Commit 6fe437cf authored by Levi Yun's avatar Levi Yun Committed by Sudeep Holla
Browse files

firmware: arm_ffa: Fix the race around setting ffa_dev->properties 



Currently, ffa_dev->properties is set after the ffa_device_register()
call return in ffa_setup_partitions(). This could potentially result in
a race where the partition's properties is accessed while probing
struct ffa_device before it is set.

Update the ffa_device_register() to receive ffa_partition_info so all
the data from the partition information received from the firmware can
be updated into the struct ffa_device before the calling device_register()
in ffa_device_register().

Fixes: e7818584 ("firmware: arm_ffa: Add initial FFA bus support for device enumeration")
Signed-off-by: default avatarLevi Yun <yeoreum.yun@arm.com>
Message-Id: <20241203143109.1030514-2-yeoreum.yun@arm.com>
Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 40384c84

drivers/firmware/arm_ffa/bus.c

+11 −4
Original line number Diff line number Diff line
@@ -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,

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) {

drivers/firmware/arm_ffa/driver.c

+1 −6
Original line number Diff line number Diff line
@@ -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);

include/linux/arm_ffa.h

+8 −5
Original line number Diff line number Diff line
@@ -166,8 +166,11 @@ 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,

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,
@@ -176,8 +179,8 @@ 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,

static inline struct ffa_device *

ffa_device_register(const struct ffa_partition_info *part_info,

		    const struct ffa_ops *ops)

{

	return NULL;