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authorYuri Tikhonov <yur@emcraft.com>2008-02-02 10:47:31 +0300
committerKumar Gala <galak@kernel.crashing.org>2008-03-07 16:56:54 -0600
commit1757f2d12dce775982aaa006bce1cf4f7ce90111 (patch)
tree068d45767a864ad383ece702fbcbcf3cd2e2752e
parent3e0d65bf6d5b464949b749a8da7977f6b197d301 (diff)
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[PPC] 8xx: swap bug-fix
This makes swap routines operate correctly on the ppc_8xx based machines. Recent kernel's size makes swap feature very important on low-memory platfor those are actually non-operable without it. Signed-off-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
-rw-r--r--arch/ppc/kernel/head_8xx.S30
-rw-r--r--include/asm-ppc/pgtable.h8
2 files changed, 29 insertions, 9 deletions
diff --git a/arch/ppc/kernel/head_8xx.S b/arch/ppc/kernel/head_8xx.S
index eb8d26f..321bda2 100644
--- a/arch/ppc/kernel/head_8xx.S
+++ b/arch/ppc/kernel/head_8xx.S
@@ -329,8 +329,18 @@ 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.
@@ -395,8 +405,17 @@ 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.
@@ -575,7 +594,16 @@ 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 */
diff --git a/include/asm-ppc/pgtable.h b/include/asm-ppc/pgtable.h
index 69347bd..70435d3 100644
--- a/include/asm-ppc/pgtable.h
+++ b/include/asm-ppc/pgtable.h
@@ -299,14 +299,6 @@ extern unsigned long ioremap_bot, ioremap_base;
#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 */