gpu: nvgpu: fix misra violation in bug unit

Modify the callback interface from bug to quiesce unit to remove
a possible cyclic dependency in the bug unit. Make the list of
callbacks from bug unit, UT specific. The quiesce callback function
and argument are kept in separate variables, and in a normal run the
only callback that bug unit would invoke will be the quiesce specific
function. These changes will fix the violation of Rule 17.2 in bug unit.

JIRA NVGPU-6537

Change-Id: Icb6bc92077f8d26c87425768b09a7194a98e015d
Signed-off-by: ajesh <akv@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2527207
(cherry picked from commit 7696565648c5dd573a03be19ba9525856b781ea6)
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2530900
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: svc-mobile-misra <svc-mobile-misra@nvidia.com>
Reviewed-by: svc-mobile-cert <svc-mobile-cert@nvidia.com>
Reviewed-by: svc_kernel_abi <svc_kernel_abi@nvidia.com>
Reviewed-by: Rajesh Devaraj <rdevaraj@nvidia.com>
Reviewed-by: Vaibhav Kachore <vkachore@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/common/init/nvgpu_init.c

@@ -163,6 +163,7 @@ static int nvgpu_sw_quiesce_init_support(struct gk20a *g)
 	/* register callback to SW quiesce GPU in case of BUG() */
 	g->sw_quiesce_bug_cb.cb = nvgpu_sw_quiesce_bug_cb;
 	g->sw_quiesce_bug_cb.arg = g;
+	g->sw_quiesce_bug_cb.sw_quiesce_data = true;
 	nvgpu_bug_register_cb(&g->sw_quiesce_bug_cb);
 
 #ifdef CONFIG_NVGPU_RECOVERY

drivers/gpu/nvgpu/include/nvgpu/bug.h

@@ -92,6 +92,7 @@ struct nvgpu_bug_cb
 	void (*cb)(void *arg);
 	void *arg;
 	struct nvgpu_list_node node;
+	bool sw_quiesce_data;
 };
 
 static inline struct nvgpu_bug_cb *

drivers/gpu/nvgpu/include/nvgpu/posix/bug.h

@@ -99,7 +99,7 @@ void nvgpu_bug_cb_longjmp(void *arg);
 	({							\
 		jmp_buf handler;				\
 		volatile bool bug_result = true;		\
-		struct nvgpu_bug_cb callback;			\
+		struct nvgpu_bug_cb callback = {0};		\
 		callback.cb = nvgpu_bug_cb_longjmp;		\
 		callback.arg = &handler;			\
 		nvgpu_bug_register_cb(&callback);		\

drivers/gpu/nvgpu/os/posix/bug.c

@@ -40,14 +40,20 @@
 #endif
 
 struct nvgpu_bug_desc {
+#ifdef __NVGPU_UNIT_TEST__
 	bool in_use;
 	pthread_once_t once;
 	struct nvgpu_spinlock lock;
 	struct nvgpu_list_node head;
+#endif
+	void (*quiesce_cb)(void *arg);
+	void *quiesce_arg;
 };
 
 static struct nvgpu_bug_desc bug_desc = {
+#ifdef __NVGPU_UNIT_TEST__
 	.once = PTHREAD_ONCE_INIT
+#endif
 };
 
 #ifdef __NVGPU_UNIT_TEST__
@@ -84,12 +90,14 @@ void dump_stack(void)
 	nvgpu_posix_dump_stack(frames);
 }
 
+#ifdef __NVGPU_UNIT_TEST__
 static void nvgpu_bug_init(void)
 {
 	nvgpu_spinlock_init(&bug_desc.lock);
 	nvgpu_init_list_node(&bug_desc.head);
 	bug_desc.in_use = true;
 }
+#endif
 
 void nvgpu_bug_exit(int status)
 {
@@ -101,27 +109,40 @@ void nvgpu_bug_exit(int status)
 
 void nvgpu_bug_register_cb(struct nvgpu_bug_cb *cb)
 {
+#ifdef __NVGPU_UNIT_TEST__
 	int err;
+#endif
 
+	if (cb->sw_quiesce_data) {
+		bug_desc.quiesce_cb = cb->cb;
+		bug_desc.quiesce_arg = cb->arg;
+	} else {
+#ifdef __NVGPU_UNIT_TEST__
 		err = pthread_once(&bug_desc.once, nvgpu_bug_init);
 		nvgpu_assert(err == 0);
 
 		nvgpu_spinlock_acquire(&bug_desc.lock);
 		nvgpu_list_add_tail(&cb->node, &bug_desc.head);
 		nvgpu_spinlock_release(&bug_desc.lock);
+#endif
+	}
 }
 
 void nvgpu_bug_unregister_cb(struct nvgpu_bug_cb *cb)
 {
-	int err;
+	if (cb->sw_quiesce_data) {
-
+		bug_desc.quiesce_cb = NULL;
-	err = pthread_once(&bug_desc.once, nvgpu_bug_init);
+		bug_desc.quiesce_arg = NULL;
-	nvgpu_assert(err == 0);
+	} else {
-
+#ifdef __NVGPU_UNIT_TEST__
+		if (bug_desc.in_use) {
 			nvgpu_spinlock_acquire(&bug_desc.lock);
 			nvgpu_list_del(&cb->node);
 			nvgpu_spinlock_release(&bug_desc.lock);
 		}
+#endif
+	}
+}
 
 /*
  * Ahhh! A bug!
@@ -129,13 +150,21 @@ void nvgpu_bug_unregister_cb(struct nvgpu_bug_cb *cb)
 void nvgpu_posix_bug(const char *msg, int line_no)
 {
 	int err;
+#ifdef __NVGPU_UNIT_TEST__
 	struct nvgpu_bug_cb *cb;
+#endif
 
 	nvgpu_err(NULL, "%s:%d BUG detected!", msg, line_no);
+
 #ifndef __NVGPU_UNIT_TEST__
 	dump_stack();
 #endif
 
+	if (bug_desc.quiesce_cb != NULL) {
+		bug_desc.quiesce_cb(bug_desc.quiesce_arg);
+	}
+
+#ifdef __NVGPU_UNIT_TEST__
 	if (!bug_desc.in_use) {
 		goto done;
 	}
@@ -164,6 +193,8 @@ void nvgpu_posix_bug(const char *msg, int line_no)
 	nvgpu_spinlock_release(&bug_desc.lock);
 
 done:
+#endif
+
 #ifdef __NVGPU_UNIT_TEST__
 	dump_stack();
 #endif

userspace/units/posix/bug/posix-bug.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2020, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2019-2021, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -117,8 +117,8 @@ static void other_bug_cb(void *arg)
 int test_bug_cb(struct unit_module *m,
 		struct gk20a *g, void *args)
 {
-	struct nvgpu_bug_cb callback;
+	struct nvgpu_bug_cb callback = {0};
-	struct nvgpu_bug_cb other_callback;
+	struct nvgpu_bug_cb other_callback = {0};
 	jmp_buf handler;