[PATCH] ARM: mm: ensure TLB invalidation is complete before enabling MMU
From: Will Deacon <hidden>
Date: 2014-02-04 12:28:22
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
During __v{6,7}_setup, we invalidate the TLBs since we are about to
enable the MMU on return to head.S. Unfortunately, without a subsequent
dsb instruction, the invalidation is not guaranteed to have completed by
the time we write to the sctlr, potentially exposing us to junk/stale
translations cached in the TLB.
This patch reworks the init functions so that the dsb used to ensure
completion of cache/predictor maintenance is also used to ensure
completion of the TLB invalidation.
Cc: <redacted>
Reported-by: Albin Tonnerre <redacted>
Signed-off-by: Will Deacon <redacted>
---
arch/arm/mm/proc-v6.S | 3 ++-
arch/arm/mm/proc-v7.S | 2 +-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S
index 45dc29f85d56..32b3558321c4 100644
--- a/arch/arm/mm/proc-v6.S
+++ b/arch/arm/mm/proc-v6.S@@ -208,7 +208,6 @@ __v6_setup: mcr p15, 0, r0, c7, c14, 0 @ clean+invalidate D cache mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache mcr p15, 0, r0, c7, c15, 0 @ clean+invalidate cache - mcr p15, 0, r0, c7, c10, 4 @ drain write buffer #ifdef CONFIG_MMU mcr p15, 0, r0, c8, c7, 0 @ invalidate I + D TLBs mcr p15, 0, r0, c2, c0, 2 @ TTB control register
@@ -218,6 +217,8 @@ __v6_setup: ALT_UP(orr r8, r8, #TTB_FLAGS_UP) mcr p15, 0, r8, c2, c0, 1 @ load TTB1 #endif /* CONFIG_MMU */ + mcr p15, 0, r0, c7, c10, 4 @ drain write buffer and + @ complete invalidations adr r5, v6_crval ldmia r5, {r5, r6} ARM_BE8(orr r6, r6, #1 << 25) @ big-endian page tables
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index bd1781979a39..74f6033e76dd 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S@@ -351,7 +351,6 @@ __v7_setup: 4: mov r10, #0 mcr p15, 0, r10, c7, c5, 0 @ I+BTB cache invalidate - dsb #ifdef CONFIG_MMU mcr p15, 0, r10, c8, c7, 0 @ invalidate I + D TLBs v7_ttb_setup r10, r4, r8, r5 @ TTBCR, TTBRx setup
@@ -360,6 +359,7 @@ __v7_setup: mcr p15, 0, r5, c10, c2, 0 @ write PRRR mcr p15, 0, r6, c10, c2, 1 @ write NMRR #endif + dsb @ Complete invalidations #ifndef CONFIG_ARM_THUMBEE mrc p15, 0, r0, c0, c1, 0 @ read ID_PFR0 for ThumbEE and r0, r0, #(0xf << 12) @ ThumbEE enabled field
--
1.8.2.2