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glibc/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
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/* Wrapper around clone system call. PowerPC64 version. | |
Copyright (C) 1997-2016 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/>. */ | |
#include <sysdep.h> | |
#define _ERRNO_H 1 | |
#include <bits/errno.h> | |
#define CLONE_VM 0x00000100 | |
#define CLONE_THREAD 0x00010000 | |
/* This is the only really unusual system call in PPC linux, but not | |
because of any weirdness in the system call itself; because of | |
all the freaky stuff we have to do to make the call useful. */ | |
/* int [r3] clone(int (*fn)(void *arg) [r3], void *child_stack [r4], | |
int flags [r5], void *arg [r6], void *parent_tid [r7], | |
void *tls [r8], void *child_tid [r9]); */ | |
ENTRY (__clone) | |
CALL_MCOUNT 7 | |
/* Check for child_stack == NULL || fn == NULL. */ | |
cmpdi cr0,r4,0 | |
cmpdi cr1,r3,0 | |
cror cr0*4+eq,cr1*4+eq,cr0*4+eq | |
beq- cr0,L(badargs) | |
/* Save some regs in the "red zone". */ | |
std r29,-24(r1) | |
std r30,-16(r1) | |
std r31,-8(r1) | |
cfi_offset(r29,-24) | |
cfi_offset(r30,-16) | |
cfi_offset(r31,-8) | |
/* Set up stack frame for child. */ | |
clrrdi r4,r4,4 | |
li r0,0 | |
stdu r0,-FRAME_MIN_SIZE_PARM(r4) | |
/* Save fn, args, stack across syscall. */ | |
mr r30,r3 /* Function in r30. */ | |
mr r29,r5 /* Flags in r29. */ | |
mr r31,r6 /* Argument in r31. */ | |
/* 'flags' argument is first parameter to clone syscall. | |
Second is the stack pointer, already in r4. */ | |
mr r3,r5 | |
/* Move the parent_tid, child_tid and tls arguments. */ | |
mr r5,r7 | |
mr r6,r8 | |
mr r7,r9 | |
/* End FDE now, because in the child the unwind info will be | |
wrong. */ | |
cfi_endproc | |
/* Do the call. */ | |
DO_CALL(SYS_ify(clone)) | |
/* Check for child process. */ | |
cmpdi cr1,r3,0 | |
crandc cr1*4+eq,cr1*4+eq,cr0*4+so | |
bne- cr1,L(parent) /* The '-' is to minimise the race. */ | |
andis. r0,r29,CLONE_THREAD>>16 | |
bne+ cr0,L(oldpid) | |
andi. r0,r29,CLONE_VM | |
li r3,-1 | |
bne- cr0,L(nomoregetpid) | |
DO_CALL(SYS_ify(getpid)) | |
L(nomoregetpid): | |
stw r3,TID(r13) | |
stw r3,PID(r13) | |
L(oldpid): | |
std r2,FRAME_TOC_SAVE(r1) | |
/* Call procedure. */ | |
PPC64_LOAD_FUNCPTR r30 | |
mr r3,r31 | |
bctrl | |
ld r2,FRAME_TOC_SAVE(r1) | |
/* Call _exit with result from procedure. */ | |
#ifdef SHARED | |
b JUMPTARGET(__GI__exit) | |
#else | |
b JUMPTARGET(_exit) | |
/* We won't ever get here but provide a nop so that the linker | |
will insert a toc adjusting stub if necessary. */ | |
nop | |
#endif | |
L(badargs): | |
cfi_startproc | |
li r3,EINVAL | |
TAIL_CALL_SYSCALL_ERROR | |
L(parent): | |
/* Parent. Restore registers & return. */ | |
cfi_offset(r29,-24) | |
cfi_offset(r30,-16) | |
cfi_offset(r31,-8) | |
ld r29,-24(r1) | |
ld r30,-16(r1) | |
ld r31,-8(r1) | |
cfi_restore(r29) | |
cfi_restore(r30) | |
cfi_restore(r31) | |
PSEUDO_RET | |
END (__clone) | |
libc_hidden_def (__clone) | |
weak_alias (__clone, clone) |