On 02/08/2023 07:36, Anshuman Khandual wrote:

is_trbe_available() checks for the TRBE support via extracting TraceBuffer field value from ID_AA64DFR0_EL1, and ensures that it is implemented. This replaces the open encoding '0b0001' with 'ID_AA64DFR0_EL1_TraceBuffer_IMP' which is now available via sysreg tools. Functional change is not intended.

Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Leo Yan leo.yan@linaro.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com

---

drivers/hwtracing/coresight/coresight-trbe.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.h b/drivers/hwtracing/coresight/coresight-trbe.h index 94e67009848a..ebb9108d8e24 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.h +++ b/drivers/hwtracing/coresight/coresight-trbe.h @@ -24,7 +24,7 @@ static inline bool is_trbe_available(void) unsigned int trbe = cpuid_feature_extract_unsigned_field(aa64dfr0, ID_AA64DFR0_EL1_TraceBuffer_SHIFT);

• return trbe >= 0b0001;

• return trbe >= ID_AA64DFR0_EL1_TraceBuffer_IMP;

} static inline bool is_trbe_enabled(void)

Reviewed-by: James Clark james.clark@arm.com

Kind of unrelated to this change, but it seems like a lot of feature checks like this avoid using any value altogether when it's just 0 or 1. For example the same check for TRBE in kvm:

/* Check if we have TRBE implemented and available at the host */ if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceBuffer_SHIFT) && ...