Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Change some movl's to mov's. Newer GAS no longer accept 'movl' instructions
for moving between a segment register and a 32-bit memory location.

Looked at by: jhb

Assembly files put thru the C preprocessor need to have C style comments.

Remove the leading underscore from all symbols defined in x86 asm
and used in C or vice versa. The elf compiler uses the same names
for both. Remove asnames.h with great prejudice; it has served its
purpose.

Note that this does not affect the ability to generate an aout kernel
due to gcc's -mno-underscores option.

moral support from: peter, jhb

Cleanup after repo copy of sys/svr4 to sys/compat/svr4.

AT&T asm syntax requires a leading '*' in front of the operand for indirect
calls and jumps.

Include #warning about unconditionalizing VM86, which isn't supposed to work
in the svr4 emulator yet.

Add a per-signal flag to mark handlers registered with osigaction, so we
can provide the correct context to each signal handler.

Fix broken sigsuspend(): don't use p_oldsigmask as a flag, use SAS_OLDMASK
as we did before the linuxthreads support merge (submitted by bde).

Move ps_sigstk from to p_sigacts to the main proc structure since signal
stack should not be shared among threads.

Move SAS_OLDMASK and SAS_ALTSTACK flags from sigacts::ps_flags to proc::p_flag.
Move PS_NOCLDSTOP and PS_NOCLDWAIT flags from proc::p_flag to procsig::ps_flag.

Reviewed by: marcel, jdp, bde

$Id$ -> $FreeBSD$

Replace ".align 2" with "ALIGN_TEXT" as per recent discussion re: the linux
emulator.

Suggested by: bde

Add $Id$ tags.
Clean-up some unused (or to-be-used) variables in svr4_getcontext()

Back out last commit (did I get all of them?)

Submitted by: Kazutaka YOKOTA <yokota@zodiac.mech.utsunomiya-u.ac.jp>

Unifdef VM86.

Reviewed by: silence on on -current

Enable vmspace sharing on SMP. Major changes are,
- %fs register is added to trapframe and saved/restored upon kernel entry/exit.
- Per-cpu pages are no longer mapped at the same virtual address.
- Each cpu now has a separate gdt selector table. A new segment selector
is added to point to per-cpu pages, per-cpu global variables are now
accessed through this new selector (%fs). The selectors in gdt table are
rearranged for cache line optimization.
- fask_vfork is now on as default for both UP and SMP.
- Some aio code cleanup.

Reviewed by: Alan Cox <alc@cs.rice.edu>
John Dyson <dyson@iquest.net>
Julian Elischer <julian@whistel.com>
Bruce Evans <bde@zeta.org.au>
David Greenman <dg@root.com>

Added underscores to some names in svr4_locore.s so that it compiles
with -aout. Added translation back to elf names in asnames.h as
usual. The elf names were inconsistent in the aout case even
internally because a macro adds an underscore to just one of them.

Removed commented out code for a previous life of `svr4_esigcode'.
Didn't add an underscore to `svr4_esigcode' since it is correct for
aout although wrong for elf, like most internal names in assembler
files. These names should be in a different namespace so that gprof
can ignore them.

Fixed some disorder in asnames.h.

Emulator KLD for SysVR4 executables grabbed from NetBSD.
See http://www.freebsd.org/~newton/freebsd-svr4 for limitations,
capabilities, history and TO-DO list.