2a63c962fc
Remove old build system at the same time Change-Id: Ifdffe1fcd4cfece05f036d8de6e7cb74aca65f62
47 lines
2.8 KiB
Plaintext
47 lines
2.8 KiB
Plaintext
Cross compilation:
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------------------
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The standard way of cross compiling with cmake is to give cmake a "toolchain
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file" that describes the compiler prefix and where it can find libraries for
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the target system, we provide an example in cmake/cross-aarch64.cmake.
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This obviously requires installing a toolchain and a rootfs with target
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libraries to link against.
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In addition, mckernel borrows the Kbuild system from linux kernel, which also
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makes the assumption that you can run generated executables (Kbuild uses various
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scripts around module building and does not make the distinction between build
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target and host target); you can get this working by setting up qemu-user on your
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machine which the kernel will transparently use through binfmt magic when trying
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to execute other arch binaries.
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# yum install gcc-aarch64-linux-gnu qemu-user
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(dnf brings in --forcearch, we use this to setup the sysroot ; there are other
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ways of building one. It is available on el7 in extras.)
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# yum install dnf dnf-plugins-core
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(install these separately because most scripts cannot be run, and dependency hell means we need them first)
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# dnf download --releasever=7 --forcearch=aarch64 filesystem centos-release
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# rpm --root /usr/aarch64-linux-gnu/sys-root --ignorearch --nodeps -ivh filesystem-*.rpm
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# rpm --root /usr/aarch64-linux-gnu/sys-root --ignorearch --nodeps -ivh centos-release-*.rpm
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# rpm --root /usr/aarch64-linux-gnu/sys-root --import /usr/aarch64-linux-gnu/sys-root/etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
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# rpm --root /usr/aarch64-linux-gnu/sys-root --import /usr/aarch64-linux-gnu/sys-root/etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7-aarch64
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# dnf install --releasever=7 --forcearch=aarch64 --installroot=/usr/aarch64-linux-gnu/sys-root/ --setopt=tsflags=noscripts glibc-devel kernel-devel numactl-devel systemd-devel binutils-devel
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(el7 lacks a binfmt for aarch64... fix this)
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# echo ':qemu-aarch64:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/bin/qemu-aarch64:' > /etc/binfmt.d/qemu-aarch64-dynamic.conf
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# systemctl restart systemd-binfmt
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(optional) test your setup
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# gcc -xc - <<<'#include <stdio.h>'$'\n''int main() { printf("ok\n"); return 0; }'
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# export QEMU_LD_PREFIX=/usr/aarch64-linux-gnu/sys-root
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# file a.out
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a.out: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 3.7.0, BuildID[sha1]=5ff445d3353cad2dae0a22550fe4cc572287dd90, not stripped
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# ./a.out
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ok
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finally, build mckernel!
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# mkdir build; cd build
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# export QEMU_LD_PREFIX=/usr/aarch64-linux-gnu/sys-root
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# cmake -DCMAKE_INSTALL_PREFIX=/tmp/install-aarch64 -DCMAKE_TOOLCHAIN_FILE=../cmake/cross-aarch64.cmake -DUNAME_R=4.14.0-115.2.2.el7a.aarch64 -DKERNEL_DIR=/usr/aarch64-linux-gnu/sys-root/usr/src/kernels/4.14.0-115.2.2.el7a.aarch64/ -DBUILD_TARGET=smp-arm64 ..
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# make -j
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