| Message ID | 87b71debd931011f8b9204c700b3084a6c3cdab8.1720942106.git.naveen@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | powerpc: Core ftrace rework, support for ftrace direct and bpf trampolines | expand |
On Sun Jul 14, 2024 at 6:27 PM AEST, Naveen N Rao 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 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. Maybe POSTLINK should move to more like this with explicit config option too rather than just picking up Makefile.postlink... > > Signed-off-by: Naveen N Rao <naveen@kernel.org> > --- > arch/Kconfig | 6 ++++++ > scripts/Makefile.vmlinux | 8 ++++++++ > scripts/link-vmlinux.sh | 11 ++++++++--- > 3 files changed, 22 insertions(+), 3 deletions(-) > > 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 > + help > + An architecture can select this if it provides arch/<arch>/tools/Makefile > + with .arch.vmlinux.o target to be linked into vmlinux. Someone bikeshedded me before for putting comments for putting comment for non-user-selectable option in 'help'. Even though heaps of options are like that here, apparently they preferred # comment above the option for developer comments. I personally thought this looks nicer but do Kconfig maintainers prefer #? > + > endmenu > diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux > index 49946cb96844..6410e0be7f52 100644 > --- a/scripts/Makefile.vmlinux > +++ b/scripts/Makefile.vmlinux > @@ -22,6 +22,14 @@ targets += .vmlinux.export.o > vmlinux: .vmlinux.export.o > endif > > +ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX > +targets += .arch.vmlinux.o > +.arch.vmlinux.o: vmlinux.o FORCE > + $(Q)$(MAKE) $(build)=arch/$(SRCARCH)/tools .arch.vmlinux.o > + > +vmlinux: .arch.vmlinux.o > +endif Does .vmlinux.arch.o follow convention better? I guess the btf does not. So, nevermind. Could this just be done entirely in link-vmlinux.sh like kallsyms and btf? > + > ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink) > > # Final link of vmlinux with optional arch pass after final link > diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh > index 518c70b8db50..aafaed1412ea 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} ${1} BTF generation needs the prelink .o? > @@ -178,7 +178,7 @@ kallsyms_step() > kallsymso=${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} > > @@ -223,6 +223,11 @@ 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.vmlinux.o > +fi > + > btf_vmlinux_bin_o="" > if is_enabled CONFIG_DEBUG_INFO_BTF; then > btf_vmlinux_bin_o=.btf.vmlinux.bin.o > @@ -273,7 +278,7 @@ 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 I guess it looks okay, similar to btf although I'm not a kbuild expert. Thanks, Nick
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 + help + An architecture can select this if it provides arch/<arch>/tools/Makefile + with .arch.vmlinux.o target to be linked into vmlinux. + endmenu diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux index 49946cb96844..6410e0be7f52 100644 --- a/scripts/Makefile.vmlinux +++ b/scripts/Makefile.vmlinux @@ -22,6 +22,14 @@ targets += .vmlinux.export.o vmlinux: .vmlinux.export.o endif +ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX +targets += .arch.vmlinux.o +.arch.vmlinux.o: vmlinux.o FORCE + $(Q)$(MAKE) $(build)=arch/$(SRCARCH)/tools .arch.vmlinux.o + +vmlinux: .arch.vmlinux.o +endif + ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink) # Final link of vmlinux with optional arch pass after final link diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 518c70b8db50..aafaed1412ea 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} @@ -223,6 +223,11 @@ 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.vmlinux.o +fi + btf_vmlinux_bin_o="" if is_enabled CONFIG_DEBUG_INFO_BTF; then btf_vmlinux_bin_o=.btf.vmlinux.bin.o @@ -273,7 +278,7 @@ 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
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> --- arch/Kconfig | 6 ++++++ scripts/Makefile.vmlinux | 8 ++++++++ scripts/link-vmlinux.sh | 11 ++++++++--- 3 files changed, 22 insertions(+), 3 deletions(-)