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    Subject[PATCH] [31/35] i386: Fix usage of -mtune when X86_GENERIC=y or CONFIG_MCORE2=y

    From: Lasse Collin <>

    I sent this simple patch to lkml about two weeks ago and also cc'ed
    to Linus, but seems that the patch got ignored. I decided to write to
    you, because you have modified the relevant file most recently.

    Below is a copy of the mail that is also available at

    Signed-off-by: Andi Kleen <>


    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.

    arch/i386/Makefile.cpu | 8 ++++----
    1 file changed, 4 insertions(+), 4 deletions(-)

    Index: linux/arch/i386/Makefile.cpu
    --- linux.orig/arch/i386/Makefile.cpu
    +++ linux/arch/i386/Makefile.cpu
    @@ -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))
    -tune = $(call cc-option,-mcpu=$(1),)
    +tune = $(call cc-option,-mcpu=$(1),$(2))

    align := $(cc-option-align)
    @@ -33,7 +33,7 @@ cflags-$(CONFIG_MWINCHIP3D) += $(call cc
    cflags-$(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_MVIAC7) += -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-$(CONFIG_X86_ELAN) += -march=i486
    @@ -43,5 +43,5 @@ cflags-$(CONFIG_MGEODEGX1) += -march=pen

    # 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))

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      Last update: 2007-04-28 19:57    [W:0.020 / U:97.996 seconds]
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