lkml.org 
[lkml]   [2011]   [May]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v6 02/18] ARM: LPAE: add ISBs around MMU enabling code
Date
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 49f5b2e..ef22486 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -526,6 +526,7 @@ __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 bc2d2d7..2bcc456 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -184,6 +184,17 @@
#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 8224b1d..b7101ff 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 6398ead..1ac5dce 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


\
 
 \ /
  Last update: 2011-05-24 23:41    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site