[PATCH v2] arm64: Add workaround for Cavium erratum 27456
From: David Daney <hidden>
Date: 2016-02-09 21:16:49
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), documentation, the rest · Maintainers:
Catalin Marinas, Will Deacon, Jonathan Corbet, Linus Torvalds
From: Andrew Pinski <redacted> On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI instructions may cause the icache to become invalid if it contains data for a non-current ASID. This patch implements the workaround (which flushes the local icache when switching the mm) by using code patching. Signed-off-by: Andrew Pinski <redacted> Signed-off-by: David Daney <redacted> --- Changes from v1: Add entry to silicon-errata.txt Documentation/arm64/silicon-errata.txt | 1 + arch/arm64/Kconfig | 11 +++++++++++ arch/arm64/include/asm/cpufeature.h | 3 ++- arch/arm64/kernel/cpu_errata.c | 9 +++++++++ arch/arm64/mm/proc.S | 12 ++++++++++++ 5 files changed, 35 insertions(+), 1 deletion(-)
diff --git a/Documentation/arm64/silicon-errata.txt b/Documentation/arm64/silicon-errata.txt
index 58b71dd..ba4b6ac 100644
--- a/Documentation/arm64/silicon-errata.txt
+++ b/Documentation/arm64/silicon-errata.txt@@ -56,3 +56,4 @@ stable kernels. | | | | | | Cavium | ThunderX ITS | #22375, #24313 | CAVIUM_ERRATUM_22375 | | Cavium | ThunderX GICv3 | #23154 | CAVIUM_ERRATUM_23154 | +| Cavium | ThunderX Core | #27456 | CAVIUM_ERRATUM_27456 |
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 8cc6228..a969970 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig@@ -432,6 +432,17 @@ config CAVIUM_ERRATUM_23154 If unsure, say Y. +config CAVIUM_ERRATUM_27456 + bool "Cavium erratum 27456: Broadcast TLBI instructions may cause the icache to become invalid" + default y + help + On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI + instructions may cause the icache to become invalid if it + contains data for a non-current ASID. The fix is to flush + the icache when changing the mm context. + + If unsure, say Y. + endmenu
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 8f271b8..8136afc 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h@@ -30,8 +30,9 @@ #define ARM64_HAS_LSE_ATOMICS 5 #define ARM64_WORKAROUND_CAVIUM_23154 6 #define ARM64_WORKAROUND_834220 7 +#define ARM64_WORKAROUND_CAVIUM_27456 8 -#define ARM64_NCAPS 8 +#define ARM64_NCAPS 9 #ifndef __ASSEMBLY__
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index feb6b4e..a3e846a 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c@@ -100,6 +100,15 @@ const struct arm64_cpu_capabilities arm64_errata[] = { MIDR_RANGE(MIDR_THUNDERX, 0x00, 0x01), }, #endif +#ifdef CONFIG_CAVIUM_ERRATUM_27456 + { + /* Cavium ThunderX, T88 pass 1.x - 2.1 */ + .desc = "Cavium erratum 27456", + .capability = ARM64_WORKAROUND_CAVIUM_27456, + MIDR_RANGE(MIDR_THUNDERX, 0x00, + (1 << MIDR_VARIANT_SHIFT) | 1), + }, +#endif { } };
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index c164d2c..0f3be00 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S@@ -25,6 +25,8 @@ #include <asm/hwcap.h> #include <asm/pgtable-hwdef.h> #include <asm/pgtable.h> +#include <asm/cpufeature.h> +#include <asm/alternative.h> #include "proc-macros.S"
@@ -137,7 +139,17 @@ ENTRY(cpu_do_switch_mm) bfi x0, x1, #48, #16 // set the ASID msr ttbr0_el1, x0 // set TTBR0 isb +alternative_if_not ARM64_WORKAROUND_CAVIUM_27456 ret + nop + nop + nop +alternative_else + ic iallu + dsb nsh + isb + ret +alternative_endif ENDPROC(cpu_do_switch_mm) /*
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1.8.3.1