x86: use setters/getters for MSR_{FS,GS}_BASE
[akaros.git] / kern / arch / x86 / uaccess.h
1 /* Copyright (c) 2015 Google Inc
2  * Davide Libenzi <dlibenzi@google.com>
3  * See LICENSE for details.
4  *
5  * Part of this code coming from a Linux kernel file:
6  *
7  * linux/arch/x86/include/asm/uaccess.h
8  *
9  * Which, even though missing specific copyright, it is supposed to be
10  * ruled by the overall Linux copyright.
11  */
12
13 #pragma once
14
15 #include <ros/errno.h>
16 #include <compiler.h>
17 #include <stdint.h>
18 #include <umem.h>
19 #include <arch/fixup.h>
20
21 #define __m(x) *(x)
22
23 struct extable_ip_fixup {
24         uint64_t insn;
25         uint64_t fixup;
26 };
27
28 #define __read_msr_asm(eax, edx, addr, err, errret)                                             \
29         asm volatile(ASM_STAC "\n"                                                                                      \
30                                  "1:            rdmsr\n"                                                                        \
31                                  "                      mfence\n"                                                                       \
32                                  "2: " ASM_CLAC "\n"                                                                    \
33                                  ".section .fixup,\"ax\"\n"                                                             \
34                                  "3:            mov %4,%0\n"                                                            \
35                                  "      jmp 2b\n"                                                                                       \
36                                  ".previous\n"                                                                                  \
37                                  _ASM_EXTABLE(1b, 3b)                                                                   \
38                                  : "=r" (err), "=d" (edx), "=a" (eax)                                   \
39                                  : "c" (addr), "i" (errret), "0" (err))
40
41 #define __write_msr_asm(val, addr, err, errret)                                                 \
42         asm volatile(ASM_STAC "\n"                                                                                      \
43                                  "1:            wrmsr\n"                                                                        \
44                                  "2: " ASM_CLAC "\n"                                                                    \
45                                  ".section .fixup,\"ax\"\n"                                                             \
46                                  "3:            mov %4,%0\n"                                                            \
47                                  "      jmp 2b\n"                                                                                       \
48                                  ".previous\n"                                                                                  \
49                                  _ASM_EXTABLE(1b, 3b)                                                                   \
50                                  : "=r" (err)                                                                                   \
51                                  : "d" ((uint32_t) (val >> 32)),                                                \
52                                    "a" ((uint32_t) (val & 0xffffffff)), "c" (addr),             \
53                                    "i" (errret), "0" (err))
54
55 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret)               \
56         asm volatile(ASM_STAC "\n"                                                                                      \
57                                  "1:            mov"itype" %"rtype"1,%2\n"                                      \
58                                  "2: " ASM_CLAC "\n"                                                                    \
59                                  ".section .fixup,\"ax\"\n"                                                             \
60                                  "3:            mov %3,%0\n"                                                            \
61                                  "      jmp 2b\n"                                                                                       \
62                                  ".previous\n"                                                                                  \
63                                  _ASM_EXTABLE(1b, 3b)                                                                   \
64                                  : "=r"(err)                                                                                    \
65                                  : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
66
67 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret)       \
68         asm volatile(ASM_STAC "\n"                                                                              \
69                                  "1:            mov"itype" %2,%"rtype"1\n"                              \
70                                  "2: " ASM_CLAC "\n"                                                            \
71                                  ".section .fixup,\"ax\"\n"                                                     \
72                                  "3:            mov %3,%0\n"                                                    \
73                                  "      xor"itype" %"rtype"1,%"rtype"1\n"                               \
74                                  "      jmp 2b\n"                                                                               \
75                                  ".previous\n"                                                                          \
76                                  _ASM_EXTABLE(1b, 3b)                                                           \
77                                  : "=r" (err), ltype(x)                                                         \
78                                  : "m" (__m(addr)), "i" (errret), "0" (err))
79
80 #define __user_memcpy(dst, src, count, err, errret)                                             \
81         asm volatile(ASM_STAC "\n"                                                                                      \
82                                  "              cld\n"                                                                          \
83                                  "1:            rep movsb\n"                                                            \
84                                  "2: " ASM_CLAC "\n"                                                                    \
85                                  ".section .fixup,\"ax\"\n"                                                             \
86                                  "3:            mov %4,%0\n"                                                            \
87                                  "      jmp 2b\n"                                                                                       \
88                                  ".previous\n"                                                                                  \
89                                  _ASM_EXTABLE(1b, 3b)                                                                   \
90                                  : "=r"(err), "+D" (dst), "+S" (src), "+c" (count)              \
91                                  : "i" (errret), "0" (err)                                                              \
92                                  : "memory")
93
94 static inline int __put_user(void *dst, const void *src, unsigned int count)
95 {
96         int err = 0;
97
98         switch (count) {
99         case 1:
100                 __put_user_asm(*(const uint8_t *) src, (uint8_t *) dst, err, "b",
101                                            "b", "iq", -EFAULT);
102                 break;
103         case 2:
104                 __put_user_asm(*(const uint16_t *) src, (uint16_t *) dst, err, "w",
105                                            "w", "ir", -EFAULT);
106                 break;
107         case 4:
108                 __put_user_asm(*(const uint32_t *) src, (uint32_t *) dst, err, "l",
109                                            "k", "ir", -EFAULT);
110                 break;
111         case 8:
112                 __put_user_asm(*(const uint64_t *) src, (uint64_t *) dst, err, "q",
113                                            "", "er", -EFAULT);
114                 break;
115         default:
116                 __user_memcpy(dst, src, count, err, -EFAULT);
117         }
118
119         return err;
120 }
121
122 static inline int copy_to_user(void *dst, const void *src, unsigned int count)
123 {
124         int err = 0;
125
126         if (unlikely(!is_user_rwaddr(dst, count))) {
127                 err = -EFAULT;
128         } else if (!__builtin_constant_p(count)) {
129                 __user_memcpy(dst, src, count, err, -EFAULT);
130         } else {
131                 err = __put_user(dst, src, count);
132         }
133
134         return err;
135 }
136
137 static inline int __get_user(void *dst, const void *src, unsigned int count)
138 {
139         int err = 0;
140
141         switch (count) {
142         case 1:
143                 __get_user_asm(*(uint8_t *) dst, (const uint8_t *) src, err, "b",
144                                            "b", "=q", -EFAULT);
145                 break;
146         case 2:
147                 __get_user_asm(*(uint16_t *) dst, (const uint16_t *) src, err, "w",
148                                            "w", "=r", -EFAULT);
149                 break;
150         case 4:
151                 __get_user_asm(*(uint32_t *) dst, (const uint32_t *) src, err, "l",
152                                            "k", "=r", -EFAULT);
153                 break;
154         case 8:
155                 __get_user_asm(*(uint64_t *) dst, (const uint64_t *) src, err, "q",
156                                            "", "=r", -EFAULT);
157                 break;
158         default:
159                 __user_memcpy(dst, src, count, err, -EFAULT);
160         }
161
162         return err;
163 }
164
165 static inline int copy_from_user(void *dst, const void *src,
166                                                                  unsigned int count)
167 {
168         int err = 0;
169
170         if (unlikely(!is_user_raddr((void *) src, count))) {
171                 err = -EFAULT;
172         } else if (!__builtin_constant_p(count)) {
173                 __user_memcpy(dst, src, count, err, -EFAULT);
174         } else {
175                 err = __get_user(dst, src, count);
176         }
177
178         return err;
179 }
180
181 static inline int safe_read_msr(uint32_t addr, uint64_t *value)
182 {
183         int err = 0;
184         uint32_t edx, eax;
185
186         __read_msr_asm(eax, edx, addr, err, -EFAULT);
187         if (likely(err == 0))
188                 *value = ((uint64_t) edx << 32) | eax;
189
190         return err;
191 }
192
193 static inline int safe_write_msr(uint32_t addr, uint64_t value)
194 {
195         int err = 0;
196
197         __write_msr_asm(value, addr, err, -EFAULT);
198
199         return err;
200 }
201
202 static inline uintptr_t ex_insn_addr(const struct extable_ip_fixup *x)
203 {
204         return (uintptr_t) &x->insn + x->insn;
205 }
206
207 static inline uintptr_t ex_fixup_addr(const struct extable_ip_fixup *x)
208 {
209         return (uintptr_t) &x->fixup + x->fixup;
210 }