drm/amdgpu: Fix koops when accessing RAS EEPROM

[ Upstream commit 1d9d2ca ]

Debugfs RAS EEPROM files are available when
the ASIC supports RAS, and when the debugfs is
enabled, an also when "ras_enable" module
parameter is set to 0. However in this case,
we get a kernel oops when accessing some of
the "ras_..." controls in debugfs. The reason
for this is that struct amdgpu_ras::adev is
unset. This commit sets it, thus enabling access
to those facilities. Note that this facilitates
EEPROM access and not necessarily RAS features or
functionality.

Cc: Alexander Deucher <Alexander.Deucher@amd.com>
Cc: John Clements <john.clements@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Acked-by: Alexander Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c

@@ -1966,11 +1966,20 @@ int amdgpu_ras_recovery_init(struct amdgpu_device *adev)
 	bool exc_err_limit = false;
 	int ret;
 
-	if (adev->ras_enabled && con)
-		data = &con->eh_data;
-	else
+	if (!con)
+		return 0;
+
+	/* Allow access to RAS EEPROM via debugfs, when the ASIC
+	 * supports RAS and debugfs is enabled, but when
+	 * adev->ras_enabled is unset, i.e. when "ras_enable"
+	 * module parameter is set to 0.
+	 */
+	con->adev = adev;
+
+	if (!adev->ras_enabled)
 		return 0;
 
+	data = &con->eh_data;
 	*data = kmalloc(sizeof(**data), GFP_KERNEL | __GFP_ZERO);
 	if (!*data) {
 		ret = -ENOMEM;
@@ -1980,7 +1989,6 @@ int amdgpu_ras_recovery_init(struct amdgpu_device *adev)
 	mutex_init(&con->recovery_lock);
 	INIT_WORK(&con->recovery_work, amdgpu_ras_do_recovery);
 	atomic_set(&con->in_recovery, 0);
-	con->adev = adev;
 
 	max_eeprom_records_len = amdgpu_ras_eeprom_get_record_max_length();
 	amdgpu_ras_validate_threshold(adev, max_eeprom_records_len);