6.15-stable review patch. If anyone has any objections, please let me know.
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From: James Clark james.clark@linaro.org
[ Upstream commit a4e65842e1142aa18ef36113fbd81d614eaefe5a ]
The use of the whole register and == could break the claim mechanism if any of the other bits are used in the future. The referenced doc "PSCI - ARM DEN 0022D" also says to only read and clear the bottom two bits.
Use FIELD_GET() to extract only the relevant part.
Reviewed-by: Leo Yan leo.yan@arm.com Reviewed-by: Yeoreum Yun yeoreum.yun@arm.com Signed-off-by: James Clark james.clark@linaro.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Link: https://lore.kernel.org/r/20250325-james-coresight-claim-tags-v4-2-dfbd3822b... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hwtracing/coresight/coresight-core.c | 3 ++- drivers/hwtracing/coresight/coresight-priv.h | 1 + 2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index d3523f0262af8..dfcb30da2e20b 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -131,7 +131,8 @@ coresight_find_out_connection(struct coresight_device *csdev,
static inline u32 coresight_read_claim_tags(struct coresight_device *csdev) { - return csdev_access_relaxed_read32(&csdev->access, CORESIGHT_CLAIMCLR); + return FIELD_GET(CORESIGHT_CLAIM_MASK, + csdev_access_relaxed_read32(&csdev->access, CORESIGHT_CLAIMCLR)); }
static inline bool coresight_is_claimed_self_hosted(struct coresight_device *csdev) diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index 82644aff8d2b7..38bb4e8b50ef6 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -35,6 +35,7 @@ extern const struct device_type coresight_dev_type[]; * Coresight device CLAIM protocol. * See PSCI - ARM DEN 0022D, Section: 6.8.1 Debug and Trace save and restore. */ +#define CORESIGHT_CLAIM_MASK GENMASK(1, 0) #define CORESIGHT_CLAIM_SELF_HOSTED BIT(1)
#define TIMEOUT_US 100