1 #ifndef _ASM_X86_UACCESS_H
2 #define _ASM_X86_UACCESS_H
4 * User space memory access functions
6 #include <linux/errno.h>
7 #include <linux/compiler.h>
8 #include <linux/thread_info.h>
9 #include <linux/string.h>
14 #define VERIFY_WRITE 1
17 * The fs value determines whether argument validity checking should be
18 * performed or not. If get_fs() == USER_DS, checking is performed, with
19 * get_fs() == KERNEL_DS, checking is bypassed.
21 * For historical reasons, these macros are grossly misnamed.
24 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
26 #define KERNEL_DS MAKE_MM_SEG(-1UL)
27 #define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX)
29 #define get_ds() (KERNEL_DS)
30 #define get_fs() (current_thread_info()->addr_limit)
31 #define set_fs(x) (current_thread_info()->addr_limit = (x))
33 #define segment_eq(a, b) ((a).seg == (b).seg)
35 #define user_addr_max() (current_thread_info()->addr_limit.seg)
36 #define __addr_ok(addr) \
37 ((unsigned long __force)(addr) < \
38 (current_thread_info()->addr_limit.seg))
41 * Test whether a block of memory is a valid user space address.
42 * Returns 0 if the range is valid, nonzero otherwise.
44 * This is equivalent to the following test:
45 * (u33)addr + (u33)size > (u33)current->addr_limit.seg (u65 for x86_64)
47 * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry...
50 #define __range_not_ok(addr, size) \
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)); \
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
69 * Context: User context only. This function may sleep.
71 * Checks if a pointer to a block of memory in user space is valid.
73 * Returns true (nonzero) if the memory block may be valid, false (zero)
74 * if it is definitely invalid.
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.
80 #define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0))
83 * The exception table consists of pairs of addresses relative to the
84 * exception table enty itself: the first is the address of an
85 * instruction that is allowed to fault, and the second is the address
86 * at which the program should continue. No registers are modified,
87 * so it is entirely up to the continuation code to figure out what to
90 * All the routines below use bits of fixup code that are out of line
91 * with the main instruction path. This means when everything is well,
92 * we don't even have to jump over them. Further, they do not intrude
93 * on our cache or tlb entries.
96 struct exception_table_entry {
99 /* This is not the generic standard exception_table_entry format */
100 #define ARCH_HAS_SORT_EXTABLE
101 #define ARCH_HAS_SEARCH_EXTABLE
103 extern int fixup_exception(struct pt_regs *regs);
104 extern int early_fixup_exception(unsigned long *ip);
107 * These are the main single-value transfer routines. They automatically
108 * use the right size if we just have the right pointer type.
110 * This gets kind of ugly. We want to return _two_ values in "get_user()"
111 * and yet we don't want to do any pointers, because that is too much
112 * of a performance impact. Thus we have a few rather ugly macros here,
113 * and hide all the ugliness from the user.
115 * The "__xxx" versions of the user access functions are versions that
116 * do not verify the address space, that must have been done previously
117 * with a separate "access_ok()" call (this is used when we do multiple
118 * accesses to the same area of user memory).
121 extern int __get_user_1(void);
122 extern int __get_user_2(void);
123 extern int __get_user_4(void);
124 extern int __get_user_8(void);
125 extern int __get_user_bad(void);
127 #define __get_user_x(size, ret, x, ptr) \
128 asm volatile("call __get_user_" #size \
129 : "=a" (ret), "=d" (x) \
132 /* Careful: we have to cast the result to the type of the pointer
133 * for sign reasons */
136 * get_user: - Get a simple variable from user space.
137 * @x: Variable to store result.
138 * @ptr: Source address, in user space.
140 * Context: User context only. This function may sleep.
142 * This macro copies a single simple variable from user space to kernel
143 * space. It supports simple types like char and int, but not larger
144 * data types like structures or arrays.
146 * @ptr must have pointer-to-simple-variable type, and the result of
147 * dereferencing @ptr must be assignable to @x without a cast.
149 * Returns zero on success, or -EFAULT on error.
150 * On error, the variable @x is set to zero.
153 #define __get_user_8(__ret_gu, __val_gu, ptr) \
154 __get_user_x(X, __ret_gu, __val_gu, ptr)
156 #define __get_user_8(__ret_gu, __val_gu, ptr) \
157 __get_user_x(8, __ret_gu, __val_gu, ptr)
160 #define get_user(x, ptr) \
163 unsigned long __val_gu; \
164 __chk_user_ptr(ptr); \
166 switch (sizeof(*(ptr))) { \
168 __get_user_x(1, __ret_gu, __val_gu, ptr); \
171 __get_user_x(2, __ret_gu, __val_gu, ptr); \
174 __get_user_x(4, __ret_gu, __val_gu, ptr); \
177 __get_user_8(__ret_gu, __val_gu, ptr); \
180 __get_user_x(X, __ret_gu, __val_gu, ptr); \
183 (x) = (__typeof__(*(ptr)))__val_gu; \
187 #define __put_user_x(size, x, ptr, __ret_pu) \
188 asm volatile("call __put_user_" #size : "=a" (__ret_pu) \
189 : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
194 #define __put_user_asm_u64(x, addr, err, errret) \
195 asm volatile("1: movl %%eax,0(%2)\n" \
196 "2: movl %%edx,4(%2)\n" \
198 ".section .fixup,\"ax\"\n" \
202 _ASM_EXTABLE(1b, 4b) \
203 _ASM_EXTABLE(2b, 4b) \
205 : "A" (x), "r" (addr), "i" (errret), "0" (err))
207 #define __put_user_asm_ex_u64(x, addr) \
208 asm volatile("1: movl %%eax,0(%1)\n" \
209 "2: movl %%edx,4(%1)\n" \
211 _ASM_EXTABLE_EX(1b, 2b) \
212 _ASM_EXTABLE_EX(2b, 3b) \
213 : : "A" (x), "r" (addr))
215 #define __put_user_x8(x, ptr, __ret_pu) \
216 asm volatile("call __put_user_8" : "=a" (__ret_pu) \
217 : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
219 #define __put_user_asm_u64(x, ptr, retval, errret) \
220 __put_user_asm(x, ptr, retval, "q", "", "er", errret)
221 #define __put_user_asm_ex_u64(x, addr) \
222 __put_user_asm_ex(x, addr, "q", "", "er")
223 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
226 extern void __put_user_bad(void);
229 * Strange magic calling convention: pointer in %ecx,
230 * value in %eax(:%edx), return value in %eax. clobbers %rbx
232 extern void __put_user_1(void);
233 extern void __put_user_2(void);
234 extern void __put_user_4(void);
235 extern void __put_user_8(void);
237 #ifdef CONFIG_X86_WP_WORKS_OK
240 * put_user: - Write a simple value into user space.
241 * @x: Value to copy to user space.
242 * @ptr: Destination address, in user space.
244 * Context: User context only. This function may sleep.
246 * This macro copies a single simple value from kernel space to user
247 * space. It supports simple types like char and int, but not larger
248 * data types like structures or arrays.
250 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
251 * to the result of dereferencing @ptr.
253 * Returns zero on success, or -EFAULT on error.
255 #define put_user(x, ptr) \
258 __typeof__(*(ptr)) __pu_val; \
259 __chk_user_ptr(ptr); \
262 switch (sizeof(*(ptr))) { \
264 __put_user_x(1, __pu_val, ptr, __ret_pu); \
267 __put_user_x(2, __pu_val, ptr, __ret_pu); \
270 __put_user_x(4, __pu_val, ptr, __ret_pu); \
273 __put_user_x8(__pu_val, ptr, __ret_pu); \
276 __put_user_x(X, __pu_val, ptr, __ret_pu); \
282 #define __put_user_size(x, ptr, size, retval, errret) \
285 __chk_user_ptr(ptr); \
288 __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \
291 __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \
294 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \
297 __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval, \
305 #define __put_user_size_ex(x, ptr, size) \
307 __chk_user_ptr(ptr); \
310 __put_user_asm_ex(x, ptr, "b", "b", "iq"); \
313 __put_user_asm_ex(x, ptr, "w", "w", "ir"); \
316 __put_user_asm_ex(x, ptr, "l", "k", "ir"); \
319 __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \
328 #define __put_user_size(x, ptr, size, retval, errret) \
330 __typeof__(*(ptr))__pus_tmp = x; \
333 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \
337 #define put_user(x, ptr) \
340 __typeof__(*(ptr))__pus_tmp = x; \
342 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \
343 sizeof(*(ptr))) != 0)) \
344 __ret_pu = -EFAULT; \
350 #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad()
351 #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad()
353 #define __get_user_asm_u64(x, ptr, retval, errret) \
354 __get_user_asm(x, ptr, retval, "q", "", "=r", errret)
355 #define __get_user_asm_ex_u64(x, ptr) \
356 __get_user_asm_ex(x, ptr, "q", "", "=r")
359 #define __get_user_size(x, ptr, size, retval, errret) \
362 __chk_user_ptr(ptr); \
365 __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
368 __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
371 __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \
374 __get_user_asm_u64(x, ptr, retval, errret); \
377 (x) = __get_user_bad(); \
381 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \
382 asm volatile("1: mov"itype" %2,%"rtype"1\n" \
384 ".section .fixup,\"ax\"\n" \
386 " xor"itype" %"rtype"1,%"rtype"1\n" \
389 _ASM_EXTABLE(1b, 3b) \
390 : "=r" (err), ltype(x) \
391 : "m" (__m(addr)), "i" (errret), "0" (err))
393 #define __get_user_size_ex(x, ptr, size) \
395 __chk_user_ptr(ptr); \
398 __get_user_asm_ex(x, ptr, "b", "b", "=q"); \
401 __get_user_asm_ex(x, ptr, "w", "w", "=r"); \
404 __get_user_asm_ex(x, ptr, "l", "k", "=r"); \
407 __get_user_asm_ex_u64(x, ptr); \
410 (x) = __get_user_bad(); \
414 #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \
415 asm volatile("1: mov"itype" %1,%"rtype"0\n" \
417 _ASM_EXTABLE_EX(1b, 2b) \
418 : ltype(x) : "m" (__m(addr)))
420 #define __put_user_nocheck(x, ptr, size) \
423 __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \
427 #define __get_user_nocheck(x, ptr, size) \
430 unsigned long __gu_val; \
431 __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
432 (x) = (__force __typeof__(*(ptr)))__gu_val; \
436 /* FIXME: this hack is definitely wrong -AK */
437 struct __large_struct { unsigned long buf[100]; };
438 #define __m(x) (*(struct __large_struct __user *)(x))
441 * Tell gcc we read from memory instead of writing: this is because
442 * we do not write to any memory gcc knows about, so there are no
445 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \
446 asm volatile("1: mov"itype" %"rtype"1,%2\n" \
448 ".section .fixup,\"ax\"\n" \
452 _ASM_EXTABLE(1b, 3b) \
454 : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
456 #define __put_user_asm_ex(x, addr, itype, rtype, ltype) \
457 asm volatile("1: mov"itype" %"rtype"0,%1\n" \
459 _ASM_EXTABLE_EX(1b, 2b) \
460 : : ltype(x), "m" (__m(addr)))
463 * uaccess_try and catch
465 #define uaccess_try do { \
466 int prev_err = current_thread_info()->uaccess_err; \
467 current_thread_info()->uaccess_err = 0; \
470 #define uaccess_catch(err) \
471 (err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0); \
472 current_thread_info()->uaccess_err = prev_err; \
476 * __get_user: - Get a simple variable from user space, with less checking.
477 * @x: Variable to store result.
478 * @ptr: Source address, in user space.
480 * Context: User context only. This function may sleep.
482 * This macro copies a single simple variable from user space to kernel
483 * space. It supports simple types like char and int, but not larger
484 * data types like structures or arrays.
486 * @ptr must have pointer-to-simple-variable type, and the result of
487 * dereferencing @ptr must be assignable to @x without a cast.
489 * Caller must check the pointer with access_ok() before calling this
492 * Returns zero on success, or -EFAULT on error.
493 * On error, the variable @x is set to zero.
496 #define __get_user(x, ptr) \
497 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
500 * __put_user: - Write a simple value into user space, with less checking.
501 * @x: Value to copy to user space.
502 * @ptr: Destination address, in user space.
504 * Context: User context only. This function may sleep.
506 * This macro copies a single simple value from kernel space to user
507 * space. It supports simple types like char and int, but not larger
508 * data types like structures or arrays.
510 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
511 * to the result of dereferencing @ptr.
513 * Caller must check the pointer with access_ok() before calling this
516 * Returns zero on success, or -EFAULT on error.
519 #define __put_user(x, ptr) \
520 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
522 #define __get_user_unaligned __get_user
523 #define __put_user_unaligned __put_user
526 * {get|put}_user_try and catch
530 * } get_user_catch(err)
532 #define get_user_try uaccess_try
533 #define get_user_catch(err) uaccess_catch(err)
535 #define get_user_ex(x, ptr) do { \
536 unsigned long __gue_val; \
537 __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr)))); \
538 (x) = (__force __typeof__(*(ptr)))__gue_val; \
541 #ifdef CONFIG_X86_WP_WORKS_OK
543 #define put_user_try uaccess_try
544 #define put_user_catch(err) uaccess_catch(err)
546 #define put_user_ex(x, ptr) \
547 __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
549 #else /* !CONFIG_X86_WP_WORKS_OK */
551 #define put_user_try do { \
552 int __uaccess_err = 0;
554 #define put_user_catch(err) \
555 (err) |= __uaccess_err; \
558 #define put_user_ex(x, ptr) do { \
559 __uaccess_err |= __put_user(x, ptr); \
562 #endif /* CONFIG_X86_WP_WORKS_OK */
565 copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
566 extern __must_check long
567 strncpy_from_user(char *dst, const char __user *src, long count);
569 extern __must_check long strlen_user(const char __user *str);
570 extern __must_check long strnlen_user(const char __user *str, long n);
573 * movsl can be slow when source and dest are not both 8-byte aligned
575 #ifdef CONFIG_X86_INTEL_USERCOPY
576 extern struct movsl_mask {
578 } ____cacheline_aligned_in_smp movsl_mask;
581 #define ARCH_HAS_NOCACHE_UACCESS 1
584 # include "uaccess_32.h"
586 # include "uaccess_64.h"
589 #endif /* _ASM_X86_UACCESS_H */