linux-kernel - [PATCH v3 1/7] coresight: Convert tag clear function to take a struct cs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250320-james-coresight-claim-tags-v3-1-d3145c153820@linaro.org>
Date: Thu, 20 Mar 2025 14:34:10 +0000
From: James Clark <james.clark@...aro.org>
To: Suzuki K Poulose <suzuki.poulose@....com>, 
 Mike Leach <mike.leach@...aro.org>, James Clark <james.clark@...aro.org>, 
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
 Maxime Coquelin <mcoquelin.stm32@...il.com>, 
 Alexandre Torgue <alexandre.torgue@...s.st.com>, Suzuki.Poulose@....com, 
 leo.yan@....com
Cc: coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, linux-stm32@...md-mailman.stormreply.com
Subject: [PATCH v3 1/7] coresight: Convert tag clear function to take a
 struct cs_access

The self hosted claim tag will be reset on device probe in a later
commit. We'll want to do this before coresight_register() is called so
won't have a coresight_device and have to use cs_access instead.

Also make them public and create locked and unlocked versions for
later use.

These look functions look like they set the whole tags register as one
value, but they only set and clear the self hosted bit using a SET/CLR
bits mechanism so also rename the functions to reflect this better.

Reviewed-by: Leo Yan <leo.yan@....com>
Signed-off-by: James Clark <james.clark@...aro.org>
---
 drivers/hwtracing/coresight/coresight-core.c | 27 +++++++++++++++++++--------
 include/linux/coresight.h                    |  3 ++-
 2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index fb43ef6a3b1f..8471aefeac76 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -144,19 +144,30 @@ static inline bool coresight_is_claimed_any(struct coresight_device *csdev)
 	return coresight_read_claim_tags(csdev) != 0;
 }
 
-static inline void coresight_set_claim_tags(struct coresight_device *csdev)
+static inline void coresight_set_self_claim_tag(struct coresight_device *csdev)
 {
 	csdev_access_relaxed_write32(&csdev->access, CORESIGHT_CLAIM_SELF_HOSTED,
 				     CORESIGHT_CLAIMSET);
 	isb();
 }
 
-static inline void coresight_clear_claim_tags(struct coresight_device *csdev)
+void coresight_clear_self_claim_tag(struct csdev_access *csa)
 {
-	csdev_access_relaxed_write32(&csdev->access, CORESIGHT_CLAIM_SELF_HOSTED,
+	if (csa->io_mem)
+		CS_UNLOCK(csa->base);
+	coresight_clear_self_claim_tag_unlocked(csa);
+	if (csa->io_mem)
+		CS_LOCK(csa->base);
+}
+EXPORT_SYMBOL_GPL(coresight_clear_self_claim_tag);
+
+void coresight_clear_self_claim_tag_unlocked(struct csdev_access *csa)
+{
+	csdev_access_relaxed_write32(csa, CORESIGHT_CLAIM_SELF_HOSTED,
 				     CORESIGHT_CLAIMCLR);
 	isb();
 }
+EXPORT_SYMBOL_GPL(coresight_clear_self_claim_tag_unlocked);
 
 /*
  * coresight_claim_device_unlocked : Claim the device for self-hosted usage
@@ -176,11 +187,11 @@ int coresight_claim_device_unlocked(struct coresight_device *csdev)
 	if (coresight_is_claimed_any(csdev))
 		return -EBUSY;
 
-	coresight_set_claim_tags(csdev);
+	coresight_set_self_claim_tag(csdev);
 	if (coresight_is_claimed_self_hosted(csdev))
 		return 0;
-	/* There was a race setting the tags, clean up and fail */
-	coresight_clear_claim_tags(csdev);
+	/* There was a race setting the tag, clean up and fail */
+	coresight_clear_self_claim_tag_unlocked(&csdev->access);
 	return -EBUSY;
 }
 EXPORT_SYMBOL_GPL(coresight_claim_device_unlocked);
@@ -201,7 +212,7 @@ int coresight_claim_device(struct coresight_device *csdev)
 EXPORT_SYMBOL_GPL(coresight_claim_device);
 
 /*
- * coresight_disclaim_device_unlocked : Clear the claim tags for the device.
+ * coresight_disclaim_device_unlocked : Clear the claim tag for the device.
  * Called with CS_UNLOCKed for the component.
  */
 void coresight_disclaim_device_unlocked(struct coresight_device *csdev)
@@ -211,7 +222,7 @@ void coresight_disclaim_device_unlocked(struct coresight_device *csdev)
 		return;
 
 	if (coresight_is_claimed_self_hosted(csdev))
-		coresight_clear_claim_tags(csdev);
+		coresight_clear_self_claim_tag_unlocked(&csdev->access);
 	else
 		/*
 		 * The external agent may have not honoured our claim
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index d79a242b271d..00134a80d358 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -685,7 +685,8 @@ extern int coresight_timeout_action(struct csdev_access *csa, u32 offset,
 
 extern int coresight_claim_device(struct coresight_device *csdev);
 extern int coresight_claim_device_unlocked(struct coresight_device *csdev);
-
+void coresight_clear_self_claim_tag(struct csdev_access *csa);
+void coresight_clear_self_claim_tag_unlocked(struct csdev_access *csa);
 extern void coresight_disclaim_device(struct coresight_device *csdev);
 extern void coresight_disclaim_device_unlocked(struct coresight_device *csdev);
 extern char *coresight_alloc_device_name(struct coresight_dev_list *devs,

-- 
2.34.1