1271661c1SWilly Tarreau /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
2271661c1SWilly Tarreau /*
3271661c1SWilly Tarreau * MIPS specific definitions for NOLIBC
4271661c1SWilly Tarreau * Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu>
5271661c1SWilly Tarreau */
6271661c1SWilly Tarreau
7271661c1SWilly Tarreau #ifndef _NOLIBC_ARCH_MIPS_H
8271661c1SWilly Tarreau #define _NOLIBC_ARCH_MIPS_H
9271661c1SWilly Tarreau
10818924d1SThomas Weißschuh #include "compiler.h"
11*431b806bSZhangjin Wu #include "crt.h"
12818924d1SThomas Weißschuh
13271661c1SWilly Tarreau /* Syscalls for MIPS ABI O32 :
14271661c1SWilly Tarreau * - WARNING! there's always a delayed slot!
15271661c1SWilly Tarreau * - WARNING again, the syntax is different, registers take a '$' and numbers
16271661c1SWilly Tarreau * do not.
17271661c1SWilly Tarreau * - registers are 32-bit
18271661c1SWilly Tarreau * - stack is 8-byte aligned
19271661c1SWilly Tarreau * - syscall number is passed in v0 (starts at 0xfa0).
20271661c1SWilly Tarreau * - arguments are in a0, a1, a2, a3, then the stack. The caller needs to
21271661c1SWilly Tarreau * leave some room in the stack for the callee to save a0..a3 if needed.
22271661c1SWilly Tarreau * - Many registers are clobbered, in fact only a0..a2 and s0..s8 are
23271661c1SWilly Tarreau * preserved. See: https://www.linux-mips.org/wiki/Syscall as well as
24271661c1SWilly Tarreau * scall32-o32.S in the kernel sources.
25271661c1SWilly Tarreau * - the system call is performed by calling "syscall"
26271661c1SWilly Tarreau * - syscall return comes in v0, and register a3 needs to be checked to know
27271661c1SWilly Tarreau * if an error occurred, in which case errno is in v0.
28271661c1SWilly Tarreau * - the arguments are cast to long and assigned into the target registers
29271661c1SWilly Tarreau * which are then simply passed as registers to the asm code, so that we
30271661c1SWilly Tarreau * don't have to experience issues with register constraints.
31271661c1SWilly Tarreau */
32271661c1SWilly Tarreau
338b9bdab6SZhangjin Wu #define _NOLIBC_SYSCALL_CLOBBERLIST \
348b9bdab6SZhangjin Wu "memory", "cc", "at", "v1", "hi", "lo", \
358b9bdab6SZhangjin Wu "t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9"
368b9bdab6SZhangjin Wu
37271661c1SWilly Tarreau #define my_syscall0(num) \
38271661c1SWilly Tarreau ({ \
3937d62758SAmmar Faizi register long _num __asm__ ("v0") = (num); \
4037d62758SAmmar Faizi register long _arg4 __asm__ ("a3"); \
41271661c1SWilly Tarreau \
4237d62758SAmmar Faizi __asm__ volatile ( \
43271661c1SWilly Tarreau "addiu $sp, $sp, -32\n" \
44271661c1SWilly Tarreau "syscall\n" \
45271661c1SWilly Tarreau "addiu $sp, $sp, 32\n" \
46271661c1SWilly Tarreau : "=r"(_num), "=r"(_arg4) \
47271661c1SWilly Tarreau : "r"(_num) \
488b9bdab6SZhangjin Wu : _NOLIBC_SYSCALL_CLOBBERLIST \
49271661c1SWilly Tarreau ); \
50271661c1SWilly Tarreau _arg4 ? -_num : _num; \
51271661c1SWilly Tarreau })
52271661c1SWilly Tarreau
53271661c1SWilly Tarreau #define my_syscall1(num, arg1) \
54271661c1SWilly Tarreau ({ \
5537d62758SAmmar Faizi register long _num __asm__ ("v0") = (num); \
5637d62758SAmmar Faizi register long _arg1 __asm__ ("a0") = (long)(arg1); \
5737d62758SAmmar Faizi register long _arg4 __asm__ ("a3"); \
58271661c1SWilly Tarreau \
5937d62758SAmmar Faizi __asm__ volatile ( \
60271661c1SWilly Tarreau "addiu $sp, $sp, -32\n" \
61271661c1SWilly Tarreau "syscall\n" \
62271661c1SWilly Tarreau "addiu $sp, $sp, 32\n" \
63271661c1SWilly Tarreau : "=r"(_num), "=r"(_arg4) \
64271661c1SWilly Tarreau : "0"(_num), \
65271661c1SWilly Tarreau "r"(_arg1) \
668b9bdab6SZhangjin Wu : _NOLIBC_SYSCALL_CLOBBERLIST \
67271661c1SWilly Tarreau ); \
68271661c1SWilly Tarreau _arg4 ? -_num : _num; \
69271661c1SWilly Tarreau })
70271661c1SWilly Tarreau
71271661c1SWilly Tarreau #define my_syscall2(num, arg1, arg2) \
72271661c1SWilly Tarreau ({ \
7337d62758SAmmar Faizi register long _num __asm__ ("v0") = (num); \
7437d62758SAmmar Faizi register long _arg1 __asm__ ("a0") = (long)(arg1); \
7537d62758SAmmar Faizi register long _arg2 __asm__ ("a1") = (long)(arg2); \
7637d62758SAmmar Faizi register long _arg4 __asm__ ("a3"); \
77271661c1SWilly Tarreau \
7837d62758SAmmar Faizi __asm__ volatile ( \
79271661c1SWilly Tarreau "addiu $sp, $sp, -32\n" \
80271661c1SWilly Tarreau "syscall\n" \
81271661c1SWilly Tarreau "addiu $sp, $sp, 32\n" \
82271661c1SWilly Tarreau : "=r"(_num), "=r"(_arg4) \
83271661c1SWilly Tarreau : "0"(_num), \
84271661c1SWilly Tarreau "r"(_arg1), "r"(_arg2) \
858b9bdab6SZhangjin Wu : _NOLIBC_SYSCALL_CLOBBERLIST \
86271661c1SWilly Tarreau ); \
87271661c1SWilly Tarreau _arg4 ? -_num : _num; \
88271661c1SWilly Tarreau })
89271661c1SWilly Tarreau
90271661c1SWilly Tarreau #define my_syscall3(num, arg1, arg2, arg3) \
91271661c1SWilly Tarreau ({ \
9237d62758SAmmar Faizi register long _num __asm__ ("v0") = (num); \
9337d62758SAmmar Faizi register long _arg1 __asm__ ("a0") = (long)(arg1); \
9437d62758SAmmar Faizi register long _arg2 __asm__ ("a1") = (long)(arg2); \
9537d62758SAmmar Faizi register long _arg3 __asm__ ("a2") = (long)(arg3); \
9637d62758SAmmar Faizi register long _arg4 __asm__ ("a3"); \
97271661c1SWilly Tarreau \
9837d62758SAmmar Faizi __asm__ volatile ( \
99271661c1SWilly Tarreau "addiu $sp, $sp, -32\n" \
100271661c1SWilly Tarreau "syscall\n" \
101271661c1SWilly Tarreau "addiu $sp, $sp, 32\n" \
102271661c1SWilly Tarreau : "=r"(_num), "=r"(_arg4) \
103271661c1SWilly Tarreau : "0"(_num), \
104271661c1SWilly Tarreau "r"(_arg1), "r"(_arg2), "r"(_arg3) \
1058b9bdab6SZhangjin Wu : _NOLIBC_SYSCALL_CLOBBERLIST \
106271661c1SWilly Tarreau ); \
107271661c1SWilly Tarreau _arg4 ? -_num : _num; \
108271661c1SWilly Tarreau })
109271661c1SWilly Tarreau
110271661c1SWilly Tarreau #define my_syscall4(num, arg1, arg2, arg3, arg4) \
111271661c1SWilly Tarreau ({ \
11237d62758SAmmar Faizi register long _num __asm__ ("v0") = (num); \
11337d62758SAmmar Faizi register long _arg1 __asm__ ("a0") = (long)(arg1); \
11437d62758SAmmar Faizi register long _arg2 __asm__ ("a1") = (long)(arg2); \
11537d62758SAmmar Faizi register long _arg3 __asm__ ("a2") = (long)(arg3); \
11637d62758SAmmar Faizi register long _arg4 __asm__ ("a3") = (long)(arg4); \
117271661c1SWilly Tarreau \
11837d62758SAmmar Faizi __asm__ volatile ( \
119271661c1SWilly Tarreau "addiu $sp, $sp, -32\n" \
120271661c1SWilly Tarreau "syscall\n" \
121271661c1SWilly Tarreau "addiu $sp, $sp, 32\n" \
122271661c1SWilly Tarreau : "=r" (_num), "=r"(_arg4) \
123271661c1SWilly Tarreau : "0"(_num), \
124271661c1SWilly Tarreau "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4) \
1258b9bdab6SZhangjin Wu : _NOLIBC_SYSCALL_CLOBBERLIST \
126271661c1SWilly Tarreau ); \
127271661c1SWilly Tarreau _arg4 ? -_num : _num; \
128271661c1SWilly Tarreau })
129271661c1SWilly Tarreau
130271661c1SWilly Tarreau #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
131271661c1SWilly Tarreau ({ \
13237d62758SAmmar Faizi register long _num __asm__ ("v0") = (num); \
13337d62758SAmmar Faizi register long _arg1 __asm__ ("a0") = (long)(arg1); \
13437d62758SAmmar Faizi register long _arg2 __asm__ ("a1") = (long)(arg2); \
13537d62758SAmmar Faizi register long _arg3 __asm__ ("a2") = (long)(arg3); \
13637d62758SAmmar Faizi register long _arg4 __asm__ ("a3") = (long)(arg4); \
137271661c1SWilly Tarreau register long _arg5 = (long)(arg5); \
138271661c1SWilly Tarreau \
13937d62758SAmmar Faizi __asm__ volatile ( \
140271661c1SWilly Tarreau "addiu $sp, $sp, -32\n" \
141271661c1SWilly Tarreau "sw %7, 16($sp)\n" \
142271661c1SWilly Tarreau "syscall\n" \
143271661c1SWilly Tarreau "addiu $sp, $sp, 32\n" \
144271661c1SWilly Tarreau : "=r" (_num), "=r"(_arg4) \
145271661c1SWilly Tarreau : "0"(_num), \
146271661c1SWilly Tarreau "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5) \
1476d1970e1SZhangjin Wu : _NOLIBC_SYSCALL_CLOBBERLIST \
1486d1970e1SZhangjin Wu ); \
1496d1970e1SZhangjin Wu _arg4 ? -_num : _num; \
1506d1970e1SZhangjin Wu })
1516d1970e1SZhangjin Wu
1526d1970e1SZhangjin Wu #define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
1536d1970e1SZhangjin Wu ({ \
1546d1970e1SZhangjin Wu register long _num __asm__ ("v0") = (num); \
1556d1970e1SZhangjin Wu register long _arg1 __asm__ ("a0") = (long)(arg1); \
1566d1970e1SZhangjin Wu register long _arg2 __asm__ ("a1") = (long)(arg2); \
1576d1970e1SZhangjin Wu register long _arg3 __asm__ ("a2") = (long)(arg3); \
1586d1970e1SZhangjin Wu register long _arg4 __asm__ ("a3") = (long)(arg4); \
1596d1970e1SZhangjin Wu register long _arg5 = (long)(arg5); \
1606d1970e1SZhangjin Wu register long _arg6 = (long)(arg6); \
1616d1970e1SZhangjin Wu \
1626d1970e1SZhangjin Wu __asm__ volatile ( \
1636d1970e1SZhangjin Wu "addiu $sp, $sp, -32\n" \
1646d1970e1SZhangjin Wu "sw %7, 16($sp)\n" \
1656d1970e1SZhangjin Wu "sw %8, 20($sp)\n" \
1666d1970e1SZhangjin Wu "syscall\n" \
1676d1970e1SZhangjin Wu "addiu $sp, $sp, 32\n" \
1686d1970e1SZhangjin Wu : "=r" (_num), "=r"(_arg4) \
1696d1970e1SZhangjin Wu : "0"(_num), \
1706d1970e1SZhangjin Wu "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
1716d1970e1SZhangjin Wu "r"(_arg6) \
1728b9bdab6SZhangjin Wu : _NOLIBC_SYSCALL_CLOBBERLIST \
173271661c1SWilly Tarreau ); \
174271661c1SWilly Tarreau _arg4 ? -_num : _num; \
175271661c1SWilly Tarreau })
176271661c1SWilly Tarreau
177271661c1SWilly Tarreau /* startup code, note that it's called __start on MIPS */
__start(void)178bff60150SZhangjin Wu void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector __start(void)
1797f854858SWilly Tarreau {
1807f854858SWilly Tarreau __asm__ volatile (
181184177c3SWilly Tarreau ".set push\n"
182271661c1SWilly Tarreau ".set noreorder\n"
183271661c1SWilly Tarreau ".option pic0\n"
184*431b806bSZhangjin Wu "move $a0, $sp\n" /* save stack pointer to $a0, as arg1 of _start_c */
185271661c1SWilly Tarreau "li $t0, -8\n"
186*431b806bSZhangjin Wu "and $sp, $sp, $t0\n" /* $sp must be 8-byte aligned */
187*431b806bSZhangjin Wu "addiu $sp, $sp, -16\n" /* the callee expects to save a0..a3 there */
188*431b806bSZhangjin Wu "jal _start_c\n" /* transfer to c runtime */
189fddc8f81SThomas Weißschuh " nop\n" /* delayed slot */
190184177c3SWilly Tarreau ".set pop\n"
1917f854858SWilly Tarreau );
1927f854858SWilly Tarreau __builtin_unreachable();
1937f854858SWilly Tarreau }
194271661c1SWilly Tarreau
195fddc8f81SThomas Weißschuh #endif /* _NOLIBC_ARCH_MIPS_H */
196