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30891f35fa
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>
167 lines
4.3 KiB
ArmAsm
167 lines
4.3 KiB
ArmAsm
/* Copyright (C) 1996-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<https://www.gnu.org/licenses/>. */
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/* clone() is even more special than fork() as it mucks with stacks
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and invokes a function in the right context after its all over. */
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#include <sysdep.h>
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#define _ERRNO_H 1
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#include <bits/errno.h>
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#include <tcb-offsets.h>
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/* Non-thread code calls __clone with the following parameters:
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int clone(int (*fn)(void *arg),
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void *child_stack,
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int flags,
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void *arg)
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NPTL Code will call __clone with the following parameters:
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int clone(int (*fn)(void *arg),
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void *child_stack,
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int flags,
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void *arg,
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int *parent_tidptr,
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struct user_desc *newtls,
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int *child_pidptr)
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The code should not mangle the extra input registers.
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Syscall expects: Input to __clone:
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4(r25) - function pointer (r26, arg0)
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0(r25) - argument (r23, arg3)
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r26 - clone flags. (r24, arg2)
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r25+64 - user stack pointer. (r25, arg1)
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r24 - parent tid pointer. (stack - 52)
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r23 - struct user_desc newtls pointer. (stack - 56)
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r22 - child tid pointer. (stack - 60)
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r20 - clone syscall number (constant)
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Return:
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On success the thread ID of the child process is returend in
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the callers context.
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On error return -1, and set errno to the value returned by
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the syscall.
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*/
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.text
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ENTRY(__clone)
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/* Prologue */
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stwm %r4, 64(%sp)
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.cfi_def_cfa_offset -64
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.cfi_offset 4, 0
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stw %sp, -4(%sp)
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#ifdef PIC
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stw %r19, -32(%sp)
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.cfi_offset 19, 32
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#endif
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/* Sanity check arguments. */
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comib,=,n 0,%arg0,.LerrorSanity /* no NULL function pointers */
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comib,=,n 0,%arg1,.LerrorSanity /* no NULL stack pointers */
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/* Ensure stack argument is 8-byte aligned. */
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ldo 7(%r25),%r25
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depi 0,31,3,%r25
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/* Save the function pointer, arg, and flags on the new stack. */
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stwm %r26, 64(%r25)
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stw %r23, -60(%r25)
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stw %r24, -56(%r25)
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/* Clone arguments are (int flags, void * child_stack) */
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copy %r24, %r26 /* flags are first */
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/* User stack pointer is in the correct register already */
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/* Load args from stack... */
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ldw -116(%sp), %r24 /* Load parent_tidptr */
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ldw -120(%sp), %r23 /* Load newtls */
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ldw -124(%sp), %r22 /* Load child_tidptr */
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/* Save the PIC register. */
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#ifdef PIC
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copy %r19, %r4 /* parent */
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#endif
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/* Do the system call */
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ble 0x100(%sr2, %r0)
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ldi __NR_clone, %r20
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ldi -4096, %r1
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comclr,>>= %r1, %ret0, %r0 /* Note: unsigned compare. */
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b,n .LerrorRest
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/* Restore the PIC register. */
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#ifdef PIC
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copy %r4, %r19 /* parent */
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#endif
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comib,=,n 0, %ret0, .LthreadStart
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/* Successful return from the parent
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No need to restore the PIC register,
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since we return immediately. */
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ldw -84(%sp), %rp
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bv %r0(%rp)
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ldwm -64(%sp), %r4
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.LerrorRest:
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/* Something bad happened -- no child created */
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bl __syscall_error, %rp
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sub %r0, %ret0, %arg0
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ldw -84(%sp), %rp
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/* Return after setting errno, ret0 is set to -1 by __syscall_error. */
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bv %r0(%rp)
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ldwm -64(%sp), %r4
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.LerrorSanity:
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/* Sanity checks failed, return -1, and set errno to EINVAL. */
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bl __syscall_error, %rp
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ldi EINVAL, %arg0
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ldw -84(%sp), %rp
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bv %r0(%rp)
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ldwm -64(%sp), %r4
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.LthreadStart:
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/* Load up the arguments. */
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ldw -60(%sp), %arg0
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ldw -64(%sp), %r22
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/* $$dyncall fixes child's PIC register */
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/* Call the user's function */
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#ifdef PIC
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copy %r19, %r4
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#endif
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bl $$dyncall, %r31
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copy %r31, %rp
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#ifdef PIC
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copy %r4, %r19
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#endif
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copy %r28, %r26
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ble 0x100(%sr2, %r0)
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ldi __NR_exit, %r20
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/* We should not return from exit.
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We do not restore r4, or the stack state. */
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iitlbp %r0, (%sr0, %r0)
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PSEUDO_END(__clone)
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libc_hidden_def (__clone)
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weak_alias (__clone, clone)
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