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Commit 112e5847 authored by Paul Mundt's avatar Paul Mundt
Browse files

sh: TLB protection violation exception optimizations. 



This adds a bit of rework to have the TLB protection violations skip the
TLB miss fastpath and go directly in to do_page_fault(), as these require
slow path handling.

Based on an earlier patch by SUGIOKA Toshinobu.

Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent e7b8b7f1

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

+19 −11
Original line number Diff line number Diff line
@@ -113,34 +113,33 @@ OFF_TRA = (16*4+6*4) 
#if defined(CONFIG_MMU)

	.align	2

ENTRY(tlb_miss_load)

	bra	call_dpf

	bra	call_handle_tlbmiss

	 mov	#0, r5



	.align	2

ENTRY(tlb_miss_store)

	bra	call_dpf

	bra	call_handle_tlbmiss

	 mov	#1, r5



	.align	2

ENTRY(initial_page_write)

	bra	call_dpf

	bra	call_handle_tlbmiss

	 mov	#1, r5



	.align	2

ENTRY(tlb_protection_violation_load)

	bra	call_dpf

	bra	call_do_page_fault

	 mov	#0, r5



	.align	2

ENTRY(tlb_protection_violation_store)

	bra	call_dpf

	bra	call_do_page_fault

	 mov	#1, r5



call_dpf:

call_handle_tlbmiss:

	mov.l	1f, r0

	mov	r5, r8

	mov.l	@r0, r6

	mov	r6, r9

	mov.l	2f, r0

	sts	pr, r10

	jsr	@r0
@@ -151,16 +150,25 @@ call_dpf: 
	 lds	r10, pr

	rts

	 nop

0:	mov.l	3f, r0

	mov	r9, r6

0:

	mov	r8, r5

	jmp	@r0

call_do_page_fault:

	mov.l	1f, r0

	mov.l	@r0, r6



	sti



	mov.l	3f, r0

	mov.l	4f, r1

	mov	r15, r4

	jmp	@r0

	 lds	r1, pr



	.align 2

1:	.long	MMU_TEA

2:	.long	__do_page_fault

2:	.long	handle_tlbmiss

3:	.long	do_page_fault

4:	.long	ret_from_exception



	.align	2

ENTRY(address_error_load)

arch/sh/mm/fault_32.c

+3 −3
Original line number Diff line number Diff line
@@ -318,8 +318,8 @@ do_sigbus: 
/*

 * Called with interrupts disabled.

 */

asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,

					 unsigned long writeaccess,

asmlinkage int __kprobes

handle_tlbmiss(struct pt_regs *regs, unsigned long writeaccess,

	       unsigned long address)

{

	pgd_t *pgd;