tools/include/nolibc/arch-aarch64.h


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

/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
/*
 * AARCH64 specific definitions for NOLIBC
 * Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu>
 */

#ifndef _NOLIBC_ARCH_AARCH64_H
#define _NOLIBC_ARCH_AARCH64_H

#include "compiler.h"
#include "crt.h"

/* Syscalls for AARCH64 :
 *   - registers are 64-bit
 *   - stack is 16-byte aligned
 *   - syscall number is passed in x8
 *   - arguments are in x0, x1, x2, x3, x4, x5
 *   - the system call is performed by calling svc 0
 *   - syscall return comes in x0.
 *   - the arguments are cast to long and assigned into the target registers
 *     which are then simply passed as registers to the asm code, so that we
 *     don't have to experience issues with register constraints.
 */

#define my_syscall0(num)                                                      \
({                                                                            \
	register long _num  __asm__ ("x8") = (num);                           \
	register long _arg1 __asm__ ("x0");                                   \
									      \
	__asm__ volatile (                                                    \
		"svc #0\n"                                                    \
		: "=r"(_arg1)                                                 \
		: "r"(_num)                                                   \
		: "memory", "cc"                                              \
	);                                                                    \
	_arg1;                                                                \
})

#define my_syscall1(num, arg1)                                                \
({                                                                            \
	register long _num  __asm__ ("x8") = (num);                           \
	register long _arg1 __asm__ ("x0") = (long)(arg1);                    \
									      \
	__asm__ volatile (                                                    \
		"svc #0\n"                                                    \
		: "=r"(_arg1)                                                 \
		: "r"(_arg1),                                                 \
		  "r"(_num)                                                   \
		: "memory", "cc"                                              \
	);                                                                    \
	_arg1;                                                                \
})

#define my_syscall2(num, arg1, arg2)                                          \
({                                                                            \
	register long _num  __asm__ ("x8") = (num);                           \
	register long _arg1 __asm__ ("x0") = (long)(arg1);                    \
	register long _arg2 __asm__ ("x1") = (long)(arg2);                    \
									      \
	__asm__ volatile (                                                    \
		"svc #0\n"                                                    \
		: "=r"(_arg1)                                                 \
		: "r"(_arg1), "r"(_arg2),                                     \
		  "r"(_num)                                                   \
		: "memory", "cc"                                              \
	);                                                                    \
	_arg1;                                                                \
})

#define my_syscall3(num, arg1, arg2, arg3)                                    \
({                                                                            \
	register long _num  __asm__ ("x8") = (num);                           \
	register long _arg1 __asm__ ("x0") = (long)(arg1);                    \
	register long _arg2 __asm__ ("x1") = (long)(arg2);                    \
	register long _arg3 __asm__ ("x2") = (long)(arg3);                    \
									      \
	__asm__ volatile (                                                    \
		"svc #0\n"                                                    \
		: "=r"(_arg1)                                                 \
		: "r"(_arg1), "r"(_arg2), "r"(_arg3),                         \
		  "r"(_num)                                                   \
		: "memory", "cc"                                              \
	);                                                                    \
	_arg1;                                                                \
})

#define my_syscall4(num, arg1, arg2, arg3, arg4)                              \
({                                                                            \
	register long _num  __asm__ ("x8") = (num);                           \
	register long _arg1 __asm__ ("x0") = (long)(arg1);                    \
	register long _arg2 __asm__ ("x1") = (long)(arg2);                    \
	register long _arg3 __asm__ ("x2") = (long)(arg3);                    \
	register long _arg4 __asm__ ("x3") = (long)(arg4);                    \
									      \
	__asm__ volatile (                                                    \
		"svc #0\n"                                                    \
		: "=r"(_arg1)                                                 \
		: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4),             \
		  "r"(_num)                                                   \
		: "memory", "cc"                                              \
	);                                                                    \
	_arg1;                                                                \
})

#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5)                        \
({                                                                            \
	register long _num  __asm__ ("x8") = (num);                           \
	register long _arg1 __asm__ ("x0") = (long)(arg1);                    \
	register long _arg2 __asm__ ("x1") = (long)(arg2);                    \
	register long _arg3 __asm__ ("x2") = (long)(arg3);                    \
	register long _arg4 __asm__ ("x3") = (long)(arg4);                    \
	register long _arg5 __asm__ ("x4") = (long)(arg5);                    \
									      \
	__asm__ volatile (                                                    \
		"svc #0\n"                                                    \
		: "=r" (_arg1)                                                \
		: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
		  "r"(_num)                                                   \
		: "memory", "cc"                                              \
	);                                                                    \
	_arg1;                                                                \
})

#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6)                  \
({                                                                            \
	register long _num  __asm__ ("x8") = (num);                           \
	register long _arg1 __asm__ ("x0") = (long)(arg1);                    \
	register long _arg2 __asm__ ("x1") = (long)(arg2);                    \
	register long _arg3 __asm__ ("x2") = (long)(arg3);                    \
	register long _arg4 __asm__ ("x3") = (long)(arg4);                    \
	register long _arg5 __asm__ ("x4") = (long)(arg5);                    \
	register long _arg6 __asm__ ("x5") = (long)(arg6);                    \
									      \
	__asm__ volatile (                                                    \
		"svc #0\n"                                                    \
		: "=r" (_arg1)                                                \
		: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
		  "r"(_arg6), "r"(_num)                                       \
		: "memory", "cc"                                              \
	);                                                                    \
	_arg1;                                                                \
})

/* startup code */
void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
{
	__asm__ volatile (
		"mov x0, sp\n"          /* save stack pointer to x0, as arg1 of _start_c */
		"and sp, x0, -16\n"     /* sp must be 16-byte aligned in the callee      */
		"bl  _start_c\n"        /* transfer to c runtime                         */
	);
	__builtin_unreachable();
}
#endif /* _NOLIBC_ARCH_AARCH64_H */