kernel/scripts/gdb/linux/tasks.py

   1 #
   2 # gdb helper commands and functions for Linux kernel debugging
   3 #
   4 #  task & thread tools
   5 #
   6 # Copyright (c) Siemens AG, 2011-2013
   7 #
   8 # Authors:
   9 #  Jan Kiszka <jan.kiszka@siemens.com>
  10 #
  11 # This work is licensed under the terms of the GNU GPL version 2.
  12 #
  13
  14 import gdb
  15
  16 from linux import utils
  17
  18
  19 task_type = utils.CachedType("struct task_struct")
  20
  21 def task_lists():
  22     global task_type
  23     task_ptr_type = task_type.get_type().pointer()
  24     init_task = gdb.parse_and_eval("init_task").address
  25     t = g = init_task
  26
  27     while True:
  28         while True:
  29             yield t
  30
  31             t = utils.container_of(t['thread_group']['next'],
  32                                    task_ptr_type, "thread_group")
  33             if t == g:
  34                 break
  35
  36         t = g = utils.container_of(g['tasks']['next'],
  37                                    task_ptr_type, "tasks")
  38         if t == init_task:
  39             return
  40
  41 def get_task_by_pid(pid):
  42     for task in task_lists():
  43         if int(task['pid']) == pid:
  44             return task
  45     return None
  46
  47
  48 class LxTaskByPidFunc(gdb.Function):
  49     """Find Linux task by PID and return the task_struct variable.
  50
  51 $lx_task_by_pid(PID): Given PID, iterate over all tasks of the target and
  52 return that task_struct variable which PID matches."""
  53
  54     def __init__(self):
  55         super(LxTaskByPidFunc, self).__init__("lx_task_by_pid")
  56
  57     def invoke(self, pid):
  58         task = get_task_by_pid(pid)
  59         if task:
  60             return task.dereference()
  61         else:
  62             raise gdb.GdbError("No task of PID " + str(pid))
  63
  64
  65 LxTaskByPidFunc()
  66
  67
  68 thread_info_type = utils.CachedType("struct thread_info")
  69
  70 ia64_task_size = None
  71
  72
  73 def get_thread_info(task):
  74     global thread_info_type
  75     thread_info_ptr_type = thread_info_type.get_type().pointer()
  76     if utils.is_target_arch("ia64"):
  77         global ia64_task_size
  78         if ia64_task_size is None:
  79             ia64_task_size = gdb.parse_and_eval("sizeof(struct task_struct)")
  80         thread_info_addr = task.address + ia64_task_size
  81         thread_info = thread_info_addr.cast(thread_info_ptr_type)
  82     else:
  83         thread_info = task['stack'].cast(thread_info_ptr_type)
  84     return thread_info.dereference()
  85
  86
  87 class LxThreadInfoFunc (gdb.Function):
  88     """Calculate Linux thread_info from task variable.
  89
  90 $lx_thread_info(TASK): Given TASK, return the corresponding thread_info
  91 variable."""
  92
  93     def __init__(self):
  94         super(LxThreadInfoFunc, self).__init__("lx_thread_info")
  95
  96     def invoke(self, task):
  97         return get_thread_info(task)
  98
  99
 100 LxThreadInfoFunc()