[Skiboot] [PATCH 04/10] Add CONFIG_P8 with PHB3 behind it

[Nicholas Piggin]

From: Stewart Smith <stewart at flamingspork.com>

We can use a base CPU of POWER9 if we don't have P8.
We can also hide PHB3 code behind this,
and shave 12kb off skiboot.lid.xz

[npiggin: add cpp define, fail gracefully on P8]
Signed-off-by: Stewart Smith <stewart at flamingspork.com>
---
 Makefile        |  2 ++
 Makefile.main   | 15 ++++++++++++++-
 core/cpu.c      | 11 +++++++++--
 hw/Makefile.inc |  8 ++++++--
 4 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index d236df9ec..625f212ea 100644
--- a/Makefile
+++ b/Makefile
@@ -59,6 +59,8 @@ ELF_ABI_v2 ?= $(LITTLE_ENDIAN)
 DEAD_CODE_ELIMINATION ?= 0
 # Try to build without FSP code
 CONFIG_FSP?=1
+# Try to build without POWER8 support
+CONFIG_P8?=1
 
 #
 # Where is the source directory, must be a full path (no ~)
diff --git a/Makefile.main b/Makefile.main
index d21f27be3..ef8ee6289 100644
--- a/Makefile.main
+++ b/Makefile.main
@@ -99,7 +99,11 @@ CPPFLAGS += -DDEBUG -DCCAN_LIST_DEBUG
 endif
 
 CFLAGS := -fno-strict-aliasing -pie -fpie -fno-pic -m64 -fno-asynchronous-unwind-tables
+ifeq ($(CONFIG_P8),1)
 CFLAGS += -mcpu=power8
+else
+CFLAGS += -mcpu=power9
+endif
 CFLAGS += -Wl,--oformat,elf64-powerpc -ggdb
 # r13,r14,r15 are preserved for OS to use as fixed registers.
 # These could be saved and restored in and out of skiboot, but it's more
@@ -159,6 +163,10 @@ else
 CFLAGS += -fno-stack-protector
 endif
 
+# Add preprocessor defines for CONFIG_ options here
+ifeq ($(CONFIG_P8),1)
+CFLAGS += -DCONFIG_P8=1
+endif
 
 CFLAGS += $(call try-cflag,$(CC),-Wjump-misses-init) \
 	  $(call try-cflag,$(CC),-Wsuggest-attribute=const) \
@@ -174,7 +182,12 @@ LDFLAGS := -m64 -static -nostdlib -pie
 LDFLAGS += -Wl,-pie
 LDFLAGS += -Wl,-Ttext-segment,$(LD_TEXT) -Wl,-N -Wl,--build-id=none
 LDFLAGS += -Wl,--no-multi-toc
-LDFLAGS += -mcpu=power8 -Wl,--oformat,elf64-powerpc
+ifeq ($(CONFIG_P8),1)
+LDFLAGS += -mcpu=power8
+else
+LDFLAGS += -mcpu=power9
+endif
+LDFLAGS += -Wl,--oformat,elf64-powerpc
 LDFLAGS_FINAL = -m elf64lppc --no-multi-toc -N --build-id=none --whole-archive
 LDFLAGS_FINAL += -static -nostdlib -pie -Ttext-segment=$(LD_TEXT) --oformat=elf64-powerpc
 LDFLAGS_FINAL += --orphan-handling=warn
diff --git a/core/cpu.c b/core/cpu.c
index 16660a14d..353a0372d 100644
--- a/core/cpu.c
+++ b/core/cpu.c
@@ -1029,9 +1029,16 @@ void init_boot_cpu(void)
 		cpu_thread_count = 1;
 	}
 
-	if (proc_gen == proc_gen_p8 && (PVR_VERS_MAJ(mfspr(SPR_PVR)) == 1)) {
-		prerror("CPU: POWER8 DD1 is not supported\n");
+	if (proc_gen == proc_gen_p8) {
+#ifdef CONFIG_P8
+		if (PVR_VERS_MAJ(mfspr(SPR_PVR)) == 1) {
+			prerror("CPU: POWER8 DD1 is not supported\n");
+			abort();
+		}
+#else
+		prerror("CPU: POWER8 detected but CONFIG_P8 not set\n");
 		abort();
+#endif
 	}
 
 	if (is_power9n(pvr) && (PVR_VERS_MAJ(pvr) == 1)) {
diff --git a/hw/Makefile.inc b/hw/Makefile.inc
index a7f450cf7..1f042c239 100644
--- a/hw/Makefile.inc
+++ b/hw/Makefile.inc
@@ -3,13 +3,17 @@ SUBDIRS += hw
 HW_OBJS  = xscom.o chiptod.o lpc.o lpc-uart.o psi.o
 HW_OBJS += homer.o slw.o occ.o fsi-master.o centaur.o imc.o
 HW_OBJS += nx.o nx-rng.o nx-crypto.o nx-compress.o nx-842.o nx-gzip.o
-HW_OBJS += phb3.o sfc-ctrl.o fake-rtc.o bt.o p8-i2c.o prd.o
-HW_OBJS += dts.o lpc-rtc.o npu.o npu-hw-procedures.o xive.o phb4.o
+HW_OBJS += sfc-ctrl.o fake-rtc.o bt.o p8-i2c.o prd.o
+HW_OBJS += dts.o lpc-rtc.o xive.o phb4.o
 HW_OBJS += fake-nvram.o lpc-mbox.o npu2.o npu2-hw-procedures.o
 HW_OBJS += npu2-common.o npu2-opencapi.o phys-map.o sbe-p9.o capp.o
 HW_OBJS += occ-sensor.o vas.o sbe-p8.o dio-p9.o lpc-port80h.o cache-p9.o
 HW_OBJS += npu-opal.o npu3.o npu3-nvlink.o npu3-hw-procedures.o
 HW_OBJS += ocmb.o
+HW_OBJS += npu.o npu-hw-procedures.o
+ifeq ($(CONFIG_P8),1)
+HW_OBJS += phb3.o
+endif
 HW=hw/built-in.a
 
 include $(SRC)/hw/fsp/Makefile.inc
-- 
2.23.0