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uaccess_64.h
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1 #ifndef _ASM_X86_UACCESS_64_H
2 #define _ASM_X86_UACCESS_64_H
3 
4 /*
5  * User space memory access functions
6  */
7 #include <linux/compiler.h>
8 #include <linux/errno.h>
9 #include <linux/lockdep.h>
10 #include <asm/alternative.h>
11 #include <asm/cpufeature.h>
12 #include <asm/page.h>
13 
14 /*
15  * Copy To/From Userspace
16  */
17 
18 /* Handles exceptions in both to and from, but doesn't do access_ok */
19 __must_check unsigned long
20 copy_user_enhanced_fast_string(void *to, const void *from, unsigned len);
21 __must_check unsigned long
22 copy_user_generic_string(void *to, const void *from, unsigned len);
23 __must_check unsigned long
24 copy_user_generic_unrolled(void *to, const void *from, unsigned len);
25 
26 static __always_inline __must_check unsigned long
27 copy_user_generic(void *to, const void *from, unsigned len)
28 {
29  unsigned ret;
30 
31  /*
32  * If CPU has ERMS feature, use copy_user_enhanced_fast_string.
33  * Otherwise, if CPU has rep_good feature, use copy_user_generic_string.
34  * Otherwise, use copy_user_generic_unrolled.
35  */
41  ASM_OUTPUT2("=a" (ret), "=D" (to), "=S" (from),
42  "=d" (len)),
43  "1" (to), "2" (from), "3" (len)
44  : "memory", "rcx", "r8", "r9", "r10", "r11");
45  return ret;
46 }
47 
48 __must_check unsigned long
49 _copy_to_user(void __user *to, const void *from, unsigned len);
50 __must_check unsigned long
51 _copy_from_user(void *to, const void __user *from, unsigned len);
52 __must_check unsigned long
53 copy_in_user(void __user *to, const void __user *from, unsigned len);
54 
55 static inline unsigned long __must_check copy_from_user(void *to,
56  const void __user *from,
57  unsigned long n)
58 {
59  int sz = __compiletime_object_size(to);
60 
61  might_fault();
62  if (likely(sz == -1 || sz >= n))
63  n = _copy_from_user(to, from, n);
64 #ifdef CONFIG_DEBUG_VM
65  else
66  WARN(1, "Buffer overflow detected!\n");
67 #endif
68  return n;
69 }
70 
72 int copy_to_user(void __user *dst, const void *src, unsigned size)
73 {
74  might_fault();
75 
76  return _copy_to_user(dst, src, size);
77 }
78 
80 int __copy_from_user(void *dst, const void __user *src, unsigned size)
81 {
82  int ret = 0;
83 
84  might_fault();
85  if (!__builtin_constant_p(size))
86  return copy_user_generic(dst, (__force void *)src, size);
87  switch (size) {
88  case 1:__get_user_asm(*(u8 *)dst, (u8 __user *)src,
89  ret, "b", "b", "=q", 1);
90  return ret;
91  case 2:__get_user_asm(*(u16 *)dst, (u16 __user *)src,
92  ret, "w", "w", "=r", 2);
93  return ret;
94  case 4:__get_user_asm(*(u32 *)dst, (u32 __user *)src,
95  ret, "l", "k", "=r", 4);
96  return ret;
97  case 8:__get_user_asm(*(u64 *)dst, (u64 __user *)src,
98  ret, "q", "", "=r", 8);
99  return ret;
100  case 10:
101  __get_user_asm(*(u64 *)dst, (u64 __user *)src,
102  ret, "q", "", "=r", 10);
103  if (unlikely(ret))
104  return ret;
105  __get_user_asm(*(u16 *)(8 + (char *)dst),
106  (u16 __user *)(8 + (char __user *)src),
107  ret, "w", "w", "=r", 2);
108  return ret;
109  case 16:
110  __get_user_asm(*(u64 *)dst, (u64 __user *)src,
111  ret, "q", "", "=r", 16);
112  if (unlikely(ret))
113  return ret;
114  __get_user_asm(*(u64 *)(8 + (char *)dst),
115  (u64 __user *)(8 + (char __user *)src),
116  ret, "q", "", "=r", 8);
117  return ret;
118  default:
119  return copy_user_generic(dst, (__force void *)src, size);
120  }
121 }
122 
124 int __copy_to_user(void __user *dst, const void *src, unsigned size)
125 {
126  int ret = 0;
127 
128  might_fault();
129  if (!__builtin_constant_p(size))
130  return copy_user_generic((__force void *)dst, src, size);
131  switch (size) {
132  case 1:__put_user_asm(*(u8 *)src, (u8 __user *)dst,
133  ret, "b", "b", "iq", 1);
134  return ret;
135  case 2:__put_user_asm(*(u16 *)src, (u16 __user *)dst,
136  ret, "w", "w", "ir", 2);
137  return ret;
138  case 4:__put_user_asm(*(u32 *)src, (u32 __user *)dst,
139  ret, "l", "k", "ir", 4);
140  return ret;
141  case 8:__put_user_asm(*(u64 *)src, (u64 __user *)dst,
142  ret, "q", "", "er", 8);
143  return ret;
144  case 10:
145  __put_user_asm(*(u64 *)src, (u64 __user *)dst,
146  ret, "q", "", "er", 10);
147  if (unlikely(ret))
148  return ret;
149  asm("":::"memory");
150  __put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst,
151  ret, "w", "w", "ir", 2);
152  return ret;
153  case 16:
154  __put_user_asm(*(u64 *)src, (u64 __user *)dst,
155  ret, "q", "", "er", 16);
156  if (unlikely(ret))
157  return ret;
158  asm("":::"memory");
159  __put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
160  ret, "q", "", "er", 8);
161  return ret;
162  default:
163  return copy_user_generic((__force void *)dst, src, size);
164  }
165 }
166 
168 int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
169 {
170  int ret = 0;
171 
172  might_fault();
173  if (!__builtin_constant_p(size))
174  return copy_user_generic((__force void *)dst,
175  (__force void *)src, size);
176  switch (size) {
177  case 1: {
178  u8 tmp;
179  __get_user_asm(tmp, (u8 __user *)src,
180  ret, "b", "b", "=q", 1);
181  if (likely(!ret))
182  __put_user_asm(tmp, (u8 __user *)dst,
183  ret, "b", "b", "iq", 1);
184  return ret;
185  }
186  case 2: {
187  u16 tmp;
188  __get_user_asm(tmp, (u16 __user *)src,
189  ret, "w", "w", "=r", 2);
190  if (likely(!ret))
191  __put_user_asm(tmp, (u16 __user *)dst,
192  ret, "w", "w", "ir", 2);
193  return ret;
194  }
195 
196  case 4: {
197  u32 tmp;
198  __get_user_asm(tmp, (u32 __user *)src,
199  ret, "l", "k", "=r", 4);
200  if (likely(!ret))
201  __put_user_asm(tmp, (u32 __user *)dst,
202  ret, "l", "k", "ir", 4);
203  return ret;
204  }
205  case 8: {
206  u64 tmp;
207  __get_user_asm(tmp, (u64 __user *)src,
208  ret, "q", "", "=r", 8);
209  if (likely(!ret))
210  __put_user_asm(tmp, (u64 __user *)dst,
211  ret, "q", "", "er", 8);
212  return ret;
213  }
214  default:
215  return copy_user_generic((__force void *)dst,
216  (__force void *)src, size);
217  }
218 }
219 
220 static __must_check __always_inline int
221 __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size)
222 {
223  return copy_user_generic(dst, (__force const void *)src, size);
224 }
225 
226 static __must_check __always_inline int
227 __copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
228 {
229  return copy_user_generic((__force void *)dst, src, size);
230 }
231 
232 extern long __copy_user_nocache(void *dst, const void __user *src,
233  unsigned size, int zerorest);
234 
235 static inline int
236 __copy_from_user_nocache(void *dst, const void __user *src, unsigned size)
237 {
238  might_sleep();
239  return __copy_user_nocache(dst, src, size, 1);
240 }
241 
242 static inline int
243 __copy_from_user_inatomic_nocache(void *dst, const void __user *src,
244  unsigned size)
245 {
246  return __copy_user_nocache(dst, src, size, 0);
247 }
248 
249 unsigned long
250 copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest);
251 
252 #endif /* _ASM_X86_UACCESS_64_H */