scripts/gdb: add io resource readers

Provide iomem_resource and ioports_resource printers and command hooks

It can be quite interesting to halt the kernel as it's booting and check
to see this list as it is being populated.

It should be useful in the event that a kernel is not booting, you can
identify what memory resources have been registered

Link: http://lkml.kernel.org/r/f0a6b9fa9c92af4d7ed2e7343ccc84150e9c6fc5.1462865983.git.jan.kiszka@siemens.com
Signed-off-by: Kieran Bingham <kieran.bingham@linaro.org>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/gdb/linux/proc.py

@@ -39,3 +39,60 @@ class LxVersion(gdb.Command):
         gdb.write(gdb.parse_and_eval("linux_banner").string())
 
 LxVersion()
+
+
+# Resource Structure Printers
+#  /proc/iomem
+#  /proc/ioports
+
+def get_resources(resource, depth):
+    while resource:
+        yield resource, depth
+
+        child = resource['child']
+        if child:
+            for res, deep in get_resources(child, depth + 1):
+                yield res, deep
+
+        resource = resource['sibling']
+
+
+def show_lx_resources(resource_str):
+        resource = gdb.parse_and_eval(resource_str)
+        width = 4 if resource['end'] < 0x10000 else 8
+        # Iterate straight to the first child
+        for res, depth in get_resources(resource['child'], 0):
+            start = int(res['start'])
+            end = int(res['end'])
+            gdb.write(" " * depth * 2 +
+                      "{0:0{1}x}-".format(start, width) +
+                      "{0:0{1}x} : ".format(end, width) +
+                      res['name'].string() + "\n")
+
+
+class LxIOMem(gdb.Command):
+    """Identify the IO memory resource locations defined by the kernel
+
+Equivalent to cat /proc/iomem on a running target"""
+
+    def __init__(self):
+        super(LxIOMem, self).__init__("lx-iomem", gdb.COMMAND_DATA)
+
+    def invoke(self, arg, from_tty):
+        return show_lx_resources("iomem_resource")
+
+LxIOMem()
+
+
+class LxIOPorts(gdb.Command):
+    """Identify the IO port resource locations defined by the kernel
+
+Equivalent to cat /proc/ioports on a running target"""
+
+    def __init__(self):
+        super(LxIOPorts, self).__init__("lx-ioports", gdb.COMMAND_DATA)
+
+    def invoke(self, arg, from_tty):
+        return show_lx_resources("ioport_resource")
+
+LxIOPorts()