coresight: etm4x: Fix access to resource selector registers

[ 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>

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 130e9030a8bef9d0dc705607b9cafe70cf2b5290..84734c7c19158feec2d0c29d82323e47a829f92d 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1608,7 +1608,8 @@ 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++) {
@@ -1723,7 +1724,8 @@ 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++) {