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authorWill Deacon <will.deacon@arm.com>2012-08-24 15:20:59 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-08-25 09:15:56 +0100
commitdbece45894d3ab1baac15a96dc4e1e8e23f64a93 (patch)
treea1454fd7596c527fdcedde312b89679941b7061c /arch
parentd968d2b801d877601d54e35e6dd0f52d9c797c99 (diff)
downloadop-kernel-dev-dbece45894d3ab1baac15a96dc4e1e8e23f64a93.zip
op-kernel-dev-dbece45894d3ab1baac15a96dc4e1e8e23f64a93.tar.gz
ARM: 7501/1: decompressor: reset ttbcr for VMSA ARMv7 cores
When enabling the MMU for ARMv7 CPUs, the decompressor does not touch the ttbcr register, assuming that it will be zeroed (N == 0, EAE == 0). Given that only EAE is defined as 0 for non-secure copies of the register (and a bootloader such as kexec may leave it set to 1 anyway), we should ensure that we reset the register ourselves before turning on the MMU. This patch zeroes TTBCR.EAE and TTBCR.N prior to enabling the MMU for ARMv7 cores in the decompressor, configuring us exclusively for 32-bit translation tables via TTBR0. Cc: <stable@vger.kernel.org> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Matthew Leach <matthew.leach@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/boot/compressed/head.S4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index b8c64b8..81769c1 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -659,10 +659,14 @@ __armv7_mmu_cache_on:
#ifdef CONFIG_CPU_ENDIAN_BE8
orr r0, r0, #1 << 25 @ big-endian page tables
#endif
+ mrcne p15, 0, r6, c2, c0, 2 @ read ttb control reg
orrne r0, r0, #1 @ MMU enabled
movne r1, #0xfffffffd @ domain 0 = client
+ bic r6, r6, #1 << 31 @ 32-bit translation system
+ bic r6, r6, #3 << 0 @ use only ttbr0
mcrne p15, 0, r3, c2, c0, 0 @ load page table pointer
mcrne p15, 0, r1, c3, c0, 0 @ load domain access control
+ mcrne p15, 0, r6, c2, c0, 2 @ load ttb control
#endif
mcr p15, 0, r0, c7, c5, 4 @ ISB
mcr p15, 0, r0, c1, c0, 0 @ load control register
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