[PATCH 2/3] powerpc: allow compilation on cross-endian toolchain
Nicholas Piggin
npiggin at gmail.com
Thu Nov 24 20:04:23 AEDT 2016
On Thu, 24 Nov 2016 00:02:08 +1100
Nicholas Piggin <npiggin at gmail.com> wrote:
> GCC can compile with either endian, but the ABI version always
> defaults to the default endian. Alan Modra says:
Okay I was missing mcall-aixdesc, thanks again to Alan for pointing
it out.
This updated patch seems to do better, and it builds BE kernel with
powerpc64le-gcc, and LE with powerpc64-gcc here (I did see a link
failure but then couldn't reproduce it so it might have been a stale
file hanging around somewhere).
From: Nicholas Piggin <npiggin at gmail.com>
Date: Wed, 23 Nov 2016 17:27:39 +1100
Subject: [PATCH] powerpc: allow compilation on cross-endian toolchain
GCC can compile with either endian, but the ABI version always
defaults to the default endian. Alan Modra says:
you need both -mbig and -mabi=elfv1 to make a powerpc64le gcc
generate powerpc64 code
The opposite is true for powerpc64 when generating -mlittle it
requires -mabi=elfv2 to generate v2 ABI. This change adds ABI
annotations together with endianness. The kernel with ELFv2 ABI
also uses -mcall-aixdesc, but boot/ does not.
Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
arch/powerpc/Makefile | 7 +++++++
arch/powerpc/boot/Makefile | 1 +
2 files changed, 8 insertions(+)
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 617dece..8828807 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -73,13 +73,18 @@ MULTIPLEWORD := -mmultiple
endif
cflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mbig-endian)
+cflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mabi=elfv1)
+cflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mcall-aixdesc)
cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mlittle-endian
+cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mabi=elfv2
ifneq ($(cc-name),clang)
cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mno-strict-align
endif
aflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mbig-endian)
+aflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mabi=elfv1)
aflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mlittle-endian
+aflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mabi=elfv2
ifeq ($(HAS_BIARCH),y)
override AS += -a$(BITS)
@@ -113,7 +118,9 @@ ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y)
CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mabi=elfv2,$(call cc-option,-mcall-aixdesc))
AFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mabi=elfv2)
else
+CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mabi=elfv1)
CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mcall-aixdesc)
+AFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mabi=elfv1)
endif
CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mcmodel=medium,$(call cc-option,-mminimal-toc))
CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mno-pointers-to-nested-functions)
diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index eae2dc8..1d50d41 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -33,6 +33,7 @@ BOOTCFLAGS += -m64
endif
ifdef CONFIG_CPU_BIG_ENDIAN
BOOTCFLAGS += -mbig-endian
+BOOTCFLAGS += $(call cc-option,-mabi=elfv1)
else
BOOTCFLAGS += -mlittle-endian
BOOTCFLAGS += $(call cc-option,-mabi=elfv2)
--
2.10.2
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