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[POWERPC] 8xx: fix swap

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This makes swap routines operate correctly on the ppc_8xx based machines.
Code has been revalidated on mpc885ads (8M sdram) with recent kernel. Based
on patch from Yuri Tikhonov <yur@emcraft.com> to do the same on arch/ppc
instance.

Recent kernel's size makes swap feature very important on low-memory platforms,
those are actually non-operable without it.

Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Vitaly Bordug <vitb@kernel.crashing.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This commit is contained in:
Vitaly Bordug 2008-03-06 13:53:30 +03:00 committed by Kumar Gala
parent d7f46190ef
commit 76db5bd26f
2 changed files with 29 additions and 9 deletions
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30
arch/powerpc/kernel/head_8xx.S
View file

@ -332,8 +332,18 @@ InstructionTLBMiss:
mfspr r11, SPRN_MD_TWC /* ....and get the pte address */
lwz r10, 0(r11) /* Get the pte */
#ifdef CONFIG_SWAP
/* do not set the _PAGE_ACCESSED bit of a non-present page */
andi. r11, r10, _PAGE_PRESENT
beq 4f
ori r10, r10, _PAGE_ACCESSED
mfspr r11, SPRN_MD_TWC /* get the pte address again */
stw r10, 0(r11)
4:
#else
ori r10, r10, _PAGE_ACCESSED
stw r10, 0(r11)
#endif
/* The Linux PTE won't go exactly into the MMU TLB.
* Software indicator bits 21, 22 and 28 must be clear.
@ -398,8 +408,17 @@ DataStoreTLBMiss:
DO_8xx_CPU6(0x3b80, r3)
mtspr SPRN_MD_TWC, r11
mfspr r11, SPRN_MD_TWC /* get the pte address again */
#ifdef CONFIG_SWAP
/* do not set the _PAGE_ACCESSED bit of a non-present page */
andi. r11, r10, _PAGE_PRESENT
beq 4f
ori r10, r10, _PAGE_ACCESSED
4:
/* and update pte in table */
#else
ori r10, r10, _PAGE_ACCESSED
#endif
mfspr r11, SPRN_MD_TWC /* get the pte address again */
stw r10, 0(r11)
/* The Linux PTE won't go exactly into the MMU TLB.
@ -507,7 +526,16 @@ DataTLBError:
/* Update 'changed', among others.
*/
#ifdef CONFIG_SWAP
ori r10, r10, _PAGE_DIRTY|_PAGE_HWWRITE
/* do not set the _PAGE_ACCESSED bit of a non-present page */
andi. r11, r10, _PAGE_PRESENT
beq 4f
ori r10, r10, _PAGE_ACCESSED
4:
#else
ori r10, r10, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE
#endif
mfspr r11, SPRN_MD_TWC /* Get pte address again */
stw r10, 0(r11) /* and update pte in table */

8
include/asm-powerpc/pgtable-ppc32.h
View file

@ -339,14 +339,6 @@ extern int icache_44x_need_flush;
#define _PMD_PAGE_MASK 0x000c
#define _PMD_PAGE_8M 0x000c
/*
* The 8xx TLB miss handler allegedly sets _PAGE_ACCESSED in the PTE
* for an address even if _PAGE_PRESENT is not set, as a performance
* optimization. This is a bug if you ever want to use swap unless
* _PAGE_ACCESSED is 2, which it isn't, or unless you have 8xx-specific
* definitions for __swp_entry etc. below, which would be gross.
* -- paulus
*/
#define _PTE_NONE_MASK _PAGE_ACCESSED
#else /* CONFIG_6xx */