92 lines
3.2 KiB
Python
92 lines
3.2 KiB
Python
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#!/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. See
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# the COPYING file in the top-level directory.
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#
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# Contributions after 2012-01-13 are licensed under the terms of the
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# GNU GPL, version 2 or (at your option) any later version.
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import gdb
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def get_fs_base():
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'''Fetch %fs base value using arch_prctl(ARCH_GET_FS)'''
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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 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*)($rsp - 120) = %s' % old, False, True)
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return fs_base
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def get_glibc_pointer_guard():
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'''Fetch glibc pointer guard value'''
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fs_base = get_fs_base()
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return gdb.parse_and_eval('*(uint64_t*)((uint64_t)%s + 0x30)' % fs_base)
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def glibc_ptr_demangle(val, pointer_guard):
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'''Undo effect of glibc's PTR_MANGLE()'''
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return gdb.parse_and_eval('(((uint64_t)%s >> 0x11) | ((uint64_t)%s << (64 - 0x11))) ^ (uint64_t)%s' % (val, val, pointer_guard))
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def bt_jmpbuf(jmpbuf):
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'''Backtrace a jmpbuf'''
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JB_RBX = 0
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JB_RBP = 1
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JB_R12 = 2
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JB_R13 = 3
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JB_R14 = 4
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JB_R15 = 5
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JB_RSP = 6
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JB_PC = 7
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old_rbx = gdb.parse_and_eval('(uint64_t)$rbx')
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old_rbp = gdb.parse_and_eval('(uint64_t)$rbp')
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old_rsp = gdb.parse_and_eval('(uint64_t)$rsp')
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old_r12 = gdb.parse_and_eval('(uint64_t)$r12')
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old_r13 = gdb.parse_and_eval('(uint64_t)$r13')
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old_r14 = gdb.parse_and_eval('(uint64_t)$r14')
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old_r15 = gdb.parse_and_eval('(uint64_t)$r15')
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old_rip = gdb.parse_and_eval('(uint64_t)$rip')
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pointer_guard = get_glibc_pointer_guard()
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gdb.execute('set $rbx = %s' % jmpbuf[JB_RBX])
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gdb.execute('set $rbp = %s' % glibc_ptr_demangle(jmpbuf[JB_RBP], pointer_guard))
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gdb.execute('set $rsp = %s' % glibc_ptr_demangle(jmpbuf[JB_RSP], pointer_guard))
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gdb.execute('set $r12 = %s' % jmpbuf[JB_R12])
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gdb.execute('set $r13 = %s' % jmpbuf[JB_R13])
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gdb.execute('set $r14 = %s' % jmpbuf[JB_R14])
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gdb.execute('set $r15 = %s' % jmpbuf[JB_R15])
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gdb.execute('set $rip = %s' % glibc_ptr_demangle(jmpbuf[JB_PC], pointer_guard))
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gdb.execute('bt')
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gdb.execute('set $rbx = %s' % old_rbx)
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gdb.execute('set $rbp = %s' % old_rbp)
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gdb.execute('set $rsp = %s' % old_rsp)
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gdb.execute('set $r12 = %s' % old_r12)
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gdb.execute('set $r13 = %s' % old_r13)
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gdb.execute('set $r14 = %s' % old_r14)
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gdb.execute('set $r15 = %s' % old_r15)
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gdb.execute('set $rip = %s' % old_rip)
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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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coroutine_pointer = gdb.parse_and_eval(argv[0]).cast(gdb.lookup_type('CoroutineUContext').pointer())
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bt_jmpbuf(coroutine_pointer['env']['__jmpbuf'])
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