diff options
| author | Catalin Marinas <catalin.marinas@arm.com> | 2017-10-26 18:36:47 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-30 08:39:01 +0000 |
| commit | e5380004ee78a6090a52a6b8deb44577ec70daa8 (patch) | |
| tree | a881b07920b9bdb721cd31fac1f8553be55c63d2 /arch/arm64/include | |
| parent | 0d794d0d018f23fb09c50f6ae26868bd6ae343d6 (diff) | |
arm64: Implement arch-specific pte_access_permitted()
commit 6218f96c58dbf44a06aeaf767aab1f54fc397838 upstream.
The generic pte_access_permitted() implementation only checks for
pte_present() (together with the write permission where applicable).
However, for both kernel ptes and PROT_NONE mappings pte_present() also
returns true on arm64 even though such mappings are not user accessible.
Additionally, arm64 now supports execute-only user permission
(PROT_EXEC) which is implemented by clearing the PTE_USER bit.
With this patch the arm64 implementation of pte_access_permitted()
checks for the PTE_VALID and PTE_USER bits together with writable access
if applicable.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm64/include')
| -rw-r--r-- | arch/arm64/include/asm/pgtable.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 61e214015b38..7acd3c5c7643 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -91,6 +91,8 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; ((pte_val(pte) & (PTE_VALID | PTE_USER | PTE_UXN)) == (PTE_VALID | PTE_UXN)) #define pte_valid_young(pte) \ ((pte_val(pte) & (PTE_VALID | PTE_AF)) == (PTE_VALID | PTE_AF)) +#define pte_valid_user(pte) \ + ((pte_val(pte) & (PTE_VALID | PTE_USER)) == (PTE_VALID | PTE_USER)) /* * Could the pte be present in the TLB? We must check mm_tlb_flush_pending @@ -100,6 +102,18 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; #define pte_accessible(mm, pte) \ (mm_tlb_flush_pending(mm) ? pte_present(pte) : pte_valid_young(pte)) +/* + * p??_access_permitted() is true for valid user mappings (subject to the + * write permission check) other than user execute-only which do not have the + * PTE_USER bit set. PROT_NONE mappings do not have the PTE_VALID bit set. + */ +#define pte_access_permitted(pte, write) \ + (pte_valid_user(pte) && (!(write) || pte_write(pte))) +#define pmd_access_permitted(pmd, write) \ + (pte_access_permitted(pmd_pte(pmd), (write))) +#define pud_access_permitted(pud, write) \ + (pte_access_permitted(pud_pte(pud), (write))) + static inline pte_t clear_pte_bit(pte_t pte, pgprot_t prot) { pte_val(pte) &= ~pgprot_val(prot); |