flag; \ 59 }) 60 61 /** 62 * access_ok: - Checks if a user space pointer is valid 63 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that 64 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe 65 * to write to a block, it is always safe to read from it. 66 * @addr: User space pointer to start of block to check 67 * @size: Size of block to check 68 * 69 * Context: User context only. This function may sleep. 70 * 71 * Checks if a pointer to a block of memory in user space is valid. 72 * 73 * Returns true (nonzero) if the memory block may be valid, false (zero) 74 * if it is definitely invalid. 75 * 76 * Note that, depending on architecture, this function probably just 77 * checks that the pointer is in the user space range - after calling 78 * this function, memory access functions may still return -EFAULT. 79 */ 80 #define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0)) 81 82 /* 83 * The exception table consists of pairs of addresses: the first is the 84 * address of an instruction that is allowed to fault, and the second is 85 * the address at which the program should continue. No registers are 86 * modified, so it is entirely up to the continuation code to figure out 87 * what to do. 88 * 89 * All the routines below use bits of fixup code that are out of line 90 * with the main instruction path. This means when everything is well, 91 * we don't even have to jump over them. Further, they do not intrude 92 * on our cache or tlb entries. 93 */ 94 95 struct exception_table_entry { 96 unsigned long insn, fixup; 97 }; 98 99 extern int fixup_exception(struct pt_regs *regs); 100 101 /* 102 * These are the main single-value transfer routines. They automatically 103 * use the right size if we just have the right pointer type. 104 * 105 * This gets kind of ugly. We want to return _two_ values in "get_user()" 106 * and yet we don't want to do any pointers, because that is too much 107 * of a performance impact. Thus we have a few rather ugly macros here, 108 * and hide all the ugliness from the user. 109 * 110 * The "__xxx" versions of the user access functions are versions that 111 * do not verify the address space, that must have been done previously 112 * with a separate "access_ok()" call (this is used when we do multiple 113 * accesses to the same area of user memory). 114 */ 115 116 extern int __get_user_1(void); 117 extern int __get_user_2(void); 118 extern int __get_user_4(void); 119 extern int __get_user_8(void); 120 extern int __get_user_bad(void); 121 122 #define __get_user_x(size, ret, x, ptr) \ 123 asm volatile("call __get_user_" #size \ 124 : "=a" (ret),"=d" (x) \ 125 : "0" (ptr)) \ 126 127 /* Careful: we have to cast the result to the type of the pointer 128 * for sign reasons */ 129 130 /** 131 * get_user: - Get a simple variable from user space. 132 * @x: Variable to store result. 133 * @ptr: Source address, in user space. 134 * 135 * Context: User context only. This function may sleep. 136 * 137 * This macro copies a single simple variable from user space to kernel 138 * space. It supports simple types like char and int, but not larger 139 * data types like structures or arrays. 140 * 141 * @ptr must have pointer-to-simple-variable type, and the result of 142 * dereferencing @ptr must be assignable to @x without a cast. 143 * 144 * Returns zero on success, or -EFAULT on error. 145 * On error, the variable @x is set to zero. 146 */ 147 #ifdef CONFIG_X86_32 148 #define __get_user_8(__ret_gu, __val_gu, ptr) \ 149 __get_user_x(X, __ret_gu, __val_gu, ptr) 150 #else 151 #define __get_user_8(__ret_gu, __val_gu, ptr) \ 152 __get_user_x(8, __ret_gu, __val_gu, ptr) 153 #endif 154 155 #define get_user(x, ptr) \ 156 ({ \ 157 int __ret_gu; \ 158 unsigned long __val_gu; \ 159 __chk_user_ptr(ptr); \ 160 might_fault(); \ 161 switch (sizeof(*(ptr))) { \ 162 case 1: \ 163 __get_user_x(1, __ret_gu, __val_gu, ptr); \ 164 break; \ 165 case 2: \ 166 __get_user_x(2, __ret_gu, __val_gu, ptr); \ 167 break; \ 168 case 4: \ 169 __get_user_x(4, __ret_gu, __val_gu, ptr); \ 170 break; \ 171 case 8: \ 172 __get_user_8(__ret_gu, __val_gu, ptr); \ 173 break; \ 174 default: \ 175 __get_user_x(X, __ret_gu, __val_gu, ptr); \ 176 break; \ 177 } \ 178 (x) = (__typeof__(*(ptr)))__val_gu; \ 179 __ret_gu; \ 180 }) 181 182 #define __put_user_x(size, x, ptr, __ret_pu) \ 183 asm volatile("call __put_user_" #size : "=a" (__ret_pu) \ 184 :"0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") 185 186 187 188 #ifdef CONFIG_X86_32 189 #define __put_user_u64(x, addr, err) \ 190 asm volatile("1: movl %%eax,0(%2)\n" \ 191 "2: movl %%edx,4(%2)\n" \ 192 "3:\n" \ 193 ".section .fixup,\"ax\"\n" \ 194 "4: movl %3,%0\n" \ 195 " jmp 3b\n" \ 196 ".previous\n" \ 197 _ASM_EXTABLE(1b, 4b) \ 198 _ASM_EXTABLE(2b, 4b) \ 199 : "=r" (err) \ 200 : "A" (x), "r" (addr), "i" (-EFAULT), "0" (err)) 201 202 #define __put_user_x8(x, ptr, __ret_pu) \ 203 asm volatile("call __put_user_8" : "=a" (__ret_pu) \ 204 : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") 205 #else 206 #define __put_user_u64(x, ptr, retval) \ 207 __put_user_asm(x, ptr, retval, "q", "", "Zr", -EFAULT) 208 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu) 209 #endif 210 211 extern void __put_user_bad(void); 212 213 /* 214 * Strange magic calling convention: pointer in %ecx, 215 * value in %eax(:%edx), return value in %eax. clobbers %rbx 216 */ 217 extern void __put_user_1(void); 218 extern void __put_user_2(void); 219 extern void __put_user_4(void); 220 extern void __put_user_8(void); 221 222 #ifdef CONFIG_X86_WP_WORKS_OK 223 224 /** 225 * put_user: - Write a simple value into user space. 226 * @x: Value to copy to user space. 227 * @ptr: Destination address, in user space. 228 * 229 * Context: User context only. This function may sleep. 230 * 231 * This macro copies a single simple value from kernel space to user 232 * space. It supports simple types like char and int, but not larger 233 * data types like structures or arrays. 234 * 235 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 236 * to the result of dereferencing @ptr. 237 * 238 * Returns zero on success, or -EFAULT on error. 239 */ 240 #define put_user(x, ptr) \ 241 ({ \ 242 int __ret_pu; \ 243 __typeof__(*(ptr)) __pu_val; \ 244 __chk_user_ptr(ptr); \ 245 might_fault(); \ 246 __pu_val = x; \ 247 switch (sizeof(*(ptr))) { \ 248 case 1: \ 249 __put_user_x(1, __pu_val, ptr, __ret_pu); \ 250 break; \ 251 case 2: \ 252 __put_user_x(2, __pu_val, ptr, __ret_pu); \ 253 break; \ 254 case 4: \ 255 __put_user_x(4, __pu_val, ptr, __ret_pu); \ 256 break; \ 257 case 8: \ 258 __put_user_x8(__pu_val, ptr, __ret_pu); \ 259 break; \ 260 default: \ 261 __put_user_x(X, __pu_val, ptr, __ret_pu); \ 262 break; \ 263 } \ 264 __ret_pu; \ 265 }) 266 267 #define __put_user_size(x, ptr, size, retval, errret) \ 268 do { \ 269 retval = 0; \ 270 __chk_user_ptr(ptr); \ 271 switch (size) { \ 272 case 1: \ 273 __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \ 274 break; \ 275 case 2: \ 276 __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \ 277 break; \ 278 case 4: \ 279 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret);\ 280 break; \ 281 case 8: \ 282 __put_user_u64((__typeof__(*ptr))(x), ptr, retval); \ 283 break; \ 284 default: \ 285 __put_user_bad(); \ 286 } \ 287 } while (0) 288 289 #else 290 291 #define __put_user_size(x, ptr, size, retval, errret) \ 292 do { \ 293 __typeof__(*(ptr))__pus_tmp = x; \ 294 retval = 0; \ 295 \ 296 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \ 297 retval = errret; \ 298 } while (0) 299 300 #define put_user(x, ptr) \ 301 ({ \ 302 int __ret_pu; \ 303 __typeof__(*(ptr))__pus_tmp = x; \ 304 __ret_pu = 0; \ 305 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \ 306 sizeof(*(ptr))) != 0)) \ 307 __ret_pu = -EFAULT; \ 308 __ret_pu; \ 309 }) 310 #endif 311 312 #ifdef CONFIG_X86_32 313 #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() 314 #else 315 #define __get_user_asm_u64(x, ptr, retval, errret) \ 316 __get_user_asm(x, ptr, retval, "q", "", "=r", errret) 317 #endif 318 319 #define __get_user_size(x, ptr, size, retval, errret) \ 320 do { \ 321 retval = 0; \ 322 __chk_user_ptr(ptr); \ 323 switch (size) { \ 324 case 1: \ 325 __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \ 326 break; \ 327 case 2: \ 328 __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \ 329 break; \ 330 case 4: \ 331 __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \ 332 break; \ 333 case 8: \ 334 __get_user_asm_u64(x, ptr, retval, errret); \ 335 break; \ 336 default: \ 337 (x) = __get_user_bad(); \ 338 } \ 339 } while (0) 340 341 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 342 asm volatile("1: mov"itype" %2,%"rtype"1\n" \ 343 "2:\n" \ 344 ".section .fixup,\"ax\"\n" \ 345 "3: mov %3,%0\n" \ 346 " xor"itype" %"rtype"1,%"rtype"1\n" \ 347 " jmp 2b\n" \ 348 ".previous\n" \ 349 _ASM_EXTABLE(1b, 3b) \ 350 : "=r" (err), ltype(x) \ 351 : "m" (__m(addr)), "i" (errret), "0" (err)) 352 353 #define __put_user_nocheck(x, ptr, size) \ 354 ({ \ 355 int __pu_err; \ 356 __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \ 357 __pu_err; \ 358 }) 359 360 #define __get_user_nocheck(x, ptr, size) \ 361 ({ \ 362 int __gu_err; \ 363 unsigned long __gu_val; \ 364 __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ 365 (x) = (__force __typeof__(*(ptr)))__gu_val; \ 366 __gu_err; \ 367 }) 368 369 /* FIXME: this hack is definitely wrong -AK */ 370 struct __large_struct { unsigned long buf[100]; }; 371 #define __m(x) (*(struct __large_struct __user *)(x)) 372 373 /* 374 * Tell gcc we read from memory instead of writing: this is because 375 * we do not write to any memory gcc knows about, so there are no 376 * aliasing issues. 377 */ 378 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 379 asm volatile("1: mov"itype" %"rtype"1,%2\n" \ 380 "2:\n" \ 381 ".section .fixup,\"ax\"\n" \ 382 "3: mov %3,%0\n" \ 383 " jmp 2b\n" \ 384 ".previous\n" \ 385 _ASM_EXTABLE(1b, 3b) \ 386 : "=r"(err) \ 387 : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) 388 /** 389 * __get_user: - Get a simple variable from user space, with less checking. 390 * @x: Variable to store result. 391 * @ptr: Source address, in user space. 392 * 393 * Context: User context only. This function may sleep. 394 * 395 * This macro copies a single simple variable from user space to kernel 396 * space. It supports simple types like char and int, but not larger 397 * data types like structures or arrays. 398 * 399 * @ptr must have pointer-to-simple-variable type, and the result of 400 * dereferencing @ptr must be assignable to @x without a cast. 401 * 402 * Caller must check the pointer with access_ok() before calling this 403 * function. 404 * 405 * Returns zero on success, or -EFAULT on error. 406 * On error, the variable @x is set to zero. 407 */ 408 409 #define __get_user(x, ptr) \ 410 __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 411 /** 412 * __put_user: - Write a simple value into user space, with less checking. 413 * @x: Value to copy to user space. 414 * @ptr: Destination address, in user space. 415 * 416 * Context: User context only. This function may sleep. 417 * 418 * This macro copies a single simple value from kernel space to user 419 * space. It supports simple types like char and int, but not larger 420 * data types like structures or arrays. 421 * 422 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 423 * to the result of dereferencing @ptr. 424 * 425 * Caller must check the pointer with access_ok() before calling this 426 * function. 427 * 428 * Returns zero on success, or -EFAULT on error. 429 */ 430 431 #define __put_user(x, ptr) \ 432 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 433 434 #define __get_user_unaligned __get_user 435 #define __put_user_unaligned __put_user 436 437 /* 438 * movsl can be slow when source and dest are not both 8-byte aligned 439 */ 440 #ifdef CONFIG_X86_INTEL_USERCOPY 441 extern struct movsl_mask { 442 int mask; 443 } ____cacheline_aligned_in_smp movsl_mask; 444 #endif 445 446 #define ARCH_HAS_NOCACHE_UACCESS 1 447 448 #ifdef CONFIG_X86_32 449 # include "uaccess_32.h" 450 #else 451 # define ARCH_HAS_SEARCH_EXTABLE 452 # include "uaccess_64.h" 453 #endif 454 455 #endif /* _ASM_X86_UACCESS_H */ 456 457