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authorSimon Baatz <gmbnomis@gmail.com>2013-06-10 21:10:12 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-06-17 10:30:52 +0100
commit1bc39742aab09248169ef9d3727c9def3528b3f3 (patch)
tree50179be222c15d5e06f77928331d63843f6fc738
parent049be07053ebbf0ee8543caea23ae7bdf0765bb2 (diff)
downloadvexpress-lsk-1bc39742aab09248169ef9d3727c9def3528b3f3.tar.gz
ARM: 7755/1: handle user space mapped pages in flush_kernel_dcache_page
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 <gmbnomis@gmail.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: <stable@vger.kernel.org> # 3.2+ Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/include/asm/cacheflush.h4
-rw-r--r--arch/arm/mm/flush.c33
2 files changed, 34 insertions, 3 deletions
diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
index bff71388e72..17d0ae8672f 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 0d473cce501..32aa5861119 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:
*