1# 2# GDB debugging support 3# 4# Copyright 2012 Red Hat, Inc. and/or its affiliates 5# 6# Authors: 7# Avi Kivity <avi@redhat.com> 8# 9# This work is licensed under the terms of the GNU GPL, version 2 10# or later. See the COPYING file in the top-level directory. 11 12import gdb 13 14VOID_PTR = gdb.lookup_type('void').pointer() 15 16def pthread_self(): 17 '''Fetch the base address of TLS.''' 18 return gdb.parse_and_eval("$fs_base") 19 20def get_glibc_pointer_guard(): 21 '''Fetch glibc pointer guard value''' 22 fs_base = pthread_self() 23 return gdb.parse_and_eval('*(uint64_t*)((uint64_t)%s + 0x30)' % fs_base) 24 25def glibc_ptr_demangle(val, pointer_guard): 26 '''Undo effect of glibc's PTR_MANGLE()''' 27 return gdb.parse_and_eval('(((uint64_t)%s >> 0x11) | ((uint64_t)%s << (64 - 0x11))) ^ (uint64_t)%s' % (val, val, pointer_guard)) 28 29def get_jmpbuf_regs(jmpbuf): 30 JB_RBX = 0 31 JB_RBP = 1 32 JB_R12 = 2 33 JB_R13 = 3 34 JB_R14 = 4 35 JB_R15 = 5 36 JB_RSP = 6 37 JB_PC = 7 38 39 pointer_guard = get_glibc_pointer_guard() 40 return {'rbx': jmpbuf[JB_RBX], 41 'rbp': glibc_ptr_demangle(jmpbuf[JB_RBP], pointer_guard), 42 'rsp': glibc_ptr_demangle(jmpbuf[JB_RSP], pointer_guard), 43 'r12': jmpbuf[JB_R12], 44 'r13': jmpbuf[JB_R13], 45 'r14': jmpbuf[JB_R14], 46 'r15': jmpbuf[JB_R15], 47 'rip': glibc_ptr_demangle(jmpbuf[JB_PC], pointer_guard) } 48 49def bt_jmpbuf(jmpbuf): 50 '''Backtrace a jmpbuf''' 51 regs = get_jmpbuf_regs(jmpbuf) 52 old = dict() 53 54 # remember current stack frame and select the topmost 55 # so that register modifications don't wreck it 56 selected_frame = gdb.selected_frame() 57 gdb.newest_frame().select() 58 59 for i in regs: 60 old[i] = gdb.parse_and_eval('(uint64_t)$%s' % i) 61 62 for i in regs: 63 gdb.execute('set $%s = %s' % (i, regs[i])) 64 65 gdb.execute('bt') 66 67 for i in regs: 68 gdb.execute('set $%s = %s' % (i, old[i])) 69 70 selected_frame.select() 71 72def co_cast(co): 73 return co.cast(gdb.lookup_type('CoroutineUContext').pointer()) 74 75def coroutine_to_jmpbuf(co): 76 coroutine_pointer = co_cast(co) 77 return coroutine_pointer['env']['__jmpbuf'] 78 79 80class CoroutineCommand(gdb.Command): 81 '''Display coroutine backtrace''' 82 def __init__(self): 83 gdb.Command.__init__(self, 'qemu coroutine', gdb.COMMAND_DATA, 84 gdb.COMPLETE_NONE) 85 86 def invoke(self, arg, from_tty): 87 argv = gdb.string_to_argv(arg) 88 if len(argv) != 1: 89 gdb.write('usage: qemu coroutine <coroutine-pointer>\n') 90 return 91 92 bt_jmpbuf(coroutine_to_jmpbuf(gdb.parse_and_eval(argv[0]))) 93 94class CoroutineBt(gdb.Command): 95 '''Display backtrace including coroutine switches''' 96 def __init__(self): 97 gdb.Command.__init__(self, 'qemu bt', gdb.COMMAND_STACK, 98 gdb.COMPLETE_NONE) 99 100 def invoke(self, arg, from_tty): 101 102 gdb.execute("bt") 103 104 if gdb.parse_and_eval("qemu_in_coroutine()") == False: 105 return 106 107 co_ptr = gdb.parse_and_eval("qemu_coroutine_self()") 108 109 while True: 110 co = co_cast(co_ptr) 111 co_ptr = co["base"]["caller"] 112 if co_ptr == 0: 113 break 114 gdb.write("Coroutine at " + str(co_ptr) + ":\n") 115 bt_jmpbuf(coroutine_to_jmpbuf(co_ptr)) 116 117class CoroutineSPFunction(gdb.Function): 118 def __init__(self): 119 gdb.Function.__init__(self, 'qemu_coroutine_sp') 120 121 def invoke(self, addr): 122 return get_jmpbuf_regs(coroutine_to_jmpbuf(addr))['rsp'].cast(VOID_PTR) 123 124class CoroutinePCFunction(gdb.Function): 125 def __init__(self): 126 gdb.Function.__init__(self, 'qemu_coroutine_pc') 127 128 def invoke(self, addr): 129 return get_jmpbuf_regs(coroutine_to_jmpbuf(addr))['rip'].cast(VOID_PTR) 130