From 421fe93cc4b06b2f5e875cbe0f692800d4862ee5 Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Sun, 25 Oct 2009 10:23:04 +0000
Subject: ARM: ZERO_PAGE: Avoid flush_dcache_page() for zero page
The zero page is read-only, and has its cache state cleared during
boot. No further maintanence for this page is required.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/mm/fault-armv.c | 7 +++++++
1 file changed, 7 insertions(+)
(limited to 'arch/arm/mm/fault-armv.c')
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index d0d17b6a370..4fbc7de8b4a 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -151,7 +151,14 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
if (!pfn_valid(pfn))
return;
+ /*
+ * The zero page is never written to, so never has any dirty
+ * cache lines, and therefore never needs to be flushed.
+ */
page = pfn_to_page(pfn);
+ if (page == ZERO_PAGE(0))
+ return;
+
mapping = page_mapping(page);
#ifndef CONFIG_SMP
if (test_and_clear_bit(PG_dcache_dirty, &page->flags))
--
cgit v1.2.3-70-g09d2
From 7b0a1003e780193e2a11c27f5059c26b65f60679 Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Sat, 24 Oct 2009 14:11:59 +0100
Subject: ARM: Reduce __flush_dcache_page() visibility
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/include/asm/cacheflush.h | 2 --
arch/arm/mm/fault-armv.c | 2 ++
arch/arm/mm/mm.h | 2 ++
3 files changed, 4 insertions(+), 2 deletions(-)
(limited to 'arch/arm/mm/fault-armv.c')
diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
index 61ae25caaac..9fd6d3ab68c 100644
--- a/arch/arm/include/asm/cacheflush.h
+++ b/arch/arm/include/asm/cacheflush.h
@@ -420,8 +420,6 @@ extern void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
*/
extern void flush_dcache_page(struct page *);
-extern void __flush_dcache_page(struct address_space *mapping, struct page *page);
-
static inline void __flush_icache_all(void)
{
#ifdef CONFIG_ARM_ERRATA_411920
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index 4fbc7de8b4a..72960229195 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -23,6 +23,8 @@
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
+#include "mm.h"
+
static unsigned long shared_pte_mask = L_PTE_MT_BUFFERABLE;
/*
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index c4f6f05198e..a888363398f 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -24,6 +24,8 @@ struct mem_type {
const struct mem_type *get_mem_type(unsigned int type);
+extern void __flush_dcache_page(struct address_space *mapping, struct page *page);
+
#endif
struct map_desc;
--
cgit v1.2.3-70-g09d2