3 files changed, 99 insertions, 0 deletions
diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
index 2efbec6b6b8d..6c886deb0b18 100644
--- a/scripts/gdb/linux/constants.py.in
+++ b/scripts/gdb/linux/constants.py.in
@@ -17,6 +17,7 @@
 #include <linux/hrtimer.h>
 #include <linux/mount.h>
 #include <linux/of_fdt.h>
+#include <linux/radix-tree.h>
 #include <linux/threads.h>
 
 /* We need to stringify expanded macros so that they can be parsed */
@@ -68,6 +69,13 @@ LX_VALUE(NR_CPUS)
 /* linux/of_fdt.h> */
 LX_VALUE(OF_DT_HEADER)
 
+/* linux/radix-tree.h */
+LX_GDBPARSED(RADIX_TREE_ENTRY_MASK)
+LX_GDBPARSED(RADIX_TREE_INTERNAL_NODE)
+LX_GDBPARSED(RADIX_TREE_MAP_SIZE)
+LX_GDBPARSED(RADIX_TREE_MAP_SHIFT)
+LX_GDBPARSED(RADIX_TREE_MAP_MASK)
+
 /* Kernel Configs */
 LX_CONFIG(CONFIG_GENERIC_CLOCKEVENTS)
 LX_CONFIG(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)
diff --git a/scripts/gdb/linux/radixtree.py b/scripts/gdb/linux/radixtree.py
new file mode 100644
index 000000000000..074543ac763d
--- /dev/null
+++ b/scripts/gdb/linux/radixtree.py
@@ -0,0 +1,90 @@
+# 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 lookup(root, index):
+    if root.type == radix_tree_root_type.get_type().pointer():
+        node = root.dereference()
+    elif root.type != radix_tree_root_type.get_type():
+        raise gdb.GdbError("must be {} not {}"
+                           .format(radix_tree_root_type.get_type(), root.type))
+
+    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
+
+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 dereference 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()
diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py
index 3a5b44cd6bfe..4a5056f2c247 100644
--- a/scripts/gdb/vmlinux-gdb.py
+++ b/scripts/gdb/vmlinux-gdb.py
@@ -38,3 +38,4 @@ else:
     import linux.genpd
     import linux.device
     import linux.mm
+    import linux.radixtree