Merge branch 'akpm' (patches from Andrew)

Merge yet more updates from Andrew Morton:

 - Oleg's "wait/ptrace: assume __WALL if the child is traced".  It's a
   kernel-based workaround for existing userspace issues.

 - A few hotfixes

 - befs cleanups

 - nilfs2 updates

 - sys_wait() changes

 - kexec updates

 - kdump

 - scripts/gdb updates

 - the last of the MM queue

 - a few other misc things

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (84 commits)
  kgdb: depends on VT
  drm/amdgpu: make amdgpu_mn_get wait for mmap_sem killable
  drm/radeon: make radeon_mn_get wait for mmap_sem killable
  drm/i915: make i915_gem_mmap_ioctl wait for mmap_sem killable
  uprobes: wait for mmap_sem for write killable
  prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable
  exec: make exec path waiting for mmap_sem killable
  aio: make aio_setup_ring killable
  coredump: make coredump_wait wait for mmap_sem for write killable
  vdso: make arch_setup_additional_pages wait for mmap_sem for write killable
  ipc, shm: make shmem attach/detach wait for mmap_sem killable
  mm, fork: make dup_mmap wait for mmap_sem for write killable
  mm, proc: make clear_refs killable
  mm: make vm_brk killable
  mm, elf: handle vm_brk error
  mm, aout: handle vm_brk failures
  mm: make vm_munmap killable
  mm: make vm_mmap killable
  mm: make mmap_sem for write waits killable for mm syscalls
  MAINTAINERS: add co-maintainer for scripts/gdb
  ...

1 files changed, 97 insertions, 0 deletions

diff --git a/scripts/gdb/linux/radixtree.py b/scripts/gdb/linux/radixtree.py
new file mode 100644
index 000000000000..0fdef4e2971a
--- /dev/null
+++ b/scripts/gdb/linux/radixtree.py
@@ -0,0 +1,97 @@
+#
+# 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()