Commit 1d015cf0 authored by Magnus Damm's avatar Magnus Damm Committed by Paul Mundt
Browse files

sh: shared register saving code for sh3/sh4/sh4a 



This patch reworks the sh3/sh4/sh4a register saving code in
the following ways:
 - break out prepare_stack_save_dsp() from handle_exception()
 - break out save_regs() from handle_exception()
 - the register saving order is unchanged
 - align new functions to fit in cache lines
 - separate exception code from interrupt code
 - keep main code flow in a single cache line per exception vector
 - use bsr/rts for regular functions (save pr first)
 - keep data in one shared cache line (exception_data)
 - document the functions
 - tie in the hp6xx code

Signed-off-by: default avatarMagnus Damm <damm@igel.co.jp>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent b233b28e

arch/sh/boards/mach-hp6xx/pm_wakeup.S

+8 −23
Original line number Diff line number Diff line
@@ -10,47 +10,32 @@ 
#include <linux/linkage.h>

#include <cpu/mmu_context.h>



#define k0	r0

#define k1	r1

#define k2	r2

#define k3	r3

#define k4	r4



/*

 * 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)

 * For more details, please have a look at entry.S

 */



#define k0	r0

#define k1	r1



ENTRY(wakeup_start)

! clear STBY bit

	mov	#-126, k2

	mov	#-126, k1

   	and	#127, k0

	mov.b	k0, @k2

	mov.b	k0, @k1

! enable refresh

	mov.l	5f, k1

	mov.w	6f, k0

  	mov.w	k0, @k1

! jump to handler

	mov.l	2f, k2

	mov.l	3f, k3

	mov.l	@k2, k2



	mov.l	4f, k1

	jmp	@k1

	 nop



	.align	2

1:	.long	EXPEVT

2:	.long	INTEVT

3:	.long	ret_from_irq

4:	.long	handle_exception

4:	.long	handle_interrupt

5:	.long	0xffffff68

6:	.word	0x0524

arch/sh/kernel/cpu/sh3/entry.S

+147 −126
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <asm/unistd.h>

#include <cpu/mmu_context.h>

#include <asm/page.h>

#include <asm/cache.h>



! NOTE:

! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address
@@ -294,7 +295,7 @@ skip_restore: 
	mov	#0xf0, k1

	extu.b	k1, k1

	not	k1, k1

	and	k1, k2			! Mask orignal SR value

	and	k1, k2			! Mask original SR value

	!

	mov	k3, k0			! Calculate IMASK-bits

	shlr2	k0
@@ -335,82 +336,54 @@ skip_restore: 
	.balign 	4096,0,4096

ENTRY(vbr_base)

	.long	0

!

! 0x100: General exception vector

!

	.balign 	256,0,256

general_exception:

	mov.l	1f, k2

	mov.l	2f, k3

#ifdef CONFIG_CPU_SUBTYPE_SHX3

	mov.l	@k2, k2

#ifndef CONFIG_CPU_SUBTYPE_SHX3

	bra	handle_exception

	 sts	pr, k3		! save original pr value in k3

#else

	mov.l	1f, k4

	mov.l	@k4, k4



	! Is EXPEVT larger than 0x800?

	mov	#0x8, k0

	shll8	k0

	cmp/hs	k0, k2

	cmp/hs	k0, k4

	bf	0f



	! then add 0x580 (k2 is 0xd80 or 0xda0)

	mov	#0x58, k0

	shll2	k0

	shll2	k0

	add	k0, k2

	add	k0, k4

0:

	bra	handle_exception

	! Setup stack and save DSP context (k0 contains original r15 on return)

	bsr	prepare_stack_save_dsp

	 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	3f, k3

#if defined(CONFIG_KGDB)

	mov.l	2f, k2

	! 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

	! Save registers / Switch to bank 0

	bsr	save_regs	! needs original pr value in k3

	 mov.l	k4, k2		! keep vector in k2



	bra	handle_exception_special

	 nop

	.align	2

2:	.long	INTEVT

5:	.long	NMI_VEC

6:	.long	in_nmi

0:

#endif /* defined(CONFIG_KGDB) */

	bra	handle_exception

	 mov	#-1, k2		! interrupt exception marker



	.align	2

1:	.long	EXPEVT

3:	.long	ret_from_irq

4:	.long	ret_from_exception

#endif



!

!

	.align	2

ENTRY(handle_exception)

	! Using k0, k1 for scratch registers (r0_bank1, r1_bank),

	! save all registers onto stack.

	!

! prepare_stack_save_dsp()

! - roll back gRB

! - switch to kernel stack

! - save DSP

! k0 returns original sp (after roll back)

! k1 trashed

! k2 trashed



prepare_stack_save_dsp:

#ifdef CONFIG_GUSA

	! Check for roll back gRB (User and Kernel)

	mov	r15, k0
@@ -430,7 +403,7 @@ ENTRY(handle_exception) 
2:	mov	k1, r15		! SP = r1

1:

#endif



	! Switch to kernel stack if needed

	stc	ssr, k0		! Is it from kernel space?

	shll	k0		! Check MD bit (bit30) by shifting it into...

	shll	k0		!       ...the T bit
@@ -443,18 +416,17 @@ ENTRY(handle_exception) 
	add	current, k1

	mov	k1, r15		! change to kernel stack

	!

1:	mov.l	2f, k1

	!

1:

#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

	! Save DSP context if needed

	stc	sr, k1

	mov	#0x10, k2

	shll8   k2			! DSP=1 (0x00001000)

	tst	k2, k1			! Check if in DSP mode (passed in k2)

	bt/s	skip_save

	 mov	#0, k4			! Set marker for no stack frame

	 mov	#0, k1			! Set marker for no stack frame



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

	mov	k2, k1			! Save has-frame marker



	! Save DSP registers on stack

	stc.l	mod, @-r15
@@ -473,35 +445,73 @@ ENTRY(handle_exception) 
	! as we're not at all interested in supporting ancient toolchains at

	! this point. -- PFM.



	mov	r15, r2

	mov	r15, k2

	.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	k2, 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

	mov.l	k1, @-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)

	rts

	 nop

!

! 0x400: Instruction and Data TLB miss exception vector

!

	.balign 	1024,0,1024

tlb_miss:

	sts	pr, k3		! save original pr value in k3



handle_exception:

	! Setup stack and save DSP context (k0 contains original r15 on return)

	bsr	prepare_stack_save_dsp

	 nop



	! Save registers / Switch to bank 0

	mov.l	5f, k2		! vector register address

	bsr	save_regs	! needs original pr value in k3

	 mov.l	@k2, k2		! read out vector and keep in k2



handle_exception_special:

	! Setup return address and jump to exception handler

	mov.l	7f, r9		! fetch return address

	stc	r2_bank, r0	! k2 (vector)

	mov.l	6f, r10

	shlr2	r0

	shlr	r0

	mov.l	@(r0, r10), r10

	jmp	@r10

	 lds	r9, pr		! put return address in pr



	.align	L1_CACHE_SHIFT



! save_regs()

! - save vector, default tra, macl, mach, gbr, ssr, pr* and spc on the stack

! - save r15*, r14, r13, r12, r11, r10, r9, r8 on the stack

! - switch bank

! - save r7, r6, r5, r4, r3, r2, r1, r0 on the stack

! k0 contains original stack pointer*

! k1 trashed

! k2 passes vector (EXPEVT)

! k3 passes original pr*

! k4 trashed

! BL=1 on entry, on exit BL=0.



save_regs:

	mov	#-1, r1

	mov.l	k2, @-r15	! vector in k2

	mov.l	k1, @-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

	mov.l	k3, @-r15	! original pr in k3

	stc.l	spc, @-r15

	!

	lds	k3, pr		! Set the return address to pr

	!

	mov.l	k0, @-r15	! save orignal stack



	mov.l	k0, @-r15	! original stack pointer in k0

	mov.l	r14, @-r15

	mov.l	r13, @-r15

	mov.l	r12, @-r15
@@ -509,13 +519,15 @@ skip_save: 
	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	0f, k3		! SR bits to set in k3

	mov.l	1f, k4		! SR bits to clear in k4



	stc	sr, r8

	or	k3, r8

	and	k4, r8

	ldc	r8, sr



	mov.l	r7, @-r15

	mov.l	r6, @-r15

	mov.l	r5, @-r15
@@ -523,52 +535,61 @@ skip_save: 
	mov.l	r3, @-r15

	mov.l	r2, @-r15

	mov.l	r1, @-r15

	rts

	 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

!

! 0x600: Interrupt / NMI vector

!

	.balign 	512,0,512

ENTRY(handle_interrupt)

#if defined(CONFIG_KGDB)

	mov.l	2f, k2

	! Debounce (filter nested NMI)

	mov.l	@k2, k0

	mov.l	9f, k1

	cmp/eq	k1, k0

	bf	11f

	mov.l	10f, k1

	tas.b	@k1

	bt	11f

	rte

	 nop

	rts

	.align	2

9:	.long	NMI_VEC

10:	.long	in_nmi

11:

#endif /* defined(CONFIG_KGDB) */

	sts	pr, k3		! save original pr value in k3



	! Setup stack and save DSP context (k0 contains original r15 on return)

	bsr	prepare_stack_save_dsp

	 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

	! Save registers / Switch to bank 0

	bsr	save_regs	! needs original pr value in k3

	 mov	#-1, k2		! default vector kept in k2



interrupt_exception:

	mov.l	1f, r9

	! Setup return address and jump to do_IRQ

	mov.l	4f, r9		! fetch return address

	lds	r9, pr		! put return address in pr

	mov.l	2f, r4

	mov.l	@r4, r4

	mov.l	3f, r9

	mov.l	@r4, r4		! pass INTEVT vector as arg0

	jmp	@r9

	 mov	r15, r5

	rts

	 nop



	.align 2

1:	.long	do_IRQ

2:	.long	INTEVT

	 mov	r15, r5		! pass saved registers as arg1



	.align	2

ENTRY(exception_none)

	rts

	 nop



	.align	L1_CACHE_SHIFT

exception_data:

0:	.long	0x000080f0	! FD=1, IMASK=15

1:	.long	0xcfffffff	! RB=0, BL=0

2:	.long	INTEVT

3:	.long	do_IRQ

4:	.long	ret_from_irq

5:	.long	EXPEVT

6:	.long	exception_handling_table

7:	.long	ret_from_exception

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