Re: [PATCH v5 11/17] kbuild: Add generic hook for architectures to use before the final vmlinux link
From: Masahiro Yamada <masahiroy@kernel.org>
Date: 2024-10-09 15:23:59
Also in:
bpf, linux-kbuild, linux-trace-kernel, lkml
On Mon, Sep 16, 2024 at 5:58 AM Hari Bathini [off-list ref] wrote:
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From: Naveen N Rao <naveen@kernel.org> 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 Makefile.vmlinux that architectures can use for this purpose. Architectures need to select CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX and must provide arch/<arch>/tools/Makefile with .arch.vmlinux.o target, which will be invoked prior to the final vmlinux link step. Signed-off-by: Naveen N Rao <naveen@kernel.org> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com> --- Changes in v5: * Intermediate files named .vmlinux.arch.* instead of .arch.vmlinux.* arch/Kconfig | 6 ++++++ scripts/Makefile.vmlinux | 7 +++++++ scripts/link-vmlinux.sh | 7 ++++++- 3 files changed, 19 insertions(+), 1 deletion(-)diff --git a/arch/Kconfig b/arch/Kconfig index 975dd22a2dbd..ef868ff8156a 100644 --- a/arch/Kconfig +++ b/arch/Kconfig@@ -1643,4 +1643,10 @@ config CC_HAS_SANE_FUNCTION_ALIGNMENT config ARCH_NEED_CMPXCHG_1_EMU bool +config ARCH_WANTS_PRE_LINK_VMLINUX + def_bool n
Redundant default. This line should be "bool".
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+ help + An architecture can select this if it provides arch/<arch>/tools/Makefile + with .arch.vmlinux.o target to be linked into vmlinux. + endmenudiff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux index 49946cb96844..edf6fae8d960 100644 --- a/scripts/Makefile.vmlinux +++ b/scripts/Makefile.vmlinux@@ -22,6 +22,13 @@ targets += .vmlinux.export.o vmlinux: .vmlinux.export.o endif +ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX +vmlinux: arch/$(SRCARCH)/tools/.vmlinux.arch.o
If you move this to arch/*/tools/, there is no reason to make it a hidden file. vmlinux: arch/$(SRCARCH)/tools/vmlinux.arch.o
+arch/$(SRCARCH)/tools/.vmlinux.arch.o: vmlinux.o
FORCE is missing. arch/$(SRCARCH)/tools/vmlinux.arch.o: vmlinux.o FORCE
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+ $(Q)$(MAKE) $(build)=arch/$(SRCARCH)/tools $@ +endif + ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink) # Final link of vmlinux with optional arch pass after final linkdiff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index f7b2503cdba9..b3a940c0e6c2 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh@@ -100,7 +100,7 @@ vmlinux_link() ${ld} ${ldflags} -o ${output} \ ${wl}--whole-archive ${objs} ${wl}--no-whole-archive \ ${wl}--start-group ${libs} ${wl}--end-group \ - ${kallsymso} ${btf_vmlinux_bin_o} ${ldlibs} + ${kallsymso} ${btf_vmlinux_bin_o} ${arch_vmlinux_o} ${ldlibs} } # generate .BTF typeinfo from DWARF debuginfo@@ -214,6 +214,11 @@ 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/${SRCARCH}/tools/.vmlinux.arch.o
arch_vmlinux_o=arch/${SRCARCH}/tools/vmlinux.arch.o
+fi + btf_vmlinux_bin_o= kallsymso= strip_debug= -- 2.46.0
-- Best Regards Masahiro Yamada