328eb60dc1
qemu-gdb.py was committed after 2012-01-13, so the notice about GPL v2-only contributions does not apply. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
117 lines
3.4 KiB
Python
117 lines
3.4 KiB
Python
#!/usr/bin/python
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# GDB debugging support
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#
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# Copyright 2012 Red Hat, Inc. and/or its affiliates
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#
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# Authors:
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# Avi Kivity <avi@redhat.com>
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#
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# This work is licensed under the terms of the GNU GPL, version 2
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# or later. See the COPYING file in the top-level directory.
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import gdb
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VOID_PTR = gdb.lookup_type('void').pointer()
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def get_fs_base():
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'''Fetch %fs base value using arch_prctl(ARCH_GET_FS). This is
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pthread_self().'''
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# %rsp - 120 is scratch space according to the SystemV ABI
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old = gdb.parse_and_eval('*(uint64_t*)($rsp - 120)')
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gdb.execute('call (int)arch_prctl(0x1003, $rsp - 120)', False, True)
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fs_base = gdb.parse_and_eval('*(uint64_t*)($rsp - 120)')
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gdb.execute('set *(uint64_t*)($rsp - 120) = %s' % old, False, True)
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return fs_base
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def pthread_self():
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'''Fetch pthread_self() from the glibc start_thread function.'''
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f = gdb.newest_frame()
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while f.name() != 'start_thread':
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f = f.older()
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if f is None:
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return get_fs_base()
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try:
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return f.read_var("arg")
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except ValueError:
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return get_fs_base()
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def get_glibc_pointer_guard():
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'''Fetch glibc pointer guard value'''
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fs_base = pthread_self()
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return gdb.parse_and_eval('*(uint64_t*)((uint64_t)%s + 0x30)' % fs_base)
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def glibc_ptr_demangle(val, pointer_guard):
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'''Undo effect of glibc's PTR_MANGLE()'''
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return gdb.parse_and_eval('(((uint64_t)%s >> 0x11) | ((uint64_t)%s << (64 - 0x11))) ^ (uint64_t)%s' % (val, val, pointer_guard))
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def get_jmpbuf_regs(jmpbuf):
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JB_RBX = 0
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JB_RBP = 1
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JB_R12 = 2
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JB_R13 = 3
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JB_R14 = 4
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JB_R15 = 5
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JB_RSP = 6
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JB_PC = 7
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pointer_guard = get_glibc_pointer_guard()
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return {'rbx': jmpbuf[JB_RBX],
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'rbp': glibc_ptr_demangle(jmpbuf[JB_RBP], pointer_guard),
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'rsp': glibc_ptr_demangle(jmpbuf[JB_RSP], pointer_guard),
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'r12': jmpbuf[JB_R12],
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'r13': jmpbuf[JB_R13],
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'r14': jmpbuf[JB_R14],
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'r15': jmpbuf[JB_R15],
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'rip': glibc_ptr_demangle(jmpbuf[JB_PC], pointer_guard) }
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def bt_jmpbuf(jmpbuf):
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'''Backtrace a jmpbuf'''
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regs = get_jmpbuf_regs(jmpbuf)
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old = dict()
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for i in regs:
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old[i] = gdb.parse_and_eval('(uint64_t)$%s' % i)
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for i in regs:
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gdb.execute('set $%s = %s' % (i, regs[i]))
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gdb.execute('bt')
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for i in regs:
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gdb.execute('set $%s = %s' % (i, old[i]))
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def coroutine_to_jmpbuf(co):
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coroutine_pointer = co.cast(gdb.lookup_type('CoroutineUContext').pointer())
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return coroutine_pointer['env']['__jmpbuf']
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class CoroutineCommand(gdb.Command):
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'''Display coroutine backtrace'''
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def __init__(self):
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gdb.Command.__init__(self, 'qemu coroutine', gdb.COMMAND_DATA,
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gdb.COMPLETE_NONE)
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def invoke(self, arg, from_tty):
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argv = gdb.string_to_argv(arg)
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if len(argv) != 1:
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gdb.write('usage: qemu coroutine <coroutine-pointer>\n')
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return
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bt_jmpbuf(coroutine_to_jmpbuf(gdb.parse_and_eval(argv[0])))
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class CoroutineSPFunction(gdb.Function):
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def __init__(self):
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gdb.Function.__init__(self, 'qemu_coroutine_sp')
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def invoke(self, addr):
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return get_jmpbuf_regs(coroutine_to_jmpbuf(addr))['rsp'].cast(VOID_PTR)
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class CoroutinePCFunction(gdb.Function):
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def __init__(self):
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gdb.Function.__init__(self, 'qemu_coroutine_pc')
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def invoke(self, addr):
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return get_jmpbuf_regs(coroutine_to_jmpbuf(addr))['rip'].cast(VOID_PTR)
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