Lock sections cannot be handled by the dwarf2 unwinder.

Disadvantage is a taken branch in the hot path.
Signed-off-by: NAndi Kleen <ak@suse.de>

Changes are largely identical to the i386 version:

 * alternative #define are moved to the new alternative.h file.
 * one new elf section with pointers to the lock prefixes which can be
   nop'ed out for non-smp.
 * two new elf sections simliar to the "classic" alternatives to
   replace SMP code with simpler UP code.
 * fixup headers to use alternative.h instead of defining their own
   LOCK / LOCK_PREFIX macros.

The patch reuses the i386 version of the alternatives code to avoid code
duplication.  The code in alternatives.c was shuffled around a bit to
reduce the number of #ifdefs needed.  It also got some tweaks needed for
x86_64 (vsyscall page handling) and new features (noreplacement option
which was x86_64 only up to now).  Debug printk's are changed from
compile-time to runtime.

Loosely based on a early version from Bastian Blank <waldi@debian.org>
Signed-off-by: NGerd Hoffmann <kraxel@suse.de>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Noticed by Arjan originally on x86-64, then Ingo on x86, and finally me
grepping for it in the generic version.

Bad parenthesis nesting.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

add the x86_64 version of mutex.h, optimized in assembly.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArjan van de Ven <arjan@infradead.org>