From 18c67d2418c571a0a85592401db793b5e6a9343a Mon Sep 17 00:00:00 2001 From: n0-1 Date: Mon, 6 Jan 2025 02:27:19 +0100 Subject: [PATCH] Support for cross-compiling kernel modules In order to correctly cross-compile, one has to pass ARCH and CROSS_COMPILE make flags to kernel module build calls. Facilitate this in the same way as for custom CC flag by recognizing KERNEL_-prefixed configure environment variables of same name. Reviewed-by: Brian Behlendorf Signed-off-by: Phil Sutter Closes #16924 --- config/kernel.m4 | 5 +++++ config/zfs-build.m4 | 2 ++ module/Makefile.in | 2 ++ rpm/generic/zfs-kmod.spec.in | 4 +++- rpm/redhat/zfs-kmod.spec.in | 4 +++- 5 files changed, 15 insertions(+), 2 deletions(-) diff --git a/config/kernel.m4 b/config/kernel.m4 index ae6663390..9928ead1b 100644 --- a/config/kernel.m4 +++ b/config/kernel.m4 @@ -681,11 +681,16 @@ AC_DEFUN([ZFS_LINUX_COMPILE], [ building kernel modules]) AC_ARG_VAR([KERNEL_LLVM], [Binary option to build kernel modules with LLVM/CLANG toolchain]) + AC_ARG_VAR([KERNEL_CROSS_COMPILE], [Cross compile prefix + for kernel module builds]) + AC_ARG_VAR([KERNEL_ARCH], [Architecture to build kernel modules for]) AC_TRY_COMMAND([ KBUILD_MODPOST_NOFINAL="$5" KBUILD_MODPOST_WARN="$6" make modules -k -j$TEST_JOBS ${KERNEL_CC:+CC=$KERNEL_CC} ${KERNEL_LD:+LD=$KERNEL_LD} ${KERNEL_LLVM:+LLVM=$KERNEL_LLVM} CONFIG_MODULES=y CFLAGS_MODULE=-DCONFIG_MODULES + ${KERNEL_CROSS_COMPILE:+CROSS_COMPILE=$KERNEL_CROSS_COMPILE} + ${KERNEL_ARCH:+ARCH=$KERNEL_ARCH} -C $LINUX_OBJ $ARCH_UM M=$PWD/$1 >$1/build.log 2>&1]) AS_IF([AC_TRY_COMMAND([$2])], [$3], [$4]) ]) diff --git a/config/zfs-build.m4 b/config/zfs-build.m4 index c44a893bb..55fc029f0 100644 --- a/config/zfs-build.m4 +++ b/config/zfs-build.m4 @@ -393,6 +393,8 @@ AC_DEFUN([ZFS_AC_RPM], [ RPM_DEFINE_KMOD=${RPM_DEFINE_KMOD}' --define "kernel_cc KERNEL_CC=$(KERNEL_CC)"' RPM_DEFINE_KMOD=${RPM_DEFINE_KMOD}' --define "kernel_ld KERNEL_LD=$(KERNEL_LD)"' RPM_DEFINE_KMOD=${RPM_DEFINE_KMOD}' --define "kernel_llvm KERNEL_LLVM=$(KERNEL_LLVM)"' + RPM_DEFINE_KMOD=${RPM_DEFINE_KMOD}' --define "kernel_cross_compile KERNEL_CROSS_COMPILE=$(KERNEL_CROSS_COMPILE)"' + RPM_DEFINE_KMOD=${RPM_DEFINE_KMOD}' --define "kernel_arch KERNEL_ARCH=$(KERNEL_ARCH)"' ]) RPM_DEFINE_DKMS='' diff --git a/module/Makefile.in b/module/Makefile.in index 9b34b3dfa..529ab81dc 100644 --- a/module/Makefile.in +++ b/module/Makefile.in @@ -55,6 +55,8 @@ modules-Linux: mkdir -p $(sort $(dir $(zfs-objs) $(zfs-))) $(MAKE) -C @LINUX_OBJ@ $(if @KERNEL_CC@,CC=@KERNEL_CC@) \ $(if @KERNEL_LD@,LD=@KERNEL_LD@) $(if @KERNEL_LLVM@,LLVM=@KERNEL_LLVM@) \ + $(if @KERNEL_CROSS_COMPILE@,CROSS_COMPILE=@KERNEL_CROSS_COMPILE@) \ + $(if @KERNEL_ARCH@,ARCH=@KERNEL_ARCH@) \ M="$$PWD" @KERNEL_MAKE@ CONFIG_ZFS=m modules modules-FreeBSD: diff --git a/rpm/generic/zfs-kmod.spec.in b/rpm/generic/zfs-kmod.spec.in index 30524474d..7ed828bd0 100644 --- a/rpm/generic/zfs-kmod.spec.in +++ b/rpm/generic/zfs-kmod.spec.in @@ -144,7 +144,9 @@ for kernel_version in %{?kernel_versions}; do %{debuginfo} \ %{?kernel_cc} \ %{?kernel_ld} \ - %{?kernel_llvm} + %{?kernel_llvm} \ + %{?kernel_cross_compile} \ + %{?kernel_arch} # Pre-6.10 kernel builds didn't need to copy over the source files to the # build directory. However we do need to do it though post-6.10 due to diff --git a/rpm/redhat/zfs-kmod.spec.in b/rpm/redhat/zfs-kmod.spec.in index 876c198c6..a95bdf20f 100644 --- a/rpm/redhat/zfs-kmod.spec.in +++ b/rpm/redhat/zfs-kmod.spec.in @@ -69,7 +69,9 @@ fi %{debuginfo} \ %{?kernel_cc} \ %{?kernel_ld} \ - %{?kernel_llvm} + %{?kernel_llvm} \ + %{?kernel_cross_compile} \ + %{?kernel_arch} make %{?_smp_mflags} # Module signing (modsign)