GCC provides reasonable memset/memcpy functions itself, with __builtin_memset
and __builtin_memcpy. For the "unknown" cases, it'll fall back to our
current existing functions, but for fixed size versions it'll inline
something smart. Quite often that will be the same as we have now,
but sometimes it can do something smarter (for example, if the code
then sets the first member of a struct, it can do a shorter memset).

In addition, and this is more important, gcc knows which registers and
such are not clobbered (while for our asm version it pretty much
acts like a compiler barrier), so for various cases it can avoid reloading
values.

The effect on codesize is shown below on my typical laptop .config:

   text	   data	    bss	    dec	    hex	filename
5605675	2041100	6525148	14171923	 d83f13	vmlinux.before
5595849	2041668	6525148	14162665	 d81ae9	vmlinux.after

Due to some not-so-good behavior in the gcc 3.x series, this change
is only done for GCC 4.x and above.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <20090928142122.6fc57e9c@infradead.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Signed-off-by: NFelipe Contreras <felipe.contreras@gmail.com>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alok N Kataria <akataria@vmware.com>
Cc: "Tan Wei Chong" <wei.chong.tan@intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Bob Moore <robert.moore@intel.com>
LKML-Reference: <1253137123-18047-2-git-send-email-felipe.contreras@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The hooks that we modify are:
- Page fault handler (to handle kmemcheck faults)
- Debug exception handler (to hide pages after single-stepping
  the instruction that caused the page fault)

Also redefine memset() to use the optimized version if kmemcheck is
enabled.

(Thanks to Pekka Enberg for minimizing the impact on the page fault
handler.)

As kmemcheck doesn't handle MMX/SSE instructions (yet), we also disable
the optimized xor code, and rely instead on the generic C implementation
in order to avoid false-positive warnings.
Signed-off-by: NVegard Nossum <vegardno@ifi.uio.no>

[whitespace fixlet]
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: NVegard Nossum <vegardno@ifi.uio.no>

Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This patch is the result of an automatic script that consolidates the
format of all the headers in include/asm-x86/.

The format:

1. No leading underscore. Names with leading underscores are reserved.
2. Pathname components are separated by two underscores. So we can
   distinguish between mm_types.h and mm/types.h.
3. Everything except letters and numbers are turned into single
   underscores.
Signed-off-by: NVegard Nossum <vegard.nossum@gmail.com>

gcc 4.0 fails to allocate %eax for the pattern operand in the rep
store instructions used by memset; force it to do so by declaring a
register variable.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Looked at this file because of __memcpy warnings.
Thought it could use a style/checkpatch cleanup.

No change in vmlinux.

[tglx: fixed the remaining issues ]
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

include/asm/string_32.h:216:26: warning: cast truncates bits from constant value (cccccccc becomes cc)
include/asm/string_32.h:219:27: warning: cast truncates bits from constant value (cccccccc becomes cccc)
include/asm/string_32.h:222:27: warning: cast truncates bits from constant value (cccccccc becomes cccc)
include/asm/string_32.h:223:30: warning: cast truncates bits from constant value (cccccccc becomes cc)
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The constraints in the inline assembler implementation of i386
strrchr() were incorrect and break the build with recent gcc 4.3.
Since there are only very few callers of strrchr() and none of them
are performance relevant just remove the assembler implementation
and use the C fallback instead.

[ tglx: arch/x86 adaptation ]

Cc: rguenther@suse.de
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Move the headers to include/asm-x86 and fixup the
header install make rules
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The compiler generally generates reasonable inline code for the simple
cases and for the rest it's better for code size for them to be out of line.
Also there they can be potentially optimized more in the future.

In fact they probably should be in a .S file because they're all pure
assembly, but that's for another day.

Also some code style cleanup on them while I was on it (this seems
to be the last untouched really early Linux code)

This saves ~12k text for a defconfig kernel with gcc 4.1.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

      Arjan van de Ven <arjan@infradead.org>

Mark a number of functions as 'must inline'.  The functions affected by this
patch need to be inlined because they use knowledge that their arguments are
constant so that most of the function optimizes away.  At this point this
patch does not change behavior, it's for documentation only (and for future
patches in the inline series)
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArjan van de Ven <arjan@infradead.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

They don't actually clobber memory, but gcc doesn't even know they
_read_ memory, so can apparently re-order memory accesses around them.

Which obviously does the wrong thing if the memory access happens to
change the memory that the compare function is accessing..

Verified to fix a strange boot problem by Jens Axboe.

This patch shortens non-constant memcpy() by two bytes and fixes spurious
out-of-line constant memcpy().

# size vmlinux.org vmlinux
   text    data     bss     dec     hex filename
3954591 1553426  236544 5744561  57a7b1 vmlinux.org
3952615 1553426  236544 5742585  579ff9 vmlinux
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!