diff options
| author | Steve Capper <steve.capper@arm.com> | 2016-06-07 17:58:06 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2016-08-22 22:38:14 +0100 |
| commit | 9919761a5db2b0477f3f3a8746ac4ec582540b02 (patch) | |
| tree | 0b5f63fc5f2df8763329bed85a6abeb20802c1fb /arch | |
| parent | 9ad40548364a11604a1a82ac22a903e3127d56cd (diff) | |
ARM: 8579/1: mm: Fix definition of pmd_mknotpresent
commit 56530f5d2ddc9b9fade7ef8db9cb886e9dc689b5 upstream.
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.
[catalin.marinas@arm.com: using L_PMD_SECT_VALID instead of PMD_TYPE_SECT]
Fixes: 8d9625070073 ("ARM: mm: Transparent huge page support for LPAE systems.")
Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[bwh: Backported to 3.16: also convert from a macro to a function, as done
earlier upstream]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/include/asm/pgtable-3level.h | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h index ab7ee9205ca4..40d60a679fc8 100644 --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -243,8 +243,11 @@ 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 */ -#define pmd_mknotpresent(pmd) (__pmd(0)) +/* represent a notpresent pmd by faulting entry, this is used by pmdp_invalidate */ +static inline pmd_t pmd_mknotpresent(pmd_t pmd) +{ + return __pmd(pmd_val(pmd) & ~L_PMD_SECT_VALID); +} static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) { |