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fb476dfb13
To allow testing of vfork() support in the arm64 basic-gcs test provide an implementation for nolibc, using the vfork() syscall if one is available and otherwise clone3(). We implement in terms of clone3() since the order of the arguments for clone() varies between architectures. As for fork() SPARC returns the parent PID rather than 0 in the child for vfork() so needs custom handling. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20250703-arm64-gcs-vfork-exit-v3-2-1e9a9d2ddbbe@kernel.org Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
207 lines
8.8 KiB
C
207 lines
8.8 KiB
C
/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
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/*
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* SPARC (32bit and 64bit) specific definitions for NOLIBC
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* Copyright (C) 2025 Thomas Weißschuh <linux@weissschuh.net>
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*/
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#ifndef _NOLIBC_ARCH_SPARC_H
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#define _NOLIBC_ARCH_SPARC_H
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#include <linux/unistd.h>
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#include "compiler.h"
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#include "crt.h"
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/*
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* Syscalls for SPARC:
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* - registers are native word size
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* - syscall number is passed in g1
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* - arguments are in o0-o5
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* - the system call is performed by calling a trap instruction
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* - syscall return value is in o0
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* - syscall error flag is in the carry bit of the processor status register
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*/
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#ifdef __arch64__
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#define _NOLIBC_SYSCALL "t 0x6d\n" \
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"bcs,a %%xcc, 1f\n" \
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"sub %%g0, %%o0, %%o0\n" \
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"1:\n"
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#else
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#define _NOLIBC_SYSCALL "t 0x10\n" \
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"bcs,a 1f\n" \
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"sub %%g0, %%o0, %%o0\n" \
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"1:\n"
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#endif /* __arch64__ */
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#define my_syscall0(num) \
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({ \
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register long _num __asm__ ("g1") = (num); \
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register long _arg1 __asm__ ("o0"); \
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\
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__asm__ volatile ( \
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_NOLIBC_SYSCALL \
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: "+r"(_arg1) \
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: "r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall1(num, arg1) \
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({ \
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register long _num __asm__ ("g1") = (num); \
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register long _arg1 __asm__ ("o0") = (long)(arg1); \
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\
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__asm__ volatile ( \
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_NOLIBC_SYSCALL \
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: "+r"(_arg1) \
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: "r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall2(num, arg1, arg2) \
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({ \
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register long _num __asm__ ("g1") = (num); \
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register long _arg1 __asm__ ("o0") = (long)(arg1); \
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register long _arg2 __asm__ ("o1") = (long)(arg2); \
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\
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__asm__ volatile ( \
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_NOLIBC_SYSCALL \
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: "+r"(_arg1) \
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: "r"(_arg2), "r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall3(num, arg1, arg2, arg3) \
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({ \
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register long _num __asm__ ("g1") = (num); \
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register long _arg1 __asm__ ("o0") = (long)(arg1); \
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register long _arg2 __asm__ ("o1") = (long)(arg2); \
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register long _arg3 __asm__ ("o2") = (long)(arg3); \
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\
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__asm__ volatile ( \
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_NOLIBC_SYSCALL \
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: "+r"(_arg1) \
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: "r"(_arg2), "r"(_arg3), "r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall4(num, arg1, arg2, arg3, arg4) \
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({ \
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register long _num __asm__ ("g1") = (num); \
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register long _arg1 __asm__ ("o0") = (long)(arg1); \
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register long _arg2 __asm__ ("o1") = (long)(arg2); \
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register long _arg3 __asm__ ("o2") = (long)(arg3); \
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register long _arg4 __asm__ ("o3") = (long)(arg4); \
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\
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__asm__ volatile ( \
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_NOLIBC_SYSCALL \
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: "+r"(_arg1) \
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: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
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({ \
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register long _num __asm__ ("g1") = (num); \
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register long _arg1 __asm__ ("o0") = (long)(arg1); \
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register long _arg2 __asm__ ("o1") = (long)(arg2); \
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register long _arg3 __asm__ ("o2") = (long)(arg3); \
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register long _arg4 __asm__ ("o3") = (long)(arg4); \
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register long _arg5 __asm__ ("o4") = (long)(arg5); \
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\
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__asm__ volatile ( \
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_NOLIBC_SYSCALL \
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: "+r"(_arg1) \
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: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
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({ \
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register long _num __asm__ ("g1") = (num); \
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register long _arg1 __asm__ ("o0") = (long)(arg1); \
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register long _arg2 __asm__ ("o1") = (long)(arg2); \
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register long _arg3 __asm__ ("o2") = (long)(arg3); \
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register long _arg4 __asm__ ("o3") = (long)(arg4); \
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register long _arg5 __asm__ ("o4") = (long)(arg5); \
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register long _arg6 __asm__ ("o5") = (long)(arg6); \
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\
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__asm__ volatile ( \
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_NOLIBC_SYSCALL \
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: "+r"(_arg1) \
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: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \
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"r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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/* startup code */
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void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
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{
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__asm__ volatile (
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/*
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* Save argc pointer to o0, as arg1 of _start_c.
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* Account for the window save area, which is 16 registers wide.
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*/
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#ifdef __arch64__
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"add %sp, 128 + 2047, %o0\n" /* on sparc64 / v9 the stack is offset by 2047 */
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#else
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"add %sp, 64, %o0\n"
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#endif
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"b,a _start_c\n" /* transfer to c runtime */
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);
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__nolibc_entrypoint_epilogue();
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}
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static pid_t getpid(void);
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static __attribute__((unused))
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pid_t sys_fork(void)
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{
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pid_t parent, ret;
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parent = getpid();
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ret = my_syscall0(__NR_fork);
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/* The syscall returns the parent pid in the child instead of 0 */
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if (ret == parent)
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return 0;
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else
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return ret;
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}
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#define sys_fork sys_fork
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static __attribute__((unused))
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pid_t sys_vfork(void)
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{
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pid_t parent, ret;
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parent = getpid();
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ret = my_syscall0(__NR_vfork);
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/* The syscall returns the parent pid in the child instead of 0 */
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if (ret == parent)
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return 0;
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else
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return ret;
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}
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#define sys_vfork sys_vfork
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#endif /* _NOLIBC_ARCH_SPARC_H */
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