diff options
Diffstat (limited to 'scripts/qemu-gdb.py')
| -rw-r--r-- | scripts/qemu-gdb.py | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/scripts/qemu-gdb.py b/scripts/qemu-gdb.py new file mode 100644 index 00000000..6c7f4fbe --- /dev/null +++ b/scripts/qemu-gdb.py @@ -0,0 +1,164 @@ +#!/usr/bin/python + +# GDB debugging support +# +# Copyright 2012 Red Hat, Inc. and/or its affiliates +# +# Authors: +# Avi Kivity <avi@redhat.com> +# +# This work is licensed under the terms of the GNU GPL, version 2. See +# the COPYING file in the top-level directory. +# +# Contributions after 2012-01-13 are licensed under the terms of the +# GNU GPL, version 2 or (at your option) any later version. + + +import gdb + +def isnull(ptr): + return ptr == gdb.Value(0).cast(ptr.type) + +def int128(p): + return long(p['lo']) + (long(p['hi']) << 64) + +def get_fs_base(): + '''Fetch %fs base value using arch_prctl(ARCH_GET_FS)''' + # %rsp - 120 is scratch space according to the SystemV ABI + old = gdb.parse_and_eval('*(uint64_t*)($rsp - 120)') + gdb.execute('call arch_prctl(0x1003, $rsp - 120)', False, True) + fs_base = gdb.parse_and_eval('*(uint64_t*)($rsp - 120)') + gdb.execute('set *(uint64_t*)($rsp - 120) = %s' % old, False, True) + return fs_base + +def get_glibc_pointer_guard(): + '''Fetch glibc pointer guard value''' + fs_base = get_fs_base() + return gdb.parse_and_eval('*(uint64_t*)((uint64_t)%s + 0x30)' % fs_base) + +def glibc_ptr_demangle(val, pointer_guard): + '''Undo effect of glibc's PTR_MANGLE()''' + return gdb.parse_and_eval('(((uint64_t)%s >> 0x11) | ((uint64_t)%s << (64 - 0x11))) ^ (uint64_t)%s' % (val, val, pointer_guard)) + +def bt_jmpbuf(jmpbuf): + '''Backtrace a jmpbuf''' + JB_RBX = 0 + JB_RBP = 1 + JB_R12 = 2 + JB_R13 = 3 + JB_R14 = 4 + JB_R15 = 5 + JB_RSP = 6 + JB_PC = 7 + + old_rbx = gdb.parse_and_eval('(uint64_t)$rbx') + old_rbp = gdb.parse_and_eval('(uint64_t)$rbp') + old_rsp = gdb.parse_and_eval('(uint64_t)$rsp') + old_r12 = gdb.parse_and_eval('(uint64_t)$r12') + old_r13 = gdb.parse_and_eval('(uint64_t)$r13') + old_r14 = gdb.parse_and_eval('(uint64_t)$r14') + old_r15 = gdb.parse_and_eval('(uint64_t)$r15') + old_rip = gdb.parse_and_eval('(uint64_t)$rip') + + pointer_guard = get_glibc_pointer_guard() + gdb.execute('set $rbx = %s' % jmpbuf[JB_RBX]) + gdb.execute('set $rbp = %s' % glibc_ptr_demangle(jmpbuf[JB_RBP], pointer_guard)) + gdb.execute('set $rsp = %s' % glibc_ptr_demangle(jmpbuf[JB_RSP], pointer_guard)) + gdb.execute('set $r12 = %s' % jmpbuf[JB_R12]) + gdb.execute('set $r13 = %s' % jmpbuf[JB_R13]) + gdb.execute('set $r14 = %s' % jmpbuf[JB_R14]) + gdb.execute('set $r15 = %s' % jmpbuf[JB_R15]) + gdb.execute('set $rip = %s' % glibc_ptr_demangle(jmpbuf[JB_PC], pointer_guard)) + + gdb.execute('bt') + + gdb.execute('set $rbx = %s' % old_rbx) + gdb.execute('set $rbp = %s' % old_rbp) + gdb.execute('set $rsp = %s' % old_rsp) + gdb.execute('set $r12 = %s' % old_r12) + gdb.execute('set $r13 = %s' % old_r13) + gdb.execute('set $r14 = %s' % old_r14) + gdb.execute('set $r15 = %s' % old_r15) + gdb.execute('set $rip = %s' % old_rip) + +class QemuCommand(gdb.Command): + '''Prefix for QEMU debug support commands''' + def __init__(self): + gdb.Command.__init__(self, 'qemu', gdb.COMMAND_DATA, + gdb.COMPLETE_NONE, True) + +class CoroutineCommand(gdb.Command): + '''Display coroutine backtrace''' + def __init__(self): + gdb.Command.__init__(self, 'qemu coroutine', gdb.COMMAND_DATA, + gdb.COMPLETE_NONE) + + def invoke(self, arg, from_tty): + argv = gdb.string_to_argv(arg) + if len(argv) != 1: + gdb.write('usage: qemu coroutine <coroutine-pointer>\n') + return + + coroutine_pointer = gdb.parse_and_eval(argv[0]).cast(gdb.lookup_type('CoroutineUContext').pointer()) + bt_jmpbuf(coroutine_pointer['env']['__jmpbuf']) + +class MtreeCommand(gdb.Command): + '''Display the memory tree hierarchy''' + def __init__(self): + gdb.Command.__init__(self, 'qemu mtree', gdb.COMMAND_DATA, + gdb.COMPLETE_NONE) + self.queue = [] + def invoke(self, arg, from_tty): + self.seen = set() + self.queue_root('address_space_memory') + self.queue_root('address_space_io') + self.process_queue() + def queue_root(self, varname): + ptr = gdb.parse_and_eval(varname)['root'] + self.queue.append(ptr) + def process_queue(self): + while self.queue: + ptr = self.queue.pop(0) + if long(ptr) in self.seen: + continue + self.print_item(ptr) + def print_item(self, ptr, offset = gdb.Value(0), level = 0): + self.seen.add(long(ptr)) + addr = ptr['addr'] + addr += offset + size = int128(ptr['size']) + alias = ptr['alias'] + klass = '' + if not isnull(alias): + klass = ' (alias)' + elif not isnull(ptr['ops']): + klass = ' (I/O)' + elif bool(ptr['ram']): + klass = ' (RAM)' + gdb.write('%s%016x-%016x %s%s (@ %s)\n' + % (' ' * level, + long(addr), + long(addr + (size - 1)), + ptr['name'].string(), + klass, + ptr, + ), + gdb.STDOUT) + if not isnull(alias): + gdb.write('%s alias: %s@%016x (@ %s)\n' % + (' ' * level, + alias['name'].string(), + ptr['alias_offset'], + alias, + ), + gdb.STDOUT) + self.queue.append(alias) + subregion = ptr['subregions']['tqh_first'] + level += 1 + while not isnull(subregion): + self.print_item(subregion, addr, level) + subregion = subregion['subregions_link']['tqe_next'] + +QemuCommand() +CoroutineCommand() +MtreeCommand() |