/*
* arch/sh/kernel/cpu/sh2a/entry.S
*
* The SH-2A exception entry
*
* Copyright (C) 2008 Yoshinori Sato
* Based on arch/sh/kernel/cpu/sh2/entry.S
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/linkage.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <cpu/mmu_context.h>
#include <asm/unistd.h>
#include <asm/errno.h>
#include <asm/page.h>
/* Offsets to the stack */
OFF_R0 = 0 /* Return value. New ABI also arg4 */
OFF_R1 = 4 /* New ABI: arg5 */
OFF_R2 = 8 /* New ABI: arg6 */
OFF_R3 = 12 /* New ABI: syscall_nr */
OFF_R4 = 16 /* New ABI: arg0 */
OFF_R5 = 20 /* New ABI: arg1 */
OFF_R6 = 24 /* New ABI: arg2 */
OFF_R7 = 28 /* New ABI: arg3 */
OFF_SP = (15*4)
OFF_PC = (16*4)
OFF_SR = (16*4+2*4)
OFF_TRA = (16*4+6*4)
#include <asm/entry-macros.S>
ENTRY(exception_handler)
! stack
! r0 <- point sp
! r1
! pc
! sr
! r0 = temporary
! r1 = vector (pseudo EXPEVT / INTEVT / TRA)
mov.l r2,@-sp
cli
mov.l $cpu_mode,r2
bld.b #6,@(0,r2) !previus SR.MD
bst.b #6,@(4*4,r15) !set cpu mode to SR.MD
bt 1f
! switch to kernel mode
bset.b #6,@(0,r2) !set SR.MD
mov.l $current_thread_info,r2
mov.l @r2,r2
mov #(THREAD_SIZE >> 8),r0
shll8 r0
add r2,r0 ! r0 = kernel stack tail
mov r15,r2 ! r2 = user stack top
mov r0,r15 ! switch kernel stack
mov.l r1,@-r15 ! TRA
sts.l macl, @-r15
sts.l mach, @-r15
stc.l gbr, @-r15
mov.l @(4*4,r2),r0
mov.l r0,@-r15 ! original SR
sts.l pr,@-r15
mov.l @(3*4,r2),r0
mov.l r0,@-r15 ! original PC
mov r2,r0
add #(3+2)*4,r0 ! rewind r0 - r3 + exception frame
lds r0,pr ! pr = original SP
movmu.l r3,@-r15 ! save regs
mov r2,r8 ! r8 = previus stack top
mov r1,r9 ! r9 = interrupt vector
! restore previous stack
mov.l @r8+,r2
mov.l @r8+,r0
mov.l @r8+,r1
bra 2f
movml.l r2,@-r15
1:
! in kernel exception
mov r15,r2
add #-((OFF_TRA + 4) - OFF_PC) + 5*4,r15
movmu.l r3,@-r15
mov r2,r8 ! r8 = previous stack top
mov r1,r9 ! r9 = interrupt vector
! restore exception frame & regs
mov.l @r8+,r2 ! old R2
mov.l @r8+,r0 ! old R0
mov.l @r8+,r1 ! old R1
mov.l @r8+,r10 ! old PC
mov.l @r8+,r11 ! old SR
movml.l r2,@-r15
mov.l r10,@(OFF_PC,r15)
mov.l r11,@(OFF_SR,r15)
mov.l r8,@(OFF_SP,r15) ! save old sp
mov r15,r8
add #OFF_TRA + 4,r8
mov.l r9,@-r8
sts.l macl,@-r8
sts.l mach,@-r8
stc.l gbr,@-r8
add #-4,r8
sts.l pr,@-r8
2:
! dispatch exception / interrupt
mov #64,r8
cmp/hs r8,r9
bt interrupt_entry ! vec >= 64 is interrupt
mov #32,r8
cmp/hs r8,r9
bt trap_entry ! 64 > vec >= 32 is trap
mov.l 4f,r8
mov r9,r4
shll2 r9
add r9,r8
mov.l @r8,r8 ! exception handler address
tst r8,r8
bf 3f
mov.l 8f,r8 ! unhandled exception
3:
mov.l 5f,r10
jmp @r8
lds r10,pr
interrupt_entry:
mov r9,r4
mov r15,r5
mov.l 7f,r8
mov.l 6f,r9
jmp @r8
lds r9,pr
.align 2
4: .long exception_handling_table
5: .long ret_from_exception
6: .long ret_from_irq
7: .long do_IRQ
8: .long exception_error
trap_entry:
mov #0x30,r8
cmp/ge r8,r9 ! vector 0x20-0x2f is systemcall
bt 1f
add #-0x10,r9 ! convert SH2 to SH3/4 ABI
1:
shll2 r9 ! TRA
bra system_call ! jump common systemcall entry
mov r9,r8
#if defined(CONFIG_SH_STANDARD_BIOS)
/* Unwind the stack and jmp to the debug entry */
ENTRY(sh_bios_handler)
mov r15,r0
add #(22-4)*4-4,r0
ldc.l @r0+,gbr
lds.l @r0+,mach
lds.l @r0+,macl
mov r15,r0
mov.l @(OFF_SP,r0),r1
mov.l @(OFF_SR,r2),r3
mov.l r3,@-r1
mov.l @(OFF_SP,r2),r3
mov.l r3,@-r1
mov r15,r0
add #(22-4)*4-8,r0
mov.l 1f,r2
mov.l @r2,r2
stc sr,r3
mov.l r2,@r0
mov.l r3,@(4,r0)
mov.l r1,@(8,r0)
movml.l @r15+,r14
add #8,r15
lds.l @r15+, pr
rte
mov.l @r15+,r15
.align 2
1: .long gdb_vbr_vector
#endif /* CONFIG_SH_STANDARD_BIOS */
ENTRY(address_error_trap_handler)
mov r15,r4 ! regs
mov.l @(OFF_PC,r15),r6 ! pc
mov.l 1f,r0
jmp @r0
mov #0,r5 ! writeaccess is unknown
.align 2
1: .long do_address_error
restore_all:
stc sr,r0
or #0xf0,r0
ldc r0,sr ! all interrupt block (same BL = 1)
! restore special register
! overlap exception frame
mov r15,r0
add #17*4,r0
lds.l @r0+,pr
add #4,r0
ldc.l @r0+,gbr
lds.l @r0+,mach
lds.l @r0+,macl
mov r15,r0
mov.l $cpu_mode,r2
bld.b #6,@(OFF_SR,r15)
bst.b #6,@(0,r2) ! save CPU mode
mov.l @(OFF_SR,r0),r1
shll2 r1
shlr2 r1 ! clear MD bit
mov.l @(OFF_SP,r0),r2
add #-8,r2
mov.l r2,@(OFF_SP,r0) ! point exception frame top
mov.l r1,@(4,r2) ! set sr
mov.l @(OFF_PC,r0),r1
mov.l r1,@r2 ! set pc
get_current_thread_info r0, r1
mov.l $current_thread_info,r1
mov.l r0,@r1
movml.l @r15+,r14
mov.l @r15,r15
rte
nop
.align 2
$current_thread_info:
.long __current_thread_info
$cpu_mode:
.long __cpu_mode
! common exception handler
#include "../../entry-common.S"
.data
! cpu operation mode
! bit30 = MD (compatible SH3/4)
__cpu_mode:
.long 0x40000000
.section .bss
__current_thread_info:
.long 0
ENTRY(exception_handling_table)
.space 4*32
