The aim of these tests is to combine with an appropriate kernel
image (with symbol-file vmlinux) and check it behaves as it should.
Given a kernel it checks:
- single step
- software breakpoint
- hardware breakpoint
- access, read and write watchpoints
On success it returns 0 to the calling process.
I've not plumbed this into the "make check" logic though as we need a
solution for providing non-host binaries to the tests. However the test
is structured to work with pretty much any Linux kernel image as it
uses the basic kernel_init code which is common across architectures.
Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
---
v10:
- fixup for Py2/3 cleanliness
- drop to shell on exception
---
tests/guest-debug/test-gdbstub.py | 176 ++++++++++++++++++++++++++++++++++++++
1 file changed, 176 insertions(+)
create mode 100644 tests/guest-debug/test-gdbstub.py
diff --git a/tests/guest-debug/test-gdbstub.py b/tests/guest-debug/test-gdbstub.py
new file mode 100644
index 0000000..31ba6c9
--- /dev/null
+++ b/tests/guest-debug/test-gdbstub.py
@@ -0,0 +1,176 @@
+#
+# This script needs to be run on startup
+# qemu -kernel ${KERNEL} -s -S
+# and then:
+# gdb ${KERNEL}.vmlinux -x ${QEMU_SRC}/tests/guest-debug/test-gdbstub.py
+
+import gdb
+
+failcount = 0
+
+
+def report(cond, msg):
+ "Report success/fail of test"
+ if cond:
+ print ("PASS: %s" % (msg))
+ else:
+ print ("FAIL: %s" % (msg))
+ failcount += 1
+
+
+def check_step():
+ "Step an instruction, check it moved."
+ start_pc = gdb.parse_and_eval('$pc')
+ gdb.execute("si")
+ end_pc = gdb.parse_and_eval('$pc')
+
+ return not (start_pc == end_pc)
+
+
+def check_break(sym_name):
+ "Setup breakpoint, continue and check we stopped."
+ sym, ok = gdb.lookup_symbol(sym_name)
+ bp = gdb.Breakpoint(sym_name)
+
+ gdb.execute("c")
+
+ # hopefully we came back
+ end_pc = gdb.parse_and_eval('$pc')
+ print ("%s == %s %d" % (end_pc, sym.value(), bp.hit_count))
+ bp.delete()
+
+ # can we test we hit bp?
+ return end_pc == sym.value()
+
+
+# We need to do hbreak manually as the python interface doesn't export it
+def check_hbreak(sym_name):
+ "Setup hardware breakpoint, continue and check we stopped."
+ sym, ok = gdb.lookup_symbol(sym_name)
+ gdb.execute("hbreak %s" % (sym_name))
+ gdb.execute("c")
+
+ # hopefully we came back
+ end_pc = gdb.parse_and_eval('$pc')
+ print ("%s == %s" % (end_pc, sym.value()))
+
+ if end_pc == sym.value():
+ gdb.execute("d 1")
+ return True
+ else:
+ return False
+
+
+class WatchPoint(gdb.Breakpoint):
+
+ def get_wpstr(self, sym_name):
+ "Setup sym and wp_str for given symbol."
+ self.sym, ok = gdb.lookup_symbol(sym_name)
+ wp_addr = gdb.parse_and_eval(sym_name).address
+ self.wp_str = '*(%(type)s)(&%(address)s)' % dict(
+ type = wp_addr.type, address = sym_name)
+
+ return(self.wp_str)
+
+ def __init__(self, sym_name, type):
+ wp_str = self.get_wpstr(sym_name)
+ super(WatchPoint, self).__init__(wp_str, gdb.BP_WATCHPOINT, type)
+
+ def stop(self):
+ end_pc = gdb.parse_and_eval('$pc')
+ print ("HIT WP @ %s" % (end_pc))
+ return True
+
+
+def do_one_watch(sym, wtype, text):
+
+ wp = WatchPoint(sym, wtype)
+ gdb.execute("c")
+ report_str = "%s for %s (%s)" % (text, sym, wp.sym.value())
+
+ if wp.hit_count > 0:
+ report(True, report_str)
+ wp.delete()
+ else:
+ report(False, report_str)
+
+
+def check_watches(sym_name):
+ "Watch a symbol for any access."
+
+ # Should hit for any read
+ do_one_watch(sym_name, gdb.WP_ACCESS, "awatch")
+
+ # Again should hit for reads
+ do_one_watch(sym_name, gdb.WP_READ, "rwatch")
+
+ # Finally when it is written
+ do_one_watch(sym_name, gdb.WP_WRITE, "watch")
+
+
+class CatchBreakpoint(gdb.Breakpoint):
+ def __init__(self, sym_name):
+ super(CatchBreakpoint, self).__init__(sym_name)
+ self.sym, ok = gdb.lookup_symbol(sym_name)
+
+ def stop(self):
+ end_pc = gdb.parse_and_eval('$pc')
+ print ("CB: %s == %s" % (end_pc, self.sym.value()))
+ if end_pc == self.sym.value():
+ report(False, "Hit final catchpoint")
+
+
+def run_test():
+ "Run throught the tests one by one"
+
+ print ("Checking we can step the first few instructions")
+ step_ok = 0
+ for i in range(3):
+ if check_step():
+ step_ok += 1
+
+ report(step_ok == 3, "single step in boot code")
+
+ print ("Checking HW breakpoint works")
+ break_ok = check_hbreak("kernel_init")
+ report(break_ok, "hbreak @ kernel_init")
+
+ # Can't set this up until we are in the kernel proper
+ # if we make it to run_init_process we've over-run and
+ # one of the tests failed
+ print ("Setup catch-all for run_init_process")
+ cbp = CatchBreakpoint("run_init_process")
+ cpb2 = CatchBreakpoint("try_to_run_init_process")
+
+ print ("Checking Normal breakpoint works")
+ break_ok = check_break("wait_for_completion")
+ report(break_ok, "break @ wait_for_completion")
+
+ print ("Checking watchpoint works")
+ check_watches("system_state")
+
+#
+# This runs as the script it sourced (via -x)
+#
+
+try:
+ print ("Connecting to remote")
+ gdb.execute("target remote localhost:1234")
+
+ # These are not very useful in scripts
+ gdb.execute("set pagination off")
+ gdb.execute("set confirm off")
+
+ # Run the actual tests
+ run_test()
+
+except:
+ print ("GDB Exception: %s" % (sys.exc_info()[0]))
+ failcount += 1
+ import code
+ code.InteractiveConsole(locals=globals()).interact()
+ raise
+
+# Finally kill the inferior and exit gdb with a count of failures
+gdb.execute("kill")
+exit(failcount)
--
2.6.3
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