arch/arm/kernel/fiqasm.S

   1 /*
   2  *  linux/arch/arm/kernel/fiqasm.S
   3  *
   4  *  Derived from code originally in linux/arch/arm/kernel/fiq.c:
   5  *
   6  *  Copyright (C) 1998 Russell King
   7  *  Copyright (C) 1998, 1999 Phil Blundell
   8  *  Copyright (C) 2011, Linaro Limited
   9  *
  10  *  FIQ support written by Philip Blundell <philb@gnu.org>, 1998.
  11  *
  12  *  FIQ support re-written by Russell King to be more generic
  13  *
  14  *  v7/Thumb-2 compatibility modifications by Linaro Limited, 2011.
  15  */
  16
  17 #include <linux/linkage.h>
  18 #include <asm/assembler.h>
  19
  20 /*
  21  * Taking an interrupt in FIQ mode is death, so both these functions
  22  * disable irqs for the duration.
  23  */
  24
  25 ENTRY(__set_fiq_regs)
  26         mov     r2, #PSR_I_BIT | PSR_F_BIT | FIQ_MODE
  27         mrs     r1, cpsr
  28         msr     cpsr_c, r2      @ select FIQ mode
  29         mov     r0, r0          @ avoid hazard prior to ARMv4
  30         ldmia   r0!, {r8 - r12}
  31         ldr     sp, [r0], #4
  32         ldr     lr, [r0]
  33         msr     cpsr_c, r1      @ return to SVC mode
  34         mov     r0, r0          @ avoid hazard prior to ARMv4
  35         ret     lr
  36 ENDPROC(__set_fiq_regs)
  37
  38 ENTRY(__get_fiq_regs)
  39         mov     r2, #PSR_I_BIT | PSR_F_BIT | FIQ_MODE
  40         mrs     r1, cpsr
  41         msr     cpsr_c, r2      @ select FIQ mode
  42         mov     r0, r0          @ avoid hazard prior to ARMv4
  43         stmia   r0!, {r8 - r12}
  44         str     sp, [r0], #4
  45         str     lr, [r0]
  46         msr     cpsr_c, r1      @ return to SVC mode
  47         mov     r0, r0          @ avoid hazard prior to ARMv4
  48         ret     lr
  49 ENDPROC(__get_fiq_regs)
  50
  51 ENTRY(__FIQ_Branch)
  52         mov pc, r8
  53 ENDPROC(__FIQ_Branch)