From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Alan Modra <amodra@gmail.com>
Subject: Re: [PATCH 2/3] powerpc: allow compilation on cross-endian toolchain
Date: Sat, 26 Nov 2016 14:00:04 +1100 [thread overview]
Message-ID: <20161126140004.607d8f86@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <20161124200423.45c5ec87@roar.ozlabs.ibm.com>
On Thu, 24 Nov 2016 20:04:23 +1100
Nicholas Piggin <npiggin@gmail.com> wrote:
> On Thu, 24 Nov 2016 00:02:08 +1100
> Nicholas Piggin <npiggin@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.
Final patch here which just slightly changes how the boot code flags
are set (don't introduce unnecessary setting of elfv1 on 32-bit builds).
--
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@gmail.com>
---
arch/powerpc/Makefile | 7 +++++++
arch/powerpc/boot/Makefile | 4 +++-
2 files changed, 10 insertions(+), 1 deletion(-)
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..7c46cf3 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -28,14 +28,16 @@ BOOTCFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-isystem $(shell $(CROSS32CC) -print-file-name=include) \
-D$(compress-y)
+# PPC64_BOOT_WRAPPER is little-endian specific.
ifdef CONFIG_PPC64_BOOT_WRAPPER
BOOTCFLAGS += -m64
+BOOTCFLAGS += $(call cc-option,-mabi=elfv2)
endif
+
ifdef CONFIG_CPU_BIG_ENDIAN
BOOTCFLAGS += -mbig-endian
else
BOOTCFLAGS += -mlittle-endian
-BOOTCFLAGS += $(call cc-option,-mabi=elfv2)
endif
BOOTAFLAGS := -D__ASSEMBLY__ $(BOOTCFLAGS) -traditional -nostdinc
--
2.10.2
next prev parent reply other threads:[~2016-11-26 3:00 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-23 13:02 [PATCH 0/3] minor build fixes Nicholas Piggin
2016-11-23 13:02 ` [PATCH 1/3] powerpc/64e: convert cmpi to cmpwi in head_64.S Nicholas Piggin
2016-11-29 12:58 ` [1/3] " Michael Ellerman
2016-11-23 13:02 ` [PATCH 2/3] powerpc: allow compilation on cross-endian toolchain Nicholas Piggin
2016-11-24 9:04 ` Nicholas Piggin
2016-11-26 3:00 ` Nicholas Piggin [this message]
2016-11-26 7:30 ` Michael Ellerman
2016-11-27 2:46 ` Nicholas Piggin
2017-02-02 8:08 ` Naveen N. Rao
2017-03-08 7:25 ` [2/3] " Michael Ellerman
2016-11-23 13:02 ` [PATCH 3/3] powerpc/64e: don't branch to dot symbols Nicholas Piggin
2016-11-29 12:58 ` [3/3] " Michael Ellerman
2016-11-23 23:03 ` [PATCH 0/3] minor build fixes Alan Modra
2016-11-24 1:04 ` Nicholas Piggin
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