platform/x86/amd/pmf: Fix a potential race with policy binary sideload

The debugfs `update_policy` file is created before
amd_pmf_start_policy_engine() has completed, and thus there could be
a possible (albeit unlikely) race between sideloading a policy and the
BIOS policy getting setup.

Move the debugfs file creation after all BIOS policy is setup.

Fixes: 10817f2 ("platform/x86/amd/pmf: Add capability to sideload of policy binary")
Reported-by: Hans de Goede <[email protected]>
Closes: https://lore.kernel.org/platform-driver-x86/[email protected]/T/#m2c445f135e5ef9b53184be7fc9df84e15f89d4d9
Signed-off-by: Mario Limonciello <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Hans de Goede <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>

Author: superm1

drivers/platform/x86/amd/pmf/tee-if.c

@@ -456,8 +456,6 @@ int amd_pmf_init_smart_pc(struct amd_pmf_dev *dev)
 	memcpy(dev->policy_buf, dev->policy_base, dev->policy_sz);
 
 	amd_pmf_hex_dump_pb(dev);
-	if (pb_side_load)
-		amd_pmf_open_pb(dev, dev->dbgfs_dir);
 
 	dev->prev_data = kzalloc(sizeof(*dev->prev_data), GFP_KERNEL);
 	if (!dev->prev_data)
@@ -467,6 +465,9 @@ int amd_pmf_init_smart_pc(struct amd_pmf_dev *dev)
 	if (ret)
 		goto error;
 
+	if (pb_side_load)
+		amd_pmf_open_pb(dev, dev->dbgfs_dir);
+
 	return 0;
 
 error: