arch/arm/lib/call_with_stack.S

   1 /*
   2  * arch/arm/lib/call_with_stack.S
   3  *
   4  * Copyright (C) 2011 ARM Ltd.
   5  * Written by Will Deacon <will.deacon@arm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19  */
  20
  21 #include <linux/linkage.h>
  22 #include <asm/assembler.h>
  23
  24 /*
  25  * void call_with_stack(void (*fn)(void *), void *arg, void *sp)
  26  *
  27  * Change the stack to that pointed at by sp, then invoke fn(arg) with
  28  * the new stack.
  29  */
  30 ENTRY(call_with_stack)
  31         str     sp, [r2, #-4]!
  32         str     lr, [r2, #-4]!
  33
  34         mov     sp, r2
  35         mov     r2, r0
  36         mov     r0, r1
  37
  38         adr     lr, BSYM(1f)
  39         mov     pc, r2
  40
  41 1:      ldr     lr, [sp]
  42         ldr     sp, [sp, #4]
  43         mov     pc, lr
  44 ENDPROC(call_with_stack)