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glibc/sysdeps/unix/sysv/linux/sh/clone.S
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/* Copyright (C) 1999-2016 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 | |
<http://www.gnu.org/licenses/>. */ | |
/* clone() is even more special than fork() as it mucks with stacks | |
and invokes a function in the right context after its all over. */ | |
#include <sysdep.h> | |
#define _ERRNO_H 1 | |
#include <bits/errno.h> | |
#include <tcb-offsets.h> | |
/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, | |
pid_t *ptid, void *tls, pid_t *ctid); */ | |
.text | |
ENTRY(__clone) | |
/* sanity check arguments. */ | |
tst r4, r4 | |
bt/s 0f | |
tst r5, r5 | |
bf 1f | |
0: | |
bra .Lsyscall_error | |
mov #-EINVAL,r0 | |
1: | |
/* insert the args onto the new stack */ | |
mov.l r7, @-r5 | |
/* save the function pointer as the 0th element */ | |
mov.l r4, @-r5 | |
/* do the system call */ | |
mov r6, r4 | |
mov.l @r15, r6 | |
mov.l @(8,r15), r7 | |
mov.l @(4,r15), r0 | |
mov #+SYS_ify(clone), r3 | |
trapa #0x15 | |
mov r0, r1 | |
mov #-12, r2 | |
shad r2, r1 | |
not r1, r1 // r1=0 means r0 = -1 to -4095 | |
tst r1, r1 // i.e. error in linux | |
bf .Lclone_end | |
.Lsyscall_error: | |
SYSCALL_ERROR_HANDLER | |
.Lclone_end: | |
tst r0, r0 | |
bt 2f | |
.Lpseudo_end: | |
rts | |
nop | |
2: | |
/* terminate the stack frame */ | |
mov #0, r14 | |
mov r4, r0 | |
shlr16 r0 | |
tst #1, r0 // CLONE_THREAD = (1 << 16) | |
bf/s 4f | |
mov r4, r0 | |
/* new pid */ | |
shlr8 r0 | |
tst #1, r0 // CLONE_VM = (1 << 8) | |
bf/s 3f | |
mov #-1, r0 | |
mov #+SYS_ify(getpid), r3 | |
trapa #0x15 | |
3: | |
stc gbr, r1 | |
mov.w .Lpidoff, r2 | |
add r1, r2 | |
mov.l r0, @r2 | |
mov.w .Ltidoff, r2 | |
add r1, r2 | |
mov.l r0, @r2 | |
4: | |
/* thread starts */ | |
mov.l @r15, r1 | |
jsr @r1 | |
mov.l @(4,r15), r4 | |
/* we are done, passing the return value through r0 */ | |
mov.l .L3, r1 | |
#ifdef SHARED | |
mov.l r12, @-r15 | |
sts.l pr, @-r15 | |
mov r0, r4 | |
mova .LG, r0 | |
mov.l .LG, r12 | |
add r0, r12 | |
mova .L3, r0 | |
add r0, r1 | |
jsr @r1 | |
nop | |
lds.l @r15+, pr | |
rts | |
mov.l @r15+, r12 | |
#else | |
jmp @r1 | |
mov r0, r4 | |
#endif | |
.align 2 | |
.LG: | |
.long _GLOBAL_OFFSET_TABLE_ | |
.L3: | |
.long PLTJMP(C_SYMBOL_NAME(_exit)) | |
.Lpidoff: | |
.word PID - TLS_PRE_TCB_SIZE | |
.Ltidoff: | |
.word TID - TLS_PRE_TCB_SIZE | |
PSEUDO_END (__clone) | |
libc_hidden_def (__clone) | |
weak_alias (__clone, clone) |