From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Catalin Marinas , Will Deacon , Mark Brown Subject: [PATCH 3.10 127/129] arm64: Avoid cache flushing in flush_dcache_page() Date: Mon, 6 Jan 2014 14:39:16 -0800 Message-Id: <20140106223903.228763015@linuxfoundation.org> In-Reply-To: <20140106223859.589799655@linuxfoundation.org> References: <20140106223859.589799655@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Catalin Marinas 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 Reported-by: Will Deacon Acked-by: Will Deacon Cc: Mark Brown Signed-off-by: Greg Kroah-Hartman --- 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);