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arm64: errata: Add detection for TRBE invalid prohibited states

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TRBE implementations affected by Arm erratum #2038923 might get TRBE into
an inconsistent view on whether trace is prohibited within the CPU. As a
result, the trace buffer or trace buffer state might be corrupted. This
happens after TRBE buffer has been enabled by setting TRBLIMITR_EL1.E,
followed by just a single context synchronization event before execution
changes from a context, in which trace is prohibited to one where it isn't,
or vice versa. In these mentioned conditions, the view of whether trace is
prohibited is inconsistent between parts of the CPU, and the trace buffer
or the trace buffer state might be corrupted. This adds a new errata
ARM64_ERRATUM_2038923 in arm64 errata framework.

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>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/1643120437-14352-4-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
This commit is contained in:
Anshuman Khandual 2022-01-25 19:50:33 +05:30 committed by Mathieu Poirier
parent 607a9afaae
commit 3bd94a8759
4 changed files with 35 additions and 0 deletions
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2
Documentation/arm64/silicon-errata.rst
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@ -54,6 +54,8 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A510 | #2064142 | ARM64_ERRATUM_2064142 |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A510 | #2038923 | ARM64_ERRATUM_2038923 |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A53 | #826319 | ARM64_ERRATUM_826319 |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A53 | #827319 | ARM64_ERRATUM_827319 |

23
arch/arm64/Kconfig
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@ -796,6 +796,29 @@ config ARM64_ERRATUM_2064142
If unsure, say Y.
config ARM64_ERRATUM_2038923
bool "Cortex-A510: 2038923: workaround TRBE corruption with enable"
depends on COMPILE_TEST # Until the CoreSight TRBE driver changes are in
default y
help
This option adds the workaround for ARM Cortex-A510 erratum 2038923.
Affected Cortex-A510 core might cause an inconsistent view on whether trace is
prohibited within the CPU. As a result, the trace buffer or trace buffer state
might be corrupted. This happens after TRBE buffer has been enabled by setting
TRBLIMITR_EL1.E, followed by just a single context synchronization event before
execution changes from a context, in which trace is prohibited to one where it
isn't, or vice versa. In these mentioned conditions, the view of whether trace
is prohibited is inconsistent between parts of the CPU, and the trace buffer or
the trace buffer state might be corrupted.
Work around this in the driver by preventing an inconsistent view of whether the
trace is prohibited or not based on TRBLIMITR_EL1.E by immediately following a
change to TRBLIMITR_EL1.E with at least one ISB instruction before an ERET, or
two ISB instructions if no ERET is to take place.
If unsure, say Y.
config CAVIUM_ERRATUM_22375
bool "Cavium erratum 22375, 24313"
default y

9
arch/arm64/kernel/cpu_errata.c
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@ -607,6 +607,15 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
ERRATA_MIDR_REV_RANGE(MIDR_CORTEX_A510, 0, 0, 2)
},
#endif
#ifdef CONFIG_ARM64_ERRATUM_2038923
{
.desc = "ARM erratum 2038923",
.capability = ARM64_WORKAROUND_2038923,
/* Cortex-A510 r0p0 - r0p2 */
ERRATA_MIDR_REV_RANGE(MIDR_CORTEX_A510, 0, 0, 2)
},
#endif
{
}
};

1
arch/arm64/tools/cpucaps
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@ -56,6 +56,7 @@ WORKAROUND_1463225
WORKAROUND_1508412
WORKAROUND_1542419
WORKAROUND_2064142
WORKAROUND_2038923
WORKAROUND_TRBE_OVERWRITE_FILL_MODE
WORKAROUND_TSB_FLUSH_FAILURE
WORKAROUND_TRBE_WRITE_OUT_OF_RANGE