- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

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

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

Reduce duplication between i386/linux/linux.h and amd64/linux32/linux.h
by moving bits that are MI out into headers in compat/linux.

Reviewed by: Chagin Dmitry dmitry | gmail
MFC after: 2 weeks

Introduce the x86 kernel interfaces to allow kernel code to use
FPU/SSE hardware. Caller should provide a save area that is chained
into the stack of the areas; pcb save_area for usermode FPU state is
on top. The pcb now contains a pointer to the current FPU saved area,
used during FPUDNA handling and context switches. There is also a
facility to allow the kernel thread to use pcb save_area.

Change the dreaded warnings "npxdna in kernel mode!" into the panics
when FPU usage is not registered.

KPI discussed with: fabient
Tested by: pho, fabient
Hardware provided by: Sentex Communications
MFC after: 1 month

- Move all of the PS_ flags into either p_flag or td_flags.
- p_sflag was mostly protected by PROC_LOCK rather than the PROC_SLOCK or
previously the sched_lock. These bugs have existed for some time.
- Allow swapout to try each thread in a process individually and then
swapin the whole process if any of these fail. This allows us to move
most scheduler related swap flags into td_flags.
- Keep ki_sflag for backwards compat but change all in source tools to
use the new and more correct location of P_INMEM.

Reported by: pho
Reviewed by: attilio, kib
Approved by: re (kensmith)

Close some races between procfs/ptrace and exit(2):
- Reorder the events in exit(2) slightly so that we trigger the S_EXIT
stop event earlier. After we have signalled that, we set P_WEXIT and
then wait for any processes with a hold on the vmspace via PHOLD to
release it. PHOLD now KASSERT()'s that P_WEXIT is clear when it is
invoked, and PRELE now does a wakeup if P_WEXIT is set and p_lock drops
to zero.
- Change proc_rwmem() to require that the processing read from has its
vmspace held via PHOLD by the caller and get rid of all the junk to
screw around with the vmspace reference count as we no longer need it.
- In ptrace() and pseudofs(), treat a process with P_WEXIT set as if it
doesn't exist.
- Only do one PHOLD in kern_ptrace() now, and do it earlier so it covers
FIX_SSTEP() (since on alpha at least this can end up calling proc_rwmem()
to clear an earlier single-step simualted via a breakpoint). We only
do one to avoid races. Also, by making the EINVAL error for unknown
requests be part of the default: case in the switch, the various
switch cases can now just break out to return which removes a _lot_ of
duplicated PRELE and proc unlocks, etc. Also, it fixes at least one bug
where a LWP ptrace command could return EINVAL with the proc lock still
held.
- Changed the locking for ptrace_single_step(), ptrace_set_pc(), and
ptrace_clear_single_step() to always be called with the proc lock
held (it was a mixed bag previously). Alpha and arm have to drop
the lock while the mess around with breakpoints, but other archs
avoid extra lock release/acquires in ptrace(). I did have to fix a
couple of other consumers in kern_kse and a few other places to
hold the proc lock and PHOLD.

Tested by: ps (1 mostly, but some bits of 2-4 as well)
MFC after: 1 week

Remove the CPU_ENABLE_SSE option from the i386 and pc98 architectures,
as they are already default for I686_CPU for almost 3 years, and
CPU_DISABLE_SSE always disables it. On the other hand, CPU_ENABLE_SSE
does not work for I486_CPU and I586_CPU.

This commit has:
- Removed the option from conf/options.*
- Removed the option and comments from MD NOTES files
- Simplified the CPU_ENABLE_SSE ifdef's so they don't
deal with CPU_ENABLE_SSE from kernel configuration. (*)

For most users, this commit should be largely no-op. If you used to
place CPU_ENABLE_SSE into your kernel configuration for some reason,
it is time to remove it.

(*) The ifdef's of CPU_ENABLE_SSE are not removed at this point, since
we need to change it to !defined(CPU_DISABLE_SSE) && defined(I686_CPU),
not just !defined(CPU_DISABLE_SSE), if we really want to do so.

Discussed on: -arch
Approved by: re (scottl)

/* -> /*- for copyright notices, minor format tweaks as necessary

Fix the following race:

1. Process p1 is currently being swapped in.
2. Process p2 calls linux_ptrace(PTRACE_GETFPXREGS, p1_pid, ...)
3. After acquiring a reference to FIRST_THREAD_IN_PROC(p1),
p2 blocks in faultin() while p1 finishes being swapped in.
This means p2 won't get back the lock on p1 until after p1's
threads are runnable.
4. After p1 is swapped in, the first thread in p1 exits.
5. p2 now uses its dangling reference to p1's first thread.

Consistently use __inline instead of __inline__ as the former is an empty macro
in <sys/cdefs.h> for compilers without support for inline.

Use __FBSDID().

Prefer the proc lock to sched_lock when testing PS_INMEM now that it is
safe to do so.

Sync up with changes to ptrace() and use P_SHOULDSTOP instead of
a duplicate P_TRACED check.

Submitted by: marcel

Clean up whitespace and remove register keyword.

More caddr_t removal, in conjunction with copy{in,out}(9) this time.
Also clean up some egregious casts and incorrect use of sizeof.

Removed unused includes. Sorted includes. This is part of removing
includes of <sys/user.h> for its pollution only. <sys/user.h> wasn't
even used for its pollution here.

Include <machine/pcb.h> instead of depending on namespace pollution in
<sys/user.h>.

Automatically enable CPU_ENABLE_SSE (detect and enable SSE instructions)
if compiling with I686_CPU as a target. CPU_DISABLE_SSE will prevent
this from happening and will guarantee the code is not compiled in.

I am still not happy with this, but gcc is now generating code that uses
these instructions if you set CPUTYPE to p3/p4 or athlon-4/mp/xp or higher.

Split up ptrace() into a wrapper that does the copying to and from
user space and a kern_ptrace() implementation. Use the kern_*()
version in the Linux emulation code to remove more stack gap uses.

Approved by: des

Part 1 of KSE-III

The ability to schedule multiple threads per process
(one one cpu) by making ALL system calls optionally asynchronous.
to come: ia64 and power-pc patches, patches for gdb, test program (in tools)

Reviewed by: Almost everyone who counts
(at various times, peter, jhb, matt, alfred, mini, bernd,
and a cast of thousands)

NOTE: this is still Beta code, and contains lots of debugging stuff.
expect slight instability in signals..

o Fix race condition caused by doing ptrace() for permission
checking, followed by a lookup of the process. Do not call
ptrace() for permission checking, but do it inline.
Spotted by: rwatson

o While here, copy-in arguments before we lock. This fixes
a possible permanent lock.

Reviewed by: rwatson

Sparkling new implementation of linux_ptrace. Slight tweaking by
yours truly.

PR: 33299
Submitted by: Alexander N. Kabaev <ak03@gte.com>