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authorSuzuki K Poulose <suzuki.poulose@arm.com>2021-09-23 17:39:18 +0300
committerMathieu Poirier <mathieu.poirier@linaro.org>2021-10-27 20:45:31 +0300
commit9bef9d0850a024a07f46d13828c05becf03eb79f (patch)
treefca181ec9120ed9f3ac86dd61479a22bb1b1dc8e /drivers/hwtracing
parent0a5f355633eaacb7300598d96e8013a401a02c5e (diff)
downloadlinux-9bef9d0850a024a07f46d13828c05becf03eb79f.tar.xz
coresight: trbe: End the AUX handle on truncation
When we detect that there isn't enough space left to start a meaningful session, we disable the TRBE, marking the buffer as TRUNCATED. But we delay the notification to the perf layer by perf_aux_output_end() until the event is scheduled out, triggered from the kernel perf layer. This will cause significant black outs in the trace. Now that the CoreSight PMU layer can handle a closed "AUX" handle properly, we can close the handle as soon as we detect the case, allowing the userspace to collect and re-enable the event. Also, while in the IRQ handler, move the irq_work_run() after we have updated the handle, to make sure the "TRUNCATED" flag causes the event to be disabled as soon as possible. Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Mike Leach <mike.leach@linaro.org> Cc: Leo Yan <leo.yan@linaro.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20210923143919.2944311-5-suzuki.poulose@arm.com Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r--drivers/hwtracing/coresight/coresight-trbe.c26
1 files changed, 16 insertions, 10 deletions
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 0a9106c15639..4174300f1344 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -152,6 +152,7 @@ static void trbe_stop_and_truncate_event(struct perf_output_handle *handle)
*/
trbe_drain_and_disable_local();
perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+ perf_aux_output_end(handle, 0);
*this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL;
}
@@ -715,7 +716,7 @@ static void trbe_handle_spurious(struct perf_output_handle *handle)
isb();
}
-static void trbe_handle_overflow(struct perf_output_handle *handle)
+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);
@@ -739,9 +740,10 @@ static void trbe_handle_overflow(struct perf_output_handle *handle)
*/
trbe_drain_and_disable_local();
*this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL;
- return;
+ return -EINVAL;
}
- __arm_trbe_enable(buf, handle);
+
+ return __arm_trbe_enable(buf, handle);
}
static bool is_perf_trbe(struct perf_output_handle *handle)
@@ -772,6 +774,7 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
struct perf_output_handle *handle = *handle_ptr;
enum trbe_fault_action act;
u64 status;
+ bool truncated = false;
/* Reads to TRBSR_EL1 is fine when TRBE is active */
status = read_sysreg_s(SYS_TRBSR_EL1);
@@ -796,24 +799,27 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
if (!is_perf_trbe(handle))
return IRQ_NONE;
- /*
- * Ensure perf callbacks have completed, which may disable
- * the trace buffer in response to a TRUNCATION flag.
- */
- irq_work_run();
-
act = trbe_get_fault_act(status);
switch (act) {
case TRBE_FAULT_ACT_WRAP:
- trbe_handle_overflow(handle);
+ truncated = !!trbe_handle_overflow(handle);
break;
case TRBE_FAULT_ACT_SPURIOUS:
trbe_handle_spurious(handle);
break;
case TRBE_FAULT_ACT_FATAL:
trbe_stop_and_truncate_event(handle);
+ truncated = true;
break;
}
+
+ /*
+ * If the buffer was truncated, ensure perf callbacks
+ * have completed, which will disable the event.
+ */
+ if (truncated)
+ irq_work_run();
+
return IRQ_HANDLED;
}