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Commit d72b0801 authored by Ian Munsie's avatar Ian Munsie Committed by Benjamin Herrenschmidt
Browse files

powerpc: Add ability to build little endian kernels 



This patch allows the kbuild system to successfully compile a kernel
for the little endian PowerPC64 architecture. A subsequent patch
will add the CONFIG_CPU_LITTLE_ENDIAN kernel config option which
must be set to build such a kernel.

If cross compiling, CROSS_COMPILE must point to a suitable toolchain
(compiled for the powerpc64le-linux and powerpcle-linux targets).

Signed-off-by: default avatarIan Munsie <imunsie@au1.ibm.com>
Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 7df697c8

arch/powerpc/Makefile

+21 −3
Original line number Diff line number Diff line
@@ -65,11 +65,29 @@ endif 


UTS_MACHINE := $(OLDARCH)



ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y)

override CC	+= -mlittle-endian

override AS	+= -mlittle-endian

override LD	+= -EL

override CROSS32CC += -mlittle-endian

override CROSS32AS += -mlittle-endian

LDEMULATION	:= lppc

GNUTARGET	:= powerpcle

MULTIPLEWORD	:= -mno-multiple

else

override CC	+= -mbig-endian

override AS	+= -mbig-endian

override LD	+= -EB

LDEMULATION	:= ppc

GNUTARGET	:= powerpc

MULTIPLEWORD	:= -mmultiple

endif



ifeq ($(HAS_BIARCH),y)

override AS	+= -a$(CONFIG_WORD_SIZE)

override LD	+= -m elf$(CONFIG_WORD_SIZE)ppc

override LD	+= -m elf$(CONFIG_WORD_SIZE)$(LDEMULATION)

override CC	+= -m$(CONFIG_WORD_SIZE)

override AR	:= GNUTARGET=elf$(CONFIG_WORD_SIZE)-powerpc $(AR)

override AR	:= GNUTARGET=elf$(CONFIG_WORD_SIZE)-$(GNUTARGET) $(AR)

endif



LDFLAGS_vmlinux-y := -Bstatic
@@ -95,7 +113,7 @@ endif 
CFLAGS-$(CONFIG_PPC64)	:= -mtraceback=no -mcall-aixdesc

CFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mcmodel=medium,-mminimal-toc)

CFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mno-pointers-to-nested-functions)

CFLAGS-$(CONFIG_PPC32)	:= -ffixed-r2 -mmultiple

CFLAGS-$(CONFIG_PPC32)	:= -ffixed-r2 $(MULTIPLEWORD)



ifeq ($(CONFIG_PPC_BOOK3S_64),y)

CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=power7,-mtune=power4)

arch/powerpc/boot/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -22,7 +22,8 @@ all: $(obj)/zImage 
BOOTCFLAGS    := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \

		 -fno-strict-aliasing -Os -msoft-float -pipe \

		 -fomit-frame-pointer -fno-builtin -fPIC -nostdinc \

		 -isystem $(shell $(CROSS32CC) -print-file-name=include)

		 -isystem $(shell $(CROSS32CC) -print-file-name=include) \

		 -mbig-endian

BOOTAFLAGS	:= -D__ASSEMBLY__ $(BOOTCFLAGS) -traditional -nostdinc



ifdef CONFIG_DEBUG_INFO

arch/powerpc/kernel/vdso32/vdso32.lds.S

+4 −0
Original line number Diff line number Diff line
@@ -4,7 +4,11 @@ 
 */

#include <asm/vdso.h>



#ifdef __LITTLE_ENDIAN__

OUTPUT_FORMAT("elf32-powerpcle", "elf32-powerpcle", "elf32-powerpcle")

#else

OUTPUT_FORMAT("elf32-powerpc", "elf32-powerpc", "elf32-powerpc")

#endif

OUTPUT_ARCH(powerpc:common)

ENTRY(_start)

arch/powerpc/kernel/vdso64/vdso64.lds.S

+4 −0
Original line number Diff line number Diff line
@@ -4,7 +4,11 @@ 
 */

#include <asm/vdso.h>



#ifdef __LITTLE_ENDIAN__

OUTPUT_FORMAT("elf64-powerpcle", "elf64-powerpcle", "elf64-powerpcle")

#else

OUTPUT_FORMAT("elf64-powerpc", "elf64-powerpc", "elf64-powerpc")

#endif

OUTPUT_ARCH(powerpc:common64)

ENTRY(_start)