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coresight: trbe: Work around the trace data corruption

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TRBE implementations affected by Arm erratum #1902691 might corrupt trace
data or deadlock, when it's being written into the memory. Workaround this
problem in the driver, by preventing TRBE initialization on affected cpus.
The firmware must have disabled the access to TRBE for the kernel on such
implementations. This will cover the kernel for any firmware that doesn't
do this already. This just updates the TRBE driver as required.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-doc@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/1643120437-14352-8-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
This commit is contained in:
Anshuman Khandual 2022-01-25 19:50:37 +05:30 committed by Suzuki K Poulose
parent f209e9fe5b
commit 3a828845ae
2 changed files with 13 additions and 1 deletions
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2
arch/arm64/Kconfig
View File

@ -847,7 +847,7 @@ config ARM64_ERRATUM_2038923
config ARM64_ERRATUM_1902691
bool "Cortex-A510: 1902691: workaround TRBE trace corruption"
depends on COMPILE_TEST # Until the CoreSight TRBE driver changes are in
depends on CORESIGHT_TRBE
default y
help
This option adds the workaround for ARM Cortex-A510 erratum 1902691.

12
drivers/hwtracing/coresight/coresight-trbe.c
View File

@ -93,12 +93,14 @@ struct trbe_buf {
#define TRBE_WORKAROUND_WRITE_OUT_OF_RANGE 1
#define TRBE_NEEDS_DRAIN_AFTER_DISABLE 2
#define TRBE_NEEDS_CTXT_SYNC_AFTER_ENABLE 3
#define TRBE_IS_BROKEN 4
static int trbe_errata_cpucaps[] = {
[TRBE_WORKAROUND_OVERWRITE_FILL_MODE] = ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE,
[TRBE_WORKAROUND_WRITE_OUT_OF_RANGE] = ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE,
[TRBE_NEEDS_DRAIN_AFTER_DISABLE] = ARM64_WORKAROUND_2064142,
[TRBE_NEEDS_CTXT_SYNC_AFTER_ENABLE] = ARM64_WORKAROUND_2038923,
[TRBE_IS_BROKEN] = ARM64_WORKAROUND_1902691,
-1, /* Sentinel, must be the last entry */
};
@ -192,6 +194,11 @@ static inline bool trbe_needs_ctxt_sync_after_enable(struct trbe_cpudata *cpudat
return trbe_has_erratum(cpudata, TRBE_NEEDS_CTXT_SYNC_AFTER_ENABLE);
}
static inline bool trbe_is_broken(struct trbe_cpudata *cpudata)
{
return trbe_has_erratum(cpudata, TRBE_IS_BROKEN);
}
static int trbe_alloc_node(struct perf_event *event)
{
if (event->cpu == -1)
@ -1288,6 +1295,11 @@ static void arm_trbe_probe_cpu(void *info)
*/
trbe_check_errata(cpudata);
if (trbe_is_broken(cpudata)) {
pr_err("Disabling TRBE on cpu%d due to erratum\n", cpu);
goto cpu_clear;
}
/*
* If the TRBE is affected by erratum TRBE_WORKAROUND_OVERWRITE_FILL_MODE,
* we must always program the TBRPTR_EL1, 256bytes from a page