scripts/gdb: add internal helper and convenience function to look up a module

Add the internal helper get_module_by_name to obtain the module structure
corresponding to the given name.  Also export this service as a
convenience function.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/gdb/linux/modules.py

@@ -37,3 +37,31 @@ class ModuleList:
             return utils.container_of(entry, self.module_ptr_type, "list")
         else:
             raise StopIteration
+
+
+def find_module_by_name(name):
+    for module in ModuleList():
+        if module['name'].string() == name:
+            return module
+    return None
+
+
+class LxModule(gdb.Function):
+    """Find module by name and return the module variable.
+
+$lx_module("MODULE"): Given the name MODULE, iterate over all loaded modules
+of the target and return that module variable which MODULE matches."""
+
+    def __init__(self):
+        super(LxModule, self).__init__("lx_module")
+
+    def invoke(self, mod_name):
+        mod_name = mod_name.string()
+        module = find_module_by_name(mod_name)
+        if module:
+            return module.dereference()
+        else:
+            raise gdb.GdbError("Unable to find MODULE " + mod_name)
+
+
+LxModule()

scripts/gdb/vmlinux-gdb.py

@@ -24,3 +24,4 @@ except:
 else:
     import linux.utils
     import linux.symbols
+    import linux.modules