Messages in this thread Patch in this message | | | From | Catalin Marinas <> | Subject | [PATCH v7 01/16] ARM: LPAE: add ISBs around MMU enabling code | Date | Wed, 10 Aug 2011 16:03:24 +0100 |
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From: Will Deacon <will.deacon@arm.com>
Before we enable the MMU, we must ensure that the TTBR registers contain sane values. After the MMU has been enabled, we jump to the *virtual* address of the following function, so we also need to ensure that the SCTLR write has taken effect.
This patch adds ISB instructions around the SCTLR write to ensure the visibility of the above.
Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> --- arch/arm/boot/compressed/head.S | 1 + arch/arm/include/asm/assembler.h | 11 +++++++++++ arch/arm/kernel/head.S | 2 ++ arch/arm/kernel/sleep.S | 2 ++ 4 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index e95a598..716c7ba 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -551,6 +551,7 @@ __armv7_mmu_cache_on: mcrne p15, 0, r3, c2, c0, 0 @ load page table pointer mcrne p15, 0, r1, c3, c0, 0 @ load domain access control #endif + mcr p15, 0, r0, c7, c5, 4 @ ISB mcr p15, 0, r0, c1, c0, 0 @ load control register mrc p15, 0, r0, c1, c0, 0 @ and read it back mov r0, #0 diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 29035e8..b6e65de 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -187,6 +187,17 @@ #endif /* + * Instruction barrier + */ + .macro instr_sync +#if __LINUX_ARM_ARCH__ >= 7 + isb +#elif __LINUX_ARM_ARCH__ == 6 + mcr p15, 0, r0, c7, c5, 4 +#endif + .endm + +/* * SMP data memory barrier */ .macro smp_dmb mode diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 742b610..d8231b2 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -396,8 +396,10 @@ ENDPROC(__enable_mmu) .align 5 __turn_mmu_on: mov r0, r0 + instr_sync mcr p15, 0, r0, c1, c0, 0 @ write control reg mrc p15, 0, r3, c0, c0, 0 @ read id reg + instr_sync mov r3, r3 mov r3, r13 mov pc, r3 diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S index dc902f2..ecece65 100644 --- a/arch/arm/kernel/sleep.S +++ b/arch/arm/kernel/sleep.S @@ -85,8 +85,10 @@ ENDPROC(cpu_resume_mmu) .ltorg .align 5 cpu_resume_turn_mmu_on: + instr_sync mcr p15, 0, r1, c1, c0, 0 @ turn on MMU, I-cache, etc mrc p15, 0, r1, c0, c0, 0 @ read id reg + instr_sync mov r1, r1 mov r1, r1 mov pc, r3 @ jump to virtual address
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