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/* The clone3 syscall wrapper. Linux/arc version.
Copyright (C) 2023-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#define _ERRNO_H 1
#include <bits/errno.h>
/* The userland implementation is:
int clone3 (struct clone_args *cl_args, size_t size,
int (*func)(void *arg), void *arg);
the kernel entry is:
int clone3 (struct clone_args *cl_args, size_t size);
The parameters are passed in registers from userland:
r0: cl_args
r1: size
r2: func
r3: arg */
ENTRY(__clone3)
/* Save args for the child. */
mov r10, r0 /* cl_args */
mov r11, r2 /* func */
mov r12, r3 /* args */
/* Sanity check args. */
breq r10, 0, L (__sys_err) /* No NULL cl_args pointer. */
breq r11, 0, L (__sys_err) /* No NULL function pointer. */
/* Do the system call, the kernel expects:
r8: system call number
r0: cl_args
r1: size */
mov r0, r10
mov r8, __NR_clone3
ARC_TRAP_INSN
cmp r0, 0
beq thread_start_clone3 /* Child returns. */
blt L (__sys_err2)
j [blink] /* Parent returns. */
L (__sys_err):
mov r0, -EINVAL
L (__sys_err2):
b __syscall_error
PSEUDO_END (__clone3)
.align 4
.type thread_start_clone3, %function
thread_start_clone3:
cfi_startproc
/* Terminate call stack by noting ra is undefined. */
cfi_undefined (blink)
/* Child jumps off to @fn with @arg as argument. */
jl.d [r11]
mov r0, r12
/* exit() with result from @fn (already in r0). */
mov r8, __NR_exit
ARC_TRAP_INSN
/* In case it ever came back. */
flag 1
cfi_endproc
.size thread_start_clone3, .-thread_start_clone3
libc_hidden_def (__clone3)
weak_alias (__clone3, clone3)
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