The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 9405447ef79bc93101373e130f72e9e6cbf17dbb Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@xxxxxxxxxx>
Date: Tue, 9 Apr 2019 16:22:24 +0100
Subject: [PATCH] arm64: Avoid Cavium TX2 erratum 219 when switching TTBR
As a PRFM instruction racing against a TTBR update can have undesirable
effects on TX2, NOP-out such PRFM on cores that are affected by
the TX2-219 erratum.
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index e81e0cbd728f..ac1dbca3d0cd 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -53,7 +53,8 @@
#define ARM64_HAS_DCPODP 43
#define ARM64_WORKAROUND_1463225 44
#define ARM64_WORKAROUND_CAVIUM_TX2_219_TVM 45
+#define ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM 46
-#define ARM64_NCAPS 46
+#define ARM64_NCAPS 47
#endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index d999ca2dd760..a19bb3e4bcfb 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -884,6 +884,11 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
ERRATA_MIDR_RANGE_LIST(tx2_family_cpus),
.matches = needs_tx2_tvm_workaround,
},
+ {
+ .desc = "Cavium ThunderX2 erratum 219 (PRFM removal)",
+ .capability = ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM,
+ ERRATA_MIDR_RANGE_LIST(tx2_family_cpus),
+ },
#endif
{
}
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 84a822748c84..109894bd3194 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -1070,7 +1070,9 @@ alternative_insn isb, nop, ARM64_WORKAROUND_QCOM_FALKOR_E1003
#else
ldr x30, =vectors
#endif
+alternative_if_not ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM
prfm plil1strm, [x30, #(1b - tramp_vectors)]
+alternative_else_nop_endif
msr vbar_el1, x30
add x30, x30, #(1b - tramp_vectors)
isb
