[RFC PATCH v2 4/5] kbuild: Add generic hook for architectures to use before the final vmlinux link
Naveen N Rao
naveen at kernel.org
Wed Jun 12 20:52:01 AEST 2024
On Tue, Jun 11, 2024 at 11:05:56PM GMT, Naveen N Rao wrote:
> On Tue, Jun 11, 2024 at 06:51:51AM GMT, Masahiro Yamada wrote:
> > On Tue, Jun 11, 2024 at 2:20 AM Naveen N Rao <naveen at kernel.org> wrote:
> > >
> > > On Mon, Jun 10, 2024 at 06:14:51PM GMT, Masahiro Yamada wrote:
> > > > On Mon, Jun 10, 2024 at 5:39 PM Naveen N Rao <naveen at kernel.org> wrote:
> > > > >
> > > > > +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.
> > >
> > > Ah, yes. Something like this?
> > >
> > > diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
> > > index 49946cb96844..77d90b6ac53e 100644
> > > --- a/scripts/Makefile.vmlinux
> > > +++ b/scripts/Makefile.vmlinux
> > > @@ -22,6 +22,10 @@ targets += .vmlinux.export.o
> > > vmlinux: .vmlinux.export.o
> > > endif
> > >
> > > +ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX
> > > +vmlinux: $(srctree)/arch/$(SRCARCH)/tools/vmlinux_o.sh
> > > +endif
> > > +
> > > ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
> > >
> > > # Final link of vmlinux with optional arch pass after final link
> > >
> > >
> > > Thanks,
> > > Naveen
> > >
> >
> >
> >
> > No.
> >
> > Something like below.
> >
> > Then, you can do everything in Makefile, not a shell script.
> >
> >
> >
> > ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX
> > vmlinux: .arch.vmlinux.o
> >
> > .arch.vmlinux.o: FORCE
> > $(Q)$(MAKE) $(build)=arch/$(SRCARCH)/tools .arch.vmlinux.o
> >
> > endif
> >
> >
> >
> > I did not test it, though.
>
> Thanks for the pointer. I will try and build on that.
>
> Just to be completely sure, does the below incremetal diff on top of the
> existing patch capture your suggestion?
>
> ---
> diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
> index 49946cb96844..04e088d7a1ca 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.vmlinux.o
> +
> +.arch.vmlinux.o: FORCE
> + $(Q)$(MAKE) $(build)=arch/$(SRCARCH)/tools .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 07f70e105d82..f1b705b8cdca 100755
> --- a/scripts/link-vmlinux.sh
> +++ b/scripts/link-vmlinux.sh
> @@ -227,12 +227,6 @@ ${MAKE} -f "${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
>
> btf_vmlinux_bin_o=""
This is what I ended up with:
---
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/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 46ce5d04dbeb..eb5fb71f5207 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
---
Along with the below Makefile, things seem to be working properly in my
limited tests:
diff --git a/arch/powerpc/tools/Makefile b/arch/powerpc/tools/Makefile
new file mode 100644
index 000000000000..9e2ba9a85baa
--- /dev/null
+++ b/arch/powerpc/tools/Makefile
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+quiet_cmd_gen_ftrace_pfe_stubs = FTRACE $@
+ cmd_gen_ftrace_pfe_stubs = $< $(objtree)/vmlinux.o $@
+
+targets += .arch.vmlinux.o
+.arch.vmlinux.o: $(srctree)/arch/powerpc/tools/gen-ftrace-pfe-stubs.sh $(objtree)/vmlinux.o FORCE
+ $(call if_changed,gen_ftrace_pfe_stubs)
+
+clean-files += $(objtree)/.arch.vmlinux.S $(objtree)/.arch.vmlinux.o
- Naveen
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