Messages in this thread | | | Subject | Re: [PATCH v4 20/25] coresight: etm4x: Detect system instructions support | From | Suzuki K Poulose <> | Date | Tue, 24 Nov 2020 11:38:55 +0000 |
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On 11/24/20 12:41 AM, Tingwei Zhang wrote: > On Mon, Nov 23, 2020 at 05:39:43PM +0800, Suzuki K Poulose wrote: >> On 11/23/20 7:58 AM, Tingwei Zhang wrote: >>> Hi Suzuki, >>> >>> On Fri, Nov 20, 2020 at 12:45:42AM +0800, Suzuki K Poulose wrote: >>>> ETM v4.4 onwards adds support for system instruction access >>>> to the ETM. Detect the support on an ETM and switch to using the >>>> mode when available. >>>> >>>> Cc: Mike Leach <mike.leach@linaro.org> >>>> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> >>>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> >>>> --- >>>> .../coresight/coresight-etm4x-core.c | 39 +++++++++++++++++++ >>>> 1 file changed, 39 insertions(+) >>>> >>>> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c >>>> b/drivers/hwtracing/coresight/coresight-etm4x-core.c >>>> index 7ac0a185c146..5cbea9c27f58 100644 >>>> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c >>>> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c >>>> @@ -684,6 +684,37 @@ static const struct coresight_ops etm4_cs_ops = { >>>> .source_ops = &etm4_source_ops, >>>> }; >>>> >>>> +static inline bool cpu_supports_sysreg_trace(void) >>>> +{ >>>> + u64 dfr0 = read_sysreg_s(SYS_ID_AA64DFR0_EL1); >>>> + >>>> + return ((dfr0 >> ID_AA64DFR0_TRACEVER_SHIFT) & 0xfUL) > 0; >>>> +} >>>> + >>>> +static bool etm4_init_sysreg_access(struct etmv4_drvdata *drvdata, >>>> + struct csdev_access *csa) >>>> +{ >>>> + u32 devarch; >>>> + >>>> + if (!cpu_supports_sysreg_trace()) >>>> + return false; >>>> + >>>> + /* >>>> + * ETMs implementing sysreg access must implement TRCDEVARCH. >>>> + */ >>>> + devarch = read_etm4x_sysreg_const_offset(TRCDEVARCH); >>>> + if ((devarch & ETM_DEVARCH_ID_MASK) != ETM_DEVARCH_ETMv4x_ARCH) >>> >>> Is this driver suppose to work on ETM 5.0/ETE trace unit before ETE driver >>> is ready? >> >> No, it is not supposed to work on an ETE without the ETE support. That check >> ensures that we only detect ETMv4x for now. The ETE driver support adds the >> ETE_ARCH as one of the supported ETMs. If you hack around it might still >> probe, >> but things could go terribly wrong if we access registers that are not >> available >> on ETE. >> >> Btw, are you able to test this series on an ETMv4.4+ system ? >> > I'm trying to test this series on an ETE. Look like it's not correct. > I'll apply ETE patch on top of this and test. >
Yes please ! Much appreciated. Do you have a TRBE as well ? Or are you using a legacy CoreSight topology ?
Kind regards Suzuki
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