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Subject[PATCH 4.4 045/131] ARM: 8494/1: mm: Enable PXN when running non-LPAE kernel on LPAE processor
Date
4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit ad84f56bf6d620fe6ed4d57ce6ec9945684d7f35 ]

The VMSA field of MMFR0 (bottom 4 bits) is incremented for each
added feature. PXN is supported if the value is >= 4 and LPAE
is supported if it is >= 5.

In case a kernel with CONFIG_ARM_LPAE disabled is used on a
processor that supports LPAE, we can still use PXN in short
descriptors. So check for >= 4 not == 4.

Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm/mm/mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index e47cffd25c6c..aead23f15213 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -572,7 +572,7 @@ static void __init build_mem_type_table(void)
* in the Short-descriptor translation table format descriptors.
*/
if (cpu_arch == CPU_ARCH_ARMv7 &&
- (read_cpuid_ext(CPUID_EXT_MMFR0) & 0xF) == 4) {
+ (read_cpuid_ext(CPUID_EXT_MMFR0) & 0xF) >= 4) {
user_pmd_table |= PMD_PXNTABLE;
}
#endif
--
2.19.1


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