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author | Simon Baatz <gmbnomis@gmail.com> | 2013-06-10 21:10:12 +0100 |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-06-17 10:30:52 +0100 |
commit | 1bc39742aab09248169ef9d3727c9def3528b3f3 (patch) | |
tree | 50179be222c15d5e06f77928331d63843f6fc738 /arch/arm/mm/flush.c | |
parent | 049be07053ebbf0ee8543caea23ae7bdf0765bb2 (diff) | |
download | linux-1bc39742aab09248169ef9d3727c9def3528b3f3.tar.bz2 |
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>
Diffstat (limited to 'arch/arm/mm/flush.c')
-rw-r--r-- | arch/arm/mm/flush.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index 0d473cce501c..32aa5861119f 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: * |