[PATCH 8/9] UML - Fix biarch gcc build on x86_64

From: Jeff Dike
Date: Thu Jun 29 2006 - 17:35:52 EST


I run an x86_64 kernel with i386 userspace (Ubuntu Dapper) and decided
to try out UML today. I found that UML wasn't quite aware of biarch
compilers (which Ubuntu i386 ships). A fix similar to what was done for
x86_64 should probably be committed (see
http://marc.theaimsgroup.com/?l=linux-kernel&m=113425940204010&w=2).
Without the FLAGS changes, the build will fail at a number of places and
without the LINK change, the final link will fail.

Signed-off-by: Nishanth Aravamudan <nacc@xxxxxxxxxx>

Index: linux-2.6.17/arch/um/Makefile-x86_64
===================================================================
--- linux-2.6.17.orig/arch/um/Makefile-x86_64 2006-06-20 17:24:29.000000000 -0400
+++ linux-2.6.17/arch/um/Makefile-x86_64 2006-06-29 10:36:18.000000000 -0400
@@ -6,9 +6,11 @@ START := 0x60000000

#We #undef __x86_64__ for kernelspace, not for userspace where
#it's needed for headers to work!
-CFLAGS += -U__$(SUBARCH)__ -fno-builtin
-USER_CFLAGS += -fno-builtin
+CFLAGS += -U__$(SUBARCH)__ -fno-builtin -m64
+USER_CFLAGS += -fno-builtin -m64
CHECKFLAGS += -m64
+AFLAGS += -m64
+LDFLAGS += -m elf_x86_64

ELF_ARCH := i386:x86-64
ELF_FORMAT := elf64-x86-64
@@ -16,3 +18,4 @@ ELF_FORMAT := elf64-x86-64
# Not on all 64-bit distros /lib is a symlink to /lib64. PLD is an example.

LINK-$(CONFIG_LD_SCRIPT_DYN) += -Wl,-rpath,/lib64
+LINK-y += -m64
Index: linux-2.6.17/arch/um/kernel/vmlinux.lds.S
===================================================================
--- linux-2.6.17.orig/arch/um/kernel/vmlinux.lds.S 2005-08-28 19:41:01.000000000 -0400
+++ linux-2.6.17/arch/um/kernel/vmlinux.lds.S 2006-06-29 10:36:18.000000000 -0400
@@ -1,4 +1,6 @@
#include <linux/config.h>
+/* in case the preprocessor is a 32bit one */
+#undef i386
#ifdef CONFIG_LD_SCRIPT_STATIC
#include "uml.lds.S"
#else

-
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