[PATCH 6.1 319/473] coresight: etm4x: Fix access to resource selector registers

Greg Kroah-Hartman
2024-06-06T14:17:14Z

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

[ Upstream commit d6fc00d0f640d6010b51054aa8b0fd191177dbc9 ]

Resource selector pair 0 is always implemented and reserved. We must not
touch it, even during save/restore for CPU Idle. Rest of the driver is
well behaved. Fix the offending ones.

Reported-by: Yabin Cui <yabinc@google.com>
Fixes: f188b5e76aae ("coresight: etm4x: Save/restore state across CPU low power states")
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: Yabin Cui <yabinc@google.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Link: https://lore.kernel.org/r/20240412142702.2882478-5-suzuki.poulose@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwtracing/coresight/coresight-etm4x-core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index e2e5b1422cdb7..354267edcb45f 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1641,7 +1641,8 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
state->trccntvr[i] = etm4x_read32(csa, TRCCNTVRn(i));
}

- for (i = 0; i < drvdata->nr_resource * 2; i++)
+ /* Resource selector pair 0 is reserved */
+ for (i = 2; i < drvdata->nr_resource * 2; i++)
state->trcrsctlr[i] = etm4x_read32(csa, TRCRSCTLRn(i));

for (i = 0; i < drvdata->nr_ss_cmp; i++) {
@@ -1772,7 +1773,8 @@ static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
etm4x_relaxed_write32(csa, state->trccntvr[i], TRCCNTVRn(i));
}

- for (i = 0; i < drvdata->nr_resource * 2; i++)
+ /* Resource selector pair 0 is reserved */
+ for (i = 2; i < drvdata->nr_resource * 2; i++)
etm4x_relaxed_write32(csa, state->trcrsctlr[i], TRCRSCTLRn(i));

for (i = 0; i < drvdata->nr_ss_cmp; i++) {
--
2.43.0