Commit b0fecd8c authored by Jan Kiszka's avatar Jan Kiszka Committed by Linus Torvalds

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's avatarJan Kiszka <jan.kiszka@siemens.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2b514827
......@@ -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()
......@@ -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
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