disas

README.adoc

@@ -25348,7 +25348,7 @@ For this reason, we use it in particular often in this README to reduce the need
 
 ==== run-toolchain
 
-While you could just manually find/learn the path to toolchain tools, e.g. in LKMC b15a0e455d691afa49f3b813ad9b09394dfb02b7 they are
+While you could just manually find/learn the path to toolchain tools, e.g. in LKMC b15a0e455d691afa49f3b813ad9b09394dfb02b7 they are:
 
 ....
 ./out/buildroot/build/default/aarch64/host/bin/aarch64-buildroot-linux-gnu-gcc userland/c/hello.c
@@ -25374,6 +25374,12 @@ which outputs as of LKMC b15a0e455d691afa49f3b813ad9b09394dfb02b7:
 /path/to/linux-kernel-module-cheat/out/buildroot/build/default/aarch64/host/usr/bin/aarch64-buildroot-linux-gnu
 ....
 
+Since disassembly of a single function with GDB is such a common use case https://stackoverflow.com/questions/22769246/how-to-disassemble-one-single-function-using-objdump[], we have a shortcut for it:
+
+....
+./disas --arch aarch64 --userland userland/c/hello.c main
+....
+
 === Rebuild Buildroot while running
 
 It is not possible to rebuild the root filesystem while running QEMU because QEMU holds the file qcow2 file:

cli_function.py

@@ -231,7 +231,7 @@ class CliFunction:
     def cli_noexit(self, cli_args=None):
         '''
         Call the function from the CLI. Parse command line arguments
-        to get all arguments.
+        to get all arguments. Does not exit the program after running this function.
 
         :return: the return of main
         '''
@@ -435,6 +435,8 @@ amazing function!
 
     # Positional
     out = one_cli_function(pos_mandatory=1, pos_optional=2, args_star=['3', '4'])
+    # TODO: make actual positional arguments work.
+    # out = one_cli_function(1, 2, '3', '4')
     assert out['pos_mandatory'] == 1
     assert out['pos_optional'] == 2
     assert out['args_star'] == ['3', '4']

common.py

@@ -1345,6 +1345,8 @@ lunch aosp_{}-eng
         These are arguments that might be used by more than one script,
         and are all defined in this class instead of in the derived class
         of the script.
+
+        This can be used to forward common arguments to a call of another CLI function.
         '''
         return {
             key:self.env[key] for key in self._common_args if

disas

@@ -0,0 +1,38 @@
+#!/usr/bin/env python3
+
+import os
+
+import lkmc.import_path
+
+import common
+from shell_helpers import LF
+
+class Main(common.LkmcCliFunction):
+    def __init__(self):
+        super().__init__(
+            defaults = {
+                'show_time': False,
+            },
+            description='''\
+Disassemble one function of the given executable.
+https://cirosantilli.com/linux-kernel-module-cheat#run-toolchain
+''',
+        )
+        self.add_argument('function', help='Which function to disassemble.')
+
+    def timed_main(self):
+        lkmc.import_path.import_path_main('run-toolchain')(
+            tool='gdb',
+            extra_args=[
+                '-nh',
+                '-batch',
+                '-ex',
+                'disas/rs {}'.format(self.env['function']),
+                self.env['image'],
+            ],
+            quiet=True,
+            **self.get_common_args()
+        )
+
+if __name__ == '__main__':
+    Main().cli()

run-toolchain

@@ -34,10 +34,6 @@ Suitable for programmatic consumption by other shell programs.
         )
 
     def timed_main(self):
-        if self.env['baremetal']:
-            image = self.env['vmlinux']
-        else:
-            image = self.env['image']
         tool = self.get_toolchain_tool(self.env['tool'])
         if self.env['print_tool']:
             print(tool)