smcinvoke: Handle suspend and resume issues in smcinvoke driver

This change makes changes to smcinvoke driver to handle suspend and resume
scenarios. If the accept thread gets interrupted, do not set the server state
as defunct if the thread is in freezing state, i.e. if the thread is going in
suspend. In such cases, increase timeout of that server so that invoke thread
waits indefinitely for response from userspace until the system resumes back.

Tests:
1. Stability testing has been done on kalama.
2. smcinvoke vendor client testing is done on pineapple.

Change-Id: Iaa7b91d6ed484305349c04468263919e26a3316d
Signed-off-by: Anmolpreet Kaur <[email protected]>

include/linux/smcinvoke.h

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
 /*
  * Copyright (c) 2017-2020, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 #ifndef _UAPI_SMCINVOKE_H_
 #define _UAPI_SMCINVOKE_H_
@@ -9,6 +10,7 @@
 #include <linux/ioctl.h>
 
 #define SMCINVOKE_USERSPACE_OBJ_NULL	-1
+#define DEFAULT_CB_OBJ_THREAD_CNT	4
 
 struct smcinvoke_buf {
 	__u64 addr;

smcinvoke/smcinvoke.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2016-2021, The Linux Foundation. All rights reserved.
- * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
 #define pr_fmt(fmt) "smcinvoke: %s: " fmt, __func__
@@ -26,6 +26,7 @@
 #include <linux/of_platform.h>
 #include <linux/firmware.h>
 #include <linux/qcom_scm.h>
+#include <linux/freezer.h>
 #include <asm/cacheflush.h>
 #include <soc/qcom/qseecomi.h>
 #include <linux/qtee_shmbridge.h>
@@ -138,6 +139,8 @@
 #define TZHANDLE_GET_SERVER(h) ((uint16_t)((h) & 0xFFFF))
 #define TZHANDLE_GET_OBJID(h) (((h) >> 16) & 0x7FFF)
 #define TZHANDLE_MAKE_LOCAL(s, o) (((0x8000 | (o)) << 16) | s)
+#define SET_BIT(s,b) (s | (1 << b))
+#define UNSET_BIT(s,b) (s & (~ (1 << b)))
 
 #define TZHANDLE_IS_NULL(h) ((h) == SMCINVOKE_TZ_OBJ_NULL)
 #define TZHANDLE_IS_LOCAL(h) ((h) & 0x80000000)
@@ -304,6 +307,7 @@ struct smcinvoke_server_info {
 	DECLARE_HASHTABLE(responses_table, 4);
 	struct hlist_node hash;
 	struct list_head pending_cbobjs;
+	uint8_t is_server_suspended;
 };
 
 struct smcinvoke_cbobj {
@@ -1717,13 +1721,15 @@ static void process_tzcb_req(void *buf, size_t buf_len, struct file **arr_filp)
 					timeout_jiff);
 		}
 		if (ret == 0) {
-			pr_err("CBobj timed out cb-tzhandle:%d, retry:%d, op:%d counts :%d\n",
-					cb_req->hdr.tzhandle, cbobj_retries,
+			if (srvr_info->is_server_suspended == 0) {
+			pr_err("CBobj timed out waiting on cbtxn :%d,cb-tzhandle:%d, retry:%d, op:%d counts :%d\n",
+					cb_txn->txn_id,cb_req->hdr.tzhandle, cbobj_retries,
 					cb_req->hdr.op, cb_req->hdr.counts);
 			pr_err("CBobj %d timedout pid %x,tid %x, srvr state=%d, srvr id:%u\n",
 					cb_req->hdr.tzhandle, current->pid,
 					current->tgid, srvr_info->state,
 					srvr_info->server_id);
+			}
 		} else {
 			/* wait_event returned due to a signal */
 			if (srvr_info->state != SMCINVOKE_SERVER_STATE_DEFUNCT &&
@@ -1733,7 +1739,16 @@ static void process_tzcb_req(void *buf, size_t buf_len, struct file **arr_filp)
 				break;
 			}
 		}
-		cbobj_retries++;
+		/*
+		 * If bit corresponding to any accept thread is set, invoke threads
+		 * should wait infinitely for the accept thread to come back with
+		 * response.
+		 */
+		if (srvr_info->is_server_suspended > 0) {
+			cbobj_retries = 0;
+		} else {
+			cbobj_retries++;
+		}
 	}
 
 out:
@@ -2396,6 +2411,7 @@ static long process_server_req(struct file *filp, unsigned int cmd,
 	hash_init(server_info->reqs_table);
 	hash_init(server_info->responses_table);
 	INIT_LIST_HEAD(&server_info->pending_cbobjs);
+	server_info->is_server_suspended = 0;
 
 	mutex_lock(&g_smcinvoke_lock);
 
@@ -2459,6 +2475,9 @@ static long process_accept_req(struct file *filp, unsigned int cmd,
 	if (server_info->state == SMCINVOKE_SERVER_STATE_DEFUNCT)
 		server_info->state = 0;
 
+	server_info->is_server_suspended = UNSET_BIT(server_info->is_server_suspended,
+				(current->pid)%DEFAULT_CB_OBJ_THREAD_CNT);
+
 	mutex_unlock(&g_smcinvoke_lock);
 
 	/* First check if it has response otherwise wait for req */
@@ -2522,7 +2541,26 @@ start_waiting_for_requests:
 			 * using server_info and would crash. So dont do that.
 			 */
 			mutex_lock(&g_smcinvoke_lock);
-			server_info->state = SMCINVOKE_SERVER_STATE_DEFUNCT;
+
+			if(freezing(current)) {
+				pr_err("Server id :%d interrupted probaby due to suspend, pid:%d",
+					server_info->server_id, current->pid);
+				/*
+				 * Each accept thread is identified by bits ranging from
+				 * 0 to DEFAULT_CBOBJ_THREAD_CNT-1. When an accept thread is
+				 * interrupted by a signal other than SIGUSR1,SIGKILL,SIGTERM,
+				 * set the corresponding bit of accept thread, indicating that
+				 * current accept thread's state to be "suspended"/ or something
+				 * that needs infinite timeout for invoke thread.
+				 */
+				server_info->is_server_suspended =
+						SET_BIT(server_info->is_server_suspended,
+							(current->pid)%DEFAULT_CB_OBJ_THREAD_CNT);
+			} else {
+				pr_err("Setting pid:%d, server id : %d state to defunct",
+						current->pid, server_info->server_id);
+						server_info->state = SMCINVOKE_SERVER_STATE_DEFUNCT;
+			}
 			mutex_unlock(&g_smcinvoke_lock);
 			wake_up_interruptible(&server_info->rsp_wait_q);
 			goto out;