From 6b504201debf3de7009ab5de3ff7bad078af998c Mon Sep 17 00:00:00 2001
From: Stylon Wang <stylon.wang@amd.com>
Date: Wed, 26 Oct 2022 21:00:40 +0800
Subject: drm/amd/display: Fix invalid DPIA AUX reply causing system hang
Git-commit: 8d8494c3467d366eb0f7c8198dab80be8bdc47d2
Patch-mainline: v6.1-rc6
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849

[Why]
Some DPIA AUX replies have incorrect data length from original request.
This could lead to overwriting of destination buffer if reply length is
larger, which could cause invalid access to stack since many destination
buffers are declared as local variables.

[How]
Check for invalid length from DPIA AUX replies and trigger a retry if
reply length is not the same as original request. A DRM_WARN() dmesg log
is also produced.

Reviewed-by: Roman Li <Roman.Li@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Stylon Wang <stylon.wang@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org # 6.0.x
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 20 +++++++++++++++++++
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  6 ------
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 3fd69832fb58..b082c1092eb8 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -144,6 +144,14 @@ MODULE_FIRMWARE(FIRMWARE_NAVI12_DMCU);
 /* Number of bytes in PSP footer for firmware. */
 #define PSP_FOOTER_BYTES 0x100
 
+/*
+ * DMUB Async to Sync Mechanism Status
+ */
+#define DMUB_ASYNC_TO_SYNC_ACCESS_FAIL 1
+#define DMUB_ASYNC_TO_SYNC_ACCESS_TIMEOUT 2
+#define DMUB_ASYNC_TO_SYNC_ACCESS_SUCCESS 3
+#define DMUB_ASYNC_TO_SYNC_ACCESS_INVALID 4
+
 /**
  * DOC: overview
  *
@@ -10119,6 +10127,8 @@ static int amdgpu_dm_set_dmub_async_sync_status(bool is_cmd_aux,
 			*operation_result = AUX_RET_ERROR_TIMEOUT;
 		} else if (status_type == DMUB_ASYNC_TO_SYNC_ACCESS_FAIL) {
 			*operation_result = AUX_RET_ERROR_ENGINE_ACQUIRE;
+		} else if (status_type == DMUB_ASYNC_TO_SYNC_ACCESS_INVALID) {
+			*operation_result = AUX_RET_ERROR_INVALID_REPLY;
 		} else {
 			*operation_result = AUX_RET_ERROR_UNKNOWN;
 		}
@@ -10166,6 +10176,16 @@ int amdgpu_dm_process_dmub_aux_transfer_sync(bool is_cmd_aux, struct dc_context
 			payload->reply[0] = adev->dm.dmub_notify->aux_reply.command;
 			if (!payload->write && adev->dm.dmub_notify->aux_reply.length &&
 			    payload->reply[0] == AUX_TRANSACTION_REPLY_AUX_ACK) {
+
+				if (payload->length != adev->dm.dmub_notify->aux_reply.length) {
+					DRM_WARN("invalid read from DPIA AUX %x(%d) got length %d!\n",
+							payload->address, payload->length,
+							adev->dm.dmub_notify->aux_reply.length);
+					return amdgpu_dm_set_dmub_async_sync_status(is_cmd_aux, ctx,
+							DMUB_ASYNC_TO_SYNC_ACCESS_INVALID,
+							(uint32_t *)operation_result);
+				}
+
 				memcpy(payload->data, adev->dm.dmub_notify->aux_reply.data,
 				       adev->dm.dmub_notify->aux_reply.length);
 			}
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index b5ce15c43bcc..635c398fcefe 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -50,12 +50,6 @@
 
 #define AMDGPU_DMUB_NOTIFICATION_MAX 5
 
-/*
- * DMUB Async to Sync Mechanism Status
- */
-#define DMUB_ASYNC_TO_SYNC_ACCESS_FAIL 1
-#define DMUB_ASYNC_TO_SYNC_ACCESS_TIMEOUT 2
-#define DMUB_ASYNC_TO_SYNC_ACCESS_SUCCESS 3
 /*
 #include "include/amdgpu_dal_power_if.h"
 #include "amdgpu_dm_irq.h"
-- 
2.38.1