glibc/sysdeps/unix/sysv/linux/arm/nptl/vfork.S

/* Copyright (C) 2005, 2010 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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <tcb-offsets.h>

/* Save the PID value.  */
#define SAVE_PID \
	str	lr, [sp, #-4]!;		/* Save LR.  */			\
	cfi_adjust_cfa_offset (4);					\
	cfi_rel_offset (lr, 0);						\
	mov	r0, #0xffff0fff;	/* Point to the high page.  */	\
	mov	lr, pc;			/* Save our return address.  */	\
	sub	pc, r0, #31;		/* Jump to the TLS entry.  */	\
	ldr	lr, [sp], #4;		/* Restore LR.  */		\
	cfi_adjust_cfa_offset (-4);					\
	cfi_restore (lr);						\
	mov	r2, r0;			/* Save the TLS addr in r2.  */	\
	ldr	r3, [r2, #PID_OFFSET];	/* Load the saved PID.  */	\
	rsbs	r0, r3, #0;		/* Negate it.  */		\
	moveq	r0, #0x80000000;	/* Use 0x80000000 if it was 0.  */ \
	str	r0, [r2, #PID_OFFSET]	/* Store the temporary PID.  */

/* Restore the old PID value in the parent.  */
#define RESTORE_PID \
	cmp	r0, #0;		/* If we are the parent... */		\
	strne	r3, [r2, #PID_OFFSET]	/* ... restore the saved PID.  */

#include "../vfork.S"