From fcbdc5fe6ebe07d502c9b652cb63376bcc4227ac Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 28 Feb 2011 18:15:16 +0100 Subject: [PATCH] ARM: 6772/1: errata: possible fault MMU translations following an ASID switch On the r2p* and r3p* versions of the Cortex-A9, a speculative memory access may cause a page table walk which starts prior to an ASID switch but completes afterwards. This can populate the micro-TLB with a stale entry which may be hit with the new ASID. This workaround places two dsb instructions in the mm switching code so that no page table walks can cross the ASID switch. Acked-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/Kconfig | 11 +++++++++++ arch/arm/mm/proc-v7.S | 6 ++++++ 2 files changed, 17 insertions(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 166efa2a19c..ec0f6589af0 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1202,6 +1202,17 @@ config ARM_ERRATA_753970 This has the same effect as the cache sync operation: store buffer drain and waiting for all buffers empty. +config ARM_ERRATA_754322 + bool "ARM errata: possible faulty MMU translations following an ASID switch" + depends on CPU_V7 + help + This option enables the workaround for the 754322 Cortex-A9 (r2p*, + r3p*) erratum. A speculative memory access may cause a page table walk + which starts prior to an ASID switch but completes afterwards. This + can populate the micro-TLB with a stale entry which may be hit with + the new ASID. This workaround places two dsb instructions in the mm + switching code so that no page table walks can cross the ASID switch. + endmenu source "arch/arm/common/Kconfig" diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 8e335623913..f7498f1a2e8 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -107,11 +107,17 @@ ENTRY(cpu_v7_switch_mm) ALT_UP(orr r0, r0, #TTB_FLAGS_UP) #ifdef CONFIG_ARM_ERRATA_430973 mcr p15, 0, r2, c7, c5, 6 @ flush BTAC/BTB +#endif +#ifdef CONFIG_ARM_ERRATA_754322 + dsb #endif mcr p15, 0, r2, c13, c0, 1 @ set reserved context ID isb 1: mcr p15, 0, r0, c2, c0, 0 @ set TTB 0 isb +#ifdef CONFIG_ARM_ERRATA_754322 + dsb +#endif mcr p15, 0, r1, c13, c0, 1 @ set context ID isb #endif -- 2.39.2