[PATCH 6.9 057/374] coresight: etm4x: Safe access for TRCQCLTR

Greg Kroah-Hartman
2024-06-06T14:09:01Z

From: Suzuki K Poulose <suzuki.poulose@arm.com>

[ 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@google.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: Yabin Cui <yabinc@google.com>
Link: https://lore.kernel.org/r/20240412142702.2882478-4-suzuki.poulose@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwtracing/coresight/coresight-etm4x-core.c | 8 ++++++--
drivers/hwtracing/coresight/coresight-etm4x.h | 3 +++
2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index a9765d45a0ee8..8643b77e50f41 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1240,6 +1240,8 @@ 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);

@@ -1732,7 +1734,8 @@ 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);
@@ -1862,7 +1865,8 @@ 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 9e430f72bbd6f..9e9165f62e81f 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.
@@ -1016,6 +1018,7 @@ struct etmv4_drvdata {
bool boot_enable;
bool os_unlock;
bool instrp0;
+ bool q_filt;
bool trcbb;
bool trccond;
bool retstack;
--
2.43.0