scripts/gdb: add rb tree iterating utilities

Implement gdb functions for rb_first(), rb_last(), rb_next(), and
rb_prev().  These can be useful to iterate through the kernel's
red-black trees.

[swboyd@chromium.org: v2]
  Link: http://lkml.kernel.org/r/20190329220844.38234-4-swboyd@chromium.org
Link: http://lkml.kernel.org/r/20190325184522.260535-4-swboyd@chromium.org
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Nikolay Borisov <n.borisov.lkml@gmail.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jackie Liu <liuyun01@kylinos.cn>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Stephen Boyd 2019-05-14 15:45:56 -07:00 committed by Linus Torvalds
parent 90cf83dbd2
commit 449ca0c95e
2 changed files with 178 additions and 0 deletions

177
scripts/gdb/linux/rbtree.py Normal file
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@ -0,0 +1,177 @@
# SPDX-License-Identifier: GPL-2.0
#
# Copyright 2019 Google LLC.
import gdb
from linux import utils
rb_root_type = utils.CachedType("struct rb_root")
rb_node_type = utils.CachedType("struct rb_node")
def rb_first(root):
if root.type == rb_root_type.get_type():
node = node.address.cast(rb_root_type.get_type().pointer())
elif root.type != rb_root_type.get_type().pointer():
raise gdb.GdbError("Must be struct rb_root not {}".format(root.type))
node = root['rb_node']
if node is 0:
return None
while node['rb_left']:
node = node['rb_left']
return node
def rb_last(root):
if root.type == rb_root_type.get_type():
node = node.address.cast(rb_root_type.get_type().pointer())
elif root.type != rb_root_type.get_type().pointer():
raise gdb.GdbError("Must be struct rb_root not {}".format(root.type))
node = root['rb_node']
if node is 0:
return None
while node['rb_right']:
node = node['rb_right']
return node
def rb_parent(node):
parent = gdb.Value(node['__rb_parent_color'] & ~3)
return parent.cast(rb_node_type.get_type().pointer())
def rb_empty_node(node):
return node['__rb_parent_color'] == node.address
def rb_next(node):
if node.type == rb_node_type.get_type():
node = node.address.cast(rb_node_type.get_type().pointer())
elif node.type != rb_node_type.get_type().pointer():
raise gdb.GdbError("Must be struct rb_node not {}".format(node.type))
if rb_empty_node(node):
return None
if node['rb_right']:
node = node['rb_right']
while node['rb_left']:
node = node['rb_left']
return node
parent = rb_parent(node)
while parent and node == parent['rb_right']:
node = parent
parent = rb_parent(node)
return parent
def rb_prev(node):
if node.type == rb_node_type.get_type():
node = node.address.cast(rb_node_type.get_type().pointer())
elif node.type != rb_node_type.get_type().pointer():
raise gdb.GdbError("Must be struct rb_node not {}".format(node.type))
if rb_empty_node(node):
return None
if node['rb_left']:
node = node['rb_left']
while node['rb_right']:
node = node['rb_right']
return node.dereference()
parent = rb_parent(node)
while parent and node == parent['rb_left'].dereference():
node = parent
parent = rb_parent(node)
return parent
class LxRbFirst(gdb.Function):
"""Lookup and return a node from an RBTree
$lx_rb_first(root): Return the node at the given index.
If index is omitted, the root node is dereferenced and returned."""
def __init__(self):
super(LxRbFirst, self).__init__("lx_rb_first")
def invoke(self, root):
result = rb_first(root)
if result is None:
raise gdb.GdbError("No entry in tree")
return result
LxRbFirst()
class LxRbLast(gdb.Function):
"""Lookup and return a node from an RBTree.
$lx_rb_last(root): Return the node at the given index.
If index is omitted, the root node is dereferenced and returned."""
def __init__(self):
super(LxRbLast, self).__init__("lx_rb_last")
def invoke(self, root):
result = rb_last(root)
if result is None:
raise gdb.GdbError("No entry in tree")
return result
LxRbLast()
class LxRbNext(gdb.Function):
"""Lookup and return a node from an RBTree.
$lx_rb_next(node): Return the node at the given index.
If index is omitted, the root node is dereferenced and returned."""
def __init__(self):
super(LxRbNext, self).__init__("lx_rb_next")
def invoke(self, node):
result = rb_next(node)
if result is None:
raise gdb.GdbError("No entry in tree")
return result
LxRbNext()
class LxRbPrev(gdb.Function):
"""Lookup and return a node from an RBTree.
$lx_rb_prev(node): Return the node at the given index.
If index is omitted, the root node is dereferenced and returned."""
def __init__(self):
super(LxRbPrev, self).__init__("lx_rb_prev")
def invoke(self, node):
result = rb_prev(node)
if result is None:
raise gdb.GdbError("No entry in tree")
return result
LxRbPrev()

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@ -30,5 +30,6 @@ else:
import linux.config import linux.config
import linux.cpus import linux.cpus
import linux.lists import linux.lists
import linux.rbtree
import linux.proc import linux.proc
import linux.constants import linux.constants