diff options
| author | Will Deacon <will.deacon@arm.com> | 2012-09-01 05:22:12 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-04-30 16:23:19 +0100 |
| commit | 960bd8ae3e6402a0409b11ed18a7ba9aaf69c3c5 (patch) | |
| tree | 2d6d6beb50ddbc3cc400f4e38872ca2abfe5a61c /arch/arm/mm/proc-v7.S | |
| parent | 25f60b0397e698cce0473c7c9ff321b7765434d3 (diff) | |
ARM: mm: introduce present, faulting entries for PAGE_NONE
commit 26ffd0d43b186b0d5186354da8714a1c2d360df0 upstream.
PROT_NONE mappings apply the page protection attributes defined by _P000
which translate to PAGE_NONE for ARM. These attributes specify an XN,
RDONLY pte that is inaccessible to userspace. However, on kernels
configured without support for domains, such a pte *is* accessible to
the kernel and can be read via get_user, allowing tasks to read
PROT_NONE pages via syscalls such as read/write over a pipe.
This patch introduces a new software pte flag, L_PTE_NONE, that is set
to identify faulting, present entries.
Signed-off-by: Will Deacon <will.deacon@arm.com>
[bwh: Backported to 3.2 as dependency of commit b6ccb9803e90
('ARM: 7954/1: mm: remove remaining domain support from ARMv6'):
- Drop 3-level changes
- Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/arm/mm/proc-v7.S')
| -rw-r--r-- | arch/arm/mm/proc-v7.S | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 19d21ff27b0e..21b09f2605c4 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -171,6 +171,10 @@ ENTRY(cpu_v7_set_pte_ext) tst r1, #L_PTE_YOUNG tstne r1, #L_PTE_PRESENT +#ifndef CONFIG_CPU_USE_DOMAINS + eorne r1, r1, #L_PTE_NONE + tstne r1, #L_PTE_NONE +#endif moveq r3, #0 ARM( str r3, [r0, #2048]! ) |