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#
# gdb helper commands and functions for Linux kernel debugging
#
# Radix Tree Parser
#
# Copyright (c) 2016 Linaro Ltd
#
# Authors:
# Kieran Bingham <kieran.bingham@linaro.org>
#
# This work is licensed under the terms of the GNU GPL version 2.
#
import gdb
from linux import utils
from linux import constants
radix_tree_root_type = utils.CachedType("struct radix_tree_root")
radix_tree_node_type = utils.CachedType("struct radix_tree_node")
def is_indirect_ptr(node):
long_type = utils.get_long_type()
return (node.cast(long_type) & constants.LX_RADIX_TREE_INDIRECT_PTR)
def indirect_to_ptr(node):
long_type = utils.get_long_type()
node_type = node.type
indirect_ptr = node.cast(long_type) & ~constants.LX_RADIX_TREE_INDIRECT_PTR
return indirect_ptr.cast(node_type)
def maxindex(height):
height = height & constants.LX_RADIX_TREE_HEIGHT_MASK
return gdb.parse_and_eval("height_to_maxindex["+str(height)+"]")
def lookup(root, index):
if root.type == radix_tree_root_type.get_type().pointer():
root = root.dereference()
elif root.type != radix_tree_root_type.get_type():
raise gdb.GdbError("Must be struct radix_tree_root not {}"
.format(root.type))
node = root['rnode']
if node is 0:
return None
if not (is_indirect_ptr(node)):
if (index > 0):
return None
return node
node = indirect_to_ptr(node)
height = node['path'] & constants.LX_RADIX_TREE_HEIGHT_MASK
if (index > maxindex(height)):
return None
shift = (height-1) * constants.LX_RADIX_TREE_MAP_SHIFT
while True:
new_index = (index >> shift) & constants.LX_RADIX_TREE_MAP_MASK
slot = node['slots'][new_index]
node = slot.cast(node.type.pointer()).dereference()
if node is 0:
return None
shift -= constants.LX_RADIX_TREE_MAP_SHIFT
height -= 1
if (height <= 0):
break
return node
class LxRadixTree(gdb.Function):
""" Lookup and return a node from a RadixTree.
$lx_radix_tree_lookup(root_node [, index]): Return the node at the given index.
If index is omitted, the root node is dereferenced and returned."""
def __init__(self):
super(LxRadixTree, self).__init__("lx_radix_tree_lookup")
def invoke(self, root, index=0):
result = lookup(root, index)
if result is None:
raise gdb.GdbError("No entry in tree at index {}".format(index))
return result
LxRadixTree()
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