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Message-Id: <3e151bc496b10c4bc78dbffdc4d86fdee2f44616.1359463075.git.jan.kiszka@siemens.com>
Date: Tue, 29 Jan 2013 13:37:46 +0100
From: Jan Kiszka <jan.kiszka@...mens.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org
Cc: Jason Wessel <jason.wessel@...driver.com>,
kgdb-bugreport@...ts.sourceforge.net,
Andi Kleen <andi@...stfloor.org>,
Tom Tromey <tromey@...hat.com>,
Ben Widawsky <ben@...dawsk.net>, Borislav Petkov <bp@...en8.de>
Subject: [PATCH v5 03/20] 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 <jan.kiszka@...mens.com>
---
scripts/gdb/utils.py | 34 ++++++++++++++++++++++++++++++++++
scripts/gdb/vmlinux-gdb.py | 2 ++
2 files changed, 36 insertions(+), 0 deletions(-)
diff --git a/scripts/gdb/utils.py b/scripts/gdb/utils.py
index fdff85e..d1f6f12 100644
--- a/scripts/gdb/utils.py
+++ b/scripts/gdb/utils.py
@@ -36,3 +36,37 @@ class CachedType:
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):
+ __doc__ = "Return pointer to containing data structure.\n" \
+ "\n" \
+ "$container_of(PTR, \"TYPE\", \"ELEMENT\"): Given PTR, return a pointer to the\n" \
+ "data structure of the type TYPE in which PTR is the address of ELEMENT.\n" \
+ "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 bcb45cc..8ef76c9 100644
--- a/scripts/gdb/vmlinux-gdb.py
+++ b/scripts/gdb/vmlinux-gdb.py
@@ -20,3 +20,5 @@ from utils import gdb_version
if gdb_version < "7.1":
print "NOTE: gdb 7.1 or later required for Linux helper scripts " \
"to work."
+else:
+ import utils
--
1.7.3.4
--
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