Messages in this thread Patch in this message | | | Date | Thu, 30 Sep 2021 11:54:21 -0600 | From | Mathieu Poirier <> | Subject | Re: [PATCH v2 03/17] coresight: trbe: Add a helper to calculate the trace generated |
| |
Hi Suzuki,
On Tue, Sep 21, 2021 at 02:41:07PM +0100, Suzuki K Poulose wrote: > We collect the trace from the TRBE on FILL event from IRQ context > and when via update_buffer(), when the event is stopped. Let us
s/"and when via"/"and via"
> consolidate how we calculate the trace generated into a helper. > > Cc: Mathieu Poirier <mathieu.poirier@linaro.org> > Cc: Mike Leach <mike.leach@linaro.org> > Cc: Leo Yan <leo.yan@linaro.org> > Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > drivers/hwtracing/coresight/coresight-trbe.c | 48 ++++++++++++-------- > 1 file changed, 30 insertions(+), 18 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c > index 63f7edd5fd1f..063c4505a203 100644 > --- a/drivers/hwtracing/coresight/coresight-trbe.c > +++ b/drivers/hwtracing/coresight/coresight-trbe.c > @@ -527,6 +527,30 @@ static enum trbe_fault_action trbe_get_fault_act(u64 trbsr) > return TRBE_FAULT_ACT_SPURIOUS; > } > > +static unsigned long trbe_get_trace_size(struct perf_output_handle *handle, > + struct trbe_buf *buf, > + bool wrap)
Stacking
> +{ > + u64 write; > + u64 start_off, end_off; > + > + /* > + * If the TRBE has wrapped around the write pointer has > + * wrapped and should be treated as limit. > + */ > + if (wrap) > + write = get_trbe_limit_pointer(); > + else > + write = get_trbe_write_pointer(); > + > + end_off = write - buf->trbe_base;
In both arm_trbe_alloc_buffer() and trbe_handle_overflow() the base address is acquired using get_trbe_base_pointer() but here it is referenced directly - any reason for that? It certainly makes reviewing this simple patch quite difficult because I keep wondering if I am missing something subtle...
> + start_off = PERF_IDX2OFF(handle->head, buf); > + > + if (WARN_ON_ONCE(end_off < start_off)) > + return 0; > + return (end_off - start_off); > +} > + > static void *arm_trbe_alloc_buffer(struct coresight_device *csdev, > struct perf_event *event, void **pages, > int nr_pages, bool snapshot) > @@ -588,9 +612,9 @@ static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev, > struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev); > struct trbe_buf *buf = config; > enum trbe_fault_action act; > - unsigned long size, offset; > - unsigned long write, base, status; > + unsigned long size, status; > unsigned long flags; > + bool wrap = false; > > WARN_ON(buf->cpudata != cpudata); > WARN_ON(cpudata->cpu != smp_processor_id()); > @@ -630,8 +654,6 @@ static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev, > * handle gets freed in etm_event_stop(). > */ > trbe_drain_and_disable_local(); > - write = get_trbe_write_pointer(); > - base = get_trbe_base_pointer(); > > /* Check if there is a pending interrupt and handle it here */ > status = read_sysreg_s(SYS_TRBSR_EL1); > @@ -655,20 +677,11 @@ static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev, > goto done; > } > > - /* > - * Otherwise, the buffer is full and the write pointer > - * has reached base. Adjust this back to the Limit pointer > - * for correct size. Also, mark the buffer truncated. > - */ > - write = get_trbe_limit_pointer(); > perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION); > + wrap = true; > } > > - offset = write - base; > - if (WARN_ON_ONCE(offset < PERF_IDX2OFF(handle->head, buf))) > - size = 0; > - else > - size = offset - PERF_IDX2OFF(handle->head, buf); > + size = trbe_get_trace_size(handle, buf, wrap); > > done: > local_irq_restore(flags); > @@ -749,11 +762,10 @@ static int trbe_handle_overflow(struct perf_output_handle *handle) > { > struct perf_event *event = handle->event; > struct trbe_buf *buf = etm_perf_sink_config(handle); > - unsigned long offset, size; > + unsigned long size; > struct etm_event_data *event_data; > > - offset = get_trbe_limit_pointer() - get_trbe_base_pointer(); > - size = offset - PERF_IDX2OFF(handle->head, buf); > + size = trbe_get_trace_size(handle, buf, true); > if (buf->snapshot) > handle->head += size; > > -- > 2.24.1 >
| |