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>
This commit is contained in:
Will Deacon 2010-09-28 14:02:02 +01:00 committed by Russell King
parent c6ea21e35b
commit 475d92fc6e
2 changed files with 22 additions and 0 deletions

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@ -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"

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@ -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