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| author | Catalin Marinas <catalin.marinas@arm.com> | 2014-04-03 17:17:32 +0200 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2014-05-09 16:53:36 +0200 |
| commit | bc07c2c6e9ed125d362af0214b6313dca180cb08 (patch) | |
| tree | a5a63f1272c11e321999145b8b7e8135b094aaaa /arch/arm64/kernel/sys.c | |
| parent | arm64: Expose ESR_EL1 information to user when SIGSEGV/SIGBUS (diff) | |
| download | linux-bc07c2c6e9ed125d362af0214b6313dca180cb08.tar.xz linux-bc07c2c6e9ed125d362af0214b6313dca180cb08.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. The kernel, however, 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
implement/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_valid_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_valid_ng() macro. VM_READ is also checked now for page faults.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/sys.c')
0 files changed, 0 insertions, 0 deletions