1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
2 /*
3 * AARCH64 specific definitions for NOLIBC
4 * Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu>
5 */
6
7 #ifndef _NOLIBC_ARCH_AARCH64_H
8 #define _NOLIBC_ARCH_AARCH64_H
9
10 #include "compiler.h"
11 #include "crt.h"
12
13 /* Syscalls for AARCH64 :
14 * - registers are 64-bit
15 * - stack is 16-byte aligned
16 * - syscall number is passed in x8
17 * - arguments are in x0, x1, x2, x3, x4, x5
18 * - the system call is performed by calling svc 0
19 * - syscall return comes in x0.
20 * - the arguments are cast to long and assigned into the target registers
21 * which are then simply passed as registers to the asm code, so that we
22 * don't have to experience issues with register constraints.
23 *
24 * On aarch64, select() is not implemented so we have to use pselect6().
25 */
26 #define __ARCH_WANT_SYS_PSELECT6
27
28 #define my_syscall0(num) \
29 ({ \
30 register long _num __asm__ ("x8") = (num); \
31 register long _arg1 __asm__ ("x0"); \
32 \
33 __asm__ volatile ( \
34 "svc #0\n" \
35 : "=r"(_arg1) \
36 : "r"(_num) \
37 : "memory", "cc" \
38 ); \
39 _arg1; \
40 })
41
42 #define my_syscall1(num, arg1) \
43 ({ \
44 register long _num __asm__ ("x8") = (num); \
45 register long _arg1 __asm__ ("x0") = (long)(arg1); \
46 \
47 __asm__ volatile ( \
48 "svc #0\n" \
49 : "=r"(_arg1) \
50 : "r"(_arg1), \
51 "r"(_num) \
52 : "memory", "cc" \
53 ); \
54 _arg1; \
55 })
56
57 #define my_syscall2(num, arg1, arg2) \
58 ({ \
59 register long _num __asm__ ("x8") = (num); \
60 register long _arg1 __asm__ ("x0") = (long)(arg1); \
61 register long _arg2 __asm__ ("x1") = (long)(arg2); \
62 \
63 __asm__ volatile ( \
64 "svc #0\n" \
65 : "=r"(_arg1) \
66 : "r"(_arg1), "r"(_arg2), \
67 "r"(_num) \
68 : "memory", "cc" \
69 ); \
70 _arg1; \
71 })
72
73 #define my_syscall3(num, arg1, arg2, arg3) \
74 ({ \
75 register long _num __asm__ ("x8") = (num); \
76 register long _arg1 __asm__ ("x0") = (long)(arg1); \
77 register long _arg2 __asm__ ("x1") = (long)(arg2); \
78 register long _arg3 __asm__ ("x2") = (long)(arg3); \
79 \
80 __asm__ volatile ( \
81 "svc #0\n" \
82 : "=r"(_arg1) \
83 : "r"(_arg1), "r"(_arg2), "r"(_arg3), \
84 "r"(_num) \
85 : "memory", "cc" \
86 ); \
87 _arg1; \
88 })
89
90 #define my_syscall4(num, arg1, arg2, arg3, arg4) \
91 ({ \
92 register long _num __asm__ ("x8") = (num); \
93 register long _arg1 __asm__ ("x0") = (long)(arg1); \
94 register long _arg2 __asm__ ("x1") = (long)(arg2); \
95 register long _arg3 __asm__ ("x2") = (long)(arg3); \
96 register long _arg4 __asm__ ("x3") = (long)(arg4); \
97 \
98 __asm__ volatile ( \
99 "svc #0\n" \
100 : "=r"(_arg1) \
101 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
102 "r"(_num) \
103 : "memory", "cc" \
104 ); \
105 _arg1; \
106 })
107
108 #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
109 ({ \
110 register long _num __asm__ ("x8") = (num); \
111 register long _arg1 __asm__ ("x0") = (long)(arg1); \
112 register long _arg2 __asm__ ("x1") = (long)(arg2); \
113 register long _arg3 __asm__ ("x2") = (long)(arg3); \
114 register long _arg4 __asm__ ("x3") = (long)(arg4); \
115 register long _arg5 __asm__ ("x4") = (long)(arg5); \
116 \
117 __asm__ volatile ( \
118 "svc #0\n" \
119 : "=r" (_arg1) \
120 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
121 "r"(_num) \
122 : "memory", "cc" \
123 ); \
124 _arg1; \
125 })
126
127 #define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
128 ({ \
129 register long _num __asm__ ("x8") = (num); \
130 register long _arg1 __asm__ ("x0") = (long)(arg1); \
131 register long _arg2 __asm__ ("x1") = (long)(arg2); \
132 register long _arg3 __asm__ ("x2") = (long)(arg3); \
133 register long _arg4 __asm__ ("x3") = (long)(arg4); \
134 register long _arg5 __asm__ ("x4") = (long)(arg5); \
135 register long _arg6 __asm__ ("x5") = (long)(arg6); \
136 \
137 __asm__ volatile ( \
138 "svc #0\n" \
139 : "=r" (_arg1) \
140 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
141 "r"(_arg6), "r"(_num) \
142 : "memory", "cc" \
143 ); \
144 _arg1; \
145 })
146
147 /* startup code */
_start(void)148 void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
149 {
150 __asm__ volatile (
151 "mov x0, sp\n" /* save stack pointer to x0, as arg1 of _start_c */
152 "and sp, x0, -16\n" /* sp must be 16-byte aligned in the callee */
153 "bl _start_c\n" /* transfer to c runtime */
154 );
155 __builtin_unreachable();
156 }
157 #endif /* _NOLIBC_ARCH_AARCH64_H */
158