From b0fecd8c570310c5041035a94eda7a4610402ace Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Tue, 17 Feb 2015 13:46:41 -0800 Subject: [PATCH] scripts/gdb: add container_of helper and convenience function Provide an internal helper with container_of semantics. As type lookups are very slow in gdb-python and we need a type "long" for this, cache the reference to this type object. Then export the helper also as a convenience function form use at the gdb command line. Signed-off-by: Jan Kiszka Cc: Thomas Gleixner Cc: Jason Wessel Cc: Andi Kleen Cc: Ben Widawsky Cc: Borislav Petkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/gdb/linux/utils.py | 35 +++++++++++++++++++++++++++++++++++ scripts/gdb/vmlinux-gdb.py | 2 ++ 2 files changed, 37 insertions(+) diff --git a/scripts/gdb/linux/utils.py b/scripts/gdb/linux/utils.py index f88361130e4c..c9d705b62bfe 100644 --- a/scripts/gdb/linux/utils.py +++ b/scripts/gdb/linux/utils.py @@ -32,3 +32,38 @@ class CachedType: if hasattr(gdb, 'events') and hasattr(gdb.events, 'new_objfile'): gdb.events.new_objfile.connect(self._new_objfile_handler) return self._type + + +long_type = CachedType("long") + + +def get_long_type(): + global long_type + return long_type.get_type() + + +def offset_of(typeobj, field): + element = gdb.Value(0).cast(typeobj) + return int(str(element[field].address).split()[0], 16) + + +def container_of(ptr, typeobj, member): + return (ptr.cast(get_long_type()) - + offset_of(typeobj, member)).cast(typeobj) + + +class ContainerOf(gdb.Function): + """Return pointer to containing data structure. + +$container_of(PTR, "TYPE", "ELEMENT"): Given PTR, return a pointer to the +data structure of the type TYPE in which PTR is the address of ELEMENT. +Note that TYPE and ELEMENT have to be quoted as strings.""" + + def __init__(self): + super(ContainerOf, self).__init__("container_of") + + def invoke(self, ptr, typename, elementname): + return container_of(ptr, gdb.lookup_type(typename.string()).pointer(), + elementname.string()) + +ContainerOf() diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py index c1d90cea5288..649584105a72 100644 --- a/scripts/gdb/vmlinux-gdb.py +++ b/scripts/gdb/vmlinux-gdb.py @@ -21,3 +21,5 @@ try: except: gdb.write("NOTE: gdb 7.2 or later required for Linux helper scripts to " "work.\n") +else: + import linux.utils -- 2.34.1