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Commit 1dd22722 authored by Magnus Damm's avatar Magnus Damm Committed by Paul Mundt
Browse files

sh: rework register restore code for sh3/sh4/sh4a 



This patch reworks the sh3/sh4/sh4a register restore code in
the following ways:
 - break out restore_regs() from restore_all()
 - the register saving order is unchanged
 - use restore_regs() in sh_bios_handler and restore_all
 - document the function

Signed-off-by: default avatarMagnus Damm <damm@igel.co.jp>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 1d015cf0

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

+33 −35
Original line number Diff line number Diff line
@@ -188,44 +188,35 @@ call_dae: 
#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	1f, r8

	bsr	restore_regs

	 nop



	lds	k2, pr			! restore pr

	mov	k4, r15

	!

	mov.l	2f, k0

	mov.l	@k0, k0

	jmp	@k0

	 ldc	k1, ssr

	 ldc	k3, ssr

	.align	2

1:	.long	0x300000f0

2:	.long	gdb_vbr_vector

#endif /* CONFIG_SH_STANDARD_BIOS */



restore_all:

! restore_regs()

! - restore r0, r1, r2, r3, r4, r5, r6, r7 from the stack

! - switch bank

! - restore r8, r9, r10, r11, r12, r13, r14, r15 from the stack

! - restore spc, pr*, ssr, gbr, mach, macl, skip default tra

! k2 returns original pr

! k3 returns original sr

! k4 returns original stack pointer

! r8 passes SR bitmask, overwritten with restored data on return

! r9 trashed

! BL=0 on entry, on exit BL=1 (depending on r8).



restore_regs:

	mov.l	@r15+, r0

	mov.l	@r15+, r1

	mov.l	@r15+, r2
@@ -235,10 +226,9 @@ restore_all: 
	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

	stc	sr, r9

	or	r8, r9

	ldc	r9, sr

	!

	mov.l	@r15+, r8

	mov.l	@r15+, r9
@@ -249,12 +239,20 @@ restore_all: 
	mov.l	@r15+, r14

	mov.l	@r15+, k4		! original stack pointer

	ldc.l	@r15+, spc

	lds.l	@r15+, pr

	mov.l	@r15+, k2		! original PR

	mov.l	@r15+, k3		! original SR

	ldc.l	@r15+, gbr

	lds.l	@r15+, mach

	lds.l	@r15+, macl

	rts

	 add	#4, r15			! Skip syscall number



restore_all:

	mov.l	7f, r8

	bsr	restore_regs

	 nop



	lds	k2, pr			! restore pr

	!

#ifdef CONFIG_SH_DSP

	mov.l	@r15+, k0		! DSP mode marker