powerpc/vdso: Rework VDSO32 makefile to add a prefix to object files

In order to merge vdso32 and vdso64 build in following patch, rework
Makefile is order to add -32 suffix to VDSO32 object files.

Also change sigtramp.S to sigtramp32.S as VDSO64 sigtramp.S is too
different to be squashed into VDSO32 sigtramp.S at the first place.

gen_vdso_offsets.sh also becomes gen_vdso32_offsets.sh

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0c421b704a57b228e75a891512568339c53667ad.1642782130.git.christophe.leroy@csgroup.eu

arch/powerpc/kernel/vdso32/Makefile

@@ -5,15 +5,16 @@
 ARCH_REL_TYPE_ABS := R_PPC_JUMP_SLOT|R_PPC_GLOB_DAT|R_PPC_ADDR32|R_PPC_ADDR24|R_PPC_ADDR16|R_PPC_ADDR16_LO|R_PPC_ADDR16_HI|R_PPC_ADDR16_HA|R_PPC_ADDR14|R_PPC_ADDR14_BRTAKEN|R_PPC_ADDR14_BRNTAKEN|R_PPC_REL24
 include $(srctree)/lib/vdso/Makefile
 
-obj-vdso32 = sigtramp.o gettimeofday.o datapage.o cacheflush.o note.o getcpu.o
+obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o note-32.o getcpu-32.o
 
 ifneq ($(c-gettimeofday-y),)
-  CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
-  CFLAGS_vgettimeofday.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
-  CFLAGS_vgettimeofday.o += $(call cc-option, -fno-stack-protector)
-  CFLAGS_vgettimeofday.o += -DDISABLE_BRANCH_PROFILING
-  CFLAGS_vgettimeofday.o += -ffreestanding -fasynchronous-unwind-tables
-  CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE)
+  CFLAGS_vgettimeofday-32.o += -include $(c-gettimeofday-y)
+  CFLAGS_vgettimeofday-32.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
+  CFLAGS_vgettimeofday-32.o += $(call cc-option, -fno-stack-protector)
+  CFLAGS_vgettimeofday-32.o += -DDISABLE_BRANCH_PROFILING
+  CFLAGS_vgettimeofday-32.o += -ffreestanding -fasynchronous-unwind-tables
+  CFLAGS_REMOVE_vgettimeofday-32.o = $(CC_FLAGS_FTRACE)
+  CFLAGS_REMOVE_vgettimeofday-32.o += -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc
 endif
 
 # Build rules
@@ -24,13 +25,7 @@ else
     VDSOCC := $(CC)
 endif
 
-CC32FLAGS :=
-ifdef CONFIG_PPC64
-CC32FLAGS += -m32
-KBUILD_CFLAGS := $(filter-out -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc,$(KBUILD_CFLAGS))
-endif
-
-targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday.o
+targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o
 obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
 
 GCOV_PROFILE := n
@@ -38,36 +33,36 @@ KCOV_INSTRUMENT := n
 UBSAN_SANITIZE := n
 KASAN_SANITIZE := n
 
-ccflags-y := -shared -fno-common -fno-builtin -nostdlib \
-	-Wl,-soname=linux-vdso32.so.1 -Wl,--hash-style=both
-asflags-y := -D__VDSO32__ -s
+ccflags-y := -shared -fno-common -fno-builtin -nostdlib -Wl,--hash-style=both
+
+CC32FLAGS := -Wl,-soname=linux-vdso32.so.1 -m32
+AS32FLAGS := -D__VDSO32__ -s
 
-obj-y += vdso32_wrapper.o
 targets += vdso32.lds
 CPPFLAGS_vdso32.lds += -P -C -Upowerpc
 
 # link rule for the .so file, .lds has to be first
-$(obj)/vdso32.so.dbg: $(src)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday.o FORCE
+$(obj)/vdso32.so.dbg: $(src)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o FORCE
 	$(call if_changed,vdso32ld_and_check)
 
 # assembly rules for the .S files
-$(obj-vdso32): %.o: %.S FORCE
+$(obj-vdso32): %-32.o: %.S FORCE
 	$(call if_changed_dep,vdso32as)
-$(obj)/vgettimeofday.o: %.o: %.c FORCE
+$(obj)/vgettimeofday-32.o: %-32.o: %.c FORCE
 	$(call if_changed_dep,vdso32cc)
 
 # Generate VDSO offsets using helper script
-gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
-quiet_cmd_vdsosym = VDSOSYM $@
-      cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
+gen-vdso32sym := $(srctree)/$(src)/gen_vdso32_offsets.sh
+quiet_cmd_vdso32sym = VDSO32SYM $@
+      cmd_vdso32sym = $(NM) $< | $(gen-vdso32sym) | LC_ALL=C sort > $@
 
 include/generated/vdso32-offsets.h: $(obj)/vdso32.so.dbg FORCE
-	$(call if_changed,vdsosym)
+	$(call if_changed,vdso32sym)
 
 # actual build commands
 quiet_cmd_vdso32ld_and_check = VDSO32L $@
       cmd_vdso32ld_and_check = $(VDSOCC) $(c_flags) $(CC32FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^) ; $(cmd_vdso_check)
 quiet_cmd_vdso32as = VDSO32A $@
-      cmd_vdso32as = $(VDSOCC) $(a_flags) $(CC32FLAGS) -c -o $@ $<
+      cmd_vdso32as = $(VDSOCC) $(a_flags) $(CC32FLAGS) $(AS32FLAGS) -c -o $@ $<
 quiet_cmd_vdso32cc = VDSO32C $@
       cmd_vdso32cc = $(VDSOCC) $(c_flags) $(CC32FLAGS) -c -o $@ $<