Commit 80ab31b2 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Stefan Hajnoczi
Browse files

qemu-gdb: extract parts of "qemu coroutine" implementation 



Provide useful Python functions to reach and decipher a jmpbuf.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-id: 1444636974-19950-3-git-send-email-pbonzini@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 1138f246

scripts/qemugdb/coroutine.py

+27 −29
Original line number Diff line number Diff line
@@ -47,8 +47,7 @@ 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'''

def get_jmpbuf_regs(jmpbuf):

    JB_RBX  = 0

    JB_RBP  = 1

    JB_R12  = 2
@@ -58,35 +57,35 @@ def bt_jmpbuf(jmpbuf): 
    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))

    return {'rbx': jmpbuf[JB_RBX],

        'rbp': glibc_ptr_demangle(jmpbuf[JB_RBP], pointer_guard),

        'rsp': glibc_ptr_demangle(jmpbuf[JB_RSP], pointer_guard),

        'r12': jmpbuf[JB_R12],

        'r13': jmpbuf[JB_R13],

        'r14': jmpbuf[JB_R14],

        'r15': jmpbuf[JB_R15],

        'rip': glibc_ptr_demangle(jmpbuf[JB_PC], pointer_guard) }



def bt_jmpbuf(jmpbuf):

    '''Backtrace a jmpbuf'''

    regs = get_jmpbuf_regs(jmpbuf)

    old = dict()



    for i in regs:

        old[i] = gdb.parse_and_eval('(uint64_t)$%s' % i)



    for i in regs:

        gdb.execute('set $%s = %s' % (i, regs[i]))



    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)

    for i in regs:

        gdb.execute('set $%s = %s' % (i, old[i]))



def coroutine_to_jmpbuf(co):

    coroutine_pointer = co.cast(gdb.lookup_type('CoroutineUContext').pointer())

    return coroutine_pointer['env']['__jmpbuf']





class CoroutineCommand(gdb.Command):
@@ -101,5 +100,4 @@ class CoroutineCommand(gdb.Command): 
            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'])
 
        bt_jmpbuf(coroutine_to_jmpbuf(gdb.parse_and_eval(argv[0])))