From: Greg KH <[email protected]> 3.5-stable review patch. If anyone has any objections, please let me know.
------------------ From: Will Deacon <[email protected]> commit dbece45894d3ab1baac15a96dc4e1e8e23f64a93 upstream. 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. Acked-by: Nicolas Pitre <[email protected]> Signed-off-by: Matthew Leach <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Russell King <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/arm/boot/compressed/head.S | 4 ++++ 1 file changed, 4 insertions(+) --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
