linux-kernel - [RFC PATCH 19/20] coresight: etm3x: implementing perf's user/kernel mode

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Message-Id: <1442593594-10665-20-git-send-email-mathieu.poirier@linaro.org>
Date:	Fri, 18 Sep 2015 10:26:33 -0600
From:	Mathieu Poirier <mathieu.poirier@...aro.org>
To:	gregkh@...uxfoundation.org, a.p.zijlstra@...llo.nl,
	alexander.shishkin@...ux.intel.com, acme@...nel.org,
	mingo@...hat.com, corbet@....net
Cc:	adrian.hunter@...el.com, zhang.chunyan@...aro.org,
	mike.leach@....com, tor@...com, al.grant@....com,
	pawel.moll@....com, linux-arm-kernel@...ts.infradead.org,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH 19/20] coresight: etm3x: implementing perf's user/kernel mode

Configure tracers in accordance with the specification conveyed
by the perf cmd line tool.  For example if only user space is
requested, configure the address range comparator with the kerne's
address range and set the 'exclude' bit, which will result in
tracing everything except the kernel.

Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
---
 drivers/hwtracing/coresight/coresight-etm3x.c | 36 +++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index 077b49714259..2f818dbde099 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -320,6 +320,41 @@ static int etm_parse_event_config(struct etm_drvdata *drvdata,
 {
 	u64 config = event->attr.config;
 
+	if (event->attr.exclude_kernel || event->attr.exclude_user) {
+		u32 event_encoding;
+		u32 flags = (1 << 0 | /* instruction execute*/
+			     3 << 3 | /* ARM instruction */
+			     0 << 5 | /* No data value comparison */
+			     0 << 7 | /* No exact mach */
+			     0 << 8 | /* Ignore context ID */
+			     0 << 10); /* Security ignored */
+
+		/* Bit 0 is address range comparator 1 */
+		drvdata->enable_ctrl1 = ETMTECR1_ADDR_COMP_1;
+
+		/* Bit 24 controls whether the address range should be
+		 * included or excluded.
+		 */
+		if (event->attr.exclude_kernel)
+			drvdata->enable_ctrl1 |= BIT(24);
+
+		/* No need to worry about single address comparators */
+		drvdata->enable_ctrl2 = 0x0;
+
+		drvdata->addr_val[0] = (u32) _stext;
+		drvdata->addr_val[1] = (u32) _etext;
+		drvdata->addr_acctype[0] = flags;
+		drvdata->addr_acctype[1] = flags;
+		drvdata->addr_type[0] = ETM_ADDR_TYPE_RANGE;
+		drvdata->addr_type[1] = ETM_ADDR_TYPE_RANGE;
+
+		event_encoding = 0x00 << 14 | /* Boolean function select A */
+				 0x01 << 4  | /* Addr range comparator 0-7 */
+				 0x00 << 0;   /* Addr range comparator 1 */
+
+		drvdata->enable_event = event_encoding;
+	}
+
 	/*
 	 * At this time only cycle accurate and timestamp options are
 	 * available.  As such clear everything else that may have been
@@ -362,6 +397,7 @@ static void etm_configure_cpu(void *info)
 	etm_writel(drvdata, drvdata->startstop_ctrl, ETMTSSCR);
 	etm_writel(drvdata, drvdata->enable_event, ETMTEEVR);
 	etm_writel(drvdata, drvdata->enable_ctrl1, ETMTECR1);
+	etm_writel(drvdata, drvdata->enable_ctrl2, ETMTECR2);
 	etm_writel(drvdata, drvdata->fifofull_level, ETMFFLR);
 	for (i = 0; i < drvdata->nr_addr_cmp; i++) {
 		etm_writel(drvdata, drvdata->addr_val[i], ETMACVRn(i));
-- 
1.9.1

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