Commit 1bc39742 authored by Simon Baatz's avatar Simon Baatz Committed by Russell King
Browse files

ARM: 7755/1: handle user space mapped pages in flush_kernel_dcache_page 



Commit f8b63c18 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: default avatarSimon Baatz <gmbnomis@gmail.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org> # 3.2+
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 049be070

arch/arm/include/asm/cacheflush.h

+1 −3
Original line number Diff line number Diff line
@@ -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)

arch/arm/mm/flush.c

+33 −0
Original line number Diff line number Diff line
@@ -300,6 +300,39 @@ 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:

CRA Git | Maintained and supported by SUSTech CRA and CCSE