On Mon, Jun 10, 2024 at 5:39 PM Naveen N Rao <nav...@kernel.org> wrote:
>
> On powerpc, we would like to be able to make a pass on vmlinux.o and
> generate a new object file to be linked into vmlinux. Add a generic pass
> in link-vmlinux.sh that architectures can use for this purpose.
> Architectures need to select CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX and must
> provide arch/<arch>/tools/vmlinux_o.sh, which will be invoked prior to
> the final vmlinux link step.
>
> Signed-off-by: Naveen N Rao <nav...@kernel.org>
> ---
> arch/Kconfig | 3 +++
> scripts/link-vmlinux.sh | 18 +++++++++++++++---
> 2 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 975dd22a2dbd..649f0903e7ef 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -1643,4 +1643,7 @@ config CC_HAS_SANE_FUNCTION_ALIGNMENT
> config ARCH_NEED_CMPXCHG_1_EMU
> bool
>
> +config ARCH_WANTS_PRE_LINK_VMLINUX
> + def_bool n
> +
> endmenu
> diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
> index 46ce5d04dbeb..07f70e105d82 100755
> --- a/scripts/link-vmlinux.sh
> +++ b/scripts/link-vmlinux.sh
> @@ -122,7 +122,7 @@ gen_btf()
> return 1
> fi
>
> - vmlinux_link ${1}
> + vmlinux_link ${1} ${arch_vmlinux_o}
>
> info "BTF" ${2}
> LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}
> @@ -178,7 +178,7 @@ kallsyms_step()
> kallsymso=${kallsyms_vmlinux}.o
> kallsyms_S=${kallsyms_vmlinux}.S
>
> - vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}"
> ${btf_vmlinux_bin_o}
> + vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}"
> ${btf_vmlinux_bin_o} ${arch_vmlinux_o}
> mksysmap ${kallsyms_vmlinux} ${kallsyms_vmlinux}.syms
> kallsyms ${kallsyms_vmlinux}.syms ${kallsyms_S}
>
> @@ -203,6 +203,7 @@ sorttable()
>
> cleanup()
> {
> + rm -f .arch.vmlinux.*
> rm -f .btf.*
> rm -f System.map
> rm -f vmlinux
> @@ -223,6 +224,17 @@ fi
>
> ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
> init/version-timestamp.o
>
> +arch_vmlinux_o=""
> +if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then
> + arch_vmlinux_o=.arch.vmlinux.o
> + info "ARCH" ${arch_vmlinux_o}
> + if ! ${srctree}/arch/${SRCARCH}/tools/vmlinux_o.sh ${arch_vmlinux_o}
> ; then
> + echo >&2 "Failed to generate ${arch_vmlinux_o}"
> + echo >&2 "Try to disable CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX"
> + exit 1
> + fi
> +fi
This is wrong because scripts/link-vmlinux.sh is not triggered
even when source files under arch/powerpc/tools/ are changed.
Presumably, scripts/Makefile.vmlinux will be the right place.
> +
> btf_vmlinux_bin_o=""
> if is_enabled CONFIG_DEBUG_INFO_BTF; then
> btf_vmlinux_bin_o=.btf.vmlinux.bin.o
> @@ -273,7 +285,7 @@ if is_enabled CONFIG_KALLSYMS; then
> fi
> fi
>
> -vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
> +vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o} ${arch_vmlinux_o}
>
> # fill in BTF IDs
> if is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then
> --
> 2.45.2
>
--
Best Regards
Masahiro Yamada
