From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, will@kernel.org,
catalin.marinas@arm.com, mathieu.poirier@linaro.org,
mike.leach@linaro.org, leo.yan@linaro.org,
anshuman.khandual@arm.com, coresight@lists.linaro.org,
maz@kernel.org, james.morse@arm.com, mark.rutland@arm.com,
lcherian@marvell.com, Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH v3 03/16] arm64: errata: Add workaround for TSB flush failures
Date: Fri, 8 Oct 2021 19:28:53 +0100 [thread overview]
Message-ID: <20211008182906.1688009-4-suzuki.poulose@arm.com> (raw)
In-Reply-To: <20211008182906.1688009-1-suzuki.poulose@arm.com>
Arm Neoverse-N2 (#2067961) and Cortex-A710 (#2054223) suffers
from errata, where a TSB (trace synchronization barrier)
fails to flush the trace data completely, when executed from
a trace prohibited region. In Linux we always execute it
after we have moved the PE to trace prohibited region. So,
we can apply the workaround every time a TSB is executed.
The work around is to issue two TSB consecutively.
NOTE: This errata is defined as LOCAL_CPU_ERRATUM, implying
that a late CPU could be blocked from booting if it is the
first CPU that requires the workaround. This is because we
do not allow setting a cpu_hwcaps after the SMP boot. The
other alternative is to use "this_cpu_has_cap()" instead
of the faster system wide check, which may be a bit of an
overhead, given we may have to do this in nvhe KVM host
before a guest entry.
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
Changes since v2:
- Split the Kconfig/erratum list update to a later patch
I have retained the tags, as there were no changes to
the patches as such, except for split and move
---
arch/arm64/include/asm/barrier.h | 16 +++++++++++++++-
arch/arm64/kernel/cpu_errata.c | 19 +++++++++++++++++++
arch/arm64/tools/cpucaps | 1 +
3 files changed, 35 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index 451e11e5fd23..1c5a00598458 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -23,7 +23,7 @@
#define dsb(opt) asm volatile("dsb " #opt : : : "memory")
#define psb_csync() asm volatile("hint #17" : : : "memory")
-#define tsb_csync() asm volatile("hint #18" : : : "memory")
+#define __tsb_csync() asm volatile("hint #18" : : : "memory")
#define csdb() asm volatile("hint #20" : : : "memory")
#ifdef CONFIG_ARM64_PSEUDO_NMI
@@ -46,6 +46,20 @@
#define dma_rmb() dmb(oshld)
#define dma_wmb() dmb(oshst)
+
+#define tsb_csync() \
+ do { \
+ /* \
+ * CPUs affected by Arm Erratum 2054223 or 2067961 needs \
+ * another TSB to ensure the trace is flushed. The barriers \
+ * don't have to be strictly back to back, as long as the \
+ * CPU is in trace prohibited state. \
+ */ \
+ if (cpus_have_final_cap(ARM64_WORKAROUND_TSB_FLUSH_FAILURE)) \
+ __tsb_csync(); \
+ __tsb_csync(); \
+ } while (0)
+
/*
* Generate a mask for array_index__nospec() that is ~0UL when 0 <= idx < sz
* and 0 otherwise.
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index ccd757373f36..bdbeac75ead6 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -352,6 +352,18 @@ static const struct midr_range trbe_overwrite_fill_mode_cpus[] = {
};
#endif /* CONFIG_ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE */
+#ifdef CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE
+static const struct midr_range tsb_flush_fail_cpus[] = {
+#ifdef CONFIG_ARM64_ERRATUM_2067961
+ MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2),
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_2054223
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A710),
+#endif
+ {},
+};
+#endif /* CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE */
+
const struct arm64_cpu_capabilities arm64_errata[] = {
#ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE
{
@@ -558,6 +570,13 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
.type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
CAP_MIDR_RANGE_LIST(trbe_overwrite_fill_mode_cpus),
},
+#endif
+#ifdef CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILRE
+ {
+ .desc = "ARM erratum 2067961 or 2054223",
+ .capability = ARM64_WORKAROUND_TSB_FLUSH_FAILURE,
+ ERRATA_MIDR_RANGE_LIST(tsb_flush_fail_cpus),
+ },
#endif
{
}
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 1ccb92165bd8..2102e15af43d 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -54,6 +54,7 @@ WORKAROUND_1463225
WORKAROUND_1508412
WORKAROUND_1542419
WORKAROUND_TRBE_OVERWRITE_FILL_MODE
+WORKAROUND_TSB_FLUSH_FAILURE
WORKAROUND_CAVIUM_23154
WORKAROUND_CAVIUM_27456
WORKAROUND_CAVIUM_30115
--
2.25.4
next prev parent reply other threads:[~2021-10-08 18:29 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-08 18:28 [PATCH v3 00/16] arm64: Self-hosted trace related errata workarounds Suzuki K Poulose
2021-10-08 18:28 ` [PATCH v3 01/16] arm64: Add Neoverse-N2, Cortex-A710 CPU part definition Suzuki K Poulose
2021-10-08 18:28 ` [PATCH v3 02/16] arm64: errata: Add detection for TRBE overwrite in FILL mode Suzuki K Poulose
2021-10-08 18:28 ` Suzuki K Poulose [this message]
2021-10-11 10:20 ` [PATCH v3 03/16] arm64: errata: Add workaround for TSB flush failures Will Deacon
2021-10-08 18:28 ` [PATCH v3 04/16] arm64: errata: Add detection for TRBE write to out-of-range Suzuki K Poulose
2021-10-08 18:28 ` [PATCH v3 05/16] coresight: trbe: Add a helper to calculate the trace generated Suzuki K Poulose
2021-10-08 18:28 ` [PATCH v3 06/16] coresight: trbe: Add a helper to pad a given buffer area Suzuki K Poulose
2021-10-08 18:28 ` [PATCH v3 07/16] coresight: trbe: Decouple buffer base from the hardware base Suzuki K Poulose
2021-10-08 18:28 ` [PATCH v3 08/16] coresight: trbe: Allow driver to choose a different alignment Suzuki K Poulose
2021-10-08 18:28 ` [PATCH v3 09/16] coresight: trbe: Add infrastructure for Errata handling Suzuki K Poulose
2021-10-08 18:29 ` [PATCH v3 10/16] coresight: trbe: Workaround TRBE errata overwrite in FILL mode Suzuki K Poulose
2021-10-08 18:29 ` [PATCH v3 11/16] coresight: trbe: Add a helper to determine the minimum buffer size Suzuki K Poulose
2021-10-08 18:29 ` [PATCH v3 12/16] coresight: trbe: Make sure we have enough space Suzuki K Poulose
2021-10-08 18:29 ` [PATCH v3 13/16] coresight: trbe: Work around write to out of range Suzuki K Poulose
2021-10-08 18:29 ` [PATCH v3 14/16] arm64: errata: Advertise workaround for TRBE overwrite in FILL mode Suzuki K Poulose
2021-10-08 18:29 ` [PATCH v3 15/16] arm64: errata: Advertise the workaround for TSB flush failures Suzuki K Poulose
2021-10-11 10:18 ` Will Deacon
2021-10-11 12:32 ` Suzuki K Poulose
2021-10-08 18:29 ` [PATCH v3 16/16] arm64: errata: Advertise TRBE erratum workaround for write to out-of-range address Suzuki K Poulose
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