kernel: make copying of crtsavres.o conditional

As of the 4.13 kernel, there are configuration + linker combinations
that do not need (or build) crtsavres.o for ppc64 targets. The commit
of interest is:

    commit efe0160cfd40a99c052a00e174787c1f4158a9cd
    Author: Nicholas Piggin <npiggin@gmail.com>
    Date:   Fri May 12 01:56:52 2017 +1000

        powerpc/64: Linker on-demand sfpr functions for modules

        For final link, the powerpc64 linker generates fpr save/restore
        functions on-demand, placing them in the .sfpr section. Starting with
        binutils 2.25, these can be provided for non-final links with
        --save-restore-funcs. Use that where possible for module links.

        This saves about 200 bytes per module (~60kB) on powernv defconfig
        build.

        Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
        Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

As such, our arch test for crtsavres.o is not enough, we add a secondary
existence check before trying the copy.

[YOCTO #12576]

(From OE-Core rev: af58819253a2d4526dc8871a17e1492bd1d92951)

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/meta/classes/kernel.bbclass b/meta/classes/kernel.bbclass
index 321c0a47bb..9bc0e41251 100644
--- a/meta/classes/kernel.bbclass
+++ b/meta/classes/kernel.bbclass
@@ -466,8 +466,10 @@ do_shared_workdir () {
         # arch/powerpc/lib/crtsavres.o which is present in
         # KBUILD_LDFLAGS_MODULE, making it required to build external modules.
         if [ ${ARCH} = "powerpc" ]; then
-                mkdir -p $kerneldir/arch/powerpc/lib/
-                cp arch/powerpc/lib/crtsavres.o $kerneldir/arch/powerpc/lib/crtsavres.o
+                if [ -e arch/powerpc/lib/crtsavres.o ]; then
+                        mkdir -p $kerneldir/arch/powerpc/lib/
+                        cp arch/powerpc/lib/crtsavres.o $kerneldir/arch/powerpc/lib/crtsavres.o
+                fi
         fi
 
         if [ -d include/generated ]; then