glibc/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
Ulrich Weigand d31beafa8e PowerPC64 ELFv2 ABI 1/6: Code refactoring
This is the first patch to support the new ELFv2 ABI in glibc.

As preparation, this patch simply refactors some of the powerpc64 assembler
code to move all code related to creating function descriptors (.opd section)
or using function descriptors (function pointer call) into a central place
in sysdep.h.

Note that most locations creating .opd entries were already using macros
in sysdep.h, this patch simply extends this to the remaining places.

No relevant change in generated code expected.
2013-12-04 07:41:38 -06:00

143 lines
3.4 KiB
ArmAsm

/* Wrapper around clone system call. PowerPC64 version.
Copyright (C) 1997-2013 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 parm save area. */
#ifdef RESET_PID
std r29,48(r1)
#endif
std r30,56(r1)
std r31,64(r1)
#ifdef RESET_PID
cfi_offset(r29,48)
#endif
cfi_offset(r30,56)
cfi_offset(r31,64)
/* Set up stack frame for child. */
clrrdi r4,r4,4
li r0,0
stdu r0,-112(r4) /* min stack frame is 112 bytes per ABI */
/* Save fn, args, stack across syscall. */
mr r30,r3 /* Function in r30. */
#ifdef RESET_PID
mr r29,r5 /* Flags in r29. */
#endif
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. */
#ifdef RESET_PID
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):
#endif
std r2,40(r1)
/* Call procedure. */
PPC64_LOAD_FUNCPTR r30
mr r3,r31
bctrl
ld r2,40(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. */
#ifdef RESET_PID
cfi_offset(r29,48)
#endif
cfi_offset(r30,56)
cfi_offset(r31,64)
#ifdef RESET_PID
ld r29,48(r1)
#endif
ld r30,56(r1)
ld r31,64(r1)
#ifdef RESET_PID
cfi_restore(r29)
#endif
cfi_restore(r30)
cfi_restore(r31)
PSEUDO_RET
END (__clone)
weak_alias (__clone, clone)