From 8217fa7d92f0bdcfc61c20ba9fa2b6ae50970110 Mon Sep 17 00:00:00 2001 From: James Clark Date: Tue, 25 Mar 2025 11:58:47 +0000 Subject: [PATCH] coresight: Only check bottom two claim bits [ 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 Reviewed-by: Yeoreum Yun Signed-off-by: James Clark Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20250325-james-coresight-claim-tags-v4-2-dfbd3822b2e5@linaro.org Signed-off-by: Sasha Levin --- 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 783e259c3761..3b57851869ea 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -135,7 +135,8 @@ coresight_find_out_connection(struct coresight_device *src_dev, 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 30c051055e54..b758a42ed8c7 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -32,6 +32,7 @@ * 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