scripts/qemu-gdb: Split CoroutineCommand into its own file

Split the implementation of CoroutineCommand into its own file.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1439574392-4403-3-git-send-email-peter.maydell@linaro.org

1 files changed, 91 insertions, 0 deletions

diff --git a/scripts/qemugdb/coroutine.py b/scripts/qemugdb/coroutine.py
new file mode 100644
index 0000000000..3c54918b5d
--- /dev/null
+++ b/scripts/qemugdb/coroutine.py
@@ -0,0 +1,91 @@
+#!/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 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 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'])