Mathieu Poirier <mathieu.poir...@linaro.org> writes: > Calling function 'smp_call_function_single()' to unlock the > tracer and calling it right after to perform the default > initialisation doesn't make sense. > > Moving 'etm_os_unlock()' just before making the default > initialisation results in the same outcome while saving > one call to 'smp_call_function_single()'. > > Signed-off-by: Mathieu Poirier <mathieu.poir...@linaro.org> > --- > drivers/hwtracing/coresight/coresight-etm3x.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c > b/drivers/hwtracing/coresight/coresight-etm3x.c > index c6880c1ade55..a4c158df0fef 100644 > --- a/drivers/hwtracing/coresight/coresight-etm3x.c > +++ b/drivers/hwtracing/coresight/coresight-etm3x.c > @@ -1867,6 +1867,11 @@ static void etm_init_arch_data(void *info) > * certain registers might be ignored. > */ > etm_clr_pwrdwn(drvdata); > + > + /* Make sure all registers are accessible */ > + etm_os_unlock(drvdata);
In case of co-processor register access, this will end up unlocking the local ETM instead of the one on target cpu, by the looks of it. That's why smp_function_call() was needed there. Or you might want a etm_read_on_cpu() variant if it's really worth it. > + drvdata->os_unlock = true; > + > /* > * Set prog bit. It will be set from reset but this is included to > * ensure it is set > @@ -1961,9 +1966,6 @@ static int etm_probe(struct amba_device *adev, const > struct amba_id *id) > get_online_cpus(); > etmdrvdata[drvdata->cpu] = drvdata; > > - if (!smp_call_function_single(drvdata->cpu, etm_os_unlock, drvdata, 1)) > - drvdata->os_unlock = true; > - > if (smp_call_function_single(drvdata->cpu, > etm_init_arch_data, drvdata, 1)) > dev_err(dev, "ETM arch init failed\n"); > -- > 1.9.1 Regards, -- Alex -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
