#
 # This file contains a few gdb macros (user defined commands) to extract
 # useful information from kernel dump
 #
 # These macros can be used by copying this file in .gdbinit (put in home
 # directory or current directory) or by invoking gdb command with
 # --command=<command-file-name> option
 #
 # Based on:
 # https://www.kernel.org/doc/Documentation/kdump/gdbmacros.txt
 # http://embeddedlinuxprimer.com/gdb_macros
 #
 
 define bttnobp
 	set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
 	set $pid_off=((size_t)&((struct task_struct *)0)->thread_group.next)
 	set $init_t=&init_task
 	set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
 	set var $stacksize = sizeof(union thread_union)
 	while ($next_t != $init_t)
 		set $next_t=(struct task_struct *)$next_t
 		printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
 		printf "===================\n"
 		set var $stackp = $next_t.thread.sp
 		set var $stack_top = ($stackp & ~($stacksize - 1)) + $stacksize
 
 		while ($stackp < $stack_top)
 			if (*($stackp) > _stext && *($stackp) < _sinittext)
 				info symbol *($stackp)
 			end
 			set $stackp += 4
 		end
 		set $next_th=(((char *)$next_t->thread_group.next) - $pid_off)
 		while ($next_th != $next_t)
 			set $next_th=(struct task_struct *)$next_th
 			printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
 			printf "===================\n"
 			set var $stackp = $next_t.thread.sp
 			set var $stack_top = ($stackp & ~($stacksize - 1)) + stacksize
 
 			while ($stackp < $stack_top)
 				if (*($stackp) > _stext && *($stackp) < _sinittext)
 					info symbol *($stackp)
 				end
 				set $stackp += 4
 			end
 			set $next_th=(((char *)$next_th->thread_group.next) - $pid_off)
 		end
 		set $next_t=(char *)($next_t->tasks.next) - $tasks_off
 	end
 end
 document bttnobp
 	dump all thread stack traces on a kernel compiled with !CONFIG_FRAME_POINTER
 end
 
 define btthreadstack
 	set var $pid_task = $arg0
 
 	printf "\npid %d; comm %s:\n", $pid_task.pid, $pid_task.comm
 	printf "task struct: "
 	print $pid_task
 	printf "===================\n"
 	set var $stackp = $pid_task.thread.sp
 	set var $stacksize = sizeof(union thread_union)
 	set var $stack_top = ($stackp & ~($stacksize - 1)) + $stacksize
 	set var $stack_bot = ($stackp & ~($stacksize - 1))
 
 	set $stackp = *((unsigned long *) $stackp)
 	while (($stackp < $stack_top) && ($stackp > $stack_bot))
 		set var $addr = *(((unsigned long *) $stackp) + 1)
 		info symbol $addr
 		set $stackp = *((unsigned long *) $stackp)
 	end
 end
 document btthreadstack
 	 dump a thread stack using the given task structure pointer
 end
 
 
 define btt
 	set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
 	set $pid_off=((size_t)&((struct task_struct *)0)->thread_group.next)
 	set $init_t=&init_task
 	set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
 	while ($next_t != $init_t)
 		set $next_t=(struct task_struct *)$next_t
 		btthreadstack $next_t
 
 		set $next_th=(((char *)$next_t->thread_group.next) - $pid_off)
 		while ($next_th != $next_t)
 			set $next_th=(struct task_struct *)$next_th
 			btthreadstack $next_th
 			set $next_th=(((char *)$next_th->thread_group.next) - $pid_off)
 		end
 		set $next_t=(char *)($next_t->tasks.next) - $tasks_off
 	end
 end
 document btt
 	dump all thread stack traces on a kernel compiled with CONFIG_FRAME_POINTER
 end
 
 define btpid
 	set var $pid = $arg0
 	set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
 	set $pid_off=((size_t)&((struct task_struct *)0)->thread_group.next)
 	set $init_t=&init_task
 	set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
 	set var $pid_task = 0
 
 	while ($next_t != $init_t)
 		set $next_t=(struct task_struct *)$next_t
 
 		if ($next_t.pid == $pid)
 			set $pid_task = $next_t
 		end
 
 		set $next_th=(((char *)$next_t->thread_group.next) - $pid_off)
 		while ($next_th != $next_t)
 			set $next_th=(struct task_struct *)$next_th
 			if ($next_th.pid == $pid)
 				set $pid_task = $next_th
 			end
 			set $next_th=(((char *)$next_th->thread_group.next) - $pid_off)
 		end
 		set $next_t=(char *)($next_t->tasks.next) - $tasks_off
 	end
 
 	btthreadstack $pid_task
 end
 document btpid
 	backtrace of pid
 end
 
 
 define trapinfo
 	set var $pid = $arg0
 	set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
 	set $pid_off=((size_t)&((struct task_struct *)0)->thread_group.next)
 	set $init_t=&init_task
 	set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
 	set var $pid_task = 0
 
 	while ($next_t != $init_t)
 		set $next_t=(struct task_struct *)$next_t
 
 		if ($next_t.pid == $pid)
 			set $pid_task = $next_t
 		end
 
 		set $next_th=(((char *)$next_t->thread_group.next) - $pid_off)
 		while ($next_th != $next_t)
 			set $next_th=(struct task_struct *)$next_th
 			if ($next_th.pid == $pid)
 				set $pid_task = $next_th
 			end
 			set $next_th=(((char *)$next_th->thread_group.next) - $pid_off)
 		end
 		set $next_t=(char *)($next_t->tasks.next) - $tasks_off
 	end
 
 	printf "Trapno %ld, cr2 0x%lx, error_code %ld\n", $pid_task.thread.trap_no, \
 				$pid_task.thread.cr2, $pid_task.thread.error_code
 
 end
 document trapinfo
 	Run info threads and lookup pid of thread #1
 	'trapinfo <pid>' will tell you by which trap & possibly
 	address the kernel panicked.
 end
 
 define dump_log_idx
 	set $idx = $arg0
 	if ($argc > 1)
 		set $prev_flags = $arg1
 	else
 		set $prev_flags = 0
 	end
 	set $msg = ((struct printk_log *) (log_buf + $idx))
 	set $prefix = 1
 	set $newline = 1
 	set $log = log_buf + $idx + sizeof(*$msg)
 
 	# prev & LOG_CONT && !(msg->flags & LOG_PREFIX)
 	if (($prev_flags & 8) && !($msg->flags & 4))
 		set $prefix = 0
 	end
 
 	# msg->flags & LOG_CONT
 	if ($msg->flags & 8)
 		# (prev & LOG_CONT && !(prev & LOG_NEWLINE))
 		if (($prev_flags & 8) && !($prev_flags & 2))
 			set $prefix = 0
 		end
 		# (!(msg->flags & LOG_NEWLINE))
 		if (!($msg->flags & 2))
 			set $newline = 0
 		end
 	end
 
 	if ($prefix)
 		printf "[%5lu.%06lu] ", $msg->ts_nsec / 1000000000, $msg->ts_nsec % 1000000000
 	end
 	if ($msg->text_len != 0)
 		eval "printf \"%%%d.%ds\", $log", $msg->text_len, $msg->text_len
 	end
 	if ($newline)
 		printf "\n"
 	end
 #	if ($msg->dict_len > 0)
 	if (0)
 		set $dict = $log + $msg->text_len
 		set $idx = 0
 		set $line = 1
 		while ($idx < $msg->dict_len)
 			if ($line)
 				printf " "
 				set $line = 0
 			end
 			set $c = ((char*)$dict)[$idx]
 			if ($c == '\0')
 				printf "\n"
 				set $line = 1
 			else
 				if ($c < ' ' || $c >= 127 || $c == '\\')
 					printf "\\x%02x", $c
 				else
 					printf "%c", $c
 				end
 			end
 			set $idx = $idx + 1
 		end
 		printf "\n"
 	end
 end
 document dump_log_idx
 	Dump a single log given its index in the log buffer.  The first
 	parameter is the index into log_buf, the second is optional and
 	specified the previous log buffer's flags, used for properly
 	formatting continued lines.
 end
 
 define dmesg
 	set $i = log_first_idx
 	set $end_idx = log_first_idx
 	set $prev_flags = 0
 
 	while (1)
 		set $msg = ((struct printk_log *) (log_buf + $i))
 		if ($msg->len == 0)
 			set $i = 0
 		else
 			dump_log_idx $i $prev_flags
 			set $i = $i + $msg->len
 			set $prev_flags = $msg->flags
 		end
 		if  ( $i == $end_idx)
 			loop_break
 		end
 	end
 end
 document dmesg
 	Print the kernel ring buffer
 end
 
 define lsmod
 	set $current = modules.next
 	set $offset =  ((int)&((struct module *)0).list)
 	printf "Address            Module                         Size  Used by\n"
 	while($current.next != modules.next)
 		set $mod = (struct module *)(((void *)$current) - $offset)
 		printf "%p %-28s %6d %2d", $mod->module_core, $mod->name, $mod->core_size, $mod->refcnt.counter
 		if ($mod->refcnt.counter)
 			set $cur = $mod->source_list.next
 			while($cur.next != $mod->source_list.next)
 				# hacky cast $cur to struct module_use, use container_of instead
 				printf " %s", ((struct module_use *)$cur)->source->name
 				set $cur = $cur.next
 			end
 		end
 		printf "\n"
 		set $current = $current.next
 	end
 end
 document lsmod
 	List the loaded kernel modules and their start addresses
 end
 
 define find_task
 	# Addresses greater than _end: kernel data...
 	# ...user passed in an address
 	if ((unsigned)$arg0 > (unsigned)&_end)
 		set $t=(struct task_struct *)$arg0
 	else
 		# User entered a numeric PID
 		# Walk the task list to find it
 		set $t=&init_task
 		if (init_task.pid != (unsigned)$arg0)
 			find_next_task $t
 			while (&init_task!=$t && $t->pid != (unsigned)$arg0)
 				find_next_task $t
 			end
 			if ($t == &init_task)
 				printf "Couldn't find task; using init_task\n"
 			end
 		end
 	end
 	task_struct_show $t
 end
 document find_task
 	Find a task by the PID
 end
 
 define ps
 	set $t=&init_task
 	printf "Address              PID STAT      TTY    COMMAND\n"
 	task_struct_show $t
 	find_next_task $t
 	# Walk the list
 	while &init_task!=$t
 		# Display useful info about each task
 		task_struct_show $t
 		find_next_task $t
 	end
 end
 document ps
 	Print points of interest for all tasks
 end
 
 define task_struct_show
 	# task_struct addr and PID
 	printf "0x%16llx %5d ", $arg0, $arg0->pid
 
 	# State
 	if ($arg0->state == 0)
 		printf "Running   "
 	else
 		if ($arg0->state == 1)
 			printf "Sleeping  "
 		else
 			if ($arg0->state == 2)
 				printf "Disksleep "
 			else
 				if ($arg0->state == 4)
 					printf "Zombie    "
 				else
 					if ($arg0->state == 8)
 						printf "sTopped   "
 					else
 						if ($arg0->state == 16)
 							printf "Wpaging   "
 						else
 							printf "%2d        ", $arg0->state
 						end
 					end
 				end
 			end
 		end
 	end
 
 	# device
 	if ($arg0->signal->tty)
 		printf "%-6s ", $arg0->signal->tty->name
 	else
 		printf "?      "
 	end
 
 	# comm
 	if ($arg0->mm)
 		printf "%s\n", $arg0->comm
 	else
 		printf "[%s]\n", $arg0->comm
 	end
 end
 
 define find_next_task
 	# Given a task address, find the next task in the linked list
 	set $t = (struct task_struct *)$arg0
 	set $offset=( (char *)&$t->tasks - (char *)$t)
 	set $t=(struct task_struct *)( (char *)$t->tasks.next- (char *)$offset)
 end