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[releases.git] / x86 / include / asm / uaccess_64.h
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_UACCESS_64_H
3 #define _ASM_X86_UACCESS_64_H
4
5 /*
6  * User space memory access functions
7  */
8 #include <linux/compiler.h>
9 #include <linux/lockdep.h>
10 #include <linux/kasan-checks.h>
11 #include <asm/alternative.h>
12 #include <asm/cpufeatures.h>
13 #include <asm/page.h>
14
15 /*
16  * Copy To/From Userspace
17  */
18
19 /* Handles exceptions in both to and from, but doesn't do access_ok */
20 __must_check unsigned long
21 copy_user_enhanced_fast_string(void *to, const void *from, unsigned len);
22 __must_check unsigned long
23 copy_user_generic_string(void *to, const void *from, unsigned len);
24 __must_check unsigned long
25 copy_user_generic_unrolled(void *to, const void *from, unsigned len);
26
27 static __always_inline __must_check unsigned long
28 copy_user_generic(void *to, const void *from, unsigned len)
29 {
30         unsigned ret;
31
32         /*
33          * If CPU has ERMS feature, use copy_user_enhanced_fast_string.
34          * Otherwise, if CPU has rep_good feature, use copy_user_generic_string.
35          * Otherwise, use copy_user_generic_unrolled.
36          */
37         alternative_call_2(copy_user_generic_unrolled,
38                          copy_user_generic_string,
39                          X86_FEATURE_REP_GOOD,
40                          copy_user_enhanced_fast_string,
41                          X86_FEATURE_ERMS,
42                          ASM_OUTPUT2("=a" (ret), "=D" (to), "=S" (from),
43                                      "=d" (len)),
44                          "1" (to), "2" (from), "3" (len)
45                          : "memory", "rcx", "r8", "r9", "r10", "r11");
46         return ret;
47 }
48
49 static __always_inline __must_check unsigned long
50 raw_copy_from_user(void *dst, const void __user *src, unsigned long size)
51 {
52         return copy_user_generic(dst, (__force void *)src, size);
53 }
54
55 static __always_inline __must_check unsigned long
56 raw_copy_to_user(void __user *dst, const void *src, unsigned long size)
57 {
58         return copy_user_generic((__force void *)dst, src, size);
59 }
60
61 extern long __copy_user_nocache(void *dst, const void __user *src,
62                                 unsigned size, int zerorest);
63
64 extern long __copy_user_flushcache(void *dst, const void __user *src, unsigned size);
65 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
66                            size_t len);
67
68 static inline int
69 __copy_from_user_inatomic_nocache(void *dst, const void __user *src,
70                                   unsigned size)
71 {
72         kasan_check_write(dst, size);
73         return __copy_user_nocache(dst, src, size, 0);
74 }
75
76 static inline int
77 __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size)
78 {
79         kasan_check_write(dst, size);
80         return __copy_user_flushcache(dst, src, size);
81 }
82
83 /*
84  * Zero Userspace.
85  */
86
87 __must_check unsigned long
88 clear_user_original(void __user *addr, unsigned long len);
89 __must_check unsigned long
90 clear_user_rep_good(void __user *addr, unsigned long len);
91 __must_check unsigned long
92 clear_user_erms(void __user *addr, unsigned long len);
93
94 static __always_inline __must_check unsigned long __clear_user(void __user *addr, unsigned long size)
95 {
96         might_fault();
97         stac();
98
99         /*
100          * No memory constraint because it doesn't change any memory gcc
101          * knows about.
102          */
103         asm volatile(
104                 "1:\n\t"
105                 ALTERNATIVE_3("rep stosb",
106                               "call clear_user_erms",     ALT_NOT(X86_FEATURE_FSRM),
107                               "call clear_user_rep_good", ALT_NOT(X86_FEATURE_ERMS),
108                               "call clear_user_original", ALT_NOT(X86_FEATURE_REP_GOOD))
109                 "2:\n"
110                _ASM_EXTABLE_UA(1b, 2b)
111                : "+c" (size), "+D" (addr), ASM_CALL_CONSTRAINT
112                : "a" (0)
113                 /* rep_good clobbers %rdx */
114                : "rdx");
115
116         clac();
117
118         return size;
119 }
120
121 static __always_inline unsigned long clear_user(void __user *to, unsigned long n)
122 {
123         if (access_ok(to, n))
124                 return __clear_user(to, n);
125         return n;
126 }
127 #endif /* _ASM_X86_UACCESS_64_H */