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authorYinghai Lu <yinghai@kernel.org>2013-05-31 08:53:07 -0700
committerH. Peter Anvin <hpa@linux.intel.com>2013-05-31 13:21:32 -0700
commit7de3d66b1387ddf5a37d9689e5eb8510fb75c765 (patch)
treecd8e5fd18ad268fc8d9ccb917db2a40644668803
parenta93cb29acaa8f75618c3f202d1cf43c231984644 (diff)
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x86: Fix adjust_range_size_mask calling position
Commit 8d57470d x86, mm: setup page table in top-down causes a kernel panic while setting mem=2G. [mem 0x00000000-0x000fffff] page 4k [mem 0x7fe00000-0x7fffffff] page 1G [mem 0x7c000000-0x7fdfffff] page 1G [mem 0x00100000-0x001fffff] page 4k [mem 0x00200000-0x7bffffff] page 2M for last entry is not what we want, we should have [mem 0x00200000-0x3fffffff] page 2M [mem 0x40000000-0x7bffffff] page 1G Actually we merge the continuous ranges with same page size too early. in this case, before merging we have [mem 0x00200000-0x3fffffff] page 2M [mem 0x40000000-0x7bffffff] page 2M after merging them, will get [mem 0x00200000-0x7bffffff] page 2M even we can use 1G page to map [mem 0x40000000-0x7bffffff] that will cause problem, because we already map [mem 0x7fe00000-0x7fffffff] page 1G [mem 0x7c000000-0x7fdfffff] page 1G with 1G page, aka [0x40000000-0x7fffffff] is mapped with 1G page already. During phys_pud_init() for [0x40000000-0x7bffffff], it will not reuse existing that pud page, and allocate new one then try to use 2M page to map it instead, as page_size_mask does not include PG_LEVEL_1G. At end will have [7c000000-0x7fffffff] not mapped, loop in phys_pmd_init stop mapping at 0x7bffffff. That is right behavoir, it maps exact range with exact page size that we ask, and we should explicitly call it to map [7c000000-0x7fffffff] before or after mapping 0x40000000-0x7bffffff. Anyway we need to make sure ranges' page_size_mask correct and consistent after split_mem_range for each range. Fix that by calling adjust_range_size_mask before merging range with same page size. -v2: update change log. -v3: add more explanation why [7c000000-0x7fffffff] is not mapped, and it causes panic. Bisected-by: "Xie, ChanglongX" <changlongx.xie@intel.com> Bisected-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> Reported-and-tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1370015587-20835-1-git-send-email-yinghai@kernel.org Cc: <stable@vger.kernel.org> v3.9 Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
-rw-r--r--arch/x86/mm/init.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index eaac1743def7..1f34e9219775 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -277,6 +277,9 @@ static int __meminit split_mem_range(struct map_range *mr, int nr_range,
end_pfn = limit_pfn;
nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
+ if (!after_bootmem)
+ adjust_range_page_size_mask(mr, nr_range);
+
/* try to merge same page size and continuous */
for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
unsigned long old_start;
@@ -291,9 +294,6 @@ static int __meminit split_mem_range(struct map_range *mr, int nr_range,
nr_range--;
}
- if (!after_bootmem)
- adjust_range_page_size_mask(mr, nr_range);
-
for (i = 0; i < nr_range; i++)
printk(KERN_DEBUG " [mem %#010lx-%#010lx] page %s\n",
mr[i].start, mr[i].end - 1,