arch/sh/kernel/cpu/sh3/entry.S - linux - Git at Google

 /*
  * arch/sh/kernel/cpu/sh3/entry.S
  *
  *  Copyright (C) 1999, 2000, 2002  Niibe Yutaka
  *  Copyright (C) 2003 - 2006  Paul Mundt
  *
  * 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/sys.h>
 #include <linux/errno.h>
 #include <linux/linkage.h>
 #include <asm/asm-offsets.h>
 #include <asm/thread_info.h>
 #include <asm/cpu/mmu_context.h>
 #include <asm/unistd.h>

 ! NOTE:
 ! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address
 ! to be jumped is too far, but it causes illegal slot exception.

 /*
  * entry.S contains the system-call and fault low-level handling routines.
  * This also contains the timer-interrupt handler, as well as all interrupts
  * and faults that can result in a task-switch.
  *
  * NOTE: This code handles signal-recognition, which happens every time
  * after a timer-interrupt and after each system call.
  *
  * NOTE: This code uses a convention that instructions in the delay slot
  * of a transfer-control instruction are indented by an extra space, thus:
  *
  *    jmp	@k0	    ! control-transfer instruction
  *     ldc	k1, ssr     ! delay slot
  *
  * Stack layout in 'ret_from_syscall':
  * 	ptrace needs to have all regs on the stack.
  *	if the order here is changed, it needs to be
  *	updated in ptrace.c and ptrace.h
  *
  *	r0
  *      ...
  *	r15 = stack pointer
  *	spc
  *	pr
  *	ssr
  *	gbr
  *	mach
  *	macl
  *	syscall #
  *
  */
 #if defined(CONFIG_KGDB_NMI)
 NMI_VEC = 0x1c0			! Must catch early for debounce
 #endif

 /* 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+8)
 OFF_TRA	=  (16*4+6*4)


 #define k0	r0
 #define k1	r1
 #define k2	r2
 #define k3	r3
 #define k4	r4

 #define g_imask		r6	/* r6_bank1 */
 #define k_g_imask	r6_bank	/* r6_bank1 */
 #define current		r7	/* r7_bank1 */

 #include <asm/entry-macros.S>

 /*
  * Kernel mode register usage:
  *	k0	scratch
  *	k1	scratch
  *	k2	scratch (Exception code)
  *	k3	scratch (Return address)
  *	k4	scratch
  *	k5	reserved
  *	k6	Global Interrupt Mask (0--15 << 4)
  *	k7	CURRENT_THREAD_INFO (pointer to current thread info)
  */

 !
 ! TLB Miss / Initial Page write exception handling
 !			_and_
 ! TLB hits, but the access violate the protection.
 ! It can be valid access, such as stack grow and/or C-O-W.
 !
 !
 ! Find the pmd/pte entry and loadtlb
 ! If it's not found, cause address error (SEGV)
 !
 ! Although this could be written in assembly language (and it'd be faster),
 ! this first version depends *much* on C implementation.
 !

 #if defined(CONFIG_MMU)
 	.align	2
 ENTRY(tlb_miss_load)
 	bra	call_dpf
 	 mov	#0, r5

 	.align	2
 ENTRY(tlb_miss_store)
 	bra	call_dpf
 	 mov	#1, r5

 	.align	2
 ENTRY(initial_page_write)
 	bra	call_dpf
 	 mov	#1, r5

 	.align	2
 ENTRY(tlb_protection_violation_load)
 	bra	call_dpf
 	 mov	#0, r5

 	.align	2
 ENTRY(tlb_protection_violation_store)
 	bra	call_dpf
 	 mov	#1, r5

 call_dpf:
 	mov.l	1f, r0
 	mov	r5, r8
 	mov.l	@r0, r6
 	mov	r6, r9
 	mov.l	2f, r0
 	sts	pr, r10
 	jsr	@r0
 	 mov	r15, r4
 	!
 	tst	r0, r0
 	bf/s	0f
 	 lds	r10, pr
 	rts
 	 nop
 0:	mov.l	3f, r0
 	mov	r9, r6
 	mov	r8, r5
 	jmp	@r0
 	 mov	r15, r4

 	.align 2
 1:	.long	MMU_TEA
 2:	.long	__do_page_fault
 3:	.long	do_page_fault

 	.align	2
 ENTRY(address_error_load)
 	bra	call_dae
 	 mov	#0,r5		! writeaccess = 0

 	.align	2
 ENTRY(address_error_store)
 	bra	call_dae
 	 mov	#1,r5		! writeaccess = 1

 	.align	2
 call_dae:
 	mov.l	1f, r0
 	mov.l	@r0, r6		! address
 	mov.l	2f, r0
 	jmp	@r0
 	 mov	r15, r4		! regs

 	.align 2
 1:	.long	MMU_TEA
 2:	.long   do_address_error
 #endif /* CONFIG_MMU */

 #if defined(CONFIG_SH_STANDARD_BIOS)
 	/* Unwind the stack and jmp to the debug entry */
 ENTRY(sh_bios_handler)
 	mov.l	@r15+, r0
 	mov.l	@r15+, r1
 	mov.l	@r15+, r2
 	mov.l	@r15+, r3
 	mov.l	@r15+, r4
 	mov.l	@r15+, r5
 	mov.l	@r15+, r6
 	mov.l	@r15+, r7
 	stc	sr, r8
 	mov.l	1f, r9			! BL =1, RB=1, IMASK=0x0F
 	or	r9, r8
 	ldc	r8, sr			! here, change the register bank
 	mov.l	@r15+, r8
 	mov.l	@r15+, r9
 	mov.l	@r15+, r10
 	mov.l	@r15+, r11
 	mov.l	@r15+, r12
 	mov.l	@r15+, r13
 	mov.l	@r15+, r14
 	mov.l	@r15+, k0
 	ldc.l	@r15+, spc
 	lds.l	@r15+, pr
 	mov.l	@r15+, k1
 	ldc.l	@r15+, gbr
 	lds.l	@r15+, mach
 	lds.l	@r15+, macl
 	mov	k0, r15
 	!
 	mov.l	2f, k0
 	mov.l	@k0, k0
 	jmp	@k0
 	 ldc	k1, ssr
 	.align	2
 1:	.long	0x300000f0
 2:	.long	gdb_vbr_vector
 #endif /* CONFIG_SH_STANDARD_BIOS */

 restore_all:
 	mov.l	@r15+, r0
 	mov.l	@r15+, r1
 	mov.l	@r15+, r2
 	mov.l	@r15+, r3
 	mov.l	@r15+, r4
 	mov.l	@r15+, r5
 	mov.l	@r15+, r6
 	mov.l	@r15+, r7
 	!
 	stc	sr, r8
 	mov.l	7f, r9
 	or	r9, r8			! BL =1, RB=1
 	ldc	r8, sr			! here, change the register bank
 	!
 	mov.l	@r15+, r8
 	mov.l	@r15+, r9
 	mov.l	@r15+, r10
 	mov.l	@r15+, r11
 	mov.l	@r15+, r12
 	mov.l	@r15+, r13
 	mov.l	@r15+, r14
 	mov.l	@r15+, k4		! original stack pointer
 	ldc.l	@r15+, spc
 	lds.l	@r15+, pr
 	mov.l	@r15+, k3		! original SR
 	ldc.l	@r15+, gbr
 	lds.l	@r15+, mach
 	lds.l	@r15+, macl
 	add	#4, r15			! Skip syscall number
 	!
 #ifdef CONFIG_SH_DSP
 	mov.l	@r15+, k0		! DSP mode marker
 	mov.l	5f, k1
 	cmp/eq	k0, k1			! Do we have a DSP stack frame?
 	bf	skip_restore

 	stc	sr, k0			! Enable CPU DSP mode
 	or	k1, k0			! (within kernel it may be disabled)
 	ldc	k0, sr
 	mov	r2, k0			! Backup r2

 	! Restore DSP registers from stack
 	mov	r15, r2
 	movs.l	@r2+, a1
 	movs.l	@r2+, a0g
 	movs.l	@r2+, a1g
 	movs.l	@r2+, m0
 	movs.l	@r2+, m1
 	mov	r2, r15

 	lds.l	@r15+, a0
 	lds.l	@r15+, x0
 	lds.l	@r15+, x1
 	lds.l	@r15+, y0
 	lds.l	@r15+, y1
 	lds.l	@r15+, dsr
 	ldc.l	@r15+, rs
 	ldc.l	@r15+, re
 	ldc.l	@r15+, mod

 	mov	k0, r2			! Restore r2
 skip_restore:
 #endif
 	!
 	! Calculate new SR value
 	mov	k3, k2			! original SR value
 	mov	#0xf0, k1
 	extu.b	k1, k1
 	not	k1, k1
 	and	k1, k2			! Mask orignal SR value
 	!
 	mov	k3, k0			! Calculate IMASK-bits
 	shlr2	k0
 	and	#0x3c, k0
 	cmp/eq	#0x3c, k0
 	bt/s	6f
 	 shll2	k0
 	mov	g_imask, k0
 	!
 6:	or	k0, k2			! Set the IMASK-bits
 	ldc	k2, ssr
 	!
 #if defined(CONFIG_KGDB_NMI)
 	! Clear in_nmi
 	mov.l	6f, k0
 	mov	#0, k1
 	mov.b	k1, @k0
 #endif
 	mov.l	@r15+, k2		! restore EXPEVT
 	mov	k4, r15
 	rte
 	 nop

 	.align	2
 5:	.long	0x00001000	! DSP
 #ifdef CONFIG_KGDB_NMI
 6:	.long	in_nmi
 #endif
 7:	.long	0x30000000

 ! common exception handler
 #include "../../entry-common.S"

 ! Exception Vector Base
 !
 !	Should be aligned page boundary.
 !
 	.balign 	4096,0,4096
 ENTRY(vbr_base)
 	.long	0
 !
 	.balign 	256,0,256
 general_exception:
 	mov.l	1f, k2
 	mov.l	2f, k3
 #ifdef CONFIG_CPU_SUBTYPE_SHX3
 	mov.l	@k2, k2

 	! Is EXPEVT larger than 0x800?
 	mov	#0x8, k0
 	shll8	k0
 	cmp/hs	k0, k2
 	bf	0f

 	! then add 0x580 (k2 is 0xd80 or 0xda0)
 	mov	#0x58, k0
 	shll2	k0
 	shll2	k0
 	add	k0, k2
 0:
 	bra	handle_exception
 	 nop
 #else
 	bra	handle_exception
 	 mov.l	@k2, k2
 #endif
 	.align	2
 1:	.long	EXPEVT
 2:	.long	ret_from_exception
 !
 !

 	.balign 	1024,0,1024
 tlb_miss:
 	mov.l	1f, k2
 	mov.l	4f, k3
 	bra	handle_exception
 	 mov.l	@k2, k2
 !
 	.balign 	512,0,512
 interrupt:
 	mov.l	2f, k2
 	mov.l	3f, k3
 #if defined(CONFIG_KGDB_NMI)
 	! Debounce (filter nested NMI)
 	mov.l	@k2, k0
 	mov.l	5f, k1
 	cmp/eq	k1, k0
 	bf	0f
 	mov.l	6f, k1
 	tas.b	@k1
 	bt	0f
 	rte
 	 nop
 	.align	2
 5:	.long	NMI_VEC
 6:	.long	in_nmi
 0:
 #endif /* defined(CONFIG_KGDB_NMI) */
 	bra	handle_exception
 	 mov	#-1, k2		! interrupt exception marker

 	.align	2
 1:	.long	EXPEVT
 2:	.long	INTEVT
 3:	.long	ret_from_irq
 4:	.long	ret_from_exception

 !
 !
 	.align	2
 ENTRY(handle_exception)
 	! Using k0, k1 for scratch registers (r0_bank1, r1_bank),
 	! save all registers onto stack.
 	!
 	stc	ssr, k0		! Is it from kernel space?
 	shll	k0		! Check MD bit (bit30) by shifting it into...
 	shll	k0		!       ...the T bit
 	bt/s	1f		! It's a kernel to kernel transition.
 	 mov	r15, k0		! save original stack to k0
 	/* User space to kernel */
 	mov	#(THREAD_SIZE >> 10), k1
 	shll8	k1		! k1 := THREAD_SIZE
 	shll2	k1
 	add	current, k1
 	mov	k1, r15		! change to kernel stack
 	!
 1:	mov.l	2f, k1
 	!
 #ifdef CONFIG_SH_DSP
 	mov.l	r2, @-r15		! Save r2, we need another reg
 	stc	sr, k4
 	mov.l	1f, r2
 	tst	r2, k4			! Check if in DSP mode
 	mov.l	@r15+, r2		! Restore r2 now
 	bt/s	skip_save
 	 mov	#0, k4			! Set marker for no stack frame

 	mov	r2, k4			! Backup r2 (in k4) for later

 	! Save DSP registers on stack
 	stc.l	mod, @-r15
 	stc.l	re, @-r15
 	stc.l	rs, @-r15
 	sts.l	dsr, @-r15
 	sts.l	y1, @-r15
 	sts.l	y0, @-r15
 	sts.l	x1, @-r15
 	sts.l	x0, @-r15
 	sts.l	a0, @-r15

 	! GAS is broken, does not generate correct "movs.l Ds,@-As" instr.

 	! FIXME: Make sure that this is still the case with newer toolchains,
 	! as we're not at all interested in supporting ancient toolchains at
 	! this point. -- PFM.

 	mov	r15, r2
 	.word	0xf653			! movs.l	a1, @-r2
 	.word	0xf6f3			! movs.l	a0g, @-r2
 	.word	0xf6d3			! movs.l	a1g, @-r2
 	.word	0xf6c3			! movs.l	m0, @-r2
 	.word	0xf6e3			! movs.l	m1, @-r2
 	mov	r2, r15

 	mov	k4, r2			! Restore r2
 	mov.l	1f, k4			! Force DSP stack frame
 skip_save:
 	mov.l	k4, @-r15		! Push DSP mode marker onto stack
 #endif
 	! Save the user registers on the stack.
 	mov.l	k2, @-r15	! EXPEVT

 	mov	#-1, k4
 	mov.l	k4, @-r15	! set TRA (default: -1)
 	!
 	sts.l	macl, @-r15
 	sts.l	mach, @-r15
 	stc.l	gbr, @-r15
 	stc.l	ssr, @-r15
 	sts.l	pr, @-r15
 	stc.l	spc, @-r15
 	!
 	lds	k3, pr		! Set the return address to pr
 	!
 	mov.l	k0, @-r15	! save orignal stack
 	mov.l	r14, @-r15
 	mov.l	r13, @-r15
 	mov.l	r12, @-r15
 	mov.l	r11, @-r15
 	mov.l	r10, @-r15
 	mov.l	r9, @-r15
 	mov.l	r8, @-r15
 	!
 	stc	sr, r8		! Back to normal register bank, and
 	or	k1, r8		! Block all interrupts
 	mov.l	3f, k1
 	and	k1, r8		! ...
 	ldc	r8, sr		! ...changed here.
 	!
 	mov.l	r7, @-r15
 	mov.l	r6, @-r15
 	mov.l	r5, @-r15
 	mov.l	r4, @-r15
 	mov.l	r3, @-r15
 	mov.l	r2, @-r15
 	mov.l	r1, @-r15
 	mov.l	r0, @-r15

 	/*
 	 * This gets a bit tricky.. in the INTEVT case we don't want to use
 	 * the VBR offset as a destination in the jump call table, since all
 	 * of the destinations are the same. In this case, (interrupt) sets
 	 * a marker in r2 (now r2_bank since SR.RB changed), which we check
 	 * to determine the exception type. For all other exceptions, we
 	 * forcibly read EXPEVT from memory and fix up the jump address, in
 	 * the interrupt exception case we jump to do_IRQ() and defer the
 	 * INTEVT read until there. As a bonus, we can also clean up the SR.RB
 	 * checks that do_IRQ() was doing..
 	 */
 	stc	r2_bank, r8
 	cmp/pz	r8
 	bf	interrupt_exception
 	shlr2	r8
 	shlr	r8
 	mov.l	4f, r9
 	add	r8, r9
 	mov.l	@r9, r9
 	jmp	@r9
 	 nop
 	rts
 	 nop

 	.align	2
 1:	.long	0x00001000	! DSP=1
 2:	.long	0x000080f0	! FD=1, IMASK=15
 3:	.long	0xcfffffff	! RB=0, BL=0
 4:	.long	exception_handling_table

 interrupt_exception:
 	mov.l	1f, r9
 	mov.l	2f, r4
 	mov.l	@r4, r4
 	jmp	@r9
 	 mov	r15, r5
 	rts
 	 nop

 	.align 2
 1:	.long	do_IRQ
 2:	.long	INTEVT

 	.align	2
 ENTRY(exception_none)
 	rts
 	 nop
	/*
	* arch/sh/kernel/cpu/sh3/entry.S
	*
	* Copyright (C) 1999, 2000, 2002 Niibe Yutaka
	* Copyright (C) 2003 - 2006 Paul Mundt
	*
	* 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/sys.h>
	#include <linux/errno.h>
	#include <linux/linkage.h>
	#include <asm/asm-offsets.h>
	#include <asm/thread_info.h>
	#include <asm/cpu/mmu_context.h>
	#include <asm/unistd.h>

	! NOTE:
	! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address
	! to be jumped is too far, but it causes illegal slot exception.

	/*
	* entry.S contains the system-call and fault low-level handling routines.
	* This also contains the timer-interrupt handler, as well as all interrupts
	* and faults that can result in a task-switch.
	*
	* NOTE: This code handles signal-recognition, which happens every time
	* after a timer-interrupt and after each system call.
	*
	* NOTE: This code uses a convention that instructions in the delay slot
	* of a transfer-control instruction are indented by an extra space, thus:
	*
	* jmp @k0 ! control-transfer instruction
	* ldc k1, ssr ! delay slot
	*
	* Stack layout in 'ret_from_syscall':
	* ptrace needs to have all regs on the stack.
	* if the order here is changed, it needs to be
	* updated in ptrace.c and ptrace.h
	*
	* r0
	* ...
	* r15 = stack pointer
	* spc
	* pr
	* ssr
	* gbr
	* mach
	* macl
	* syscall #
	*
	*/
	#if defined(CONFIG_KGDB_NMI)
	NMI_VEC = 0x1c0 ! Must catch early for debounce
	#endif

	/* 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+8)
	OFF_TRA = (164+64)


	#define k0 r0
	#define k1 r1
	#define k2 r2
	#define k3 r3
	#define k4 r4

	#define g_imask r6 /* r6_bank1 */
	#define k_g_imask r6_bank /* r6_bank1 */
	#define current r7 /* r7_bank1 */

	#include <asm/entry-macros.S>

	/*
	* Kernel mode register usage:
	* k0 scratch
	* k1 scratch
	* k2 scratch (Exception code)
	* k3 scratch (Return address)
	* k4 scratch
	* k5 reserved
	* k6 Global Interrupt Mask (0--15 << 4)
	* k7 CURRENT_THREAD_INFO (pointer to current thread info)
	*/

	!
	! TLB Miss / Initial Page write exception handling
	! _and_
	! TLB hits, but the access violate the protection.
	! It can be valid access, such as stack grow and/or C-O-W.
	!
	!
	! Find the pmd/pte entry and loadtlb
	! If it's not found, cause address error (SEGV)
	!
	! Although this could be written in assembly language (and it'd be faster),
	! this first version depends much on C implementation.
	!

	#if defined(CONFIG_MMU)
	.align 2
	ENTRY(tlb_miss_load)
	bra call_dpf
	mov #0, r5

	.align 2
	ENTRY(tlb_miss_store)
	bra call_dpf
	mov #1, r5

	.align 2
	ENTRY(initial_page_write)
	bra call_dpf
	mov #1, r5

	.align 2
	ENTRY(tlb_protection_violation_load)
	bra call_dpf
	mov #0, r5

	.align 2
	ENTRY(tlb_protection_violation_store)
	bra call_dpf
	mov #1, r5

	call_dpf:
	mov.l 1f, r0
	mov r5, r8
	mov.l @r0, r6
	mov r6, r9
	mov.l 2f, r0
	sts pr, r10
	jsr @r0
	mov r15, r4
	!
	tst r0, r0
	bf/s 0f
	lds r10, pr
	rts
	nop
	0: mov.l 3f, r0
	mov r9, r6
	mov r8, r5
	jmp @r0
	mov r15, r4

	.align 2
	1: .long MMU_TEA
	2: .long __do_page_fault
	3: .long do_page_fault

	.align 2
	ENTRY(address_error_load)
	bra call_dae
	mov #0,r5 ! writeaccess = 0

	.align 2
	ENTRY(address_error_store)
	bra call_dae
	mov #1,r5 ! writeaccess = 1

	.align 2
	call_dae:
	mov.l 1f, r0
	mov.l @r0, r6 ! address
	mov.l 2f, r0
	jmp @r0
	mov r15, r4 ! regs

	.align 2
	1: .long MMU_TEA
	2: .long do_address_error
	#endif /* CONFIG_MMU */

	#if defined(CONFIG_SH_STANDARD_BIOS)
	/* Unwind the stack and jmp to the debug entry */
	ENTRY(sh_bios_handler)
	mov.l @r15+, r0
	mov.l @r15+, r1
	mov.l @r15+, r2
	mov.l @r15+, r3
	mov.l @r15+, r4
	mov.l @r15+, r5
	mov.l @r15+, r6
	mov.l @r15+, r7
	stc sr, r8
	mov.l 1f, r9 ! BL =1, RB=1, IMASK=0x0F
	or r9, r8
	ldc r8, sr ! here, change the register bank
	mov.l @r15+, r8
	mov.l @r15+, r9
	mov.l @r15+, r10
	mov.l @r15+, r11
	mov.l @r15+, r12
	mov.l @r15+, r13
	mov.l @r15+, r14
	mov.l @r15+, k0
	ldc.l @r15+, spc
	lds.l @r15+, pr
	mov.l @r15+, k1
	ldc.l @r15+, gbr
	lds.l @r15+, mach
	lds.l @r15+, macl
	mov k0, r15
	!
	mov.l 2f, k0
	mov.l @k0, k0
	jmp @k0
	ldc k1, ssr
	.align 2
	1: .long 0x300000f0
	2: .long gdb_vbr_vector
	#endif /* CONFIG_SH_STANDARD_BIOS */

	restore_all:
	mov.l @r15+, r0
	mov.l @r15+, r1
	mov.l @r15+, r2
	mov.l @r15+, r3
	mov.l @r15+, r4
	mov.l @r15+, r5
	mov.l @r15+, r6
	mov.l @r15+, r7
	!
	stc sr, r8
	mov.l 7f, r9
	or r9, r8 ! BL =1, RB=1
	ldc r8, sr ! here, change the register bank
	!
	mov.l @r15+, r8
	mov.l @r15+, r9
	mov.l @r15+, r10
	mov.l @r15+, r11
	mov.l @r15+, r12
	mov.l @r15+, r13
	mov.l @r15+, r14
	mov.l @r15+, k4 ! original stack pointer
	ldc.l @r15+, spc
	lds.l @r15+, pr
	mov.l @r15+, k3 ! original SR
	ldc.l @r15+, gbr
	lds.l @r15+, mach
	lds.l @r15+, macl
	add #4, r15 ! Skip syscall number
	!
	#ifdef CONFIG_SH_DSP
	mov.l @r15+, k0 ! DSP mode marker
	mov.l 5f, k1
	cmp/eq k0, k1 ! Do we have a DSP stack frame?
	bf skip_restore

	stc sr, k0 ! Enable CPU DSP mode
	or k1, k0 ! (within kernel it may be disabled)
	ldc k0, sr
	mov r2, k0 ! Backup r2

	! Restore DSP registers from stack
	mov r15, r2
	movs.l @r2+, a1
	movs.l @r2+, a0g
	movs.l @r2+, a1g
	movs.l @r2+, m0
	movs.l @r2+, m1
	mov r2, r15

	lds.l @r15+, a0
	lds.l @r15+, x0
	lds.l @r15+, x1
	lds.l @r15+, y0
	lds.l @r15+, y1
	lds.l @r15+, dsr
	ldc.l @r15+, rs
	ldc.l @r15+, re
	ldc.l @r15+, mod

	mov k0, r2 ! Restore r2
	skip_restore:
	#endif
	!
	! Calculate new SR value
	mov k3, k2 ! original SR value
	mov #0xf0, k1
	extu.b k1, k1
	not k1, k1
	and k1, k2 ! Mask orignal SR value
	!
	mov k3, k0 ! Calculate IMASK-bits
	shlr2 k0
	and #0x3c, k0
	cmp/eq #0x3c, k0
	bt/s 6f
	shll2 k0
	mov g_imask, k0
	!
	6: or k0, k2 ! Set the IMASK-bits
	ldc k2, ssr
	!
	#if defined(CONFIG_KGDB_NMI)
	! Clear in_nmi
	mov.l 6f, k0
	mov #0, k1
	mov.b k1, @k0
	#endif
	mov.l @r15+, k2 ! restore EXPEVT
	mov k4, r15
	rte
	nop

	.align 2
	5: .long 0x00001000 ! DSP
	#ifdef CONFIG_KGDB_NMI
	6: .long in_nmi
	#endif
	7: .long 0x30000000

	! common exception handler
	#include "../../entry-common.S"

	! Exception Vector Base
	!
	! Should be aligned page boundary.
	!
	.balign 4096,0,4096
	ENTRY(vbr_base)
	.long 0
	!
	.balign 256,0,256
	general_exception:
	mov.l 1f, k2
	mov.l 2f, k3
	#ifdef CONFIG_CPU_SUBTYPE_SHX3
	mov.l @k2, k2

	! Is EXPEVT larger than 0x800?
	mov #0x8, k0
	shll8 k0
	cmp/hs k0, k2
	bf 0f

	! then add 0x580 (k2 is 0xd80 or 0xda0)
	mov #0x58, k0
	shll2 k0
	shll2 k0
	add k0, k2
	0:
	bra handle_exception
	nop
	#else
	bra handle_exception
	mov.l @k2, k2
	#endif
	.align 2
	1: .long EXPEVT
	2: .long ret_from_exception
	!
	!

	.balign 1024,0,1024
	tlb_miss:
	mov.l 1f, k2
	mov.l 4f, k3
	bra handle_exception
	mov.l @k2, k2
	!
	.balign 512,0,512
	interrupt:
	mov.l 2f, k2
	mov.l 3f, k3
	#if defined(CONFIG_KGDB_NMI)
	! Debounce (filter nested NMI)
	mov.l @k2, k0
	mov.l 5f, k1
	cmp/eq k1, k0
	bf 0f
	mov.l 6f, k1
	tas.b @k1
	bt 0f
	rte
	nop
	.align 2
	5: .long NMI_VEC
	6: .long in_nmi
	0:
	#endif /* defined(CONFIG_KGDB_NMI) */
	bra handle_exception
	mov #-1, k2 ! interrupt exception marker

	.align 2
	1: .long EXPEVT
	2: .long INTEVT
	3: .long ret_from_irq
	4: .long ret_from_exception

	!
	!
	.align 2
	ENTRY(handle_exception)
	! Using k0, k1 for scratch registers (r0_bank1, r1_bank),
	! save all registers onto stack.
	!
	stc ssr, k0 ! Is it from kernel space?
	shll k0 ! Check MD bit (bit30) by shifting it into...
	shll k0 ! ...the T bit
	bt/s 1f ! It's a kernel to kernel transition.
	mov r15, k0 ! save original stack to k0
	/* User space to kernel */
	mov #(THREAD_SIZE >> 10), k1
	shll8 k1 ! k1 := THREAD_SIZE
	shll2 k1
	add current, k1
	mov k1, r15 ! change to kernel stack
	!
	1: mov.l 2f, k1
	!
	#ifdef CONFIG_SH_DSP
	mov.l r2, @-r15 ! Save r2, we need another reg
	stc sr, k4
	mov.l 1f, r2
	tst r2, k4 ! Check if in DSP mode
	mov.l @r15+, r2 ! Restore r2 now
	bt/s skip_save
	mov #0, k4 ! Set marker for no stack frame

	mov r2, k4 ! Backup r2 (in k4) for later

	! Save DSP registers on stack
	stc.l mod, @-r15
	stc.l re, @-r15
	stc.l rs, @-r15
	sts.l dsr, @-r15
	sts.l y1, @-r15
	sts.l y0, @-r15
	sts.l x1, @-r15
	sts.l x0, @-r15
	sts.l a0, @-r15

	! GAS is broken, does not generate correct "movs.l Ds,@-As" instr.

	! FIXME: Make sure that this is still the case with newer toolchains,
	! as we're not at all interested in supporting ancient toolchains at
	! this point. -- PFM.

	mov r15, r2
	.word 0xf653 ! movs.l a1, @-r2
	.word 0xf6f3 ! movs.l a0g, @-r2
	.word 0xf6d3 ! movs.l a1g, @-r2
	.word 0xf6c3 ! movs.l m0, @-r2
	.word 0xf6e3 ! movs.l m1, @-r2
	mov r2, r15

	mov k4, r2 ! Restore r2
	mov.l 1f, k4 ! Force DSP stack frame
	skip_save:
	mov.l k4, @-r15 ! Push DSP mode marker onto stack
	#endif
	! Save the user registers on the stack.
	mov.l k2, @-r15 ! EXPEVT

	mov #-1, k4
	mov.l k4, @-r15 ! set TRA (default: -1)
	!
	sts.l macl, @-r15
	sts.l mach, @-r15
	stc.l gbr, @-r15
	stc.l ssr, @-r15
	sts.l pr, @-r15
	stc.l spc, @-r15
	!
	lds k3, pr ! Set the return address to pr
	!
	mov.l k0, @-r15 ! save orignal stack
	mov.l r14, @-r15
	mov.l r13, @-r15
	mov.l r12, @-r15
	mov.l r11, @-r15
	mov.l r10, @-r15
	mov.l r9, @-r15
	mov.l r8, @-r15
	!
	stc sr, r8 ! Back to normal register bank, and
	or k1, r8 ! Block all interrupts
	mov.l 3f, k1
	and k1, r8 ! ...
	ldc r8, sr ! ...changed here.
	!
	mov.l r7, @-r15
	mov.l r6, @-r15
	mov.l r5, @-r15
	mov.l r4, @-r15
	mov.l r3, @-r15
	mov.l r2, @-r15
	mov.l r1, @-r15
	mov.l r0, @-r15

	/*
	* This gets a bit tricky.. in the INTEVT case we don't want to use
	* the VBR offset as a destination in the jump call table, since all
	* of the destinations are the same. In this case, (interrupt) sets
	* a marker in r2 (now r2_bank since SR.RB changed), which we check
	* to determine the exception type. For all other exceptions, we
	* forcibly read EXPEVT from memory and fix up the jump address, in
	* the interrupt exception case we jump to do_IRQ() and defer the
	* INTEVT read until there. As a bonus, we can also clean up the SR.RB
	* checks that do_IRQ() was doing..
	*/
	stc r2_bank, r8
	cmp/pz r8
	bf interrupt_exception
	shlr2 r8
	shlr r8
	mov.l 4f, r9
	add r8, r9
	mov.l @r9, r9
	jmp @r9
	nop
	rts
	nop

	.align 2
	1: .long 0x00001000 ! DSP=1
	2: .long 0x000080f0 ! FD=1, IMASK=15
	3: .long 0xcfffffff ! RB=0, BL=0
	4: .long exception_handling_table

	interrupt_exception:
	mov.l 1f, r9
	mov.l 2f, r4
	mov.l @r4, r4
	jmp @r9
	mov r15, r5
	rts
	nop

	.align 2
	1: .long do_IRQ
	2: .long INTEVT

	.align 2
	ENTRY(exception_none)
	rts
	nop