6.15-stable review patch. If anyone has any objections, please let me know.
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From: Mao Jinlong quic_jinlmao@quicinc.com
[ Upstream commit d23bc38e8aa4efbd617bf660bb1a25fee9f6c177 ]
ETF may fail to re-enable after reading, and driver->reading will not be set to false, this will cause failure to enable/disable to ETF. This change set driver->reading to false even if re-enabling fail.
Fixes: 669c4614236a ("coresight: tmc: Don't enable TMC when it's not ready.") Co-developed-by: Yuanfang Zhang quic_yuanfang@quicinc.com Signed-off-by: Yuanfang Zhang quic_yuanfang@quicinc.com Signed-off-by: Mao Jinlong quic_jinlmao@quicinc.com [ Added a comment to explain why we ignore the error ] Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Link: https://lore.kernel.org/r/20250507063716.1945213-1-quic_jinlmao@quicinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hwtracing/coresight/coresight-tmc-etf.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index d858740001c27..a922e3b709638 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -747,7 +747,6 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata) char *buf = NULL; enum tmc_mode mode; unsigned long flags; - int rc = 0;
/* config types are set a boot time and never change */ if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB && @@ -773,11 +772,11 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata) * can't be NULL. */ memset(drvdata->buf, 0, drvdata->size); - rc = __tmc_etb_enable_hw(drvdata); - if (rc) { - raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); - return rc; - } + /* + * Ignore failures to enable the TMC to make sure, we don't + * leave the TMC in a "reading" state. + */ + __tmc_etb_enable_hw(drvdata); } else { /* * The ETB/ETF is not tracing and the buffer was just read.