Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

x86: detect mwait capabilities and extensions, when present

Reviewed by: kib (earlier amd64-only version)
MFC after: 2 weeks

Add SMP/i386 suspend/resume support.
Most part is merged from amd64.

- i386/acpica/acpi_wakecode.S
Replaced with amd64 code (from realmode to paging enabling code).

- i386/acpica/acpi_wakeup.c
Replaced with amd64 code (except for wakeup_pagetables stuff).

- i386/include/pcb.h
- i386/i386/genassym.c
Added PCB new members (CR0, CR2, CR4, DS, ED, FS, SS, GDT, IDT, LDT
and TR) needed for suspend/resume, not for context switch.

- i386/i386/swtch.s
Added suspendctx() and resumectx().
Note that savectx() was not changed and used for suspending (while
amd64 code uses it).
BSP and AP execute the same sequence, suspendctx(), acpi_wakecode()
and resumectx() for suspend/resume (in case of UP system also).

- i386/i386/apic_vector.s
Added cpususpend().

- i386/i386/mp_machdep.c
- i386/include/smp.h
Added cpususpend_handler().

- i386/include/apicvar.h
- kern/subr_smp.c
- sys/smp.h
Added IPI_SUSPEND and suspend_cpus().

- i386/i386/initcpu.c
- i386/i386/machdep.c
- i386/include/md_var.h
- pc98/pc98/machdep.c
Moved initializecpu() declarations to md_var.h.

MFC after: 3 days

Remove unused i586 optimized bcopy/bzero/etc implementations that utilize
FPU registers for copying. Remove the switch table and jumps from
bcopy/bzero/... to the actual implementation.
As a side-effect, i486-optimized bzero is removed.

Reviewed by: bde
Tested by: pho (previous version)

Adapt r204907 and r205402, the amd64 implementation of the workaround for
AMD Family 10h Erratum 383, to i386.

Enable machine check exceptions by default, just like r204913 for amd64.

Enable superpage promotion only if the processor actually supports large
pages, i.e., PG_PS.

MFC after: 2 weeks

As was done in r195820 for amd64, use clflush for flushing cache lines
when memory page caching attributes changed, and CPU does not support
self-snoop, but implemented clflush, for i386.

Take care of possible mappings of the page by sf buffer by utilizing
the mapping for clflush, otherwise map the page transiently. Amd64
used direct map.

Proposed and reviewed by: alc
Approved by: re (kensmith)

Introduce cpu_vendor_id and replace a lot of strcmp(cpu_vendor, "...").

Reviewed by: jhb, peter (early amd64 version)

Detect Advanced Power Management Information for AMD CPUs.

Initialise (if necessary) the VIA C3/C7 features.
Store the capabilities for further use by random(4), padlock(4), ...

Obtained from: mostly OpenBSD
MFC after: 1 week

Use the method described in IA-32 Intel Architecture Software Developer's
Manual chapter 11.6.6 to get valid mxcsr bits, use the mxcsr mask to clear
invalid bits passed by user code.

Reviewed by: bde

Merge minidumps from amd64 where they were originally developed.

Major differences:
* since there is no direct map region, there is no custom uma memory
allocator to modify to include its pages in the dumps.
* Various data entries are reduced from 64 bit to 32 bit to match the
native size.

dump_add_page() and dump_drop_page() are still present in case one wants to
arrange for arbitary pages to be dumped. This is of marginal use though
because libkvm+kgdb cannot address physical memory that isn't mapped into
kvm.

- Print number of physical/logical cores and more CPUID info.
- Add newer CPUID definitions for future use.

Many thanks to Mike Tancsa <mike at sentex dot net> for providing test
cases for Intel Pentium D and AMD Athlon 64 X2.

Approved by: anholt (mentor)

Begin promoting the AMD-originated feature flags to first class flags, now
that newer Intel cpu hardware implements them too. This includes things
like the NX (pte no-execute) flag for execute protection. We'll need to
reference this for implementing no-exec in pmap.c at some point.

Some feature flags are duplicated in both the Intel-orignated bits and
the AMD bits. Suppress the the duplicates correctly - the old code
assumed they were a 1:1 mapping which is not correct. We can't just mask
off the bits present in cpu_feature.

Converge with amd64 where this originated from.

Intel cpu's that implement any AMD features will report them in dmesg now.

Approved by: re

Add the 2nd word of IA32 feature flags. This includes things such as SSE3.

Obtained from: sys/amd64/amd64/identcpu.

Move pc98 specific parts to the pc98 specific file.

Remove atdevbase and replace it's remaining uses with direct references to
KERNBASE instead.

- is_physical_memory()'s parameter, which is a physical address, should be
a vm_paddr_t not a vm_offset_t.

Add struct definition of the Elan MMCR registers (from jb@)

Put a CTASSERT() on the size of the struct.

Use the struct where it is easy to do so in elan_mmcr.c

Add the Elan specific hardware reset code (also from jb@).

Catch up to interrupt code changes.

- Add ss2_pagezero() for zeroing pages using the movnti instruction. This
instruction is enabled with SSE2 but does not use SSE registers. It is a
"non-temporal" move which bypasses the cache and does not dirty lines.

Further cleanup <machine/cpu.h> and <machine/md_var.h>: move the MI
prototypes of cpu_halt(), cpu_reset() and swi_vm() from md_var.h to
cpu.h. This affects db_command.c and kern_shutdown.c.

ia64: move all MD prototypes from cpu.h to md_var.h. This affects
madt.c, interrupt.c and mp_machdep.c. Remove is_physical_memory().
It's not used (vm_machdep.c).

alpha: the MD prototypes have been left in cpu.h with a comment
that they should be there. Moving them is left for later. It was
expected that the impact would be significant enough to be done in
a seperate commit.

powerpc: MD prototypes left in cpu.h. Comment added.

Suggested by: bde
Tested with: make universe (pc98 incomplete)

Tidy up leftover lazy_switch instrumentation that is no longer needed.
This cleans up some #ifdef hell.

Define ovbcopy() as a macro which expands to the equivalent bcopy() call,
to take care of the KAME IPv6 code which needs ovbcopy() because NetBSD's
bcopy() doesn't handle overlap like ours.

Remove all implementations of ovbcopy().

Previously, bzero was a function pointer on i386, to save a jmp to
bzero_vector. Get rid of this microoptimization as it only confuses
things, adds machine-dependent code to an MD header, and doesn't really
save all that much.

This commit does not add my pagezero() / pagecopy() code.

Commit a partial lazy thread switch mechanism for i386. it isn't as lazy
as it could be and can do with some more cleanup. Currently its under
options LAZY_SWITCH. What this does is avoid %cr3 reloads for short
context switches that do not involve another user process. ie: we can
take an interrupt, switch to a kthread and return to the user without
explicitly flushing the tlb. However, this isn't as exciting as it could
be, the interrupt overhead is still high and too much blocks on Giant
still. There are some debug sysctls, for stats and for an on/off switch.

The main problem with doing this has been "what if the process that you're
running on exits while we're borrowing its address space?" - in this case
we use an IPI to give it a kick when we're about to reclaim the pmap.

Its not compiled in unless you add the LAZY_SWITCH option. I want to fix a
few more things and get some more feedback before turning it on by default.

This is NOT a replacement for Bosko's lazy interrupt stuff. This was more
meant for the kthread case, while his was for interrupts. Mine helps a
little for interrupts, but his helps a lot more.

The stats are enabled with options SWTCH_OPTIM_STATS - this has been a
pseudo-option for years, I just added a bunch of stuff to it.

One non-trivial change was to select a new thread before calling
cpu_switch() in the first place. This allows us to catch the silly
case of doing a cpu_switch() to the current process. This happens
uncomfortably often. This simplifies a bit of the asm code in cpu_switch
(no longer have to call choosethread() in the middle). This has been
implemented on i386 and (thanks to jake) sparc64. The others will come
soon. This is actually seperate to the lazy switch stuff.

Glanced at by: jake, jhb

- Add vm_paddr_t, a physical address type. This is required for systems
where physical addresses larger than virtual addresses, such as i386s
with PAE.
- Use this to represent physical addresses in the MI vm system and in the
i386 pmap code. This also changes the paddr parameter to d_mmap_t.
- Fix printf formats to handle physical addresses >4G in the i386 memory
detection code, and due to kvtop returning vm_paddr_t instead of u_long.

Note that this is a name change only; vm_paddr_t is still the same as
vm_offset_t on all currently supported platforms.

Sponsored by: DARPA, Network Associates Laboratories
Discussed with: re, phk (cdevsw change)

- Move enable_sse()'s prototype to machine/md_var.h.
- Sort definition of cpu_* variables appropriately.
- Move cpu_fxsr out of the magic non-BSS set of variables and stick it in
the BSS along with hw_instruction_sse (make the latter static as well).

Submitted by: bde (partially)

Rename cpuid_cpuinfo to cpu_procinfo. bde requested that I rename this
variable to something in the cpu_* namespace since that's what all the
other cpuid variables were named and cpu_procinfo is what I came up with.

Requested by: bde

Rework part of the previous processor name changes so that we read
cpu_exthigh and cpu_brand in printcpuinfo() instead of in identify_cpu().
We also only do it for known-good values of cpu_vendor which is a bit more
conservative.

Reviewed by: bde (mostly)

- Add a cpu_exthigh variable to hold the highest extended cpuid value
returned from cpuid 0x80000000.
- Add a cpu_brand char array to hold the processor name returned by
cpuid 0x80000002-0x80000004 on AMD, Intel, Transmeta, and possibly
other CPUs.
- Use cpuid to set cpu_exthigh and read the processor name if it is present
in identify_cpu().

Add a cpuid_cpuinfo variable to hold the results of %ebx from cpuid with
%eax of 1 and set it in identify_cpu().

Split 4.x and 5.x signal handling so that we can keep 4.x signal
handling clean and functional as 5.x evolves. This allows some of the
nasty bandaids in the 5.x codepaths to be unwound.

Encapsulate 4.x signal handling under COMPAT_FREEBSD4 (there is an
anti-foot-shooting measure in place, 5.x folks need this for a while) and
finish encapsulating the older stuff under COMPAT_43. Since the ancient
stuff is required on alpha (longjmp(3) passes a 'struct osigcontext *'
to the current sigreturn(2), instead of the 'ucontext_t *' that sigreturn
is supposed to take), add a compile time check to prevent foot shooting
there too. Add uniform COMPAT_43 stubs for ia64/sparc64/powerpc.

Tested on: i386, alpha, ia64. Compiled on sparc64 (a few days ago).
Approved by: re

Change hw.physmem and hw.usermem to unsigned long like they used to be
in the original hardwired sysctl implementation.

The buf size calculator still overflows an integer on machines with large
KVA (eg: ia64) where the number of pages does not fit into an int. Use
'long' there.

Change Maxmem and physmem and related variables to 'long', mostly for
completeness. Machines are not likely to overflow 'int' pages in the
near term, but then again, 640K ought to be enough for anybody. This
comes for free on 32 bit machines, so why not?

Move a prototype to the least wrong place.

Suggested by: bde

The Elan SC520 MMCR is actually 16bit wide, so u_char is inconvenient.

Add initialization code for the AMD Elan sc520 which maps the MMCR
into KVM and sets the i8254 frequency to the correct value.

GC various bits and pieces of USERCONFIG from all over the place.

Fixed some style bugs in the removal of __P(()). The main ones were
not removing tabs before "__P((", and not outdenting continuation lines
to preserve non-KNF lining up of code with parentheses. Switch to KNF
formatting and/or rewrap the whole prototype in some cases.

Remove __P.

Back out part of KSE/M2 that snuck in under the radar: changing the
prototype of bzero() on the i386 to have a volatile first argument.

Requested by: bde, jake

Apparently during the KSE M2 commit bzero() on the i386 was changed so that
it's first parameter was volatile. Catch i486_bzero() and i586_bzero()'s
prototypes up to this to quiet warnings.

[partially forced commit due to pilot error in earlier commit attempt]

{set,fill}_{,fp,db}regs() fixup:

- Add dummy {set,fill}_dbregs() on architectures that don't have them.

- KSEfy the powerpc versions (struct proc -> struct thread).

- Some architectures had the prototypes in md_var.h, some in reg.h, and
some in both; for consistency, move them to reg.h on all platforms.

These functions aren't really MD (the implementation is MD, but the interface
is MI), so they should move to an MI header, but I haven't figured out which
one yet.

Run-tested on i386, build-tested on Alpha, untested on other platforms.

Cleanup and split of nfs client and server code.
This builds on the top of several repo-copies.

KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after: ha ha ha ha

vm_page_zero_idle() is no longer MD.

Activate SSE/SIMD. This is the extra context switching support that
we are required to do if we let user processes use the extra 128 bit
registers etc.

This is the base part of the diff I got from:
http://www.issei.org/issei/FreeBSD/sse.html
I believe this is by: Mr. SUZUKI Issei <issei@issei.org>
SMP support apparently by: Takekazu KATO <kato@chino.it.okayama-u.ac.jp>
Test code by: NAKAMURA Kazushi <kaz@kobe1995.net>, see
http://kobe1995.net/~kaz/FreeBSD/SSE.en.html

I have fixed a couple of style(9) deviations. I have some followup
commits to fix a couple of non-style things.

Remove the last of the MD netisr code. It is now all MI. Remove
spending, which was unused now that all software interrupts have
their own thread. Make the legacy schednetisr use an atomic op
for setting bits in the netisr mask.

Reviewed by: jhb

- Overhaul the software interrupt code to use interrupt threads for each
type of software interrupt. Roughly, what used to be a bit in spending
now maps to a swi thread. Each thread can have multiple handlers, just
like a hardware interrupt thread.
- Instead of using a bitmask of pending interrupts, we schedule the specific
software interrupt thread to run, so spending, NSWI, and the shandlers
array are no longer needed. We can now have an arbitrary number of
software interrupt threads. When you register a software interrupt
thread via sinthand_add(), you get back a struct intrhand that you pass
to sched_swi() when you wish to schedule your swi thread to run.
- Convert the name of 'struct intrec' to 'struct intrhand' as it is a bit
more intuitive. Also, prefix all the members of struct intrhand with
'ih_'.
- Make swi_net() a MI function since there is now no point in it being
MD.

Submitted by: cp

- Heavyweight interrupt threads on the alpha for device I/O interrupts.
- Make softinterrupts (SWI's) almost completely MI, and divorce them
completely from the x86 hardware interrupt code.
- The ihandlers array is now gone. Instead, there is a MI shandlers array
that just contains SWI handlers.
- Most of the former machine/ipl.h files have moved to a new sys/ipl.h.
- Stub out all the spl*() functions on all architectures.

Submitted by: dfr

Clean up some low level bootstrap code:

- stop using the evil 'struct trapframe' argument for mi_startup()
(formerly main()). There are much better ways of doing it.
- do not use prepare_usermode() - setregs() in execve() will do it
all for us as long as the p_md.md_regs pointer is set. (which is
now done in machdep.c rather than init_main.c. The Alpha port did it
this way all along and is much cleaner).
- collect all the magic %cr0 etc register settings into one place and
have the AP's call that instead of using magic numbers (!!) that keep
changing over and over again.
- Make it safe to call kthread_create() earlier, including during the
device probe sequence. It doesn't need the callback mechanism that
NetBSD's version uses.
- kthreads created this way are root-less as they exist before the root
filesystem is mounted. init(1) is set up so that it aquires the root
pointers prior to running. If other kthreads want filesystem acccess
we can make this code more generic.
- set all threads start times once we have decided what time it is.
- init uses a trampoline rather than the evil prepare_usermode() hack.
- kern_descrip.c has a couple of tweaks to deal with forking when there
is no rootdir or cwd etc.
- adjust the early SYSINIT() sequence so that a few prereqisites are in
place. eg: make sure the run queue is initialized before doing forks.

With this, the USB code can easily create a kthread to do the device
tree discovery. (I have tested it, it works nicely).

There are still some open issues before this is truely useful.
- tsleep() does not like working before the clock is running. It
sort-of tries to spin wait, but it can do more useful things now.
- stopping a kthread in kld code at unload time is "interesting" but
we have a solution for that.

The Alpha code needs no changes for this. It already uses pretty much the
same strategies, but a little cleaner.

Don't forget to reset the hardware debug registers when a process that
was using them exits.

Don't allow a user process to cause the kernel to take a TRCTRAP on a
user space address.

Reviewed by: jlemon, sef
Approved by: jkh

oszsigcode -> szosigcode

Pointed out by: bde

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

Simplification of the signal trampoline and other cleanups.

o Remove unused defines from genassym.c that were needed
by the trampoline.
o Add load_gs_param function to support.s that catches
a fault when %gs is loaded with an invalid descriptor.
The function returns EFAULT in that case.
o Remove struct trapframe from mcontext_t and replace it
with the list of registers.
o Modify sendsig and sigreturn accordingly.

This commit contains a patch by bde.

Reviewed by: luoqi, jdp

$Id$ -> $FreeBSD$

Implement support for hardware debug registers on the i386.

Submitted by: Brian Dean <brdean@unx.sas.com>

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>

Moved declarations related to copying and zeroing to the right place.

Add the ability to specify where on the at_shutdown queue a handler is
installed.

Remove cpu_power_down, and replace it with an entry at the end of the
SHUTDOWN_FINAL queue in the only place it's used (APM).

Submitted by: Some ideas from Bruce Walter <walter@fortean.com>

Goodbye BOUNCE_BUFFERS, for a hack it has served us well.

The last consumer of this code (the old SCSI system) has left us and
the CAM code does it's own bouncing. The isa dma system has been
doing it's own bouncing for a while too.

Reviewed by: core

Add new functions fill_fpregs() and set_fpregs(), like fill_regs()
and set_regs() but for the floating point register state. The code
is stolen from procfs_machdep.c, and moved out of there into
machdep.c.

These functions are needed for generating ELF core dumps.

Don't pretend to support ix86's with 16-bit ints by using longs just to
ensure 32-bit variables. Doing so mainly bogotified some printf formats.

Fixed disorder in md_var.h.

Fixed disordering of busdma* and swi_vm.

Add prototypes for swi_vm, setsoftvm, schedsoftvm, and splsoftvm that were
missed when I originally committed the bus dma code.

Implementation of Bus Space for FreeBSD-x86.

Obtained From: NetBSD

Moved some extern declarations to header files (unused ones to /dev/null).

Moved declaration of etext from <machine/md_var.h> to <machine/cpu.h>
and fixed everything that dependended on it being declared in the old
place. It is used in "machine-independent" code in subr_prof.c.

Moved declaration of btext from subr_prof.c to <machine/cpu.h>. It
is machine-dependent.

Revert the logic behind my last change, and use a function called
`is_physical_memory()' now for the decision whether to dump some
region of memory or not.

Suggested by: davidg

Do not ever try to coredump adapter memory regions.

PR: 4486
Submitted by: tegge@idi.ntnu.no (Tor Egge)

Implement a function is_adapter_memory() in order to determine what
should nto be dumped at all. Currently, only populated with the ``ISA
memory hole''. Adapter regions of other busses should be added.

VM86 kernel support.
Work done by BSDI, Jonathan Lemon <jlemon@americantv.com>,
Mike Smith <msmith@gsoft.com.au>, Sean Eric Fagan <sef@kithrup.com>,
and probably alot of others.
Submitted by: Jnathan Lemon <jlemon@americantv.com>

When APM is configured, turn off the power when halting for good.

Preserve %fs and %gs across context switches. This has a relatively low
cost since it is only done in cpu_switch(), not for every exception.
The extra state is kept in the pcb, and handled much like the npx state,
with similar deficiencies (the state is not preserved across signal
handlers, and error handling loses state).

Improved CPU identification and initialization routines. This
supports All Cyrix CPUs, IBM Blue Lightning CPU and NexGen (now AMD)
Nx586 CPU, and initialize special registers of Cyrix CPU and msr of
IBM Blue Lightning CPU.

If revision of Cyrix 6x86 CPU < 2.7, CPU cache is enabled in
write-through mode. This can be disabled by kernel configuration
options.

Reviewed by: Bruce Evans <bde@freebsd.org> and
Jordan K. Hubbard <jkh@freebsd.org>

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Further improved version of hadling a HALT when there is no console.

Moved declarations of non-cpu things from <machine/cpufunc.h> to better
places.

Mega-commit for Linux emulator update.. This has been stress tested under
netscape-2.0 for Linux running all the Java stuff. The scrollbars are now
working, at least on my machine. (whew! :-)

I'm uncomfortable with the size of this commit, but it's too
inter-dependant to easily seperate out.

The main changes:

COMPAT_LINUX is *GONE*. Most of the code has been moved out of the i386
machine dependent section into the linux emulator itself. The int 0x80
syscall code was almost identical to the lcall 7,0 code and a minor tweak
allows them to both be used with the same C code. All kernels can now
just modload the lkm and it'll DTRT without having to rebuild the kernel
first. Like IBCS2, you can statically compile it in with "options LINUX".

A pile of new syscalls implemented, including getdents(), llseek(),
readv(), writev(), msync(), personality(). The Linux-ELF libraries want
to use some of these.

linux_select() now obeys Linux semantics, ie: returns the time remaining
of the timeout value rather than leaving it the original value.

Quite a few bugs removed, including incorrect arguments being used in
syscalls.. eg: mixups between passing the sigset as an int, vs passing
it as a pointer and doing a copyin(), missing return values, unhandled
cases, SIOC* ioctls, etc.

The build for the code has changed. i386/conf/files now knows how
to build linux_genassym and generate linux_assym.h on the fly.

Supporting changes elsewhere in the kernel:

The user-mode signal trampoline has moved from the U area to immediately
below the top of the stack (below PS_STRINGS). This allows the different
binary emulations to have their own signal trampoline code (which gets rid
of the hardwired syscall 103 (sigreturn on BSD, syslog on Linux)) and so
that the emulator can provide the exact "struct sigcontext *" argument to
the program's signal handlers.

The sigstack's "ss_flags" now uses SS_DISABLE and SS_ONSTACK flags, which
have the same values as the re-used SA_DISABLE and SA_ONSTACK which are
intended for sigaction only. This enables the support of a SA_RESETHAND
flag to sigaction to implement the gross SYSV and Linux SA_ONESHOT signal
semantics where the signal handler is reset when it's triggered.

makesyscalls.sh no longer appends the struct sysentvec on the end of the
generated init_sysent.c code. It's a lot saner to have it in a seperate
file rather than trying to update the structure inside the awk script. :-)

At exec time, the dozen bytes or so of signal trampoline code are copied
to the top of the user's stack, rather than obtaining the trampoline code
the old way by getting a clone of the parent's user area. This allows
Linux and native binaries to freely exec each other without getting
trampolines mixed up.

Rewrote cpu_fork so that it doesn't use pmap_activate, and removed
pmap_activate since it's not used anymore. Changed cpu_fork so that
it uses one line of inline assembly rather than calling mvesp() to
get the current stack pointer. Removed mvesp() since it is no longer
being used.

Allocate DMA bounce buffers only when requested by drivers. Only the
fd and wt drivers need bounce buffers, so this normally saves 32K-1K
of kernel memory.

Keep track of which DMA channels are busy. isa_dmadone() must now be
called when DMA has finished or been aborted.

Panic for unallocated and too-small (required) bounce buffers.

fd.c:
There will be new warnings about isa_dmadone() not being called after
DMA has been aborted.

sound/dmabuf.c:
isa_dmadone() needs more parameters than are available, so temporarily
use a new interface isa_dmadone_nobounce() to avoid having to worry
about panics for fake parameters. Untested.

Completed function declarations and/or added prototypes.

devfs changes..
changes to allow devices that don't probe (e.g. /dev/mem)
to create devfs entries
this required giving 'configure' its own SYSINIT entry
so we could duck in just before it with a DEVFS init
and some device inits..
my devfs now looks like:
./misc
./misc/speaker
./misc/mem
./misc/kmem
./misc/null
./misc/zero
./misc/io
./misc/console
./misc/pcaudio
./misc/pcaudioctl
./disks
./disks/rfloppy
./disks/rfloppy/fd0.1440
./disks/rfloppy/fd1.1200
./disks/floppy
./disks/floppy/fd0.1440
./disks/floppy/fd1.1200
also some sligt cleanups.. DEVFS needs a lot of work
but I'm getting back to it..

Remove trailing whitespace.

Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) that I didn't notice when I fixed
"all" such warnings before.

Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) and most of the warnings from
`gcc -Wnested-externs'. Fix all the bugs found. There were no serious
ones.