From 9ceec7231360cb63e72607b943dd60d232eb87a4 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 7 Apr 2011 16:29:22 +0100 Subject: [PATCH] ARM: LPAE: add ISBs around MMU enabling code 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 Signed-off-by: Catalin Marinas --- 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(+) diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index f9da41921c52..706492ab0b4c 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -550,6 +550,7 @@ __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 bc2d2d75f706..2bcc456b6879 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -183,6 +183,17 @@ #define ALT_UP_B(label) b label #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 */ diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 278c1b0ebb2e..5f6bf818d82e 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -388,8 +388,10 @@ 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 6398ead9d1c0..1ac5dcecb2a2 100644 --- a/arch/arm/kernel/sleep.S +++ b/arch/arm/kernel/sleep.S @@ -88,8 +88,10 @@ 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 -- 2.39.5