1# 2# gdb helper commands and functions for Linux kernel debugging 3# 4# per-cpu tools 5# 6# Copyright (c) Siemens AG, 2011-2013 7# 8# Authors: 9# Jan Kiszka <[email protected]> 10# 11# This work is licensed under the terms of the GNU GPL version 2. 12# 13 14import gdb 15 16from linux import tasks, utils 17 18 19MAX_CPUS = 4096 20 21 22def get_current_cpu(): 23 if utils.get_gdbserver_type() == utils.GDBSERVER_QEMU: 24 return gdb.selected_thread().num - 1 25 elif utils.get_gdbserver_type() == utils.GDBSERVER_KGDB: 26 tid = gdb.selected_thread().ptid[2] 27 if tid > (0x100000000 - MAX_CPUS - 2): 28 return 0x100000000 - tid - 2 29 else: 30 return tasks.get_thread_info(tasks.get_task_by_pid(tid))['cpu'] 31 else: 32 raise gdb.GdbError("Sorry, obtaining the current CPU is not yet " 33 "supported with this gdb server.") 34 35 36def per_cpu(var_ptr, cpu): 37 if cpu == -1: 38 cpu = get_current_cpu() 39 if utils.is_target_arch("sparc:v9"): 40 offset = gdb.parse_and_eval( 41 "trap_block[{0}].__per_cpu_base".format(str(cpu))) 42 else: 43 try: 44 offset = gdb.parse_and_eval( 45 "__per_cpu_offset[{0}]".format(str(cpu))) 46 except gdb.error: 47 # !CONFIG_SMP case 48 offset = 0 49 pointer = var_ptr.cast(utils.get_long_type()) + offset 50 return pointer.cast(var_ptr.type).dereference() 51 52 53cpu_mask = {} 54 55 56def cpu_mask_invalidate(event): 57 global cpu_mask 58 cpu_mask = {} 59 gdb.events.stop.disconnect(cpu_mask_invalidate) 60 if hasattr(gdb.events, 'new_objfile'): 61 gdb.events.new_objfile.disconnect(cpu_mask_invalidate) 62 63 64class CpuList(): 65 def __init__(self, mask_name): 66 global cpu_mask 67 self.mask = None 68 if mask_name in cpu_mask: 69 self.mask = cpu_mask[mask_name] 70 if self.mask is None: 71 self.mask = gdb.parse_and_eval(mask_name + ".bits") 72 if hasattr(gdb, 'events'): 73 cpu_mask[mask_name] = self.mask 74 gdb.events.stop.connect(cpu_mask_invalidate) 75 if hasattr(gdb.events, 'new_objfile'): 76 gdb.events.new_objfile.connect(cpu_mask_invalidate) 77 self.bits_per_entry = self.mask[0].type.sizeof * 8 78 self.num_entries = self.mask.type.sizeof * 8 / self.bits_per_entry 79 self.entry = -1 80 self.bits = 0 81 82 def __iter__(self): 83 return self 84 85 def next(self): 86 while self.bits == 0: 87 self.entry += 1 88 if self.entry == self.num_entries: 89 raise StopIteration 90 self.bits = self.mask[self.entry] 91 if self.bits != 0: 92 self.bit = 0 93 break 94 95 while self.bits & 1 == 0: 96 self.bits >>= 1 97 self.bit += 1 98 99 cpu = self.entry * self.bits_per_entry + self.bit 100 101 self.bits >>= 1 102 self.bit += 1 103 104 return cpu 105 106 107class PerCpu(gdb.Function): 108 """Return per-cpu variable. 109 110$lx_per_cpu("VAR"[, CPU]): Return the per-cpu variable called VAR for the 111given CPU number. If CPU is omitted, the CPU of the current context is used. 112Note that VAR has to be quoted as string.""" 113 114 def __init__(self): 115 super(PerCpu, self).__init__("lx_per_cpu") 116 117 def invoke(self, var_name, cpu=-1): 118 var_ptr = gdb.parse_and_eval("&" + var_name.string()) 119 return per_cpu(var_ptr, cpu) 120 121 122PerCpu() 123 124 125class LxCurrentFunc(gdb.Function): 126 """Return current task. 127 128$lx_current([CPU]): Return the per-cpu task variable for the given CPU 129number. If CPU is omitted, the CPU of the current context is used.""" 130 131 def __init__(self): 132 super(LxCurrentFunc, self).__init__("lx_current") 133 134 def invoke(self, cpu=-1): 135 var_ptr = gdb.parse_and_eval("¤t_task") 136 return per_cpu(var_ptr, cpu).dereference() 137 138 139LxCurrentFunc() 140