This is a note to let you know that I've just added the patch titled
coresight: etm4x: Safe access for TRCQCLTR
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
coresight-etm4x-safe-access-for-trcqcltr.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4384f8a572258d3e79fea07cc51af1db69f78015
Author: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Date: Fri Apr 12 15:27:01 2024 +0100
coresight: etm4x: Safe access for TRCQCLTR
[ Upstream commit 46bf8d7cd8530eca607379033b9bc4ac5590a0cd ]
ETM4x implements TRCQCLTR only when the Q elements are supported
and the Q element filtering is supported (TRCIDR0.QFILT). Access
to the register otherwise could be fatal. Fix this by tracking the
availability, like the others.
Fixes: f188b5e76aae ("coresight: etm4x: Save/restore state across CPU low power states")
Reported-by: Yabin Cui <yabinc@xxxxxxxxxx>
Reviewed-by: Mike Leach <mike.leach@xxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Tested-by: Yabin Cui <yabinc@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240412142702.2882478-4-suzuki.poulose@xxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 85381f7831268..4988503f68558 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1244,6 +1244,8 @@ static void etm4_init_arch_data(void *info)
drvdata->nr_event = FIELD_GET(TRCIDR0_NUMEVENT_MASK, etmidr0);
/* QSUPP, bits[16:15] Q element support field */
drvdata->q_support = FIELD_GET(TRCIDR0_QSUPP_MASK, etmidr0);
+ if (drvdata->q_support)
+ drvdata->q_filt = !!(etmidr0 & TRCIDR0_QFILT);
/* TSSIZE, bits[28:24] Global timestamp size field */
drvdata->ts_size = FIELD_GET(TRCIDR0_TSSIZE_MASK, etmidr0);
@@ -1736,7 +1738,8 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
state->trcccctlr = etm4x_read32(csa, TRCCCCTLR);
state->trcbbctlr = etm4x_read32(csa, TRCBBCTLR);
state->trctraceidr = etm4x_read32(csa, TRCTRACEIDR);
- state->trcqctlr = etm4x_read32(csa, TRCQCTLR);
+ if (drvdata->q_filt)
+ state->trcqctlr = etm4x_read32(csa, TRCQCTLR);
state->trcvictlr = etm4x_read32(csa, TRCVICTLR);
state->trcviiectlr = etm4x_read32(csa, TRCVIIECTLR);
@@ -1866,7 +1869,8 @@ static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
etm4x_relaxed_write32(csa, state->trcccctlr, TRCCCCTLR);
etm4x_relaxed_write32(csa, state->trcbbctlr, TRCBBCTLR);
etm4x_relaxed_write32(csa, state->trctraceidr, TRCTRACEIDR);
- etm4x_relaxed_write32(csa, state->trcqctlr, TRCQCTLR);
+ if (drvdata->q_filt)
+ etm4x_relaxed_write32(csa, state->trcqctlr, TRCQCTLR);
etm4x_relaxed_write32(csa, state->trcvictlr, TRCVICTLR);
etm4x_relaxed_write32(csa, state->trcviiectlr, TRCVIIECTLR);
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 574dbaef50836..6b6760e49ed35 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -135,6 +135,7 @@
#define TRCIDR0_TRCCCI BIT(7)
#define TRCIDR0_RETSTACK BIT(9)
#define TRCIDR0_NUMEVENT_MASK GENMASK(11, 10)
+#define TRCIDR0_QFILT BIT(14)
#define TRCIDR0_QSUPP_MASK GENMASK(16, 15)
#define TRCIDR0_TSSIZE_MASK GENMASK(28, 24)
@@ -954,6 +955,7 @@ struct etmv4_save_state {
* @os_unlock: True if access to management registers is allowed.
* @instrp0: Tracing of load and store instructions
* as P0 elements is supported.
+ * @q_filt: Q element filtering support, if Q elements are supported.
* @trcbb: Indicates if the trace unit supports branch broadcast tracing.
* @trccond: If the trace unit supports conditional
* instruction tracing.
@@ -1017,6 +1019,7 @@ struct etmv4_drvdata {
bool boot_enable;
bool os_unlock;
bool instrp0;
+ bool q_filt;
bool trcbb;
bool trccond;
bool retstack;
