diff options
| author | Steve Capper <[email protected]> | 2016-06-07 17:58:06 +0100 |
|---|---|---|
| committer | Russell King <[email protected]> | 2016-06-09 17:51:47 +0100 |
| commit | 56530f5d2ddc9b9fade7ef8db9cb886e9dc689b5 (patch) | |
| tree | f9386825ee9feadc54787360aafb744d78bc9ed5 | |
| parent | 624531886987f0f1b5d01fb598034d039198e090 (diff) | |
ARM: 8579/1: mm: Fix definition of pmd_mknotpresent
Currently pmd_mknotpresent will use a zero entry to respresent an
invalidated pmd.
Unfortunately this definition clashes with pmd_none, thus it is
possible for a race condition to occur if zap_pmd_range sees pmd_none
whilst __split_huge_pmd_locked is running too with pmdp_invalidate
just called.
This patch fixes the race condition by modifying pmd_mknotpresent to
create non-zero faulting entries (as is done in other architectures),
removing the ambiguity with pmd_none.
[[email protected]: using L_PMD_SECT_VALID instead of PMD_TYPE_SECT]
Fixes: 8d9625070073 ("ARM: mm: Transparent huge page support for LPAE systems.")
Cc: <[email protected]> # 3.11+
Reported-by: Kirill A. Shutemov <[email protected]>
Acked-by: Will Deacon <[email protected]>
Cc: Russell King <[email protected]>
Signed-off-by: Steve Capper <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
Signed-off-by: Russell King <[email protected]>
| -rw-r--r-- | arch/arm/include/asm/pgtable-3level.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h index 4dce1580bc15..2a029bceaf2f 100644 --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -250,10 +250,10 @@ PMD_BIT_FUNC(mkyoung, |= PMD_SECT_AF); #define pfn_pmd(pfn,prot) (__pmd(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))) #define mk_pmd(page,prot) pfn_pmd(page_to_pfn(page),prot) -/* represent a notpresent pmd by zero, this is used by pmdp_invalidate */ +/* represent a notpresent pmd by faulting entry, this is used by pmdp_invalidate */ static inline pmd_t pmd_mknotpresent(pmd_t pmd) { - return __pmd(0); + return __pmd(pmd_val(pmd) & ~L_PMD_SECT_VALID); } static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) |