From patchwork Wed Jun 5 19:59:04 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Baatz X-Patchwork-Id: 2673491 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) by patchwork2.kernel.org (Postfix) with ESMTP id D6FEDDF264 for ; Wed, 5 Jun 2013 20:00:14 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UkJsT-0005eo-8w; Wed, 05 Jun 2013 20:00:13 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UkJsQ-0005ee-Ms; Wed, 05 Jun 2013 20:00:10 +0000 Received: from mo6-p00-ob.rzone.de ([2a01:238:20a:202:5300::1]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UkJsN-0005du-NW for linux-arm-kernel@lists.infradead.org; Wed, 05 Jun 2013 20:00:09 +0000 X-RZG-AUTH: :L20Qdkipd/NtQfa28f3iP6nsj1VEm6lxnnjU56eNUnjyVKhsqx3PYdmEEmLU9j5KiJrZ X-RZG-CLASS-ID: mo00 Received: from gandalf.schnuecks.de (p57A570FC.dip0.t-ipconnect.de [87.165.112.252]) by smtp.strato.de (jored mo36) (RZmta 31.27 DYNA|AUTH) with (DHE-RSA-AES256-SHA encrypted) ESMTPA id x03567p55IvYH6 ; Wed, 5 Jun 2013 21:59:43 +0200 (CEST) Received: by gandalf.schnuecks.de (Postfix, from userid 500) id C7B2A40099; Wed, 5 Jun 2013 21:59:42 +0200 (CEST) From: Simon Baatz To: linux-arm-kernel@lists.infradead.org Subject: [PATCH V5] ARM: handle user space mapped pages in flush_kernel_dcache_page Date: Wed, 5 Jun 2013 21:59:04 +0200 Message-Id: <1370462344-7128-1-git-send-email-gmbnomis@gmail.com> X-Mailer: git-send-email 1.7.9.5 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130605_160008_040292_0EEA6A5F X-CRM114-Status: GOOD ( 17.66 ) X-Spam-Score: -1.0 (-) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-1.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (gmbnomis[at]gmail.com) 0.0 DKIM_ADSP_CUSTOM_MED No valid author signature, adsp_override is CUSTOM_MED -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] 0.9 NML_ADSP_CUSTOM_MED ADSP custom_med hit, and not from a mailing list Cc: Catalin Marinas , Russell King , Jason Cooper X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Commit f8b63c1 made flush_kernel_dcache_page a no-op assuming that the pages it needs to handle are kernel mapped only. However, for example when doing direct I/O, pages with user space mappings may occur. Thus, continue to do lazy flushing if there are no user space mappings. Otherwise, flush the kernel cache lines directly. Signed-off-by: Simon Baatz Cc: # 3.2+ CC: Catalin Marinas Cc: Russell King Reviewed-by: Catalin Marinas --- Changes: in V5: - simplified highmem case; we can assume kmapped pages in V4: - get back to simpler version of flush_kernel_dcache_page() and use the logic from __flush_dcache_page() to flush the kernel mapping (which also takes care of highmem pages) in V3: - Followed Catalin's suggestion to reverse the order of the patches in V2: - flush_kernel_dcache_page() follows flush_dcache_page() now, except that it does not flush the user mappings arch/arm/include/asm/cacheflush.h | 4 +--- arch/arm/mm/flush.c | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 34 insertions(+), 3 deletions(-) diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h index bff7138..17d0ae8 100644 --- a/arch/arm/include/asm/cacheflush.h +++ b/arch/arm/include/asm/cacheflush.h @@ -320,9 +320,7 @@ static inline void flush_anon_page(struct vm_area_struct *vma, } #define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE -static inline void flush_kernel_dcache_page(struct page *page) -{ -} +extern void flush_kernel_dcache_page(struct page *); #define flush_dcache_mmap_lock(mapping) \ spin_lock_irq(&(mapping)->tree_lock) diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index 0d473cc..32aa586 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -301,6 +301,39 @@ void flush_dcache_page(struct page *page) EXPORT_SYMBOL(flush_dcache_page); /* + * Ensure cache coherency for the kernel mapping of this page. We can + * assume that the page is pinned via kmap. + * + * If the page only exists in the page cache and there are no user + * space mappings, this is a no-op since the page was already marked + * dirty at creation. Otherwise, we need to flush the dirty kernel + * cache lines directly. + */ +void flush_kernel_dcache_page(struct page *page) +{ + if (cache_is_vivt() || cache_is_vipt_aliasing()) { + struct address_space *mapping; + + mapping = page_mapping(page); + + if (!mapping || mapping_mapped(mapping)) { + void *addr; + + addr = page_address(page); + /* + * kmap_atomic() doesn't set the page virtual + * address for highmem pages, and + * kunmap_atomic() takes care of cache + * flushing already. + */ + if (!IS_ENABLED(CONFIG_HIGHMEM) || addr) + __cpuc_flush_dcache_area(addr, PAGE_SIZE); + } + } +} +EXPORT_SYMBOL(flush_kernel_dcache_page); + +/* * Flush an anonymous page so that users of get_user_pages() * can safely access the data. The expected sequence is: *