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| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2014-01-13 07:04:24 +0100 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-01-15 05:46:38 +0100 |
| commit | b3084f4db3aeb991c507ca774337c7e7893ed04f (patch) | |
| tree | c5cad3a6843272a173e95a87a6087d362e19073e /arch | |
| parent | Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/po... (diff) | |
| download | linux-b3084f4db3aeb991c507ca774337c7e7893ed04f.tar.xz linux-b3084f4db3aeb991c507ca774337c7e7893ed04f.zip | |
powerpc/thp: Fix crash on mremap
This patch fix the below crash
NIP [c00000000004cee4] .__hash_page_thp+0x2a4/0x440
LR [c0000000000439ac] .hash_page+0x18c/0x5e0
...
Call Trace:
[c000000736103c40] [00001ffffb000000] 0x1ffffb000000(unreliable)
[437908.479693] [c000000736103d50] [c0000000000439ac] .hash_page+0x18c/0x5e0
[437908.479699] [c000000736103e30] [c00000000000924c] .do_hash_page+0x4c/0x58
On ppc64 we use the pgtable for storing the hpte slot information and
store address to the pgtable at a constant offset (PTRS_PER_PMD) from
pmd. On mremap, when we switch the pmd, we need to withdraw and deposit
the pgtable again, so that we find the pgtable at PTRS_PER_PMD offset
from new pmd.
We also want to move the withdraw and deposit before the set_pmd so
that, when page fault find the pmd as trans huge we can be sure that
pgtable can be located at the offset.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/include/asm/pgtable-ppc64.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h index 4a191c472867..d27960c89a71 100644 --- a/arch/powerpc/include/asm/pgtable-ppc64.h +++ b/arch/powerpc/include/asm/pgtable-ppc64.h @@ -558,5 +558,19 @@ extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp); #define __HAVE_ARCH_PMDP_INVALIDATE extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp); + +#define pmd_move_must_withdraw pmd_move_must_withdraw +typedef struct spinlock spinlock_t; +static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, + spinlock_t *old_pmd_ptl) +{ + /* + * Archs like ppc64 use pgtable to store per pmd + * specific information. So when we switch the pmd, + * we should also withdraw and deposit the pgtable + */ + return true; +} + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_PGTABLE_PPC64_H_ */ |