kernel: Add kernel specific OBJDUMP

This helps in switching toolchains cleanly for kernel build
between gcc and clang

Currently, some kernels allow building with clang but not all
the distro might use clang as default system compiler but kernel
may demand gcc which is provided via KERNEL_* variables, however
kernel does use OBJCOPY at places during build and it maybe set
to use llvm objcopy when using clang. That should be a deliberate
setting when clang is used for kernel as well, otherwise it should
use binutils provided objcopy

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Cc: Bruce Ashfield <bruce.ashfield@gmail.com>
---
 meta/classes-recipe/kernel-arch.bbclass                      | 3 +++
 meta/classes-recipe/kernel-devicetree.bbclass                | 2 +-
 meta/classes-recipe/kernel-uboot.bbclass                     | 2 +-
 meta/classes-recipe/kernel-yocto.bbclass                     | 4 +++-
 meta/classes-recipe/kernel.bbclass                           | 2 +-
 meta/classes-recipe/module.bbclass                           | 5 +++--
 meta/recipes-kernel/make-mod-scripts/make-mod-scripts_1.0.bb | 3 ++-
 meta/recipes-kernel/systemtap/systemtap-uprobes_git.bb       | 4 ++--
 8 files changed, 16 insertions(+), 9 deletions(-)

On Wed, Mar 1, 2023 at 12:30 AM Khem Raj <raj.khem@gmail.com> wrote:
>
> This helps in switching toolchains cleanly for kernel build
> between gcc and clang
>
> Currently, some kernels allow building with clang but not all
> the distro might use clang as default system compiler but kernel
> may demand gcc which is provided via KERNEL_* variables, however
> kernel does use OBJCOPY at places during build and it maybe set
> to use llvm objcopy when using clang. That should be a deliberate
> setting when clang is used for kernel as well, otherwise it should
> use binutils provided objcopy

Makes sense to me. Not that I use it, but since the kernel already
provides the flexibility to vary objcopy, no concerns if we use it.

We always tend to find some lurking kernel "build" that we've missed
(i.e. a menu or mergeconfig), but those a) shouldn't use objcopy and
b) will be easy enough to fix.

Bruce

>
> Signed-off-by: Khem Raj <raj.khem@gmail.com>
> Cc: Bruce Ashfield <bruce.ashfield@gmail.com>
> ---
>  meta/classes-recipe/kernel-arch.bbclass                      | 3 +++
>  meta/classes-recipe/kernel-devicetree.bbclass                | 2 +-
>  meta/classes-recipe/kernel-uboot.bbclass                     | 2 +-
>  meta/classes-recipe/kernel-yocto.bbclass                     | 4 +++-
>  meta/classes-recipe/kernel.bbclass                           | 2 +-
>  meta/classes-recipe/module.bbclass                           | 5 +++--
>  meta/recipes-kernel/make-mod-scripts/make-mod-scripts_1.0.bb | 3 ++-
>  meta/recipes-kernel/systemtap/systemtap-uprobes_git.bb       | 4 ++--
>  8 files changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/meta/classes-recipe/kernel-arch.bbclass b/meta/classes-recipe/kernel-arch.bbclass
> index 777f900241..5877048916 100644
> --- a/meta/classes-recipe/kernel-arch.bbclass
> +++ b/meta/classes-recipe/kernel-arch.bbclass
> @@ -68,9 +68,12 @@ TARGET_LD_KERNEL_ARCH ?= ""
>  HOST_LD_KERNEL_ARCH ?= "${TARGET_LD_KERNEL_ARCH}"
>  TARGET_AR_KERNEL_ARCH ?= ""
>  HOST_AR_KERNEL_ARCH ?= "${TARGET_AR_KERNEL_ARCH}"
> +TARGET_OBJCOPY_KERNEL_ARCH ?= ""
> +HOST_OBJCOPY_KERNEL_ARCH ?= "${TARGET_OBJCOPY_KERNEL_ARCH}"
>
>  KERNEL_CC = "${CCACHE}${HOST_PREFIX}gcc ${HOST_CC_KERNEL_ARCH} -fuse-ld=bfd ${DEBUG_PREFIX_MAP} -fdebug-prefix-map=${STAGING_KERNEL_DIR}=${KERNEL_SRC_PATH} -fdebug-prefix-map=${STAGING_KERNEL_BUILDDIR}=${KERNEL_SRC_PATH}"
>  KERNEL_LD = "${CCACHE}${HOST_PREFIX}ld.bfd ${HOST_LD_KERNEL_ARCH}"
>  KERNEL_AR = "${CCACHE}${HOST_PREFIX}ar ${HOST_AR_KERNEL_ARCH}"
> +KERNEL_OBJCOPY = "${CCACHE}${HOST_PREFIX}objcopy ${HOST_OBJCOPY_KERNEL_ARCH}"
>  TOOLCHAIN ?= "gcc"
>
> diff --git a/meta/classes-recipe/kernel-devicetree.bbclass b/meta/classes-recipe/kernel-devicetree.bbclass
> index b2117de805..4d0ecb1032 100644
> --- a/meta/classes-recipe/kernel-devicetree.bbclass
> +++ b/meta/classes-recipe/kernel-devicetree.bbclass
> @@ -68,7 +68,7 @@ do_compile:append() {
>
>         for dtbf in ${KERNEL_DEVICETREE}; do
>                 dtb=`normalize_dtb "$dtbf"`
> -               oe_runmake $dtb CC="${KERNEL_CC} $cc_extra " LD="${KERNEL_LD}" ${KERNEL_EXTRA_ARGS}
> +               oe_runmake $dtb CC="${KERNEL_CC} $cc_extra " LD="${KERNEL_LD}" OBJCOPY="${KERNEL_OBJCOPY}" ${KERNEL_EXTRA_ARGS}
>         done
>  }
>
> diff --git a/meta/classes-recipe/kernel-uboot.bbclass b/meta/classes-recipe/kernel-uboot.bbclass
> index 4aab02671e..30a85ccc28 100644
> --- a/meta/classes-recipe/kernel-uboot.bbclass
> +++ b/meta/classes-recipe/kernel-uboot.bbclass
> @@ -34,7 +34,7 @@ uboot_prep_kimage() {
>                 linux_comp="${FIT_KERNEL_COMP_ALG}"
>         fi
>
> -       [ -n "${vmlinux_path}" ] && ${OBJCOPY} -O binary -R .note -R .comment -S "${vmlinux_path}" linux.bin
> +       [ -n "${vmlinux_path}" ] && ${KERNEL_OBJCOPY} -O binary -R .note -R .comment -S "${vmlinux_path}" linux.bin
>
>         if [ "${linux_comp}" != "none" ] ; then
>                 if [ "${linux_comp}" = "gzip" ] ; then
> diff --git a/meta/classes-recipe/kernel-yocto.bbclass b/meta/classes-recipe/kernel-yocto.bbclass
> index 7de99cff56..108b7e6752 100644
> --- a/meta/classes-recipe/kernel-yocto.bbclass
> +++ b/meta/classes-recipe/kernel-yocto.bbclass
> @@ -455,7 +455,7 @@ do_kernel_configme() {
>                 bbfatal_log "Could not find configuration queue (${meta_dir}/config.queue)"
>         fi
>
> -       CFLAGS="${CFLAGS} ${TOOLCHAIN_OPTIONS}" HOSTCC="${BUILD_CC} ${BUILD_CFLAGS} ${BUILD_LDFLAGS}" HOSTCPP="${BUILD_CPP}" CC="${KERNEL_CC}" LD="${KERNEL_LD}" ARCH=${ARCH} merge_config.sh -O ${B} ${config_flags} ${configs} > ${meta_dir}/cfg/merge_config_build.log 2>&1
> +       CFLAGS="${CFLAGS} ${TOOLCHAIN_OPTIONS}" HOSTCC="${BUILD_CC} ${BUILD_CFLAGS} ${BUILD_LDFLAGS}" HOSTCPP="${BUILD_CPP}" CC="${KERNEL_CC}" LD="${KERNEL_LD}" OBJCOPY="${KERNEL_OBJCOPY}" ARCH=${ARCH} merge_config.sh -O ${B} ${config_flags} ${configs} > ${meta_dir}/cfg/merge_config_build.log 2>&1
>         if [ $? -ne 0 -o ! -f ${B}/.config ]; then
>                 bberror "Could not generate a .config for ${KMACHINE}-${LINUX_KERNEL_TYPE}"
>                 if [ ${KCONF_AUDIT_LEVEL} -gt 1 ]; then
> @@ -489,6 +489,7 @@ python do_config_analysis() {
>      env['PATH'] = "%s:%s%s" % (d.getVar('PATH'), s, "/scripts/util/")
>      env['LD'] = d.getVar('KERNEL_LD')
>      env['CC'] = d.getVar('KERNEL_CC')
> +    env['OBJCOPY'] = d.getVar('KERNEL_OBJCOPY')
>      env['ARCH'] = d.getVar('ARCH')
>      env['srctree'] = s
>
> @@ -550,6 +551,7 @@ python do_kernel_configcheck() {
>      env['PATH'] = "%s:%s%s" % (d.getVar('PATH'), s, "/scripts/util/")
>      env['LD'] = d.getVar('KERNEL_LD')
>      env['CC'] = d.getVar('KERNEL_CC')
> +    env['OBJCOPY'] = d.getVar('KERNEL_OBJCOPY')
>      env['ARCH'] = d.getVar('ARCH')
>      env['srctree'] = s
>
> diff --git a/meta/classes-recipe/kernel.bbclass b/meta/classes-recipe/kernel.bbclass
> index 4fbe84c4e4..3f9c6c00e6 100644
> --- a/meta/classes-recipe/kernel.bbclass
> +++ b/meta/classes-recipe/kernel.bbclass
> @@ -234,7 +234,7 @@ UBOOT_LOADADDRESS ?= "${UBOOT_ENTRYPOINT}"
>  # Some Linux kernel configurations need additional parameters on the command line
>  KERNEL_EXTRA_ARGS ?= ""
>
> -EXTRA_OEMAKE += ' CC="${KERNEL_CC}" LD="${KERNEL_LD}"'
> +EXTRA_OEMAKE += ' CC="${KERNEL_CC}" LD="${KERNEL_LD}" OBJCOPY="${KERNEL_OBJCOPY}"'
>  EXTRA_OEMAKE += ' HOSTCC="${BUILD_CC}" HOSTCFLAGS="${BUILD_CFLAGS}" HOSTLDFLAGS="${BUILD_LDFLAGS}" HOSTCPP="${BUILD_CPP}"'
>  EXTRA_OEMAKE += ' HOSTCXX="${BUILD_CXX}" HOSTCXXFLAGS="${BUILD_CXXFLAGS}" PAHOLE=false'
>
> diff --git a/meta/classes-recipe/module.bbclass b/meta/classes-recipe/module.bbclass
> index d52d5e3098..b3b852be5f 100644
> --- a/meta/classes-recipe/module.bbclass
> +++ b/meta/classes-recipe/module.bbclass
> @@ -32,6 +32,7 @@ python do_devshell:prepend () {
>      os.environ['CC'] = d.getVar('KERNEL_CC')
>      os.environ['LD'] = d.getVar('KERNEL_LD')
>      os.environ['AR'] = d.getVar('KERNEL_AR')
> +    os.environ['OBJCOPY'] = d.getVar('KERNEL_OBJCOPY')
>      os.environ['O'] = d.getVar('STAGING_KERNEL_BUILDDIR')
>      kbuild_extra_symbols = d.getVar('KBUILD_EXTRA_SYMBOLS')
>      if kbuild_extra_symbols:
> @@ -45,7 +46,7 @@ module_do_compile() {
>         oe_runmake KERNEL_PATH=${STAGING_KERNEL_DIR}   \
>                    KERNEL_VERSION=${KERNEL_VERSION}    \
>                    CC="${KERNEL_CC}" LD="${KERNEL_LD}" \
> -                  AR="${KERNEL_AR}" \
> +                  AR="${KERNEL_AR}" OBJCOPY="${KERNEL_OBJCOPY}" \
>                    O=${STAGING_KERNEL_BUILDDIR} \
>                    KBUILD_EXTRA_SYMBOLS="${KBUILD_EXTRA_SYMBOLS}" \
>                    ${MAKE_TARGETS}
> @@ -55,7 +56,7 @@ module_do_install() {
>         unset CFLAGS CPPFLAGS CXXFLAGS LDFLAGS
>         oe_runmake DEPMOD=echo MODLIB="${D}${nonarch_base_libdir}/modules/${KERNEL_VERSION}" \
>                    INSTALL_FW_PATH="${D}${nonarch_base_libdir}/firmware" \
> -                  CC="${KERNEL_CC}" LD="${KERNEL_LD}" \
> +                  CC="${KERNEL_CC}" LD="${KERNEL_LD}" OBJCOPY="${KERNEL_OBJCOPY}" \
>                    O=${STAGING_KERNEL_BUILDDIR} \
>                    ${MODULES_INSTALL_TARGET}
>
> diff --git a/meta/recipes-kernel/make-mod-scripts/make-mod-scripts_1.0.bb b/meta/recipes-kernel/make-mod-scripts/make-mod-scripts_1.0.bb
> index 38282e58f1..28e0807d1d 100644
> --- a/meta/recipes-kernel/make-mod-scripts/make-mod-scripts_1.0.bb
> +++ b/meta/recipes-kernel/make-mod-scripts/make-mod-scripts_1.0.bb
> @@ -27,7 +27,8 @@ EXTRA_OEMAKE += " HOSTCXX="${BUILD_CXX} ${BUILD_CXXFLAGS} ${BUILD_LDFLAGS}" CROS
>  do_configure() {
>         unset CFLAGS CPPFLAGS CXXFLAGS LDFLAGS
>         for t in prepare scripts_basic scripts; do
> -               oe_runmake CC="${KERNEL_CC}" LD="${KERNEL_LD}" AR="${KERNEL_AR}" \
> +               oe_runmake CC="${KERNEL_CC}" LD="${KERNEL_LD}" \
> +               AR="${KERNEL_AR}" OBJCOPY="${KERNEL_OBJCOPY}" \
>                 -C ${STAGING_KERNEL_DIR} O=${STAGING_KERNEL_BUILDDIR} $t
>         done
>  }
> diff --git a/meta/recipes-kernel/systemtap/systemtap-uprobes_git.bb b/meta/recipes-kernel/systemtap/systemtap-uprobes_git.bb
> index 2181e45a8d..efe359ec32 100644
> --- a/meta/recipes-kernel/systemtap/systemtap-uprobes_git.bb
> +++ b/meta/recipes-kernel/systemtap/systemtap-uprobes_git.bb
> @@ -21,12 +21,12 @@ do_compile() {
>         then
>                 unset CFLAGS CPPFLAGS CXXFLAGS LDFLAGS CC LD CPP
>                 oe_runmake CC="${KERNEL_CC}" LD="${KERNEL_LD}" \
> -                          AR="${KERNEL_AR}" \
> +                          AR="${KERNEL_AR}" OBJCOPY="${KERNEL_OBJCOPY}" \
>                            -C ${STAGING_KERNEL_DIR} scripts
>                 oe_runmake KDIR=${STAGING_KERNEL_DIR}   \
>                            M="${S}/runtime/uprobes/" \
>                            CC="${KERNEL_CC}" LD="${KERNEL_LD}" \
> -                          AR="${KERNEL_AR}" \
> +                          AR="${KERNEL_AR}" OBJCOPY="${KERNEL_OBJCOPY}" \
>                            -C "${S}/runtime/uprobes/"
>         fi
>  }
> --
> 2.39.2
>