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authorDavid Woodhouse <dwmw2@infradead.org>2012-12-20 21:51:55 +0000
committerH. Peter Anvin <hpa@linux.intel.com>2012-12-20 14:37:18 -0800
commitffee0de411fd4f74f3b788892eeb075abbf26c52 (patch)
tree1b1bd2751822cdabca7d44de635369c9091ae624
parent29594404d7fe73cd80eaa4ee8c43dcc53970c60e (diff)
downloadlwn-ffee0de411fd4f74f3b788892eeb075abbf26c52.tar.gz
lwn-ffee0de411fd4f74f3b788892eeb075abbf26c52.zip
x86: Default to ARCH=x86 to avoid overriding CONFIG_64BIT
It is easy to waste a bunch of time when one takes a 32-bit .config from a test machine and try to build it on a faster 64-bit system, and its existing setting of CONFIG_64BIT=n gets *changed* to match the build host. Similarly, if one has an existing build tree it is easy to trash an entire build tree that way. This is because the default setting for $ARCH when discovered from 'uname' is one of the legacy pre-x86-merge values (i386 or x86_64), which effectively force the setting of CONFIG_64BIT to match. We should default to ARCH=x86 instead, finally completing the merge that we started so long ago. This patch preserves the behaviour of the legacy ARCH settings for commands such as: make ARCH=x86_64 randconfig make ARCH=i386 randconfig ... since making the value of CONFIG_64BIT actually random in that situation is not desirable. In time, perhaps we can retire this legacy use of the old ARCH= values. We already have a way to override values for *any* config option, using $KCONFIG_ALLCONFIG, so it could be argued that we don't necessarily need to keep ARCH={i386,x86_64} around as a special case just for overriding CONFIG_64BIT. We'd probably at least want to add a way to override config options from the command line ('make CONFIG_FOO=y oldconfig') before we talk about doing that though. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Link: http://lkml.kernel.org/r/1356040315.3198.51.camel@shinybook.infradead.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
-rw-r--r--Makefile3
-rw-r--r--arch/x86/Kconfig2
-rw-r--r--arch/x86/Makefile4
-rw-r--r--arch/x86/configs/i386_defconfig1
4 files changed, 8 insertions, 2 deletions
diff --git a/Makefile b/Makefile
index 540f7b240c77..9a07340b28a1 100644
--- a/Makefile
+++ b/Makefile
@@ -165,7 +165,8 @@ export srctree objtree VPATH
# then ARCH is assigned, getting whatever value it gets normally, and
# SUBARCH is subsequently ignored.
-SUBARCH := $(shell uname -m | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
+SUBARCH := $(shell uname -m | sed -e s/i.86/x86/ -e s/x86_64/x86/ \
+ -e s/sun4u/sparc64/ \
-e s/arm.*/arm/ -e s/sa110/arm/ \
-e s/s390x/s390/ -e s/parisc64/parisc/ \
-e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 46c3bff3ced2..9084c7bdc650 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1,7 +1,7 @@
# Select 32 or 64 bit
config 64BIT
bool "64-bit kernel" if ARCH = "x86"
- default ARCH = "x86_64"
+ default ARCH != "i386"
---help---
Say yes to build a 64-bit kernel - formerly known as x86_64
Say no to build a 32-bit kernel - formerly known as i386
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 05afcca66de6..fa981ca1bfe5 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -2,7 +2,11 @@
# select defconfig based on actual architecture
ifeq ($(ARCH),x86)
+ ifeq ($(shell uname -m),x86_64)
+ KBUILD_DEFCONFIG := x86_64_defconfig
+ else
KBUILD_DEFCONFIG := i386_defconfig
+ endif
else
KBUILD_DEFCONFIG := $(ARCH)_defconfig
endif
diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig
index 5598547281a7..94447086e551 100644
--- a/arch/x86/configs/i386_defconfig
+++ b/arch/x86/configs/i386_defconfig
@@ -1,3 +1,4 @@
+# CONFIG_64BIT is not set
CONFIG_EXPERIMENTAL=y
# CONFIG_LOCALVERSION_AUTO is not set
CONFIG_SYSVIPC=y