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author | Will Deacon <will.deacon@arm.com> | 2015-03-23 19:07:02 (GMT) |
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committer | Will Deacon <will.deacon@arm.com> | 2015-04-01 09:24:31 (GMT) |
commit | 905e8c5dcaa147163672b06fe9dcb5abaacbc711 (patch) | |
tree | 4284f6e2ecac493b6e4938e4b60e57fb521c3790 /arch/arm64/Kconfig | |
parent | cc3979b54d5f1d5b5059b404892888c304d28080 (diff) | |
download | linux-905e8c5dcaa147163672b06fe9dcb5abaacbc711.tar.xz |
arm64: errata: add workaround for cortex-a53 erratum #845719
When running a compat (AArch32) userspace on Cortex-A53, a load at EL0
from a virtual address that matches the bottom 32 bits of the virtual
address used by a recent load at (AArch64) EL1 might return incorrect
data.
This patch works around the issue by writing to the contextidr_el1
register on the exception return path when returning to a 32-bit task.
This workaround is patched in at runtime based on the MIDR value of the
processor.
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/Kconfig')
-rw-r--r-- | arch/arm64/Kconfig | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 02f67a9..23d51be 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -361,6 +361,27 @@ config ARM64_ERRATUM_832075 If unsure, say Y. +config ARM64_ERRATUM_845719 + bool "Cortex-A53: 845719: a load might read incorrect data" + depends on COMPAT + default y + help + This option adds an alternative code sequence to work around ARM + erratum 845719 on Cortex-A53 parts up to r0p4. + + When running a compat (AArch32) userspace on an affected Cortex-A53 + part, a load at EL0 from a virtual address that matches the bottom 32 + bits of the virtual address used by a recent load at (AArch64) EL1 + might return incorrect data. + + The workaround is to write the contextidr_el1 register on exception + return to a 32-bit task. + Please note that this does not necessarily enable the workaround, + as it depends on the alternative framework, which will only patch + the kernel if an affected CPU is detected. + + If unsure, say Y. + endmenu |