Merge tag 'ffa-fix-6.13' of https://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/fixes

Arm FF-A fix for v6.13

A single fix to address a possible race around setting ffa_dev->properties
in ffa_device_register() by updating ffa_device_register() to take all
the partition information received from the firmware and updating the
struct ffa_device accordingly before registering the device to the
bus/driver model in the kernel.

* tag 'ffa-fix-6.13' of https://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  firmware: arm_ffa: Fix the race around setting ffa_dev->properties

Link: https://lore.kernel.org/r/20241210101113.3232602-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

3 files changed, 20 insertions, 15 deletions

diff --git a/drivers/firmware/arm_ffa/bus.c b/drivers/firmware/arm_ffa/bus.c
index eb17d03b66fe..dfda5ffc14db 100644
--- a/drivers/firmware/arm_ffa/bus.c
+++ b/drivers/firmware/arm_ffa/bus.c
@@ -187,13 +187,18 @@ bool ffa_device_is_valid(struct ffa_device *ffa_dev)
 	return valid;
 }
 
-struct ffa_device *ffa_device_register(const uuid_t *uuid, int vm_id,
-				       const struct ffa_ops *ops)
+struct ffa_device *
+ffa_device_register(const struct ffa_partition_info *part_info,
+		    const struct ffa_ops *ops)
 {
 	int id, ret;
+	uuid_t uuid;
 	struct device *dev;
 	struct ffa_device *ffa_dev;
 
+	if (!part_info)
+		return NULL;
+
 	id = ida_alloc_min(&ffa_bus_id, 1, GFP_KERNEL);
 	if (id < 0)
 		return NULL;
@@ -210,9 +215,11 @@ struct ffa_device *ffa_device_register(const uuid_t *uuid, int vm_id,
 	dev_set_name(&ffa_dev->dev, "arm-ffa-%d", id);
 
 	ffa_dev->id = id;
-	ffa_dev->vm_id = vm_id;
+	ffa_dev->vm_id = part_info->id;
+	ffa_dev->properties = part_info->properties;
 	ffa_dev->ops = ops;
-	uuid_copy(&ffa_dev->uuid, uuid);
+	import_uuid(&uuid, (u8 *)part_info->uuid);
+	uuid_copy(&ffa_dev->uuid, &uuid);
 
 	ret = device_register(&ffa_dev->dev);
 	if (ret) {
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index b14cbdae94e8..2c2ec3c35f15 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -1387,7 +1387,6 @@ static struct notifier_block ffa_bus_nb = {
 static int ffa_setup_partitions(void)
 {
 	int count, idx, ret;
-	uuid_t uuid;
 	struct ffa_device *ffa_dev;
 	struct ffa_dev_part_info *info;
 	struct ffa_partition_info *pbuf, *tpbuf;
@@ -1406,23 +1405,19 @@ static int ffa_setup_partitions(void)
 
 	xa_init(&drv_info->partition_info);
 	for (idx = 0, tpbuf = pbuf; idx < count; idx++, tpbuf++) {
-		import_uuid(&uuid, (u8 *)tpbuf->uuid);
-
 		/* Note that if the UUID will be uuid_null, that will require
 		 * ffa_bus_notifier() to find the UUID of this partition id
 		 * with help of ffa_device_match_uuid(). FF-A v1.1 and above
 		 * provides UUID here for each partition as part of the
 		 * discovery API and the same is passed.
 		 */
-		ffa_dev = ffa_device_register(&uuid, tpbuf->id, &ffa_drv_ops);
+		ffa_dev = ffa_device_register(tpbuf, &ffa_drv_ops);
 		if (!ffa_dev) {
 			pr_err("%s: failed to register partition ID 0x%x\n",
 			       __func__, tpbuf->id);
 			continue;
 		}
 
-		ffa_dev->properties = tpbuf->properties;
-
 		if (drv_info->version > FFA_VERSION_1_0 &&
 		    !(tpbuf->properties & FFA_PARTITION_AARCH64_EXEC))
 			ffa_mode_32bit_set(ffa_dev);
diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h
index a28e2a6a13d0..74169dd0f659 100644
--- a/include/linux/arm_ffa.h
+++ b/include/linux/arm_ffa.h
@@ -166,9 +166,12 @@ static inline void *ffa_dev_get_drvdata(struct ffa_device *fdev)
 	return dev_get_drvdata(&fdev->dev);
 }
 
+struct ffa_partition_info;
+
 #if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
-struct ffa_device *ffa_device_register(const uuid_t *uuid, int vm_id,
-				       const struct ffa_ops *ops);
+struct ffa_device *
+ffa_device_register(const struct ffa_partition_info *part_info,
+		    const struct ffa_ops *ops);
 void ffa_device_unregister(struct ffa_device *ffa_dev);
 int ffa_driver_register(struct ffa_driver *driver, struct module *owner,
 			const char *mod_name);
@@ -176,9 +179,9 @@ void ffa_driver_unregister(struct ffa_driver *driver);
 bool ffa_device_is_valid(struct ffa_device *ffa_dev);
 
 #else
-static inline
-struct ffa_device *ffa_device_register(const uuid_t *uuid, int vm_id,
-				       const struct ffa_ops *ops)
+static inline struct ffa_device *
+ffa_device_register(const struct ffa_partition_info *part_info,
+		    const struct ffa_ops *ops)
 {
 	return NULL;
 }