The patch titled
Subject: scripts/gdb: add container_of helper and convenience function
has been added to the -mm tree. Its filename is
scripts-gdb-add-container_of-helper-and-convenience-function.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/scripts-gdb-add-container_of-helper-and-convenience-function.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/scripts-gdb-add-container_of-helper-and-convenience-function.patch
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------------------------------------------------------
From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Subject: 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@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Ben Widawsky <ben@xxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
scripts/gdb/linux/utils.py | 35 +++++++++++++++++++++++++++++++++++
scripts/gdb/vmlinux-gdb.py | 2 ++
2 files changed, 37 insertions(+)
diff -puN scripts/gdb/linux/utils.py~scripts-gdb-add-container_of-helper-and-convenience-function scripts/gdb/linux/utils.py
--- a/scripts/gdb/linux/utils.py~scripts-gdb-add-container_of-helper-and-convenience-function
+++ a/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 -puN scripts/gdb/vmlinux-gdb.py~scripts-gdb-add-container_of-helper-and-convenience-function scripts/gdb/vmlinux-gdb.py
--- a/scripts/gdb/vmlinux-gdb.py~scripts-gdb-add-container_of-helper-and-convenience-function
+++ a/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
_
Patches currently in -mm which might be from jan.kiszka@xxxxxxxxxxx are
scripts-gdb-add-infrastructure.patch
scripts-gdb-add-cache-for-type-objects.patch
scripts-gdb-add-container_of-helper-and-convenience-function.patch
scripts-gdb-add-module-iteration-class.patch
scripts-gdb-add-lx-symbols-command.patch
module-do-not-inline-do_init_module.patch
scripts-gdb-add-automatic-symbol-reloading-on-module-insertion.patch
scripts-gdb-add-internal-helper-and-convenience-function-to-look-up-a-module.patch
scripts-gdb-add-get_target_endianness-helper.patch
scripts-gdb-add-read_u16-32-64-helpers.patch
scripts-gdb-add-lx-dmesg-command.patch
scripts-gdb-add-task-iteration-class.patch
scripts-gdb-add-helper-and-convenience-function-to-look-up-tasks.patch
scripts-gdb-add-is_target_arch-helper.patch
scripts-gdb-add-internal-helper-and-convenience-function-to-retrieve-thread_info.patch
scripts-gdb-add-get_gdbserver_type-helper.patch
scripts-gdb-add-internal-helper-and-convenience-function-for-per-cpu-lookup.patch
scripts-gdb-add-lx_current-convenience-function.patch
scripts-gdb-add-class-to-iterate-over-cpu-masks.patch
scripts-gdb-add-lx-lsmod-command.patch
scripts-gdb-add-basic-documentation.patch
scripts-gdb-port-to-python3-gdb77.patch
scripts-gdb-ignore-byte-compiled-python-files.patch
scripts-gdb-use-a-generator-instead-of-iterator-for-task-list.patch
scripts-gdb-convert-modulelist-to-generator-function.patch
scripts-gdb-convert-cpulist-to-generator-function.patch
scripts-gdb-define-maintainer.patch
scripts-gdb-disable-pagination-while-printing-from-breakpoint-handler.patch
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