1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
|
/* SPDX-License-Identifier: MIT */
#ifndef __INTERNAL__LIBURING_SYSCALL_H
#error "This file should be included from src/syscall.h (liburing)"
#endif
#ifndef LIBURING_ARCH_X86_SYSCALL_H
#define LIBURING_ARCH_X86_SYSCALL_H
#if defined(__x86_64__)
/**
* Note for syscall registers usage (x86-64):
* - %rax is the syscall number.
* - %rax is also the return value.
* - %rdi is the 1st argument.
* - %rsi is the 2nd argument.
* - %rdx is the 3rd argument.
* - %r10 is the 4th argument (**yes it's %r10, not %rcx!**).
* - %r8 is the 5th argument.
* - %r9 is the 6th argument.
*
* `syscall` instruction will clobber %r11 and %rcx.
*
* After the syscall returns to userspace:
* - %r11 will contain %rflags.
* - %rcx will contain the return address.
*
* IOW, after the syscall returns to userspace:
* %r11 == %rflags and %rcx == %rip.
*/
#define __do_syscall0(NUM) ({ \
intptr_t rax; \
\
__asm__ volatile( \
"syscall" \
: "=a"(rax) /* %rax */ \
: "a"(NUM) /* %rax */ \
: "rcx", "r11", "memory" \
); \
rax; \
})
#define __do_syscall1(NUM, ARG1) ({ \
intptr_t rax; \
\
__asm__ volatile( \
"syscall" \
: "=a"(rax) /* %rax */ \
: "a"((NUM)), /* %rax */ \
"D"((ARG1)) /* %rdi */ \
: "rcx", "r11", "memory" \
); \
rax; \
})
#define __do_syscall2(NUM, ARG1, ARG2) ({ \
intptr_t rax; \
\
__asm__ volatile( \
"syscall" \
: "=a"(rax) /* %rax */ \
: "a"((NUM)), /* %rax */ \
"D"((ARG1)), /* %rdi */ \
"S"((ARG2)) /* %rsi */ \
: "rcx", "r11", "memory" \
); \
rax; \
})
#define __do_syscall3(NUM, ARG1, ARG2, ARG3) ({ \
intptr_t rax; \
\
__asm__ volatile( \
"syscall" \
: "=a"(rax) /* %rax */ \
: "a"((NUM)), /* %rax */ \
"D"((ARG1)), /* %rdi */ \
"S"((ARG2)), /* %rsi */ \
"d"((ARG3)) /* %rdx */ \
: "rcx", "r11", "memory" \
); \
rax; \
})
#define __do_syscall4(NUM, ARG1, ARG2, ARG3, ARG4) ({ \
intptr_t rax; \
register __typeof__(ARG4) __r10 __asm__("r10") = (ARG4); \
\
__asm__ volatile( \
"syscall" \
: "=a"(rax) /* %rax */ \
: "a"((NUM)), /* %rax */ \
"D"((ARG1)), /* %rdi */ \
"S"((ARG2)), /* %rsi */ \
"d"((ARG3)), /* %rdx */ \
"r"(__r10) /* %r10 */ \
: "rcx", "r11", "memory" \
); \
rax; \
})
#define __do_syscall5(NUM, ARG1, ARG2, ARG3, ARG4, ARG5) ({ \
intptr_t rax; \
register __typeof__(ARG4) __r10 __asm__("r10") = (ARG4); \
register __typeof__(ARG5) __r8 __asm__("r8") = (ARG5); \
\
__asm__ volatile( \
"syscall" \
: "=a"(rax) /* %rax */ \
: "a"((NUM)), /* %rax */ \
"D"((ARG1)), /* %rdi */ \
"S"((ARG2)), /* %rsi */ \
"d"((ARG3)), /* %rdx */ \
"r"(__r10), /* %r10 */ \
"r"(__r8) /* %r8 */ \
: "rcx", "r11", "memory" \
); \
rax; \
})
#define __do_syscall6(NUM, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6) ({ \
intptr_t rax; \
register __typeof__(ARG4) __r10 __asm__("r10") = (ARG4); \
register __typeof__(ARG5) __r8 __asm__("r8") = (ARG5); \
register __typeof__(ARG6) __r9 __asm__("r9") = (ARG6); \
\
__asm__ volatile( \
"syscall" \
: "=a"(rax) /* %rax */ \
: "a"((NUM)), /* %rax */ \
"D"((ARG1)), /* %rdi */ \
"S"((ARG2)), /* %rsi */ \
"d"((ARG3)), /* %rdx */ \
"r"(__r10), /* %r10 */ \
"r"(__r8), /* %r8 */ \
"r"(__r9) /* %r9 */ \
: "rcx", "r11", "memory" \
); \
rax; \
})
#include "../syscall-defs.h"
#else /* #if defined(__x86_64__) */
#ifdef CONFIG_NOLIBC
/**
* Note for syscall registers usage (x86, 32-bit):
* - %eax is the syscall number.
* - %eax is also the return value.
* - %ebx is the 1st argument.
* - %ecx is the 2nd argument.
* - %edx is the 3rd argument.
* - %esi is the 4th argument.
* - %edi is the 5th argument.
* - %ebp is the 6th argument.
*/
#define __do_syscall0(NUM) ({ \
intptr_t eax; \
\
__asm__ volatile( \
"int $0x80" \
: "=a"(eax) /* %eax */ \
: "a"(NUM) /* %eax */ \
: "memory" \
); \
eax; \
})
#define __do_syscall1(NUM, ARG1) ({ \
intptr_t eax; \
\
__asm__ volatile( \
"int $0x80" \
: "=a"(eax) /* %eax */ \
: "a"(NUM), /* %eax */ \
"b"((ARG1)) /* %ebx */ \
: "memory" \
); \
eax; \
})
#define __do_syscall2(NUM, ARG1, ARG2) ({ \
intptr_t eax; \
\
__asm__ volatile( \
"int $0x80" \
: "=a" (eax) /* %eax */ \
: "a"(NUM), /* %eax */ \
"b"((ARG1)), /* %ebx */ \
"c"((ARG2)) /* %ecx */ \
: "memory" \
); \
eax; \
})
#define __do_syscall3(NUM, ARG1, ARG2, ARG3) ({ \
intptr_t eax; \
\
__asm__ volatile( \
"int $0x80" \
: "=a" (eax) /* %eax */ \
: "a"(NUM), /* %eax */ \
"b"((ARG1)), /* %ebx */ \
"c"((ARG2)), /* %ecx */ \
"d"((ARG3)) /* %edx */ \
: "memory" \
); \
eax; \
})
#define __do_syscall4(NUM, ARG1, ARG2, ARG3, ARG4) ({ \
intptr_t eax; \
\
__asm__ volatile( \
"int $0x80" \
: "=a" (eax) /* %eax */ \
: "a"(NUM), /* %eax */ \
"b"((ARG1)), /* %ebx */ \
"c"((ARG2)), /* %ecx */ \
"d"((ARG3)), /* %edx */ \
"S"((ARG4)) /* %esi */ \
: "memory" \
); \
eax; \
})
#define __do_syscall5(NUM, ARG1, ARG2, ARG3, ARG4, ARG5) ({ \
intptr_t eax; \
\
__asm__ volatile( \
"int $0x80" \
: "=a" (eax) /* %eax */ \
: "a"(NUM), /* %eax */ \
"b"((ARG1)), /* %ebx */ \
"c"((ARG2)), /* %ecx */ \
"d"((ARG3)), /* %edx */ \
"S"((ARG4)), /* %esi */ \
"D"((ARG5)) /* %edi */ \
: "memory" \
); \
eax; \
})
/*
* On i386, the 6th argument of syscall goes in %ebp. However, both Clang
* and GCC cannot use %ebp in the clobber list and in the "r" constraint
* without using -fomit-frame-pointer. To make it always available for
* any kind of compilation, the below workaround is implemented:
*
* 1) Push the 6-th argument.
* 2) Push %ebp.
* 3) Load the 6-th argument from 4(%esp) to %ebp.
* 4) Do the syscall (int $0x80).
* 5) Pop %ebp (restore the old value of %ebp).
* 6) Add %esp by 4 (undo the stack pointer).
*
* WARNING:
* Don't use register variables for __do_syscall6(), there is a known
* GCC bug that results in an endless loop.
*
* BugLink: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105032
*
*/
#define __do_syscall6(NUM, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6) ({ \
intptr_t eax = (intptr_t)(NUM); \
intptr_t arg6 = (intptr_t)(ARG6); /* Always in memory */ \
__asm__ volatile ( \
"pushl %[_arg6]\n\t" \
"pushl %%ebp\n\t" \
"movl 4(%%esp),%%ebp\n\t" \
"int $0x80\n\t" \
"popl %%ebp\n\t" \
"addl $4,%%esp" \
: "+a"(eax) /* %eax */ \
: "b"(ARG1), /* %ebx */ \
"c"(ARG2), /* %ecx */ \
"d"(ARG3), /* %edx */ \
"S"(ARG4), /* %esi */ \
"D"(ARG5), /* %edi */ \
[_arg6]"m"(arg6) /* memory */ \
: "memory", "cc" \
); \
eax; \
})
#include "../syscall-defs.h"
#else /* #ifdef CONFIG_NOLIBC */
#include "../generic/syscall.h"
#endif /* #ifdef CONFIG_NOLIBC */
#endif /* #if defined(__x86_64__) */
#endif /* #ifndef LIBURING_ARCH_X86_SYSCALL_H */
|
