From dbece45894d3ab1baac15a96dc4e1e8e23f64a93 Mon Sep 17 00:00:00 2001 From: Will Deacon <will.deacon@arm.com> Date: Fri, 24 Aug 2012 15:20:59 +0100 Subject: [PATCH] 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> --- arch/arm/boot/compressed/head.S | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index b8c64b80bafc8..81769c1341fa7 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 -- GitLab