x86: simplify "make ARCH=x86" and fix kconfig all.config

Simplify "make ARCH=x86" and fix kconfig so we again can set 64BIT in
all.config.

For a fix the diffstat is nice:
 6 files changed, 3 insertions(+), 36 deletions(-)

The patch reverts these commits:
 - 0f855aa64b ("kconfig: add helper to set
   config symbol from environment variable")
 - 2a113281f5 ("kconfig: use $K64BIT to
   set 64BIT with all*config targets")

Roman Zippel pointed out that kconfig supported string compares so
the additional complexity introduced by the above two patches were
not needed.

With this patch we have following behaviour:

  # make {allno,allyes,allmod,rand}config [ARCH=...]
  option \ host arch      | 32bit         | 64bit
  =====================================================
  ./.                     | 32bit         | 64bit
  ARCH=x86                | 32bit         | 32bit
  ARCH=i386               | 32bit         | 32bit
  ARCH=x86_64             | 64bit         | 64bit

The general rule are that ARCH= and native architecture takes
precedence over the configuration.

So make ARCH=i386 [whatever] will always build a 32-bit kernel
no matter what the configuration says.  The configuration will
be updated to 32-bit if it was configured to 64-bit and the
other way around.

This behaviour is consistent with previous behaviour so no
suprises here.

make ARCH=x86 will per default result in a 32-bit kernel but as
the only ARCH= value x86 allow the user to select between 32-bit
and 64-bit using menuconfig.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Andreas Herrmann <aherrman@arcor.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Makefile

@@ -200,11 +200,9 @@ SRCARCH 	:= $(ARCH)
 # Additional ARCH settings for x86
 ifeq ($(ARCH),i386)
         SRCARCH := x86
-        K64BIT  := n
 endif
 ifeq ($(ARCH),x86_64)
         SRCARCH := x86
-        K64BIT  := y
 endif
 
 KCONFIG_CONFIG	?= .config
@@ -341,7 +339,7 @@ KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
 KERNELVERSION = $(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
 
 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
-export ARCH SRCARCH K64BIT CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
+export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP MAKE AWK GENKSYMS PERL UTS_MACHINE
 export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
 

README

@@ -194,8 +194,6 @@ CONFIGURING the kernel:
    "make *config" checks for a file named "all{yes/mod/no/random}.config"
    for symbol values that are to be forced.  If this file is not found,
    it checks for a file named "all.config" to contain forced values.
-   Finally it checks the environment variable K64BIT and if found, sets
-   the config symbol "64BIT" to the value of the K64BIT variable.
    
 	NOTES on "make config":
 	- having unnecessary drivers will make the kernel bigger, and can

arch/x86/Kconfig

@@ -3,8 +3,8 @@ mainmenu "Linux Kernel Configuration for x86"
 
 # Select 32 or 64 bit
 config 64BIT
-	bool "64-bit kernel"
-	default n
+	bool "64-bit kernel" if ARCH = "x86"
+	default ARCH = "x86_64"
 	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

scripts/kconfig/conf.c

@@ -591,7 +591,6 @@ int main(int ac, char **av)
 			conf_read_simple(name, S_DEF_USER);
 		else if (!stat("all.config", &tmpstat))
 			conf_read_simple("all.config", S_DEF_USER);
-		conf_set_env_sym("K64BIT", "64BIT", S_DEF_USER);
 		break;
 	default:
 		break;

scripts/kconfig/confdata.c

@@ -145,33 +145,6 @@ static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
 	return 0;
 }
 
-/* Read an environment variable and assign the value to the symbol */
-int conf_set_env_sym(const char *env, const char *symname, int def)
-{
-	struct symbol *sym;
-	char *p;
-	int def_flags;
-
-	p = getenv(env);
-	if (p) {
-		char warning[200];
-		sprintf(warning, "Environment variable (%s = \"%s\")", env, p);
-		conf_filename = warning;
-		def_flags = SYMBOL_DEF << def;
-		if (def == S_DEF_USER) {
-			sym = sym_find(symname);
-			if (!sym)
-				return 1;
-		} else {
-			sym = sym_lookup(symname, 0);
-			if (sym->type == S_UNKNOWN)
-				sym->type = S_OTHER;
-		}
-		conf_set_sym_val(sym, def, def_flags, p);
-	}
-	return 0;
-}
-
 int conf_read_simple(const char *name, int def)
 {
 	FILE *in = NULL;

scripts/kconfig/lkc_proto.h

@@ -1,7 +1,6 @@
 
 /* confdata.c */
 P(conf_parse,void,(const char *name));
-P(conf_set_env_sym,int,(const char *envname, const char *symname, int def));
 P(conf_read,int,(const char *name));
 P(conf_read_simple,int,(const char *name, int));
 P(conf_write,int,(const char *name));