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| author | Catalin Marinas <catalin.marinas@arm.com> | 2016-08-11 18:44:50 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2016-08-25 18:00:29 +0100 |
| commit | cab15ce604e550020bb7115b779013b91bcdbc21 (patch) | |
| tree | 0ba025b8ad16505532aaa6e1b4cc665473f026fa /arch/arm64/include/asm/pgtable.h | |
| parent | 7419333fa15ec958d12845fcc79b7bdd16de06ec (diff) | |
| download | linux-cab15ce604e550020bb7115b779013b91bcdbc21.tar.gz linux-cab15ce604e550020bb7115b779013b91bcdbc21.tar.bz2 linux-cab15ce604e550020bb7115b779013b91bcdbc21.zip | |
arm64: Introduce execute-only page access permissions
The ARMv8 architecture allows execute-only user permissions by clearing
the PTE_UXN and PTE_USER bits. However, the kernel running on a CPU
implementation without User Access Override (ARMv8.2 onwards) can still
access such page, so execute-only page permission does not protect
against read(2)/write(2) etc. accesses. Systems requiring such
protection must enable features like SECCOMP.
This patch changes the arm64 __P100 and __S100 protection_map[] macros
to the new __PAGE_EXECONLY attributes. A side effect is that
pte_user() no longer triggers for __PAGE_EXECONLY since PTE_USER isn't
set. To work around this, the check is done on the PTE_NG bit via the
pte_ng() macro. VM_READ is also checked now for page faults.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/pgtable.h')
| -rw-r--r-- | arch/arm64/include/asm/pgtable.h | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index e20bd431184a..7ba1cebb64d9 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -73,7 +73,7 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; #define pte_write(pte) (!!(pte_val(pte) & PTE_WRITE)) #define pte_exec(pte) (!(pte_val(pte) & PTE_UXN)) #define pte_cont(pte) (!!(pte_val(pte) & PTE_CONT)) -#define pte_user(pte) (!!(pte_val(pte) & PTE_USER)) +#define pte_ng(pte) (!!(pte_val(pte) & PTE_NG)) #ifdef CONFIG_ARM64_HW_AFDBM #define pte_hw_dirty(pte) (pte_write(pte) && !(pte_val(pte) & PTE_RDONLY)) @@ -84,8 +84,8 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; #define pte_dirty(pte) (pte_sw_dirty(pte) || pte_hw_dirty(pte)) #define pte_valid(pte) (!!(pte_val(pte) & PTE_VALID)) -#define pte_valid_not_user(pte) \ - ((pte_val(pte) & (PTE_VALID | PTE_USER)) == PTE_VALID) +#define pte_valid_global(pte) \ + ((pte_val(pte) & (PTE_VALID | PTE_NG)) == PTE_VALID) #define pte_valid_young(pte) \ ((pte_val(pte) & (PTE_VALID | PTE_AF)) == (PTE_VALID | PTE_AF)) @@ -168,7 +168,7 @@ static inline void set_pte(pte_t *ptep, pte_t pte) * Only if the new pte is valid and kernel, otherwise TLB maintenance * or update_mmu_cache() have the necessary barriers. */ - if (pte_valid_not_user(pte)) { + if (pte_valid_global(pte)) { dsb(ishst); isb(); } @@ -202,7 +202,7 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_val(pte) &= ~PTE_RDONLY; else pte_val(pte) |= PTE_RDONLY; - if (pte_user(pte) && pte_exec(pte) && !pte_special(pte)) + if (pte_ng(pte) && pte_exec(pte) && !pte_special(pte)) __sync_icache_dcache(pte, addr); } |