Add another option when selecting CPU family so the kernel can be
optimized for Intel Atom CPUs. If GCC supports tuning options for
Intel Atom they will be used.
Signed-off-by: NTobias Doerffel <tobias.doerffel@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
LKML-Reference: <1251018457-19157-1-git-send-email-tobias.doerffel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The Winchip-2 and Winchip-2A cpu choices select the
same options for kernel and compiler.

Merge them to save few bytes and reduce confusion.
Signed-off-by: NKrzysztof Helt <krzysztof.h1@wp.pl>
Acked-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

binutils, contrary to documented behaviour, will generate long NOPs (a
P6-or-higher instruction which is broken on at least some VIA chips,
Virtual PC/Virtual Server, and some versions of Qemu) depending on the
-mtune= option, which is not supposed to change architectural
behaviour.

Pass an explicit override to the assembler, in case ends up passing
the -mtune= parameter to gas (gcc 4.3.0 does not appear to.)
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Moving the ARCH specific Makefiles for i386 and x86_64
required a litle bit tweaking in the top-lvel Makefile.

SRCARCH is now set in the top-level Makefile
because we need this info to include the correct
arch Makefile.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Hi!

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
<http://lkml.org/lkml/2007/2/28/230>.
Signed-off-by: NAndi Kleen <ak@suse.de>

The VIA C7 is a 686 (with TSC) that supports MMX, SSE and SSE2, it also has
a cache line length of 64 according to
http://www.digit-life.com/articles2/cpu/rmma-via-c7.html.  This patch sets
gcc to -march=686 and select s the correct cache shift.
Signed-off-by: NSimon Arlott <simon@fire.lp0.eu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

gcc doesn't support -mtune=core2 yet, but will be soon. Use -mtune=generic or -mtune=i686
as fallback

TBD need benchmarking for INTEL_USERCOPY etc. So far I used the same defaults as MPENTIUMM
Signed-off-by: NAndi Kleen <ak@suse.de>

The upcomming gcc 4.2 got a new option -mtune=generic to tune
code for both common AMD and Intel CPUs. Use this option
when available for generic kernels.

On x86-64 it is used with CONFIG_GENERIC_CPU. On i386 it is
enabled with CONFIG_X86_GENERIC.  It won't affect the base
line CPU support in any ways and also not the minimum supported CPU.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove various things which were checking for gcc-1.x and gcc-2.x compilers.

From: Adrian Bunk <bunk@stusta.de>

    Some documentation updates and removes some code paths for gcc < 3.2.
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I just noted that -mtune is used, which is only supported on recent GCCs; by
reading http://gcc.gnu.org/gcc-3.4/changes.html, you see "-mcpu has been
renamed to -mtune.", so for GCC < 3.4 we're not using any specific tuning in
the appropriate cases.  However -mcpu is deprecated, so use -mtune when
possible.

This was introduced by commit e9d4dce954a60dc23dd1d967766ca2347b780e54 of the
old tree (between 2.6.10-rc3 and 2.6.10) by Linus Torvalds, to remove the use
of -march, since that could trigger gcc using SSE on its own.  But no
attention was used about using -mcpu vs.  -mtune.

And btw, the old 2.6.4 code (for instance) was:
cflags-$(CONFIG_MPENTIUMII)     += $(call check_gcc,-march=pentium2,-march=i686)
cflags-$(CONFIG_MPENTIUMIII)    += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUMM)      += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUM4)      += $(call check_gcc,-march=pentium4,-march=i686)
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Make UML share the underlying cpu-specific tuning done on i386.

Actually, for now many config options aren't used a lot - but that can be done
later.  Also, UML relies on GCC optimization for things like memcpy and such
more than i386, so specifying the correct -march and -mtune should be enough.
Later, we may want to correct some other stuff.

For instance, since FPU context switching, for us, is done (at least
partially, i.e.  between our kernelspace and userspace) by the host, we may
allow usage of FPU operations by GCC.  This doesn't hold for kernelspace vs.
kernelspace, but we don't support preemption.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>