[PATCH 2/2] powerpc: add ALTIVEC support to lib/ when PPC_FPU not set

[Randy Dunlap]

When PPC_FPU is not set and ALTIVEC=y, arch/powerpc/lib/ldstfp.c is not
being built, but it is also needed when ALTIVEC=y for get_vr() and
put_vr().

../arch/powerpc/lib/sstep.c: In function 'do_vec_load':
../arch/powerpc/lib/sstep.c:637:3: error: implicit declaration of function 'put_vr' [-Werror=implicit-function-declaration]
  637 |   put_vr(rn, &u.v);
      |   ^~~~~~
../arch/powerpc/lib/sstep.c: In function 'do_vec_store':
../arch/powerpc/lib/sstep.c:660:3: error: implicit declaration of function 'get_vr'; did you mean 'get_oc'? [-Werror=implicit-function-declaration]
  660 |   get_vr(rn, &u.v);
      |   ^~~~~~


Add ldstfp.o to the Makefile for CONFIG_ALTIVEC and add
externs for get_vr() and put_vr() in lib/sstep.c to fix the
build errors.

This was seen in a kernel config from kernel test robot <lkp@xxxxxxxxx>
that reported a different build issue (for pmac32-cpufreq.c).

Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx>
Cc: lkp@xxxxxxxxx
---
 arch/powerpc/lib/Makefile |    1 +
 arch/powerpc/lib/sstep.c  |    5 +++++
 2 files changed, 6 insertions(+)

--- linux-next-20210416.orig/arch/powerpc/lib/Makefile
+++ linux-next-20210416/arch/powerpc/lib/Makefile
@@ -54,6 +54,7 @@ obj-y			+= checksum_$(BITS).o checksum_w
 
 obj-y			+= sstep.o
 obj-$(CONFIG_PPC_FPU)	+= ldstfp.o
+obj-$(CONFIG_ALTIVEC)	+= ldstfp.o
 obj64-y			+= quad.o
 
 obj-$(CONFIG_PPC_LIB_RHEAP) += rheap.o
--- linux-next-20210416.orig/arch/powerpc/lib/sstep.c
+++ linux-next-20210416/arch/powerpc/lib/sstep.c
@@ -50,6 +50,11 @@ extern void conv_sp_to_dp(const float *s
 extern void conv_dp_to_sp(const double *dp, float *sp);
 #endif
 
+#ifdef CONFIG_ALTIVEC
+extern void get_vr(int rn, __vector128 *p);
+extern void put_vr(int rn, __vector128 *p);
+#endif /* CONFIG_ALTIVEC */
+
 #ifdef __powerpc64__
 /*
  * Functions in quad.S