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Subject[PATCH 4.18 191/235] coresight: tpiu: Fix disabling timeouts
Date
4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Robin Murphy <robin.murphy@arm.com>

[ Upstream commit ccff2dfaceaca4517432f5c149594215fe9098cc ]

Probing the TPIU driver under UBSan triggers an out-of-bounds shift
warning in coresight_timeout():

...
[ 5.677530] UBSAN: Undefined behaviour in drivers/hwtracing/coresight/coresight.c:929:16
[ 5.685542] shift exponent 64 is too large for 64-bit type 'long unsigned int'
...

On closer inspection things are exponentially out of whack because we're
passing a bitmask where a bit number should be. Amusingly, it seems that
both calls will find their expected values by sheer luck and appear to
succeed: 1 << FFCR_FON_MAN ends up at bit 64 which whilst undefined
evaluates as zero in practice, while 1 << FFSR_FT_STOPPED finds bit 2
(TCPresent) which apparently is usually tied high.

Following the examples of other drivers, define separate FOO and FOO_BIT
macros for masks vs. indices, and put things right.

CC: Robert Walker <robert.walker@arm.com>
CC: Mike Leach <mike.leach@linaro.org>
CC: Mathieu Poirier <mathieu.poirier@linaro.org>
Fixes: 11595db8e17f ("coresight: Fix disabling of CoreSight TPIU")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hwtracing/coresight/coresight-tpiu.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/hwtracing/coresight/coresight-tpiu.c
+++ b/drivers/hwtracing/coresight/coresight-tpiu.c
@@ -40,8 +40,9 @@

/** register definition **/
/* FFSR - 0x300 */
-#define FFSR_FT_STOPPED BIT(1)
+#define FFSR_FT_STOPPED_BIT 1
/* FFCR - 0x304 */
+#define FFCR_FON_MAN_BIT 6
#define FFCR_FON_MAN BIT(6)
#define FFCR_STOP_FI BIT(12)

@@ -86,9 +87,9 @@ static void tpiu_disable_hw(struct tpiu_
/* Generate manual flush */
writel_relaxed(FFCR_STOP_FI | FFCR_FON_MAN, drvdata->base + TPIU_FFCR);
/* Wait for flush to complete */
- coresight_timeout(drvdata->base, TPIU_FFCR, FFCR_FON_MAN, 0);
+ coresight_timeout(drvdata->base, TPIU_FFCR, FFCR_FON_MAN_BIT, 0);
/* Wait for formatter to stop */
- coresight_timeout(drvdata->base, TPIU_FFSR, FFSR_FT_STOPPED, 1);
+ coresight_timeout(drvdata->base, TPIU_FFSR, FFSR_FT_STOPPED_BIT, 1);

CS_LOCK(drvdata->base);
}

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