[PATCH] i386: Fix usage of -mtune when X86_GENERIC=y or CONFIG_MCORE2=y

[Lasse Collin]

Two fixes to arch/i386/Makefile.cpu:

1) When X86_GENERIC=y is set, use -mtune=i686 if $(CC) doesn't
   support -mtune=generic. GCC 4.1.2 and earlier don't support
   -mtune=generic. When building a generic kernel for a distro
   that runs on i586 and better, it is nice to use
   -march=i586 -mtune=i686 instead of plain -march=i586.

2) Use $(call tune) instead of hardcoded -mtune when CONFIG_MCORE2=y.
   This makes it possible to have CONFIG_MCORE2=y when using GCC 3.3,
   which uses -mcpu instead of -mtune. Also dropped fallback to
   -mtune=generic and -mtune=i686, because -march=i686 already
   implies -mtune=i686.

The patch is against 2.6.20, but Makefile.cpu hasn't changed recently.

--- linux-2.6.20/arch/i386/Makefile.cpu.orig	2007-02-04 20:44:54.000000000 +0200
+++ linux-2.6.20/arch/i386/Makefile.cpu	2007-02-28 21:22:47.000000000 +0200
@@ -4,9 +4,9 @@
 #-mtune exists since gcc 3.4
 HAS_MTUNE	:= $(call cc-option-yn, -mtune=i386)
 ifeq ($(HAS_MTUNE),y)
-tune		= $(call cc-option,-mtune=$(1),)
+tune		= $(call cc-option,-mtune=$(1),$(2))
 else
-tune		= $(call cc-option,-mcpu=$(1),)
+tune		= $(call cc-option,-mcpu=$(1),$(2))
 endif
 
 align := $(cc-option-align)
@@ -32,7 +32,7 @@
 cflags-$(CONFIG_MWINCHIP3D)	+= $(call cc-option,-march=winchip2,-march=i586)
 cflags-$(CONFIG_MCYRIXIII)	+= $(call cc-option,-march=c3,-march=i486) $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0
 cflags-$(CONFIG_MVIAC3_2)	+= $(call cc-option,-march=c3-2,-march=i686)
-cflags-$(CONFIG_MCORE2)		+= -march=i686 $(call cc-option,-mtune=core2,$(call cc-option,-mtune=generic,-mtune=i686))
+cflags-$(CONFIG_MCORE2)		+= -march=i686 $(call tune,core2)
 
 # AMD Elan support
 cflags-$(CONFIG_X86_ELAN)	+= -march=i486
@@ -42,5 +42,5 @@
 
 # add at the end to overwrite eventual tuning options from earlier
 # cpu entries
-cflags-$(CONFIG_X86_GENERIC) 	+= $(call tune,generic)
+cflags-$(CONFIG_X86_GENERIC) 	+= $(call tune,generic,$(call tune,i686))
 

-- 
Lasse Collin  |  IRC: Larhzu @ IRCnet & Freenode
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