Re: [PATCH 07/10] arm64: Add erratum detection for TRBE overwrite in FILL mode
From: Suzuki K Poulose
Date: Tue Sep 07 2021 - 05:10:16 EST
On 06/08/2021 13:44, Linu Cherian wrote:
Hi Suzuki,
On Wed, Jul 28, 2021 at 7:23 PM Suzuki K Poulose <suzuki.poulose@xxxxxxx> wrote:
Arm Neoverse-N2 and the Cortex-A710 cores are affected
by a CPU erratum where the TRBE will overwrite the trace buffer
in FILL mode. The TRBE doesn't stop (as expected in FILL mode)
when it reaches the limit and wraps to the base to continue
writing upto 3 cache lines. This will overwrite any trace that
was written previously.
Add the Neoverse-N2 erratumi(#2139208) and Cortex-A710 erratum
(#2119858) to the detection logic.
This will be used by the TRBE driver in later patches to work
around the issue. The detection has been kept with the core
arm64 errata framework list to make sure :
- We don't duplicate the framework in TRBE driver
- The errata detection is advertised like the rest
of the CPU errata.
Note that the Kconfig entries will be added after we have added
the work around in the TRBE driver, which depends on the cpucap
from here.
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
cc: Leo Yan <leo.yan@xxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 49305c2e6dfd..1ccb92165bd8 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -53,6 +53,7 @@ WORKAROUND_1418040
WORKAROUND_1463225
WORKAROUND_1508412
WORKAROUND_1542419
+WORKAROUND_TRBE_OVERWRITE_FILL_MODE
WORKAROUND_CAVIUM_23154
WORKAROUND_CAVIUM_27456
WORKAROUND_CAVIUM_30115
We need to keep this list sorted ?
Not necessary, anymore. For a given kernel the numbers are
autogenerated by the script.
See arch/arm64/tools/gen-cpucaps.awk
Suzuki