glibc/sysdeps/unix/sysv/linux/arc/clone.S
Siddhesh Poyarekar 30891f35fa Remove "Contributed by" lines
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date.  Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.

Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions.  These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.

The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively.  These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:

https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc
https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-09-03 22:06:44 +05:30

93 lines
3.0 KiB
ArmAsm

/* clone() implementation for ARC.
Copyright (C) 2020-2021 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>
#include <tcb-offsets.h>
#define CLONE_SETTLS 0x00080000
/* int clone(int (*fn)(void *), void *child_stack,
int flags, void *arg, ...
< pid_t *ptid, struct user_desc *tls, pid_t *ctid > );
NOTE: I'm assuming that the last 3 args are NOT var-args and in case all
3 are not relevant, caller will nevertheless pass those as NULL.
clone syscall in kernel (ABI: CONFIG_CLONE_BACKWARDS)
int sys_clone(unsigned long int clone_flags,
unsigned long int newsp,
int __user *parent_tidptr,
void *tls,
int __user *child_tidptr). */
ENTRY (__clone)
cmp r0, 0 /* @fn can't be NULL. */
cmp.ne r1, 0 /* @child_stack can't be NULL. */
bz L (__sys_err)
/* save some of the orig args
r0 containg @fn will be clobbered AFTER syscall (with ret val)
rest are clobbered BEFORE syscall due to different arg ordering. */
mov r10, r0 /* @fn. */
mov r11, r3 /* @args. */
mov r12, r2 /* @clone_flags. */
mov r9, r5 /* @tls. */
/* adjust libc args for syscall. */
mov r0, r2 /* libc @flags is 1st syscall arg. */
mov r2, r4 /* libc @ptid. */
mov r3, r5 /* libc @tls. */
mov r4, r6 /* libc @ctid. */
mov r8, __NR_clone
ARC_TRAP_INSN
cmp r0, 0 /* return code : 0 new process, !0 parent. */
blt L (__sys_err2) /* < 0 (signed) error. */
jnz [blink] /* Parent returns. */
/* child jumps off to @fn with @arg as argument
TP register already set by kernel. */
jl.d [r10]
mov r0, r11
/* exit() with result from @fn (already in r0). */
mov r8, __NR_exit
ARC_TRAP_INSN
/* In case it ever came back. */
flag 1
L (__sys_err):
mov r0, -EINVAL
L (__sys_err2):
/* (1) No need to make -ve kernel error code as positive errno
__syscall_error expects the -ve error code returned by kernel
(2) r0 still had orig -ve kernel error code
(3) Tail call to __syscall_error so we dont have to come back
here hence instead of jmp-n-link (reg push/pop) we do jmp
(4) No need to route __syscall_error via PLT, B is inherently
position independent. */
b __syscall_error
PSEUDO_END (__clone)
libc_hidden_def (__clone)
weak_alias (__clone, clone)