I am building a custom kernel using Buildroot 2020.02.1 for a PC mounting a AMD GX-222GC SOC.
The default external toolchain is amd-2016.11-19 from CodeBench. Kernel built with that toolchain boots correctly. Instead, if I build the same kernel, same configuration, with the toolchain automatically built by buildroot, the kernel doen not boot! Not even a kernel panic, machine just resets.
It is clear the problem is related to the toolchain.
These are the results of gcc -v
CodeBench:
$ output/host/usr/bin/x86_64-amd-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/media/AAA/tmp/buildroot_toolchain/output/host/opt/ext-toolchain/bin/x86_64-amd-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/media/AAA/tmp/buildroot_toolchain/output/host/opt/ext-toolchain/bin/../libexec/gcc/x86_64-amd-linux-gnu/6.2.0/lto-wrapper
Target: x86_64-amd-linux-gnu
Configured with: /scratch/jmyers/amd-lite/src/gcc-6-2016.11/configure --build=i686-pc-linux-gnu --host=i686-pc-linux-gnu --target=x86_64-amd-linux-gnu --enable-threads --disable-libmudflap --disable-libstdcxx-pch --enable-extra-sgxxlite-multilibs --with-arch=btver2 --with-cpu=btver2 --with-gnu-as --with-gnu-ld --with-specs='-D__CS_SOURCERYGXX_MAJ__=2016 -D__CS_SOURCERYGXX_MIN__=11 -D__CS_SOURCERYGXX_REV__=19' --enable-languages=c,c++ --enable-shared --enable-lto --enable-symvers=gnu --enable-__cxa_atexit --with-glibc-version=2.24 --with-pkgversion='Sourcery CodeBench Lite 2016.11-19' --with-bugurl=https://sourcery.mentor.com/GNUToolchain/ --disable-nls --prefix=/opt/codesourcery --with-sysroot=/opt/codesourcery/x86_64-amd-linux-gnu/libc --with-build-sysroot=/scratch/jmyers/amd-lite/install/opt/codesourcery/x86_64-amd-linux-gnu/libc --with-gmp=/scratch/jmyers/amd-lite/obj/pkg-2016.11-19-x86_64-amd-linux-gnu/amd-2016.11-19-x86_64-amd-linux-gnu.extras/host-libs-i686-pc-linux-gnu/usr --with-mpfr=/scratch/jmyers/amd-lite/obj/pkg-2016.11-19-x86_64-amd-linux-gnu/amd-2016.11-19-x86_64-amd-linux-gnu.extras/host-libs-i686-pc-linux-gnu/usr --with-mpc=/scratch/jmyers/amd-lite/obj/pkg-2016.11-19-x86_64-amd-linux-gnu/amd-2016.11-19-x86_64-amd-linux-gnu.extras/host-libs-i686-pc-linux-gnu/usr --with-isl=/scratch/jmyers/amd-lite/obj/pkg-2016.11-19-x86_64-amd-linux-gnu/amd-2016.11-19-x86_64-amd-linux-gnu.extras/host-libs-i686-pc-linux-gnu/usr --enable-libgomp --enable-libitm --enable-libatomic --disable-libssp --disable-libcc1 --enable-poison-system-directories --with-python-dir=x86_64-amd-linux-gnu/share/gdb/python --with-build-time-tools=/scratch/jmyers/amd-lite/install/opt/codesourcery/x86_64-amd-linux-gnu/bin --with-build-time-tools=/scratch/jmyers/amd-lite/install/opt/codesourcery/x86_64-amd-linux-gnu/bin SED=sed
Thread model: posix
gcc version 6.2.0 (Sourcery CodeBench Lite 2016.11-19)
Buildroot:
Using built-in specs.
COLLECT_GCC=/media/AAA/tmp/buildroot_toolchain/output/host/opt/ext-toolchain/bin/x86_64-linux-gcc.br_real
COLLECT_LTO_WRAPPER=/media/AAA/tmp/buildroot_toolchain/output/host/opt/ext-toolchain/bin/../libexec/gcc/x86_64-buildroot-linux-gnu/7.5.0/lto-wrapper
Target: x86_64-buildroot-linux-gnu
Configured with: ./configure --prefix=/media/AAA/tmp/buildroot_toolchain/output/host --sysconfdir=/media/AAA/tmp/buildroot_toolchain/output/host/etc --enable-static --target=x86_64-buildroot-linux-gnu --with-sysroot=/media/AAA/tmp/buildroot_toolchain/output/host/x86_64-buildroot-linux-gnu/sysroot --enable-__cxa_atexit --with-gnu-ld --disable-libssp --disable-multilib --disable-decimal-float --with-gmp=/media/AAA/tmp/buildroot_toolchain/output/host --with-mpc=/media/AAA/tmp/buildroot_toolchain/output/host --with-mpfr=/media/AAA/tmp/buildroot_toolchain/output/host --with-pkgversion='Buildroot 2020.02.1-00007-g345f377da1-dirty' --with-bugurl=http://bugs.buildroot.net/ --enable-libquadmath --enable-tls --enable-threads --without-isl --without-cloog --with-arch=btver2 --enable-languages=c,c++ --with-build-time-tools=/media/AAA/tmp/buildroot_toolchain/output/host/x86_64-buildroot-linux-gnu/bin --enable-shared --disable-libgomp
Thread model: posix
gcc version 7.5.0 (Buildroot 2020.02.1-00007-g345f377da1-dirty)
Do you see some options that might be required for gcc and buildroot toolchain is missing?
Thanks in advance.
PS: I even tried gcc 8 without resolving.
The early 4.4.x kernels do not boot when built with binutils >= 2.31. This was fixed in commit https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=073bb7ddd35ca8f17a170258dacbe384935a43c8 in the 4.4.x stable branch, which was merged in 4.4.124. So any 4.4.x earlier than that, when built with binutils >= 2.31, will not boot.