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authorCatalin Marinas <catalin.marinas@arm.com>2016-03-09 16:31:29 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2016-03-11 11:03:34 +0000
commitfdc69e7df3cb24f18a93192641786e5b7ecd1dfe (patch)
treed0662c6d5f96c6ee153ef8fbaa9f8546a4908d65 /arch/arm64/include/asm/pgtable.h
parentarm64: Fix misspellings in comments. (diff)
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linux-dev-fdc69e7df3cb24f18a93192641786e5b7ecd1dfe.zip
arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE permission
The set_pte_at() function must update the hardware PTE_RDONLY bit depending on the state of the PTE_WRITE and PTE_DIRTY bits of the given entry value. However, it currently only performs this for pte_valid() entries, ignoring PTE_PROT_NONE. The side-effect is that PROT_NONE mappings would not have the PTE_RDONLY bit set. Without CONFIG_ARM64_HW_AFDBM, this is not an issue since such PROT_NONE pages are not accessible anyway. With commit 2f4b829c625e ("arm64: Add support for hardware updates of the access and dirty pte bits"), the ptep_set_wrprotect() function was re-written to cope with automatic hardware updates of the dirty state. As an optimisation, only PTE_RDONLY is checked to assess the "dirty" status. Since set_pte_at() does not set this bit for PROT_NONE mappings, such pages may be considered "dirty" as a result of ptep_set_wrprotect(). This patch updates the pte_valid() check to pte_present() in set_pte_at(). It also adds PTE_PROT_NONE to the swap entry bits comment. Fixes: 2f4b829c625e ("arm64: Add support for hardware updates of the access and dirty pte bits") Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com> Tested-by: Ganapatrao Kulkarni <gkulkarni@cavium.com> Cc: <stable@vger.kernel.org>
Diffstat (limited to '')
-rw-r--r--arch/arm64/include/asm/pgtable.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7c73b365fcfa..e308807105e2 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -201,7 +201,7 @@ extern void __sync_icache_dcache(pte_t pteval, unsigned long addr);
static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
- if (pte_valid(pte)) {
+ if (pte_present(pte)) {
if (pte_sw_dirty(pte) && pte_write(pte))
pte_val(pte) &= ~PTE_RDONLY;
else
@@ -626,6 +626,7 @@ extern pgd_t idmap_pg_dir[PTRS_PER_PGD];
* bits 0-1: present (must be zero)
* bits 2-7: swap type
* bits 8-57: swap offset
+ * bit 58: PTE_PROT_NONE (must be zero)
*/
#define __SWP_TYPE_SHIFT 2
#define __SWP_TYPE_BITS 6