Some early gdb/Python macros for working with NuttX.

Note; only tested with gdb 7.6. Will definitely not work with the stock PX4 toolchain's gdb.

Debug/Nuttx.py

+# GDB/Python functions for dealing with NuttX
+
+import gdb, gdb.types
+
+class NX_task(object):
+	"""Reference to a NuttX task and methods for introspecting it"""
+
+	def __init__(self, tcb_ptr):
+		self._tcb = tcb_ptr.dereference()
+		self._group = self._tcb['group'].dereference()
+		self.pid = tcb_ptr['pid']
+
+	@classmethod
+	def for_tcb(cls, tcb):
+		"""return a task with the given TCB pointer"""
+		pidhash_sym = gdb.lookup_global_symbol('g_pidhash')
+		pidhash_value = pidhash_sym.value()
+		pidhash_type = pidhash_sym.type
+		for i in range(pidhash_type.range()[0],pidhash_type.range()[1]):
+			pidhash_entry = pidhash_value[i]
+			if pidhash_entry['tcb'] == tcb:
+				return cls(pidhash_entry['tcb'])
+		return None
+
+	@classmethod
+	def for_pid(cls, pid):
+		"""return a task for the given PID"""
+		pidhash_sym = gdb.lookup_global_symbol('g_pidhash')
+		pidhash_value = pidhash_sym.value()
+		pidhash_type = pidhash_sym.type
+		for i in range(pidhash_type.range()[0],pidhash_type.range()[1]):
+			pidhash_entry = pidhash_value[i]
+			if pidhash_entry['pid'] == pid:
+				return cls(pidhash_entry['tcb'])
+		return None
+
+	@staticmethod
+	def pids():
+		"""return a list of all PIDs"""
+		pidhash_sym = gdb.lookup_global_symbol('g_pidhash')
+		pidhash_value = pidhash_sym.value()
+		pidhash_type = pidhash_sym.type
+		result = []
+		for i in range(pidhash_type.range()[0],pidhash_type.range()[1]):
+			entry = pidhash_value[i]
+			pid = int(entry['pid'])
+			if pid is not -1:
+				result.append(pid)
+		return result
+
+	@staticmethod
+	def tasks():
+		"""return a list of all tasks"""
+		tasks = []
+		for pid in NX_task.pids():
+			tasks.append(NX_task.for_pid(pid))
+		return tasks
+
+	def _state_is(self, state):
+		"""tests the current state of the task against the passed-in state name"""
+		statenames = gdb.types.make_enum_dict(gdb.lookup_type('enum tstate_e'))
+		if self._tcb['task_state'] == statenames[state]:
+			return True
+		return False
+
+	@property
+	def stack_used(self):
+		"""calculate the stack used by the thread"""
+		if 'stack_used' not in self.__dict__:
+			stack_base = self._tcb['stack_alloc_ptr'].cast(gdb.lookup_type('unsigned char').pointer())
+			if stack_base == 0:
+				self.__dict__['stack_used'] = 0
+			else:
+				stack_limit = self._tcb['adj_stack_size']
+				for offset in range(0, stack_limit):
+					if stack_base[offset] != 0xff:
+						break
+				self.__dict__['stack_used'] = stack_limit - offset
+		return self.__dict__['stack_used']
+
+	@property
+	def name(self):
+		"""return the task's name"""
+		return self._tcb['name'].string()
+
+	@property
+	def state(self):
+		"""return the name of the task's current state"""
+		statenames = gdb.types.make_enum_dict(gdb.lookup_type('enum tstate_e'))
+		for name,value in statenames.iteritems():
+			if value == self._tcb['task_state']:
+				return name
+		return 'UNKNOWN'
+
+	@property
+	def waiting_for(self):
+		"""return a description of what the task is waiting for, if it is waiting"""
+		if self._state_is('TSTATE_WAIT_SEM'):
+			waitsem = self._tcb['waitsem'].dereference()
+			waitsem_holder = waitsem['holder']
+			holder = NX_task.for_tcb(waitsem_holder['htcb'])
+			if holder is not None:
+				return '{}({})'.format(waitsem.address, holder.name)
+			else:
+				return '{}(<bad holder>)'.format(waitsem.address)
+		if self._state_is('TSTATE_WAIT_SIG'):
+			return 'signal'
+		return None
+
+	@property
+	def is_waiting(self):
+		"""tests whether the task is waiting for something"""
+		if self._state_is('TSTATE_WAIT_SEM') or self._state_is('TSTATE_WAIT_SIG'):
+			return True
+
+	@property
+	def is_runnable(self):
+		"""tests whether the task is runnable"""
+		if (self._state_is('TSTATE_TASK_PENDING') or 
+			self._state_is('TSTATE_TASK_READYTORUN') or 
+			self._state_is('TSTATE_TASK_RUNNING')):
+			return True
+		return False
+
+	@property
+	def file_descriptors(self):
+		"""return a dictionary of file descriptors and inode pointers"""
+		filelist = self._group['tg_filelist']
+		filearray = filelist['fl_files']
+		result = dict()
+		for i in range(filearray.type.range()[0],filearray.type.range()[1]):
+			inode = long(filearray[i]['f_inode'])
+			if inode != 0:
+				result[i] = inode
+		return result
+
+	@property
+	def registers(self):
+		if 'registers' not in self.__dict__:
+			registers = dict()
+			if self._state_is('TSTATE_TASK_RUNNING'):
+				# XXX need to fix this to handle interrupt context
+				registers['R0']         = long(gdb.parse_and_eval('$r0'))
+				registers['R1']         = long(gdb.parse_and_eval('$r1'))
+				registers['R2']         = long(gdb.parse_and_eval('$r2'))
+				registers['R3']         = long(gdb.parse_and_eval('$r3'))
+				registers['R4']         = long(gdb.parse_and_eval('$r4'))
+				registers['R5']         = long(gdb.parse_and_eval('$r5'))
+				registers['R6']         = long(gdb.parse_and_eval('$r6'))
+				registers['R7']         = long(gdb.parse_and_eval('$r7'))
+				registers['R8']         = long(gdb.parse_and_eval('$r8'))
+				registers['R9']         = long(gdb.parse_and_eval('$r9'))
+				registers['R10']        = long(gdb.parse_and_eval('$r10'))
+				registers['R11']        = long(gdb.parse_and_eval('$r11'))
+				registers['R12']        = long(gdb.parse_and_eval('$r12'))
+				registers['R13']        = long(gdb.parse_and_eval('$r13'))
+				registers['SP']         = long(gdb.parse_and_eval('$sp'))
+				registers['R14']        = long(gdb.parse_and_eval('$r14'))
+				registers['LR']         = long(gdb.parse_and_eval('$lr'))
+				registers['R15']        = long(gdb.parse_and_eval('$r15'))
+				registers['PC']         = long(gdb.parse_and_eval('$pc'))
+				registers['XPSR']       = long(gdb.parse_and_eval('$xpsr'))
+				# this would only be valid if we were in an interrupt
+				registers['EXC_RETURN'] = 0
+				# we should be able to get this...
+				registers['PRIMASK']    = 0
+			else:
+				context = self._tcb['xcp']
+				regs = context['regs']
+				registers['R0']         = long(regs[27])
+				registers['R1']         = long(regs[28])
+				registers['R2']         = long(regs[29])
+				registers['R3']         = long(regs[30])
+				registers['R4']         = long(regs[2])
+				registers['R5']         = long(regs[3])
+				registers['R6']         = long(regs[4])
+				registers['R7']         = long(regs[5])
+				registers['R8']         = long(regs[6])
+				registers['R9']         = long(regs[7])
+				registers['R10']        = long(regs[8])
+				registers['R11']        = long(regs[9])
+				registers['R12']        = long(regs[31])
+				registers['R13']        = long(regs[0])
+				registers['SP']         = long(regs[0])
+				registers['R14']        = long(regs[32])
+				registers['LR']         = long(regs[32])
+				registers['R15']        = long(regs[33])
+				registers['PC']         = long(regs[33])
+				registers['XPSR']       = long(regs[34])
+				registers['EXC_RETURN'] = long(regs[10])
+				registers['PRIMASK']    = long(regs[1])
+			self.__dict__['registers'] = registers
+		return self.__dict__['registers']
+
+	def __repr__(self):
+		return "<NX_task {}>".format(self.pid)
+
+	def __str__(self):
+		return "{}:{}".format(self.pid, self.name)
+
+	def __format__(self, format_spec):
+		return format_spec.format(
+			pid              = self.pid,
+			name             = self.name,
+			state            = self.state,
+			waiting_for      = self.waiting_for,
+			stack_used       = self.stack_used,
+			stack_limit      = self._tcb['adj_stack_size'],
+			file_descriptors = self.file_descriptors,
+			registers	 = self.registers
+			)
+
+class NX_show_task (gdb.Command):
+	"""(NuttX) prints information about a task"""
+
+	def __init__(self):
+		super(NX_show_task, self).__init__("show task", gdb.COMMAND_USER)
+
+	def invoke(self, arg, from_tty):
+		t = NX_task.for_pid(int(arg))
+		if t is not None:
+			my_fmt = 'PID:{pid}  name:{name}  state:{state}\n'
+			my_fmt += '  stack used {stack_used} of {stack_limit}\n'
+			if t.is_waiting:
+				my_fmt += '  waiting for {waiting_for}\n'
+			my_fmt += '  open files: {file_descriptors}\n'
+			my_fmt += '  R0  {registers[R0]:#010x} {registers[R1]:#010x} {registers[R2]:#010x} {registers[R3]:#010x}\n'
+			my_fmt += '  R4  {registers[R4]:#010x} {registers[R5]:#010x} {registers[R6]:#010x} {registers[R7]:#010x}\n'
+			my_fmt += '  R8  {registers[R8]:#010x} {registers[R9]:#010x} {registers[R10]:#010x} {registers[R11]:#010x}\n'
+			my_fmt += '  R12 {registers[PC]:#010x}\n'
+			my_fmt += '  SP  {registers[SP]:#010x} LR {registers[LR]:#010x} PC {registers[PC]:#010x} XPSR {registers[XPSR]:#010x}\n'
+			print format(t, my_fmt)
+
+class NX_show_tasks (gdb.Command):
+	"""(NuttX) prints a list of tasks"""
+
+	def __init__(self):
+		super(NX_show_tasks, self).__init__('show tasks', gdb.COMMAND_USER)
+
+	def invoke(self, args, from_tty):
+		tasks = NX_task.tasks()
+		for t in tasks:
+			print format(t, '{pid:<2} {name:<16} {state:<20} {stack_used:>4}/{stack_limit:<4}')
+
+NX_show_task()
+NX_show_tasks()
+
+class NX_show_heap (gdb.Command):
+	"""(NuttX) prints the heap"""
+
+	def __init__(self):
+		super(NX_show_heap, self).__init__('show heap', gdb.COMMAND_USER)
+		if gdb.lookup_type('struct mm_allocnode_s').sizeof == 8:
+			self._allocflag = 0x80000000
+			self._allocnodesize = 8
+		else:
+			self._allocflag = 0x8000
+			self._allocnodesize = 4
+
+	def _node_allocated(self, allocnode):
+		if allocnode['preceding'] & self._allocflag:
+			return True
+		return False
+
+	def _node_size(self, allocnode):
+		return allocnode['size'] & ~self._allocflag
+
+	def _print_allocations(self, region_start, region_end):
+		if region_start >= region_end:
+			print 'heap region {} corrupt'.format(hex(region_start))
+			return
+		nodecount = region_end - region_start
+		print 'heap {} - {}'.format(region_start, region_end)
+		cursor = 1
+		while cursor < nodecount:
+			allocnode = region_start[cursor]
+			if self._node_allocated(allocnode):
+				state = ''
+			else:
+				state = '(free)'
+			print '  {} {} {}'.format(allocnode.address + 8, self._node_size(allocnode), state)
+			cursor += self._node_size(allocnode) / self._allocnodesize
+
+	def invoke(self, args, from_tty):
+		heap = gdb.lookup_global_symbol('g_mmheap').value()
+		nregions = heap['mm_nregions']
+		region_starts = heap['mm_heapstart']
+		region_ends = heap['mm_heapend']
+		print "{} heap(s)".format(nregions)
+		# walk the heaps
+		for i in range(0, nregions):
+			self._print_allocations(region_starts[i], region_ends[i])
+
+NX_show_heap()
+
+
+
+