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authorWill Deacon <will.deacon@arm.com>2010-09-28 14:02:02 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-10-04 19:20:14 +0100
commit475d92fc6e72cd123dc5dbb9e70cdb80b0cfdf2d (patch)
treec2c3e98575957a0eab1492da35921c982c5d2e1e
parentc6ea21e35bf3691cad59647c771e6606067f627d (diff)
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ARM: 6416/1: errata: faulty hazard checking in the Store Buffer may lead to data corruption
On the r2p0, r2p1 and r2p2 versions of the Cortex-A9, data corruption can occur under very rare conditions due to a store buffer optimisation. This workaround sets a bit in the diagnostic register of the Cortex-A9, disabling the optimisation and preventing the problem from occurring. Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/Kconfig14
-rw-r--r--arch/arm/mm/proc-v7.S8
2 files changed, 22 insertions, 0 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 88c97bc7a6f..9c26ba7244f 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1101,6 +1101,20 @@ config ARM_ERRATA_720789
invalidated are not, resulting in an incoherency in the system page
tables. The workaround changes the TLB flushing routines to invalidate
entries regardless of the ASID.
+
+config ARM_ERRATA_743622
+ bool "ARM errata: Faulty hazard checking in the Store Buffer may lead to data corruption"
+ depends on CPU_V7
+ help
+ This option enables the workaround for the 743622 Cortex-A9
+ (r2p0..r2p2) erratum. Under very rare conditions, a faulty
+ optimisation in the Cortex-A9 Store Buffer may lead to data
+ corruption. This workaround sets a specific bit in the diagnostic
+ register of the Cortex-A9 which disables the Store Buffer
+ optimisation, preventing the defect from occurring. This has no
+ visible impact on the overall performance or power consumption of the
+ processor.
+
endmenu
source "arch/arm/common/Kconfig"
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 7563ff0141b..75619c55f13 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -253,6 +253,14 @@ __v7_setup:
orreq r10, r10, #1 << 22 @ set bit #22
mcreq p15, 0, r10, c15, c0, 1 @ write diagnostic register
#endif
+#ifdef CONFIG_ARM_ERRATA_743622
+ teq r6, #0x20 @ present in r2p0
+ teqne r6, #0x21 @ present in r2p1
+ teqne r6, #0x22 @ present in r2p2
+ mrceq p15, 0, r10, c15, c0, 1 @ read diagnostic register
+ orreq r10, r10, #1 << 6 @ set bit #6
+ mcreq p15, 0, r10, c15, c0, 1 @ write diagnostic register
+#endif
3: mov r10, #0
#ifdef HARVARD_CACHE