3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Catalin Marinas <catalin.marinas@xxxxxxx>
commit b5b6c9e9149d8a7c3f1d7b9d0c046c6184e1dd17 upstream.
The flush_dcache_page() function is called when the kernel modified a
page cache page. Since the D-cache on AArch64 does not have aliases
this function can simply mark the page as dirty for later flushing via
set_pte_at()/__sync_icache_dcache() if the page is executable (to ensure
the I-D cache coherency).
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Reported-by: Will Deacon <will.deacon@xxxxxxx>
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/mm/flush.c | 22 ++++------------------
1 file changed, 4 insertions(+), 18 deletions(-)
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -94,28 +94,14 @@ void __sync_icache_dcache(pte_t pte, uns
}
/*
- * Ensure cache coherency between kernel mapping and userspace mapping of this
- * page.
+ * This function is called when a page has been modified by the kernel. Mark
+ * it as dirty for later flushing when mapped in user space (if executable,
+ * see __sync_icache_dcache).
*/
void flush_dcache_page(struct page *page)
{
- struct address_space *mapping;
-
- /*
- * The zero page is never written to, so never has any dirty cache
- * lines, and therefore never needs to be flushed.
- */
- if (page == ZERO_PAGE(0))
- return;
-
- mapping = page_mapping(page);
- if (mapping && mapping_mapped(mapping)) {
- __flush_dcache_page(page);
- __flush_icache_all();
- set_bit(PG_dcache_clean, &page->flags);
- } else {
+ if (test_bit(PG_dcache_clean, &page->flags))
clear_bit(PG_dcache_clean, &page->flags);
- }
}
EXPORT_SYMBOL(flush_dcache_page);
--
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