linux-kernel-module-cheat/build-baremetal

#!/usr/bin/env python3
import os

import common
import thread_pool
from shell_helpers import LF

class Main(common.BuildCliFunction):
    def __init__(self):
        super().__init__(
            defaults={
                'gcc_which': 'crosstool-ng',
                'mode': 'baremetal',
            },
            description='''\
Build the baremetal examples with crosstool-NG.
''',
        )
        self._add_argument('--ccflags')
        self._add_argument('--force-rebuild')
        self._add_argument('--optimization-level')
        self.add_argument(
            'targets',
            default=[],
            help='Analogous to ./build-userland target selection',
            nargs='*',
        )

    def build(self):
        build_dir = self.get_build_dir()
        extra_obj_baremetal_bootloader = os.path.join(
            self.env['baremetal_build_lib_dir'],
            'bootloader{}'.format(self.env['obj_ext'])
        )
        extra_obj_lkmc_common = os.path.join(
            self.env['baremetal_build_lib_dir'],
            self.env['common_basename_noext'] + self.env['obj_ext']
        )
        cc_flags = [
            '-I', self.env['root_dir'], LF,
            '-O{}'.format(self.env['optimization_level']), LF,
            '-nostartfiles', LF,
        ]
        if self.env['arch'] == 'arm':
            cc_flags.extend([
                '-mhard-float', LF,
                # This uses the soft float ABI for calling functions from objets in Newlib which
                # our crosstool-NG config compiles with soft floats, while emiting hard float
                # from C and allowing us to use it from assembly, e.g. for the VMRS instruction:
                # which would otherwise fail "with selected processor does not support XXX in ARM mode"
                # Bibliography:
                # - https://stackoverflow.com/questions/9753749/arm-compilation-error-vfp-registered-used-by-executable-not-object-file
                # - https://stackoverflow.com/questions/41131432/cross-compiling-error-selected-processor-does-not-support-fmrx-r3-fpexc-in/41131782#41131782
                # - https://embeddedartistry.com/blog/2017/10/9/r1q7pksku2q3gww9rpqef0dnskphtc
                '-mfloat-abi=softfp', LF,
                '-mfpu=crypto-neon-fp-armv8', LF,
            ])
        if self.env['emulator'] == 'gem5':
            if self.env['machine'] == 'VExpress_GEM5_V1':
                entry_address = 0x80000000
                uart_address = 0x1c090000
            elif self.env['machine'] == 'RealViewPBX':
                entry_address = 0x10000
                uart_address = 0x10009000
            else:
                raise Exception('unknown machine: ' + self.env['machine'])
            cc_flags.extend([
                '-DLKMC_GEM5=1', LF,
                '-DLKMC_M5OPS_ENABLE=1', LF,
            ])
        else:
            entry_address = 0x40000000
            uart_address = 0x09000000
            cc_flags.extend(['-D', 'LKMC_QEMU=1', LF])
        cc_flags.extend(['-D', 'LKMC_UART0_ADDR={:#x}'.format(uart_address), LF])
        cc_flags.extend(self.sh.shlex_split(self.env['ccflags']))
        bootloader_src = os.path.join(
            self.env['baremetal_source_lib_dir'],
            '{}{}'.format(
                self.env['arch'],
                self.env['asm_ext']
            )
        )
        for in_path, out_path in [
            (bootloader_src, extra_obj_baremetal_bootloader),
            (self.env['common_c'], extra_obj_lkmc_common),
            (
                self.env['baremetal_syscalls_src'],
                self.env['baremetal_syscalls_obj']
            ),
            (
                self.env['baremetal_syscalls_asm_src'],
                self.env['baremetal_syscalls_asm_obj']
            ),
        ]:
            self._build_one(
                in_path=in_path,
                out_path=out_path,
                cc_flags=cc_flags,
                extra_deps=[self.env['common_h']],
                link=False,
            )
        cc_flags.extend([
            '-Wl,--section-start=.text={:#x}'.format(entry_address), LF,
            '-T', self.env['baremetal_link_script'], LF,
        ])
        with thread_pool.ThreadPool(
            self._build_one,
            nthreads=self.env['nproc'],
            submit_raise_exit=self.env['quit_on_fail'],
        ) as my_thread_pool:
            for target in self.env['targets']:
                for path, in_dirnames, in_filenames in self.sh.walk(target):
                    for in_filename in in_filenames:
                        in_ext = os.path.splitext(in_filename)[1]
                        if not in_ext in self.env['baremetal_build_in_exts']:
                            continue
                        in_path = os.path.join(path, in_filename)
                        my_thread_pool.submit({
                            'cc_flags': cc_flags,
                            'extra_deps': [
                                self.env['baremetal_link_script'],
                                self.env['common_h']
                            ],
                            'extra_objs': [
                                self.env['baremetal_syscalls_obj'],
                                self.env['baremetal_syscalls_asm_obj']
                            ],
                            'extra_objs_baremetal_bootloader': [extra_obj_baremetal_bootloader],
                            'extra_objs_lkmc_common': [extra_obj_lkmc_common],
                            'in_path': in_path,
                            'out_path': self.resolve_baremetal_executable(in_path),
                        })
        return self._handle_thread_pool_errors(my_thread_pool)

    def get_build_dir(self):
        return self.env['baremetal_build_dir']

    def setup_one(self):
        self.env['targets'] = self.resolve_targets(
            [
                self.env['baremetal_source_dir'],
                self.env['userland_source_dir']
            ],
            self.env['targets']
        )

if __name__ == '__main__':
    Main().cli()