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authorCatalin Marinas <catalin.marinas@arm.com>2013-05-01 12:23:05 +0100
committerMark Brown <broonie@linaro.org>2014-05-14 12:17:43 +0100
commit84ddb8b066d3750c9971b9eed826e8d1dd4f9c53 (patch)
tree21f9e39a009d490b3ba9a657fb73b4fa29886df0
parent66effa189f8ded4d968dd9c310137c50244477ad (diff)
downloadlinux-linaro-stable-84ddb8b066d3750c9971b9eed826e8d1dd4f9c53.tar.gz
arm64: Avoid cache flushing in flush_dcache_page()
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@arm.com> Reported-by: Will Deacon <will.deacon@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (cherry picked from commit 1e616427f20943c9966296dfff9e7a2b825846aa) Signed-off-by: Mark Brown <broonie@linaro.org>
-rw-r--r--arch/arm64/mm/flush.c22
1 files changed, 4 insertions, 18 deletions
diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index 88611c3a421a..b9cd7a4deeca 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -94,28 +94,14 @@ void __sync_icache_dcache(pte_t pte, unsigned long addr)
}
/*
- * 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);