On Thu, Nov 19, 2020 at 04:45:47PM +0000, Suzuki K Poulose wrote:
From: Jonathan Zhou jonathan.zhouwen@huawei.com
v8.4 tracing extensions added support for trace filtering controlled by TRFCR_ELx. This must be programmed to allow tracing at EL1/EL2 and EL0. The timestamp used is the virtual time. Also enable CONTEXIDR_EL2 tracing if we are running the kernel at EL2.
Cc: Catalin Marinas catalin.marinas@arm.com Cc: Mathieu Poirier mathieu.poirier@linaro.org Cc: Mike Leach mike.leach@linaro.org Cc: Will Deacon will@kernel.org Signed-off-by: Jonathan Zhou jonathan.zhouwen@huawei.com [ Move the trace filtering setup etm_init_arch_data() and clean ups] Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com
.../coresight/coresight-etm4x-core.c | 25 +++++++++++++++++++ 1 file changed, 25 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 1d054d2ab2a0..647685736134 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -760,6 +760,30 @@ static bool etm4_init_csdev_access(struct etmv4_drvdata *drvdata, return false; } +static void cpu_enable_tracing(void) +{
- u64 dfr0 = read_sysreg(id_aa64dfr0_el1);
- u64 trfcr;
- if (!(dfr0 >> ID_AA64DFR0_TRACE_FILT_SHIFT))
return;
What if we get a new field at position 44 while the FILT one at 40 is 0? We should use cpuid_feature_extract_field() here.
BTW, can this function not go in the cpufeature.c code?