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authorZhang Lei <zhang.lei@jp.fujitsu.com>2019-02-26 18:43:41 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2019-02-28 16:24:25 +0000
commit3e32131abc311a5cb9fddecc72cbd0b95ffcc10d (patch)
tree7f3c6887b2ea7c18d9d7929cdd9123cae95e0038 /arch/arm64/Kconfig
parentarm64: Rename get_thread_info() (diff)
downloadlinux-dev-3e32131abc311a5cb9fddecc72cbd0b95ffcc10d.tar.xz
linux-dev-3e32131abc311a5cb9fddecc72cbd0b95ffcc10d.zip
arm64: Add workaround for Fujitsu A64FX erratum 010001
On the Fujitsu-A64FX cores ver(1.0, 1.1), memory access may cause an undefined fault (Data abort, DFSC=0b111111). This fault occurs under a specific hardware condition when a load/store instruction performs an address translation. Any load/store instruction, except non-fault access including Armv8 and SVE might cause this undefined fault. The TCR_ELx.NFD1 bit is used by the kernel when CONFIG_RANDOMIZE_BASE is enabled to mitigate timing attacks against KASLR where the kernel address space could be probed using the FFR and suppressed fault on SVE loads. Since this erratum causes spurious exceptions, which may corrupt the exception registers, we clear the TCR_ELx.NFDx=1 bits when booting on an affected CPU. Signed-off-by: Zhang Lei <zhang.lei@jp.fujitsu.com> [Generated MIDR value/mask for __cpu_setup(), removed spurious-fault handler and always disabled the NFDx bits on affected CPUs] Signed-off-by: James Morse <james.morse@arm.com> Tested-by: zhang.lei <zhang.lei@jp.fujitsu.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to '')
-rw-r--r--arch/arm64/Kconfig19
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c7a44bcfc385..3fd266a177b5 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -643,6 +643,25 @@ config QCOM_FALKOR_ERRATUM_E1041
If unsure, say Y.
+config FUJITSU_ERRATUM_010001
+ bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
+ default y
+ help
+ This option adds workaround for Fujitsu-A64FX erratum E#010001.
+ On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
+ accesses may cause undefined fault (Data abort, DFSC=0b111111).
+ This fault occurs under a specific hardware condition when a
+ load/store instruction performs an address translation using:
+ case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1.
+ case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1.
+ case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1.
+ case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1.
+
+ The workaround is to ensure these bits are clear in TCR_ELx.
+ The workaround only affect the Fujitsu-A64FX.
+
+ If unsure, say Y.
+
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