From 835997725ca3b7b6230fc5e0a16bf0e5543673e0 Mon Sep 17 00:00:00 2001 From: Henri Beauchamp Date: Wed, 8 Oct 2025 02:03:56 +0200 Subject: [PATCH 1/2] Allow cross-compilation of Linux arm64 builds on Linux x86_64 build hosts These changes to run.py allow to build an arm64 WebRTC SDK package on a x86_64 build host under Linux. --- build/run.py | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/build/run.py b/build/run.py index f8789a5..73d5ee6 100644 --- a/build/run.py +++ b/build/run.py @@ -812,10 +812,13 @@ def build_webrtc( elif target in ('raspberry-pi-os_armv8', 'ubuntu-18.04_armv8', 'ubuntu-20.04_armv8'): + if platform.machine() in ['AMD64', 'x86_64']: + gn_args += [ 'host_cpu="x64"' ] + else: # Assume ARM64 build host + gn_args += [ 'host_cpu="arm64"' ] gn_args += [ 'host_os="linux"', 'target_os="linux"', - 'host_cpu="arm64"', 'target_cpu="arm64"', 'use_custom_libcxx=false', 'use_custom_libcxx_for_host=false', @@ -1267,6 +1270,11 @@ def main(): webrtc_source_dir=webrtc_source_dir, fetch=args.webrtc_fetch, force=args.webrtc_fetch_force) + if args.target in ['ubuntu-18.04_armv8', 'ubuntu-20.04_armv8']: + if platform.machine() in ['AMD64', 'x86_64']: + install_sysroot = os.path.join(source_dir, 'webrtc', 'src', 'build', 'linux', 'sysroot_scripts', 'install-sysroot.py') + cmd(['python3', install_sysroot, '--arch=arm64']) + # ビルド # Build build_webrtc_args = { From 65e8e37a0d94357fc5fdf3ca62a774224cd4f703 Mon Sep 17 00:00:00 2001 From: Henri Beauchamp Date: Wed, 8 Oct 2025 10:42:10 +0200 Subject: [PATCH 2/2] Fix missing symbol at runtime for arm64. Reimplement check_target. This commit fixes the following issue seen on Linux arm64 viewer builds at runtime: "undefined symbol __arm_tpidr2_save" This error is due to unconditional intrinsics optimizations enabling by the build system in third party libraries for Linux arm64, without regard for the target system NEON version. Here, the error comes from an optimisation of libyuv; thankfully, we can force-disable it with: 'libyuv_use_sme=false'. The commmit also adds (untested) cross-compiling support for the 'raspberry-pi-os_armv8' target. Finally, this commit reimplements (and re-enables) the check_target() function in run.py so that it works without ostracizing the build hosts, i.e. not forcing specific Ubuntu distro and version, since we are using a virtual build environment and therefore do not care about the host Linux distro. Note however that I did not allow ARM v6/7 and android targets in check_target since those would require further modifications to run.py (see my comment in check_target); but do we care at all about them for SL viewers ? --- build/run.py | 56 +++++++++++----------------------------------------- 1 file changed, 12 insertions(+), 44 deletions(-) diff --git a/build/run.py b/build/run.py index 73d5ee6..773efa5 100644 --- a/build/run.py +++ b/build/run.py @@ -823,6 +823,7 @@ def build_webrtc( 'use_custom_libcxx=false', 'use_custom_libcxx_for_host=false', 'clang_use_chrome_plugins=false', + 'libyuv_use_sme=false', 'rtc_use_x11=false', 'rtc_use_pipewire=false', 'rtc_include_pulse_audio=false', @@ -1073,50 +1074,20 @@ def package_webrtc(source_dir, build_dir, package_dir, target, def check_target(target): logging.debug(f'uname: {platform.uname()}') + logging.info(f'OS: {platform.system()}') if platform.system() == 'Windows': - logging.info(f'OS: {platform.system()}') return target in ['windows_x86_64', 'windows_x86', 'windows_arm64'] elif platform.system() == 'Darwin': - logging.info(f'OS: {platform.system()}') return target in ('macos_x86_64', 'macos_arm64', 'ios', 'apple', 'apple_prefixed') elif platform.system() == 'Linux': - release = read_version_file('/etc/os-release') - os = release['NAME'] - logging.info(f'OS: {os}') - if os != 'Ubuntu': - return False - - # x86_64 環境以外ではビルド不可 - # Requires an x86_64 machine to build. - arch = platform.machine() - logging.info(f'Arch: {arch}') - if arch not in ('AMD64', 'x86_64'): - return False - - # クロスコンパイルなので Ubuntu だったら任意のバージョンでビルド可能（なはず） - # Cross compiling: if it's Ubuntu, any version should be able to build the following targets (theoretically) - if target in ('ubuntu-18.04_armv8', - 'ubuntu-20.04_armv8', - 'raspberry-pi-os_armv6', - 'raspberry-pi-os_armv7', - 'raspberry-pi-os_armv8', - 'android', - 'android_prefixed'): - return True - - # x86_64 用ビルドはバージョンが合っている必要がある - # Builds for x86_64 require the version to match. - osver = release['VERSION_ID'] - logging.info(f'OS Version: {osver}') - if target == 'ubuntu-18.04_x86_64' and osver == '18.04': - return True - if target == 'ubuntu-20.04_x86_64' and osver == '20.04': - return True - if target == 'ubuntu-22.04_x86_64' and osver == '22.04': - return True - - return False + return target in ('ubuntu-18.04_x86_64', 'ubuntu-20.04_x86_64', 'ubuntu-22.04_x86_64', + 'ubuntu-18.04_armv8', 'ubuntu-20.04_armv8', 'raspberry-pi-os_armv8') + # These are untested/not catered for: 'android', 'android_prefixed', + # 'raspberry-pi-os_armv6', 'raspberry-pi-os_armv7'. They likely require + # cross-compiling on a x86_64 system, with the installation of a proper + # ARM system root (search for "install_sysroot" below to see how to + # proceed). HB else: return False @@ -1191,11 +1162,8 @@ def main(): if not hasattr(args, 'op'): parser.error('Required subcommand') - # Do not error out when the Linux distribution used to build the library is - # not known from the build system: we do not care since we use a virtual - # environment for the build... HB - #if not check_target(args.target): - # raise Exception(f'Target {args.target} is not supported on your platform') + if not check_target(args.target): + raise Exception(f'Target {args.target} is not supported on your platform') configuration = 'debug' if args.debug else 'release' @@ -1270,7 +1238,7 @@ def main(): webrtc_source_dir=webrtc_source_dir, fetch=args.webrtc_fetch, force=args.webrtc_fetch_force) - if args.target in ['ubuntu-18.04_armv8', 'ubuntu-20.04_armv8']: + if args.target in ['ubuntu-18.04_armv8', 'ubuntu-20.04_armv8', 'raspberry-pi-os_armv8']: if platform.machine() in ['AMD64', 'x86_64']: install_sysroot = os.path.join(source_dir, 'webrtc', 'src', 'build', 'linux', 'sysroot_scripts', 'install-sysroot.py') cmd(['python3', install_sysroot, '--arch=arm64'])