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| author | Catalin Marinas <catalin.marinas@arm.com> | 2016-03-09 16:31:29 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-12 07:33:34 -0700 |
| commit | a47d746eb510afbba2aefcdd52494e3bf44936f2 (patch) | |
| tree | 45561580902da77398c5968e5c6c99578904d933 /arch | |
| parent | ba6d9e63dc9c43466ce711e685c2fb483749e0ab (diff) | |
| download | lwn-a47d746eb510afbba2aefcdd52494e3bf44936f2.tar.gz lwn-a47d746eb510afbba2aefcdd52494e3bf44936f2.zip | |
arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE permission
commit fdc69e7df3cb24f18a93192641786e5b7ecd1dfe upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/pgtable.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 819aff5d593f..7273210782d5 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -279,7 +279,7 @@ 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 @@ -649,6 +649,7 @@ 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 |