linux-kernel - [tip:x86/urgent] x86, build: Globally set -fno-pic

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Date:	Fri, 10 Aug 2012 17:01:14 -0700
From:	tip-bot for Andrew Boie <andrew.p.boie@...el.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	andrew.p.boie@...el.com, tglx@...utronix.de, hpa@...ux.intel.com
Subject: [tip:x86/urgent] x86, build: Globally set -fno-pic

Commit-ID:  484d90eec884d814b005c9736bcf3fd018acba65
Gitweb:     http://git.kernel.org/tip/484d90eec884d814b005c9736bcf3fd018acba65
Author:     Andrew Boie <andrew.p.boie@...el.com>
AuthorDate: Fri, 10 Aug 2012 11:49:06 -0700
Committer:  H. Peter Anvin <hpa@...ux.intel.com>
CommitDate: Fri, 10 Aug 2012 16:12:30 -0700

x86, build: Globally set -fno-pic

GCC built with nonstandard options can enable -fpic by default.
We never want this for 32-bit kernels and it will break the build.

[ hpa: Notably the Android toolchain apparently does this. ]

Change-Id: Iaab7d66e598b1c65ac4a4f0229eca2cd3d0d2898
Signed-off-by: Andrew Boie <andrew.p.boie@...el.com>
Link: http://lkml.kernel.org/r/1344624546-29691-1-git-send-email-andrew.p.boie@intel.com
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
---
 arch/x86/Makefile             |    4 ++++
 arch/x86/boot/Makefile        |    2 +-
 arch/x86/realmode/rm/Makefile |    2 +-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index b0c5276..682e9c2 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -27,6 +27,10 @@ ifeq ($(CONFIG_X86_32),y)
 
         KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
 
+        # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
+        # with nonstandard options
+        KBUILD_CFLAGS += -fno-pic
+
         # prevent gcc from keeping the stack 16 byte aligned
         KBUILD_CFLAGS += $(call cc-option,-mpreferred-stack-boundary=2)
 
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index 5a747dd..f7535be 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -57,7 +57,7 @@ KBUILD_CFLAGS	:= $(LINUXINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \
 		   -Wall -Wstrict-prototypes \
 		   -march=i386 -mregparm=3 \
 		   -include $(srctree)/$(src)/code16gcc.h \
-		   -fno-strict-aliasing -fomit-frame-pointer \
+		   -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
 		   $(call cc-option, -ffreestanding) \
 		   $(call cc-option, -fno-toplevel-reorder,\
 			$(call cc-option, -fno-unit-at-a-time)) \
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index b2d534c..8869287 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -72,7 +72,7 @@ KBUILD_CFLAGS	:= $(LINUXINCLUDE) -m32 -g -Os -D_SETUP -D__KERNEL__ -D_WAKEUP \
 		   -Wall -Wstrict-prototypes \
 		   -march=i386 -mregparm=3 \
 		   -include $(srctree)/$(src)/../../boot/code16gcc.h \
-		   -fno-strict-aliasing -fomit-frame-pointer \
+		   -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
 		   $(call cc-option, -ffreestanding) \
 		   $(call cc-option, -fno-toplevel-reorder,\
 			$(call cc-option, -fno-unit-at-a-time)) \
--
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