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| author | Mark Rutland <mark.rutland@arm.com> | 2014-08-15 12:11:50 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2014-08-27 15:40:13 +0100 |
| commit | 2c32c65e3726c773760038910be30cce1b4d4149 (patch) | |
| tree | 5882204a965a7b819f20bc8cc7ae33088d3bde88 /arch/arm/mach-exynos | |
| parent | 85868313177700d20644263a782351262d2aff84 (diff) | |
| download | linux-2c32c65e3726c773760038910be30cce1b4d4149.tar.bz2 | |
ARM: 8129/1: errata: work around Cortex-A15 erratum 830321 using dummy strex
On revisions of Cortex-A15 prior to r3p3, a CLREX instruction at PL1 may
falsely trigger a watchpoint exception, leading to potential data aborts
during exception return and/or livelock.
This patch resolves the issue in the following ways:
- Replacing our uses of CLREX with a dummy STREX sequence instead (as
we did for v6 CPUs).
- Removing the clrex code from v7_exit_coherency_flush and derivatives,
since this only exists as a minor performance improvement when
non-cached exclusives are in use (Linux doesn't use these).
Benchmarking on a variety of ARM cores revealed no measurable
performance difference with this change applied, so the change is
performed unconditionally and no new Kconfig entry is added.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-exynos')
| -rw-r--r-- | arch/arm/mach-exynos/mcpm-exynos.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c index b2f8b60cf0e9..dc9a764a7c37 100644 --- a/arch/arm/mach-exynos/mcpm-exynos.c +++ b/arch/arm/mach-exynos/mcpm-exynos.c @@ -43,7 +43,6 @@ "mcr p15, 0, r0, c1, c0, 0 @ set SCTLR\n\t" \ "isb\n\t"\ "bl v7_flush_dcache_"__stringify(level)"\n\t" \ - "clrex\n\t"\ "mrc p15, 0, r0, c1, c0, 1 @ get ACTLR\n\t" \ "bic r0, r0, #(1 << 6) @ disable local coherency\n\t" \ /* Dummy Load of a device register to avoid Erratum 799270 */ \ |