1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */ 1
2 /*
3 * i386 specific definitions for NOLIBC
4 * Copyright (C) 2017-2022 Willy Tarreau <w@1w
5 */
6
7 #ifndef _NOLIBC_ARCH_I386_H
8 #define _NOLIBC_ARCH_I386_H
9
10 #include "compiler.h"
11 #include "crt.h"
12
13 /* Syscalls for i386 :
14 * - mostly similar to x86_64
15 * - registers are 32-bit
16 * - syscall number is passed in eax
17 * - arguments are in ebx, ecx, edx, esi, ed
18 * - all registers are preserved (except eax
19 * - the system call is performed by calling
20 * - syscall return comes in eax
21 * - the arguments are cast to long and assi
22 * which are then simply passed as registe
23 * don't have to experience issues with re
24 * - the syscall number is always specified
25 * some registers before (gcc refuses a %-
26 *
27 * Also, i386 supports the old_select syscall
28 */
29 #define __ARCH_WANT_SYS_OLD_SELECT
30
31 #define my_syscall0(num)
32 ({
33 long _ret;
34 register long _num __asm__ ("eax") = (
35
36 __asm__ volatile (
37 "int $0x80\n"
38 : "=a" (_ret)
39 : ""(_num)
40 : "memory", "cc"
41 );
42 _ret;
43 })
44
45 #define my_syscall1(num, arg1)
46 ({
47 long _ret;
48 register long _num __asm__ ("eax") = (
49 register long _arg1 __asm__ ("ebx") =
50
51 __asm__ volatile (
52 "int $0x80\n"
53 : "=a" (_ret)
54 : "r"(_arg1),
55 ""(_num)
56 : "memory", "cc"
57 );
58 _ret;
59 })
60
61 #define my_syscall2(num, arg1, arg2)
62 ({
63 long _ret;
64 register long _num __asm__ ("eax") = (
65 register long _arg1 __asm__ ("ebx") =
66 register long _arg2 __asm__ ("ecx") =
67
68 __asm__ volatile (
69 "int $0x80\n"
70 : "=a" (_ret)
71 : "r"(_arg1), "r"(_arg2),
72 ""(_num)
73 : "memory", "cc"
74 );
75 _ret;
76 })
77
78 #define my_syscall3(num, arg1, arg2, arg3)
79 ({
80 long _ret;
81 register long _num __asm__ ("eax") = (
82 register long _arg1 __asm__ ("ebx") =
83 register long _arg2 __asm__ ("ecx") =
84 register long _arg3 __asm__ ("edx") =
85
86 __asm__ volatile (
87 "int $0x80\n"
88 : "=a" (_ret)
89 : "r"(_arg1), "r"(_arg2), "r"(
90 ""(_num)
91 : "memory", "cc"
92 );
93 _ret;
94 })
95
96 #define my_syscall4(num, arg1, arg2, arg3, arg
97 ({
98 long _ret;
99 register long _num __asm__ ("eax") = (
100 register long _arg1 __asm__ ("ebx") =
101 register long _arg2 __asm__ ("ecx") =
102 register long _arg3 __asm__ ("edx") =
103 register long _arg4 __asm__ ("esi") =
104
105 __asm__ volatile (
106 "int $0x80\n"
107 : "=a" (_ret)
108 : "r"(_arg1), "r"(_arg2), "r"(
109 ""(_num)
110 : "memory", "cc"
111 );
112 _ret;
113 })
114
115 #define my_syscall5(num, arg1, arg2, arg3, arg
116 ({
117 long _ret;
118 register long _num __asm__ ("eax") = (
119 register long _arg1 __asm__ ("ebx") =
120 register long _arg2 __asm__ ("ecx") =
121 register long _arg3 __asm__ ("edx") =
122 register long _arg4 __asm__ ("esi") =
123 register long _arg5 __asm__ ("edi") =
124
125 __asm__ volatile (
126 "int $0x80\n"
127 : "=a" (_ret)
128 : "r"(_arg1), "r"(_arg2), "r"(
129 ""(_num)
130 : "memory", "cc"
131 );
132 _ret;
133 })
134
135 #define my_syscall6(num, arg1, arg2, arg3, arg
136 ({
137 long _eax = (long)(num);
138 long _arg6 = (long)(arg6); /* Always i
139 __asm__ volatile (
140 "pushl %[_arg6]\n\t"
141 "pushl %%ebp\n\t"
142 "movl 4(%%esp),%%ebp\n\t"
143 "int $0x80\n\t"
144 "popl %%ebp\n\t"
145 "addl $4,%%esp\n\t"
146 : "+a"(_eax) /* %ea
147 : "b"(arg1), /* %eb
148 "c"(arg2), /* %ec
149 "d"(arg3), /* %ed
150 "S"(arg4), /* %es
151 "D"(arg5), /* %ed
152 [_arg6]"m"(_arg6) /* mem
153 : "memory", "cc"
154 );
155 _eax;
156 })
157
158 /* startup code */
159 /*
160 * i386 System V ABI mandates:
161 * 1) last pushed argument must be 16-byte ali
162 * 2) The deepest stack frame should be set to
163 *
164 */
165 void __attribute__((weak, noreturn)) __nolibc_
166 {
167 __asm__ volatile (
168 "xor %ebp, %ebp\n" /* z
169 "mov %esp, %eax\n" /* s
170 "add $12, %esp\n" /* a
171 "and $-16, %esp\n" /* t
172 "sub $12, %esp\n" /* s
173 "push %eax\n" /* p
174 "call _start_c\n" /* t
175 "hlt\n" /* e
176 );
177 __nolibc_entrypoint_epilogue();
178 }
179
180 #endif /* _NOLIBC_ARCH_I386_H */
181
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