Skip to content

toolchain.md

Latest commit

 

History

History
75 lines (63 loc) · 4.38 KB

toolchain.md

File metadata and controls

75 lines (63 loc) · 4.38 KB
Raw

Toolchain

Why the userland is built with Arm GNU 13.3 and not the SDK's toolchain

Moss-zero28 builds the rootfs twice: phase 1 with the SDK's prebuilt Linaro GCC 6.4 / glibc 2.23, then phase 2 with a from-source Linaro GCC 7.4 / glibc 2.29 / binutils 2.28 toolchain. That gives a libstdc++ capped at GLIBCXX_3.4.24.

docs/DEPENDENCIES.md (an ELF-closure survey of everything the spruceOS card runs) shows that is not enough for the launcher's payload: RetroArch (ra64.universal) needs GLIBCXX_3.4.26, flycast, yabasanshiro and the GLideN64 plugins need newer symbols still, four bin64 tools want GLIBC_2.34, and PortMaster's Godot/FRT and Solarus runtimes need GLIBCXX_3.4.26. spruceOS ships no aarch64 libstdc++ of its own: on the TrimUI Smart Pro the vendor rootfs provides it (its LD_LIBRARY_PATH starts with /usr/trimui/lib). So the base image has to.

Two more facts closed the door on the Moss toolchain: Linaro's site no longer serves gcc-linaro-7.4-2019.02.tar.xz (the SDK's dl/ has no copy and no mirror was found), and even the GNU GCC 7.5.0 stand-in added for it (sdk-patches/tree/030-*, configs/phase2-gcc750.config) would still cap libstdc++ too low.

What the build does instead

Tina's OpenWrt build system supports an external toolchain. The override in sdk-patches/tree/010-rules-mk-external-toolchain-override.patch is driven by environment variables (TINA_EXT_TOOLCHAIN_ROOT, _PREFIX, _TARGET_NAME, _SYSROOT, TINA_EXT_KERNEL_CROSS) so that the SDK is untouched unless scripts/run-in-sdk.sh sets them (TOOLCHAIN=armgnu13, the default):

  • Userland: Arm GNU Toolchain 13.3.Rel1 aarch64-none-linux-gnu (glibc 2.38, GLIBCXX_3.4.32, glibc's minimum kernel 3.7.0, so fine on 4.9.191).
  • Kernel and the PowerVR GE8300 kernel module: the SDK's own GCC 6.4 through KERNEL_CROSS (sdk-patches/tree/040-gpu-km-kernel-cross.patch makes the module use it too; the rogue_km build keys its compiler config on the prefix).
  • tina-sysroot/: the SDK's CONFIG_LIBC_FILE_SPEC globs expect glibc under ./lib and libstdc++/libgcc_s/libatomic under ./usr/lib; Arm keeps them in lib64/. scripts/prepare-toolchain.sh copies them into that shape. The override sets the file specs twice because rules.mk reassigns CONFIG_LIBC_FILE_SPEC late (the second block is marked TINA_EXT_LIBC_SPEC_LATE). ./lib/libc.so -> libc.so.6 is there for Allwinner's prebuilt libresamplerate_64.so, which NEEDs the unversioned name.
  • wrap/: Allwinner's prebuilt toolchain has a sysroot pre-populated with package headers and libraries, so several Tina packages (libsocket_db, ustream-ssl, jsonfilter, usign, ubus) compile without any CPPFLAGS/LDFLAGS. A clean toolchain needs the OpenWrt staging paths injected: the wrapper appends -idirafter $STAGING_DIR/{usr/include,include,usr/include/libxml2} and trailing -L/-rpath-link. CONFIG_TOOLCHAIN_BIN_PATH="./wrap ./bin" puts it first.

GCC 13 against 2017-era packages needed the fixes listed in docs/sdk-mods.md (-fcommon, a set of -Wno-error= flags for packages that build with -Werror, uClibc++ replaced by libstdc++, ncurses 5.9 replaced by 6.2, libffi's multi-os directory, and one-line patches to busybox, bluez, e2fsprogs, libubox).

Fallbacks

  • scripts/build.sh phase1 / phase2 with TOOLCHAIN=vendor run Moss's recipe as published (configs/phase1.config, then configs/phase2-gcc750.config; configs/phase2.config if the Linaro 7.4 tarball ever reappears in dl/). The result boots but cannot run spruce's RetroArch.
  • Bootlin's aarch64--glibc--stable-2022.08-1 (GCC 11.3, glibc 2.35, kernel headers 4.9) is the next candidate if GCC 13 ever breaks too many SDK packages. It has not been needed.

Iterating on the SDK

  • scripts/build.sh cont resumes the current build without wiping.
  • After changing a package Makefile: rm -rf sdk/lichee/out/a133-aw3/compile_dir/target/<pkg>-*.
  • After changing the libc file spec: rm -rf sdk/lichee/out/a133-aw3/compile_dir/target/toolchain.
  • The kernel's non-interactive silentoldconfig aborts on NEW symbols: resolve them with make olddefconfig in lichee/linux-4.9 and append the result to config-4.9 (that is where the XRADIO block in 020-kernel-config-4.9.patch came from).
  • build/toplevel.mk copies target/allwinner/a133-aw3/defconfig over .config on every make, so a config only sticks when installed there (build.sh does).