diff options
| author | Nicolas Pitre <nico@cam.org> | 2009-09-01 22:01:27 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-09-02 11:33:24 +0100 |
| commit | 13f96d8f4c5a3f6a6b5e578d08869d79d690e0b2 (patch) | |
| tree | fe33eb0bce77b41d9e7a491b1241db6a70a93df2 | |
| parent | 37d0892c5a94e208cf863e3b7bac014edee4346d (diff) | |
ARM: 5687/1: fix an oops with highmem
In xdr_partial_copy_from_skb() there is that sequence:
kaddr = kmap_atomic(*ppage, KM_SKB_SUNRPC_DATA);
[...]
flush_dcache_page(*ppage);
kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA);
Mixing flush_dcache_page() and kmap_atomic() is a bit odd,
especially since kunmap_atomic() must deal with cache issues
already. OTOH the non-highmem case must use flush_dcache_page()
as kunmap_atomic() becomes a no op with no cache maintenance.
Problem is that with highmem the implementation of kmap_atomic()
doesn't set page->virtual, and page_address(page) returns 0 in
that case. Here flush_dcache_page() calls __flush_dcache_page()
which calls __cpuc_flush_dcache_page(page_address(page)) resulting
in a kernel oops.
None of the kmap_atomic() implementations uses set_page_address().
Hence we can assume page_address() is always expected to return 0 in
that case. Let's conditionally call __cpuc_flush_dcache_page() only
when the page address is non zero, and perform that test only when
highmem is configured.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
| -rw-r--r-- | arch/arm/mm/flush.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index c07222eb5ce..575f3ad722e 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -144,7 +144,14 @@ void __flush_dcache_page(struct address_space *mapping, struct page *page) * page. This ensures that data in the physical page is mutually * coherent with the kernels mapping. */ - __cpuc_flush_dcache_page(page_address(page)); +#ifdef CONFIG_HIGHMEM + /* + * kmap_atomic() doesn't set the page virtual address, and + * kunmap_atomic() takes care of cache flushing already. + */ + if (page_address(page)) +#endif + __cpuc_flush_dcache_page(page_address(page)); /* * If this is a page cache page, and we have an aliasing VIPT cache, |