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ARM: 8861/1: errata: Workaround errata A12 857271 / A17 857272

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This adds support for working around errata A12 857271 / A17 857272.
These errata were causing hangs on rk3288-based Chromebooks and it was
confirmed that this workaround fixed the problems.  In the Chrome OS
3.14 kernel this was treated as two errata: ERRATA_FOOBAR [1] and
ERRATA_CR711784 [2].  Apparently the two errata got lumped together at
some point in time.

Let's actually get the workaround landed.

[1] https://crrev.com/c/342753
[2] https://crbug.com/711784

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Sonny Rao <sonnyrao@chromium.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Doug Anderson 2019-04-26 23:35:46 +01:00 committed by Russell King
parent b777a981d5
commit 304009a182
2 changed files with 28 additions and 0 deletions
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18
arch/arm/Kconfig
View File

@ -1175,6 +1175,14 @@ config ARM_ERRATA_825619
DMB NSHST or DMB ISHST instruction followed by a mix of Cacheable
and Device/Strongly-Ordered loads and stores might cause deadlock
config ARM_ERRATA_857271
bool "ARM errata: A12: CPU might deadlock under some very rare internal conditions"
depends on CPU_V7
help
This option enables the workaround for the 857271 Cortex-A12
(all revs) erratum. Under very rare timing conditions, the CPU might
hang. The workaround is expected to have a < 1% performance impact.
config ARM_ERRATA_852421
bool "ARM errata: A17: DMB ST might fail to create order between stores"
depends on CPU_V7
@ -1196,6 +1204,16 @@ config ARM_ERRATA_852423
config option from the A12 erratum due to the way errata are checked
for and handled.
config ARM_ERRATA_857272
bool "ARM errata: A17: CPU might deadlock under some very rare internal conditions"
depends on CPU_V7
help
This option enables the workaround for the 857272 Cortex-A17 erratum.
This erratum is not known to be fixed in any A17 revision.
This is identical to Cortex-A12 erratum 857271. It is a separate
config option from the A12 erratum due to the way errata are checked
for and handled.
endmenu
source "arch/arm/common/Kconfig"

10
arch/arm/mm/proc-v7.S
View File

@ -391,6 +391,11 @@ __ca12_errata:
mrc p15, 0, r10, c15, c0, 1 @ read diagnostic register
orr r10, r10, #1 << 24 @ set bit #24
mcr p15, 0, r10, c15, c0, 1 @ write diagnostic register
#endif
#ifdef CONFIG_ARM_ERRATA_857271
mrc p15, 0, r10, c15, c0, 1 @ read diagnostic register
orr r10, r10, #3 << 10 @ set bits #10 and #11
mcr p15, 0, r10, c15, c0, 1 @ write diagnostic register
#endif
b __errata_finish
@ -406,6 +411,11 @@ __ca17_errata:
mrcle p15, 0, r10, c15, c0, 1 @ read diagnostic register
orrle r10, r10, #1 << 12 @ set bit #12
mcrle p15, 0, r10, c15, c0, 1 @ write diagnostic register
#endif
#ifdef CONFIG_ARM_ERRATA_857272
mrc p15, 0, r10, c15, c0, 1 @ read diagnostic register
orr r10, r10, #3 << 10 @ set bits #10 and #11
mcr p15, 0, r10, c15, c0, 1 @ write diagnostic register
#endif
b __errata_finish