On Thu, Nov 19, 2020 at 04:45:47PM +0000, Suzuki K Poulose wrote: > From: Jonathan Zhou <[email protected]> > > 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 <[email protected]> > Cc: Mathieu Poirier <[email protected]> > Cc: Mike Leach <[email protected]> > Cc: Will Deacon <[email protected]> > Signed-off-by: Jonathan Zhou <[email protected]> > [ Move the trace filtering setup etm_init_arch_data() and > clean ups] > Signed-off-by: Suzuki K Poulose <[email protected]> > --- > .../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? -- Catalin
