On Tue, Nov 21, 2023 at 10:51:34AM +1000, Nicholas Piggin wrote:

On Tue Nov 21, 2023 at 9:23 AM AEST, Masahiro Yamada wrote:

quoted

crtsavres.o is linked to modules. However, as explained in commit
d0e628cd817f ("kbuild: doc: clarify the difference between extra-y
and always-y"), 'make modules' does not build extra-y.

For example, the following command fails:

  $ make ARCH=powerpc LLVM=1 KBUILD_MODPOST_WARN=1 mrproper ps3_defconfig modules
    [snip]
    LD [M]  arch/powerpc/platforms/cell/spufs/spufs.ko
  ld.lld: error: cannot open arch/powerpc/lib/crtsavres.o: No such file or directory
  make[3]: *** [scripts/Makefile.modfinal:56: arch/powerpc/platforms/cell/spufs/spufs.ko] Error 1
  make[2]: *** [Makefile:1844: modules] Error 2
  make[1]: *** [/home/masahiro/workspace/linux-kbuild/Makefile:350: __build_one_by_one] Error 2
  make: *** [Makefile:234: __sub-make] Error 2

Thanks. Is this the correct Fixes tag?

Fixes: d0e628cd817f ("powerpc/64: Do not link crtsavres.o in vmlinux")

Hmm, looks like LLD might just do this now automatically for us
too without --save-restore-funcs (https://reviews.llvm.org/D79977).
But we probably still need it for older versions, so we still need
your patch.

Hi,

I'm still seeing the error of crtsavres.o missing when building external modules
after "make LLVM=1 modules_prepare". Should it be built also in archprepare?

Thanks,
Jan

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 051247027..a62334194 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile

@@ -57,8 +57,11 @@ ifeq ($(CONFIG_PPC64)$(CONFIG_LD_IS_BFD),yy)
  # Have the linker provide sfpr if possible.
  # There is a corresponding test in arch/powerpc/lib/Makefile
  KBUILD_LDFLAGS_MODULE += --save-restore-funcs
+crtsavres_prepare:
  else
  KBUILD_LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o
+crtsavres_prepare:
+       $(MAKE) $(build)=arch/powerpc/lib arch/powerpc/lib/crtsavres.o
  endif

  ifdef CONFIG_CPU_LITTLE_ENDIAN

@@ -389,7 +392,7 @@ vdso_prepare: prepare0
                 $(build)=arch/powerpc/kernel/vdso include/generated/vdso64-offsets.h)
  endif

-archprepare: checkbin
+archprepare: checkbin crtsavres_prepare

  archheaders:
         $(Q)$(MAKE) $(build)=arch/powerpc/kernel/syscalls all