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# SPDX-License-Identifier: GPL-2.0
#
# Radix Tree Parser
#
# Copyright (c) 2016 Linaro Ltd
# Copyright (c) 2023 Broadcom
#
# Authors:
# Kieran Bingham <kieran.bingham@linaro.org>
# Florian Fainelli <f.fainelli@gmail.com>
import gdb
from linux import utils
from linux import constants
radix_tree_root_type = utils.CachedType("struct xarray")
radix_tree_node_type = utils.CachedType("struct xa_node")
def is_internal_node(node):
long_type = utils.get_long_type()
return ((node.cast(long_type) & constants.LX_RADIX_TREE_ENTRY_MASK) == constants.LX_RADIX_TREE_INTERNAL_NODE)
def entry_to_node(node):
long_type = utils.get_long_type()
node_type = node.type
indirect_ptr = node.cast(long_type) & ~constants.LX_RADIX_TREE_INTERNAL_NODE
return indirect_ptr.cast(radix_tree_node_type.get_type().pointer())
def node_maxindex(node):
return (constants.LX_RADIX_TREE_MAP_SIZE << node['shift']) - 1
def resolve_root(root):
if root.type == radix_tree_root_type.get_type():
return root
if root.type == radix_tree_root_type.get_type().pointer():
return root.dereference()
raise gdb.GdbError("must be {} not {}"
.format(radix_tree_root_type.get_type(), root.type))
def lookup(root, index):
root = resolve_root(root)
node = root['xa_head']
if node == 0:
return None
if not (is_internal_node(node)):
if (index > 0):
return None
return node
node = entry_to_node(node)
maxindex = node_maxindex(node)
if (index > maxindex):
return None
shift = node['shift'] + constants.LX_RADIX_TREE_MAP_SHIFT
while True:
offset = (index >> node['shift']) & constants.LX_RADIX_TREE_MAP_MASK
slot = node['slots'][offset]
if slot == 0:
return None
node = slot.cast(node.type.pointer()).dereference()
if node == 0:
return None
shift -= constants.LX_RADIX_TREE_MAP_SHIFT
if (shift <= 0):
break
return node
def descend(parent, index):
offset = (index >> int(parent["shift"])) & constants.LX_RADIX_TREE_MAP_MASK
return offset, parent["slots"][offset]
def load_root(root):
node = root["xa_head"]
nodep = node
if is_internal_node(node):
node = entry_to_node(node)
maxindex = node_maxindex(node)
return int(node["shift"]) + constants.LX_RADIX_TREE_MAP_SHIFT, \
nodep, maxindex
return 0, nodep, 0
class RadixTreeIter:
def __init__(self, start):
self.index = 0
self.next_index = start
self.node = None
def xa_mk_internal(v):
return (v << 2) | 2
LX_XA_RETRY_ENTRY = xa_mk_internal(256)
LX_RADIX_TREE_RETRY = LX_XA_RETRY_ENTRY
def next_chunk(root, iter):
mask = (1 << (utils.get_ulong_type().sizeof * 8)) - 1
index = iter.next_index
if index == 0 and iter.index != 0:
return None
restart = True
while restart:
restart = False
_, child, maxindex = load_root(root)
if index > maxindex:
return None
if not child:
return None
if not is_internal_node(child):
iter.index = index
iter.next_index = (maxindex + 1) & mask
iter.node = None
return root["xa_head"].address
while True:
node = entry_to_node(child)
offset, child = descend(node, index)
if not child:
while True:
offset += 1
if offset >= constants.LX_RADIX_TREE_MAP_SIZE:
break
slot = node["slots"][offset]
if slot:
break
index &= ~node_maxindex(node)
index = (index + (offset << int(node["shift"]))) & mask
if index == 0:
return None
if offset == constants.LX_RADIX_TREE_MAP_SIZE:
restart = True
break
child = node["slots"][offset]
if not child:
restart = True
break
if child == LX_XA_RETRY_ENTRY:
break
if not node["shift"] or not is_internal_node(child):
break
iter.index = (index & ~node_maxindex(node)) | offset
iter.next_index = ((index | node_maxindex(node)) + 1) & mask
iter.node = node
return node["slots"][offset].address
def next_slot(slot, iter):
mask = (1 << (utils.get_ulong_type().sizeof * 8)) - 1
for _ in range(iter.next_index - iter.index - 1):
slot += 1
iter.index = (iter.index + 1) & mask
if slot.dereference():
return slot
return None
def for_each_slot(root, start=0):
iter = RadixTreeIter(start)
slot = None
while True:
if not slot:
slot = next_chunk(root, iter)
if not slot:
break
yield iter.index, slot
slot = next_slot(slot, iter)
class LxRadixTreeLookup(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 dereference and returned."""
def __init__(self):
super(LxRadixTreeLookup, 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
class LxRadixTree(gdb.Command):
"""Show all values stored in a RadixTree."""
def __init__(self):
super(LxRadixTree, self).__init__("lx-radix-tree", gdb.COMMAND_DATA,
gdb.COMPLETE_NONE)
def invoke(self, argument, from_tty):
args = gdb.string_to_argv(argument)
if len(args) != 1:
raise gdb.GdbError("Usage: lx-radix-tree ROOT")
root = gdb.parse_and_eval(args[0])
for index, slot in for_each_slot(root):
gdb.write("[{}] = {}\n".format(index, slot.dereference()))
LxRadixTree()
LxRadixTreeLookup()
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