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H. Peter Anvin1965aae2008-10-22 22:26:29 -07001#ifndef _ASM_X86_UACCESS_H
2#define _ASM_X86_UACCESS_H
Glauber Costaca233862008-06-13 14:39:25 -03003/*
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
Glauber Costa002ca162008-06-25 11:08:51 -030036#define __addr_ok(addr) \
37 ((unsigned long __force)(addr) < \
38 (current_thread_info()->addr_limit.seg))
39
Glauber Costaca233862008-06-13 14:39:25 -030040/*
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
95struct exception_table_entry {
96 unsigned long insn, fixup;
97};
98
99extern 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
116extern int __get_user_1(void);
117extern int __get_user_2(void);
118extern int __get_user_4(void);
119extern int __get_user_8(void);
120extern int __get_user_bad(void);
121
122#define __get_user_x(size, ret, x, ptr) \
123 asm volatile("call __get_user_" #size \
Hiroshi Shimamoto4d5d7832009-01-19 16:34:26 -0800124 : "=a" (ret), "=d" (x) \
Glauber Costaca233862008-06-13 14:39:25 -0300125 : "0" (ptr)) \
126
Glauber Costa865e5b72008-06-25 11:05:11 -0300127/* 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); \
Ingo Molnard1a76182008-10-28 16:54:49 +0100160 might_fault(); \
Glauber Costa865e5b72008-06-25 11:05:11 -0300161 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
Glauber Costae30a44f2008-06-25 13:17:43 -0300182#define __put_user_x(size, x, ptr, __ret_pu) \
183 asm volatile("call __put_user_" #size : "=a" (__ret_pu) \
Hiroshi Shimamoto4d5d7832009-01-19 16:34:26 -0800184 : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
Glauber Costae30a44f2008-06-25 13:17:43 -0300185
186
187
Glauber Costadc70ddf2008-06-25 11:48:29 -0300188#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))
Glauber Costae30a44f2008-06-25 13:17:43 -0300201
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")
Glauber Costadc70ddf2008-06-25 11:48:29 -0300205#else
206#define __put_user_u64(x, ptr, retval) \
207 __put_user_asm(x, ptr, retval, "q", "", "Zr", -EFAULT)
Glauber Costae30a44f2008-06-25 13:17:43 -0300208#define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
Glauber Costadc70ddf2008-06-25 11:48:29 -0300209#endif
210
Glauber Costae30a44f2008-06-25 13:17:43 -0300211extern 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 */
217extern void __put_user_1(void);
218extern void __put_user_2(void);
219extern void __put_user_4(void);
220extern void __put_user_8(void);
221
Glauber Costadc70ddf2008-06-25 11:48:29 -0300222#ifdef CONFIG_X86_WP_WORKS_OK
223
Glauber Costae30a44f2008-06-25 13:17:43 -0300224/**
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); \
Ingo Molnard1a76182008-10-28 16:54:49 +0100245 might_fault(); \
Glauber Costae30a44f2008-06-25 13:17:43 -0300246 __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
Glauber Costadc70ddf2008-06-25 11:48:29 -0300267#define __put_user_size(x, ptr, size, retval, errret) \
268do { \
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: \
Hiroshi Shimamoto4d5d7832009-01-19 16:34:26 -0800279 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \
Glauber Costadc70ddf2008-06-25 11:48:29 -0300280 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) \
292do { \
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
Glauber Costae30a44f2008-06-25 13:17:43 -0300300#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})
Glauber Costadc70ddf2008-06-25 11:48:29 -0300310#endif
311
Glauber Costa3f168222008-06-25 12:48:47 -0300312#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) \
320do { \
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
Glauber Costadc70ddf2008-06-25 11:48:29 -0300353#define __put_user_nocheck(x, ptr, size) \
354({ \
Hiroshi Shimamoto16855f82008-12-08 19:18:38 -0800355 int __pu_err; \
Glauber Costadc70ddf2008-06-25 11:48:29 -0300356 __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \
357 __pu_err; \
358})
359
Glauber Costa3f168222008-06-25 12:48:47 -0300360#define __get_user_nocheck(x, ptr, size) \
361({ \
Hiroshi Shimamoto16855f82008-12-08 19:18:38 -0800362 int __gu_err; \
Glauber Costa3f168222008-06-25 12:48:47 -0300363 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})
Glauber Costadc70ddf2008-06-25 11:48:29 -0300368
369/* FIXME: this hack is definitely wrong -AK */
370struct __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))
Glauber Costa8cb834e2008-06-25 14:43:30 -0300388/**
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 */
Glauber Costadc70ddf2008-06-25 11:48:29 -0300408
Glauber Costa8cb834e2008-06-25 14:43:30 -0300409#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
Glauber Costa865e5b72008-06-25 11:05:11 -0300436
Glauber Costa8bc7de02008-06-25 14:53:41 -0300437/*
438 * movsl can be slow when source and dest are not both 8-byte aligned
439 */
440#ifdef CONFIG_X86_INTEL_USERCOPY
441extern struct movsl_mask {
442 int mask;
443} ____cacheline_aligned_in_smp movsl_mask;
444#endif
445
Glauber Costa22cac162008-06-25 14:56:53 -0300446#define ARCH_HAS_NOCACHE_UACCESS 1
447
Thomas Gleixner96a388d2007-10-11 11:20:03 +0200448#ifdef CONFIG_X86_32
449# include "uaccess_32.h"
450#else
Glauber Costa22cac162008-06-25 14:56:53 -0300451# define ARCH_HAS_SEARCH_EXTABLE
Thomas Gleixner96a388d2007-10-11 11:20:03 +0200452# include "uaccess_64.h"
453#endif
Glauber Costaca233862008-06-13 14:39:25 -0300454
H. Peter Anvin1965aae2008-10-22 22:26:29 -0700455#endif /* _ASM_X86_UACCESS_H */
Nick Piggin8174c432008-07-25 19:45:24 -0700456