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authorSuzuki K Poulose <suzuki.poulose@arm.com>2021-10-19 17:31:42 +0100
committerWill Deacon <will@kernel.org>2021-10-21 17:49:17 +0100
commit8d81b2a38ddfc4b03662d2359765648c8b4cc73c (patch)
tree49b9cd7a8a984366df725888a977762679d839ec /Documentation/arm64
parentarm64: errata: Add workaround for TSB flush failures (diff)
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arm64: errata: Add detection for TRBE write to out-of-range
Arm Neoverse-N2 and Cortex-A710 cores are affected by an erratum where the trbe, under some circumstances, might write upto 64bytes to an address after the Limit as programmed by the TRBLIMITR_EL1.LIMIT. This might - - Corrupt a page in the ring buffer, which may corrupt trace from a previous session, consumed by userspace. - Hit the guard page at the end of the vmalloc area and raise a fault. To keep the handling simpler, we always leave the last page from the range, which TRBE is allowed to write. This can be achieved by ensuring that we always have more than a PAGE worth space in the range, while calculating the LIMIT for TRBE. And then the LIMIT pointer can be adjusted to leave the PAGE (TRBLIMITR.LIMIT -= PAGE_SIZE), out of the TRBE range while enabling it. This makes sure that the TRBE will only write to an area within its allowed limit (i.e, [head-head+size]) and we do not have to handle address faults within the driver. Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Mike Leach <mike.leach@linaro.org> Cc: Leo Yan <leo.yan@linaro.org> Cc: Will Deacon <will@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20211019163153.3692640-5-suzuki.poulose@arm.com Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'Documentation/arm64')
-rw-r--r--Documentation/arm64/silicon-errata.rst4
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst
index 569a92411dcd..5342e895fb60 100644
--- a/Documentation/arm64/silicon-errata.rst
+++ b/Documentation/arm64/silicon-errata.rst
@@ -96,6 +96,8 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A710 | #2054223 | ARM64_ERRATUM_2054223 |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | Cortex-A710 | #2224489 | ARM64_ERRATUM_2224489 |
++----------------+-----------------+-----------------+-----------------------------+
| ARM | Neoverse-N1 | #1188873,1418040| ARM64_ERRATUM_1418040 |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Neoverse-N1 | #1349291 | N/A |
@@ -106,6 +108,8 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Neoverse-N2 | #2067961 | ARM64_ERRATUM_2067961 |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | Neoverse-N2 | #2253138 | ARM64_ERRATUM_2253138 |
++----------------+-----------------+-----------------+-----------------------------+
| ARM | MMU-500 | #841119,826419 | N/A |
+----------------+-----------------+-----------------+-----------------------------+
+----------------+-----------------+-----------------+-----------------------------+