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 switch (sizeof(*(ptr))) { \ 161 case 1: \ 162 __get_user_x(1, __ret_gu, __val_gu, ptr); \ 163 break; \ 164 case 2: \ 165 __get_user_x(2, __ret_gu, __val_gu, ptr); \ 166 break; \ 167 case 4: \ 168 __get_user_x(4, __ret_gu, __val_gu, ptr); \ 169 break; \ 170 case 8: \ 171 __get_user_8(__ret_gu, __val_gu, ptr); \ 172 break; \ 173 default: \ 174 __get_user_x(X, __ret_gu, __val_gu, ptr); \ 175 break; \ 176 } \ 177 (x) = (__typeof__(*(ptr)))__val_gu; \ 178 __ret_gu; \ 179 }) 180 181 #define __put_user_x(size, x, ptr, __ret_pu) \ 182 asm volatile("call __put_user_" #size : "=a" (__ret_pu) \ 183 :"0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") 184 185 186 187 #ifdef CONFIG_X86_32 188 #define __put_user_u64(x, addr, err) \ 189 asm volatile("1: movl %%eax,0(%2)\n" \ 190 "2: movl %%edx,4(%2)\n" \ 191 "3:\n" \ 192 ".section .fixup,\"ax\"\n" \ 193 "4: movl %3,%0\n" \ 194 " jmp 3b\n" \ 195 ".previous\n" \ 196 _ASM_EXTABLE(1b, 4b) \ 197 _ASM_EXTABLE(2b, 4b) \ 198 : "=r" (err) \ 199 : "A" (x), "r" (addr), "i" (-EFAULT), "0" (err)) 200 201 #define __put_user_x8(x, ptr, __ret_pu) \ 202 asm volatile("call __put_user_8" : "=a" (__ret_pu) \ 203 : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") 204 #else 205 #define __put_user_u64(x, ptr, retval) \ 206 __put_user_asm(x, ptr, retval, "q", "", "Zr", -EFAULT) 207 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu) 208 #endif 209 210 extern void __put_user_bad(void); 211 212 /* 213 * Strange magic calling convention: pointer in %ecx, 214 * value in %eax(:%edx), return value in %eax. clobbers %rbx 215 */ 216 extern void __put_user_1(void); 217 extern void __put_user_2(void); 218 extern void __put_user_4(void); 219 extern void __put_user_8(void); 220 221 #ifdef CONFIG_X86_WP_WORKS_OK 222 223 /** 224 * put_user: - Write a simple value into user space. 225 * @x: Value to copy to user space. 226 * @ptr: Destination address, in user space. 227 * 228 * Context: User context only. This function may sleep. 229 * 230 * This macro copies a single simple value from kernel space to user 231 * space. It supports simple types like char and int, but not larger 232 * data types like structures or arrays. 233 * 234 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 235 * to the result of dereferencing @ptr. 236 * 237 * Returns zero on success, or -EFAULT on error. 238 */ 239 #define put_user(x, ptr) \ 240 ({ \ 241 int __ret_pu; \ 242 __typeof__(*(ptr)) __pu_val; \ 243 __chk_user_ptr(ptr); \ 244 __pu_val = x; \ 245 switch (sizeof(*(ptr))) { \ 246 case 1: \ 247 __put_user_x(1, __pu_val, ptr, __ret_pu); \ 248 break; \ 249 case 2: \ 250 __put_user_x(2, __pu_val, ptr, __ret_pu); \ 251 break; \ 252 case 4: \ 253 __put_user_x(4, __pu_val, ptr, __ret_pu); \ 254 break; \ 255 case 8: \ 256 __put_user_x8(__pu_val, ptr, __ret_pu); \ 257 break; \ 258 default: \ 259 __put_user_x(X, __pu_val, ptr, __ret_pu); \ 260 break; \ 261 } \ 262 __ret_pu; \ 263 }) 264 265 #define __put_user_size(x, ptr, size, retval, errret) \ 266 do { \ 267 retval = 0; \ 268 __chk_user_ptr(ptr); \ 269 switch (size) { \ 270 case 1: \ 271 __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \ 272 break; \ 273 case 2: \ 274 __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \ 275 break; \ 276 case 4: \ 277 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret);\ 278 break; \ 279 case 8: \ 280 __put_user_u64((__typeof__(*ptr))(x), ptr, retval); \ 281 break; \ 282 default: \ 283 __put_user_bad(); \ 284 } \ 285 } while (0) 286 287 #else 288 289 #define __put_user_size(x, ptr, size, retval, errret) \ 290 do { \ 291 __typeof__(*(ptr))__pus_tmp = x; \ 292 retval = 0; \ 293 \ 294 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \ 295 retval = errret; \ 296 } while (0) 297 298 #define put_user(x, ptr) \ 299 ({ \ 300 int __ret_pu; \ 301 __typeof__(*(ptr))__pus_tmp = x; \ 302 __ret_pu = 0; \ 303 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \ 304 sizeof(*(ptr))) != 0)) \ 305 __ret_pu = -EFAULT; \ 306 __ret_pu; \ 307 }) 308 #endif 309 310 #ifdef CONFIG_X86_32 311 #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() 312 #else 313 #define __get_user_asm_u64(x, ptr, retval, errret) \ 314 __get_user_asm(x, ptr, retval, "q", "", "=r", errret) 315 #endif 316 317 #define __get_user_size(x, ptr, size, retval, errret) \ 318 do { \ 319 retval = 0; \ 320 __chk_user_ptr(ptr); \ 321 switch (size) { \ 322 case 1: \ 323 __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \ 324 break; \ 325 case 2: \ 326 __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \ 327 break; \ 328 case 4: \ 329 __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \ 330 break; \ 331 case 8: \ 332 __get_user_asm_u64(x, ptr, retval, errret); \ 333 break; \ 334 default: \ 335 (x) = __get_user_bad(); \ 336 } \ 337 } while (0) 338 339 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 340 asm volatile("1: mov"itype" %2,%"rtype"1\n" \ 341 "2:\n" \ 342 ".section .fixup,\"ax\"\n" \ 343 "3: mov %3,%0\n" \ 344 " xor"itype" %"rtype"1,%"rtype"1\n" \ 345 " jmp 2b\n" \ 346 ".previous\n" \ 347 _ASM_EXTABLE(1b, 3b) \ 348 : "=r" (err), ltype(x) \ 349 : "m" (__m(addr)), "i" (errret), "0" (err)) 350 351 #define __put_user_nocheck(x, ptr, size) \ 352 ({ \ 353 long __pu_err; \ 354 __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \ 355 __pu_err; \ 356 }) 357 358 #define __get_user_nocheck(x, ptr, size) \ 359 ({ \ 360 long __gu_err; \ 361 unsigned long __gu_val; \ 362 __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ 363 (x) = (__force __typeof__(*(ptr)))__gu_val; \ 364 __gu_err; \ 365 }) 366 367 /* FIXME: this hack is definitely wrong -AK */ 368 struct __large_struct { unsigned long buf[100]; }; 369 #define __m(x) (*(struct __large_struct __user *)(x)) 370 371 /* 372 * Tell gcc we read from memory instead of writing: this is because 373 * we do not write to any memory gcc knows about, so there are no 374 * aliasing issues. 375 */ 376 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 377 asm volatile("1: mov"itype" %"rtype"1,%2\n" \ 378 "2:\n" \ 379 ".section .fixup,\"ax\"\n" \ 380 "3: mov %3,%0\n" \ 381 " jmp 2b\n" \ 382 ".previous\n" \ 383 _ASM_EXTABLE(1b, 3b) \ 384 : "=r"(err) \ 385 : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) 386 /** 387 * __get_user: - Get a simple variable from user space, with less checking. 388 * @x: Variable to store result. 389 * @ptr: Source address, in user space. 390 * 391 * Context: User context only. This function may sleep. 392 * 393 * This macro copies a single simple variable from user space to kernel 394 * space. It supports simple types like char and int, but not larger 395 * data types like structures or arrays. 396 * 397 * @ptr must have pointer-to-simple-variable type, and the result of 398 * dereferencing @ptr must be assignable to @x without a cast. 399 * 400 * Caller must check the pointer with access_ok() before calling this 401 * function. 402 * 403 * Returns zero on success, or -EFAULT on error. 404 * On error, the variable @x is set to zero. 405 */ 406 407 #define __get_user(x, ptr) \ 408 __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 409 /** 410 * __put_user: - Write a simple value into user space, with less checking. 411 * @x: Value to copy to user space. 412 * @ptr: Destination address, in user space. 413 * 414 * Context: User context only. This function may sleep. 415 * 416 * This macro copies a single simple value from kernel space to user 417 * space. It supports simple types like char and int, but not larger 418 * data types like structures or arrays. 419 * 420 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 421 * to the result of dereferencing @ptr. 422 * 423 * Caller must check the pointer with access_ok() before calling this 424 * function. 425 * 426 * Returns zero on success, or -EFAULT on error. 427 */ 428 429 #define __put_user(x, ptr) \ 430 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 431 432 #define __get_user_unaligned __get_user 433 #define __put_user_unaligned __put_user 434 435 /* 436 * movsl can be slow when source and dest are not both 8-byte aligned 437 */ 438 #ifdef CONFIG_X86_INTEL_USERCOPY 439 extern struct movsl_mask { 440 int mask; 441 } ____cacheline_aligned_in_smp movsl_mask; 442 #endif 443 444 #define ARCH_HAS_NOCACHE_UACCESS 1 445 446 #ifdef CONFIG_X86_32 447 # include "uaccess_32.h" 448 #else 449 # define ARCH_HAS_SEARCH_EXTABLE 450 # include "uaccess_64.h" 451 #endif 452 453 #endif /* _ASM_X86_UACCESS_H */ 454 455