[PATCH] ARM: Fix delayed dcache flush for ARMv6 non-aliasing caches
flush_dcache_page() did nothing for these caches, but since they
suffer from I/D cache coherency issues, we need to ensure that data
is written back to RAM.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index 01967dd..be4ab3d 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -77,9 +77,8 @@
}
static void
-make_coherent(struct vm_area_struct *vma, unsigned long addr, struct page *page, int dirty)
+make_coherent(struct address_space *mapping, struct vm_area_struct *vma, unsigned long addr, unsigned long pfn)
{
- struct address_space *mapping = page_mapping(page);
struct mm_struct *mm = vma->vm_mm;
struct vm_area_struct *mpnt;
struct prio_tree_iter iter;
@@ -87,9 +86,6 @@
pgoff_t pgoff;
int aliases = 0;
- if (!mapping)
- return;
-
pgoff = vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT);
/*
@@ -115,9 +111,11 @@
if (aliases)
adjust_pte(vma, addr);
else
- flush_cache_page(vma, addr, page_to_pfn(page));
+ flush_cache_page(vma, addr, pfn);
}
+void __flush_dcache_page(struct address_space *mapping, struct page *page);
+
/*
* Take care of architecture specific things when placing a new PTE into
* a page table, or changing an existing PTE. Basically, there are two
@@ -134,29 +132,22 @@
void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
{
unsigned long pfn = pte_pfn(pte);
+ struct address_space *mapping;
struct page *page;
if (!pfn_valid(pfn))
return;
+
page = pfn_to_page(pfn);
- if (page_mapping(page)) {
+ mapping = page_mapping(page);
+ if (mapping) {
int dirty = test_and_clear_bit(PG_dcache_dirty, &page->flags);
- if (dirty) {
- /*
- * This is our first userspace mapping of this page.
- * Ensure that the physical page is coherent with
- * the kernel mapping.
- *
- * FIXME: only need to do this on VIVT and aliasing
- * VIPT cache architectures. We can do that
- * by choosing whether to set this bit...
- */
- __cpuc_flush_dcache_page(page_address(page));
- }
+ if (dirty)
+ __flush_dcache_page(mapping, page);
if (cache_is_vivt())
- make_coherent(vma, addr, page, dirty);
+ make_coherent(mapping, vma, addr, pfn);
}
}
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 4085ed9..191788f 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -37,13 +37,8 @@
#define flush_pfn_alias(pfn,vaddr) do { } while (0)
#endif
-static void __flush_dcache_page(struct address_space *mapping, struct page *page)
+void __flush_dcache_page(struct address_space *mapping, struct page *page)
{
- struct mm_struct *mm = current->active_mm;
- struct vm_area_struct *mpnt;
- struct prio_tree_iter iter;
- pgoff_t pgoff;
-
/*
* Writeback any data associated with the kernel mapping of this
* page. This ensures that data in the physical page is mutually
@@ -52,24 +47,21 @@
__cpuc_flush_dcache_page(page_address(page));
/*
- * If there's no mapping pointer here, then this page isn't
- * visible to userspace yet, so there are no cache lines
- * associated with any other aliases.
- */
- if (!mapping)
- return;
-
- /*
- * This is a page cache page. If we have a VIPT cache, we
- * only need to do one flush - which would be at the relevant
+ * If this is a page cache page, and we have an aliasing VIPT cache,
+ * we only need to do one flush - which would be at the relevant
* userspace colour, which is congruent with page->index.
*/
- if (cache_is_vipt()) {
- if (cache_is_vipt_aliasing())
- flush_pfn_alias(page_to_pfn(page),
- page->index << PAGE_CACHE_SHIFT);
- return;
- }
+ if (mapping && cache_is_vipt_aliasing())
+ flush_pfn_alias(page_to_pfn(page),
+ page->index << PAGE_CACHE_SHIFT);
+}
+
+static void __flush_dcache_aliases(struct address_space *mapping, struct page *page)
+{
+ struct mm_struct *mm = current->active_mm;
+ struct vm_area_struct *mpnt;
+ struct prio_tree_iter iter;
+ pgoff_t pgoff;
/*
* There are possible user space mappings of this page:
@@ -116,12 +108,12 @@
{
struct address_space *mapping = page_mapping(page);
- if (cache_is_vipt_nonaliasing())
- return;
-
if (mapping && !mapping_mapped(mapping))
set_bit(PG_dcache_dirty, &page->flags);
- else
+ else {
__flush_dcache_page(mapping, page);
+ if (mapping && cache_is_vivt())
+ __flush_dcache_aliases(mapping, page);
+ }
}
EXPORT_SYMBOL(flush_dcache_page);