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| author | Dave Hansen <dave@sr71.net> | 2013-03-07 20:31:51 +0400 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2013-03-08 01:23:28 +0400 |
| commit | 60f583d56aa515b896a9d94f860f52640c1e8a75 (patch) | |
| tree | b3e140c991bbdfe01eaa029d452784ef5242feb8 /arch/x86 | |
| parent | 3c4aff6b9a183b4f24eb7b8dd6c8a92cdba3bc75 (diff) | |
| download | linux-60f583d56aa515b896a9d94f860f52640c1e8a75.tar.xz | |
x86: Do not try to sync identity map for non-mapped pages
kernel_map_sync_memtype() is called from a variety of contexts. The
pat.c code that calls it seems to ensure that it is not called for
non-ram areas by checking via pat_pagerange_is_ram(). It is important
that it only be called on the actual identity map because there *IS*
no map to sync for highmem pages, or for memory holes.
The ioremap.c uses are not as careful as those from pat.c, and call
kernel_map_sync_memtype() on PCI space which is in the middle of the
kernel identity map _range_, but is not actually mapped.
This patch adds a check to kernel_map_sync_memtype() which probably
duplicates some of the checks already in pat.c. But, it is necessary
for the ioremap.c uses and shouldn't hurt other callers.
I have reproduced this bug and this patch fixes it for me and the
original bug reporter:
https://lkml.org/lkml/2013/2/5/396
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20130307163151.D9B58C4E@kernel.stglabs.ibm.com
Signed-off-by: Dave Hansen <dave@sr71.net>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/mm/pat.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 2610bd93c896..657438858e83 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -563,6 +563,13 @@ int kernel_map_sync_memtype(u64 base, unsigned long size, unsigned long flags) if (base > __pa(high_memory-1)) return 0; + /* + * some areas in the middle of the kernel identity range + * are not mapped, like the PCI space. + */ + if (!page_is_ram(base >> PAGE_SHIFT)) + return 0; + id_sz = (__pa(high_memory-1) <= base + size) ? __pa(high_memory) - base : size; |