Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Include machine/acle-compat.h in cdefs.h on arm if the compiler doesn't
have ACLE support built in. The ACLE (ARM C Language Extensions) defines
a set of standardized symbols which indicate the architecture version and
features available. ACLE support is built in to modern compilers (both
clang and gcc), but absent from gcc prior to 4.4.

ARM (the company) provides the acle-compat.h header file to define the
right symbols for older versions of gcc. Basically, acle-compat.h does
for arm about the same thing cdefs.h does for freebsd: defines
standardized macros that work no matter which compiler you use. If ARM
hadn't provided this file we would have ended up with a big #ifdef __arm__
section in cdefs.h with our own compatibility shims.

Remove #include <machine/acle-compat.h> from the zillion other places (an
ever-growing list) that it appears. Since style(9) requires sys/types.h
or sys/param.h early in the include list, and both of those lead to
including cdefs.h, only a couple special cases still need to include
acle-compat.h directly.

Loves it: imp

Replace broken implementation of fuswintr() and suswintr() by functions
which return -1 as well as on tier 1 archs. Remove block_userspace_access
used only in these implementations.

(1) These functions may be called in interrupt context and pcb_onfault
can be already set in this time. Thus, prior pcb_onfault must be saved
and restored afterwards.

(2) The check that an abort came either from nested interrupt or while
in critical section or holding not sleepable lock must be avoided for
this case.

These functions are called only for profiling reason, so there will be
only small gain by making the code more complex.

Fix the spelling of fueword* to eliminate compile warnings about mismatched
begin/end symbols when the warning level is turned up.

Submitted by: Steve Kiernan <stevek@juniper.net>

ARM userspace accessors, e.g. {s,f}uword(9), copy{in,out}(9),
casuword(9) and others, use LDRT and STRT instructions to access
memory with the privileges of userspace. If the *RT instruction
faults on the kernel address, then additional checks must be done to
not confuse the VM system with invalid kernel-mode faults.

Put ARM on line with other FreeBSD architectures and disallow usermode
buffers which intersect with the kernel address space in advance,
before any accesses are performed. In other words, vm_fault(9) is no
longer called when e.g. suword(9) stores to invalid (i.e. not
userspace) address.

Also, switch ARM to use fueword(9) and casueword(9).

Note: there is a pending patch in D3617, which adds the special
processing for faults from LDRT and STRT. The addition of the
processing is useful for potential other uses of the instructions and
for completeness, but standard userspace accessors are better served
by not allowing such faults beforehand.

Reviewed by: andrew
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3816
MFC after: 2 weeks

Remove trailing whitespace from sys/arm/arm

Move to use __ARM_ARCH in more places in the kernel.

Fix alignment directives in arm asm code after clang 3.5 import.

The ancient gas we've been using interprets .align 0 as align to the
minimum required alignment for the current section. Clang's integrated
assembler interprets it as align to a byte boundary. Fortunately both
assemblers interpret a non-zero value as align to 2^N so just make sure
we have appropriate non-zero values everywhere.

Set the alignment to 4-bytes after a string as clang 3.5 can switch to
thumb mode if this is incorrect.

MFC after: 1 week
Sponsored by: ABT Systems Ltd

Use the unified syntax in a few more assembly files

MFC after: 1 week
Sponsored by: ABT Systems Ltd

Correctly a few incorrect uses of ENTRY/EENTRY and END/EEND

Sponsored by: ABT Systems Ltd

Fix unwind-info errors in our hand-written arm assembler code.

We have functions nested within functions, and places where we start a
function then never end it, we just jump to the middle of something else.
We tried to express this with nested ENTRY()/END() macros (which result
in .fnstart and .fnend directives), but it turns out there's no way to
express that nesting in ARM EHABI unwind info, and newer tools treat
multiple .fnstart directives without an intervening .fnend as an error.

These changes introduce two new macros, EENTRY() and EEND(). EENTRY()
creates a global label you can call/jump to just like ENTRY(), but it
doesn't emit a .fnstart. EEND() is a no-op that just documents the
conceptual endpoint that matches up with the same-named EENTRY().

This is based on patches submitted by Stepan Dyatkovskiy, but I made some
changes and added the EEND() stuff, so blame any problems on me.

Submitted by: Stepan Dyatkovskiy <stpworld@narod.ru>

Remove #include <machine/asmacros.h> from files that don't need it.

Change the way pcpu and curthread are stored per-core:
the old way was to store pcpu in a register, and get curthread from pcpu,
which is not very atomic, and led to issues if the thread was migrated
to another core between the time we got the pcpu address and the time we
got curthread.
Instead, we now store curthread where pcpu used to be store, and we
calculate the pcpu address based on the cpu id.

KERNBASE is unsigned, so we'd better use hs instead of ge.

Pointy hat to: cognet
Suggested by: ian

Make casuword() atomic for armv6

Add an END macro to ARM. This is mostly used to tell gas where the bounds
of the functions are when creating the EABI unwind tables.

Merging projects/armv6, part 1

Cummulative patch of changes that are not vendor-specific:
- ARMv6 and ARMv7 architecture support
- ARM SMP support
- VFP/Neon support
- ARM Generic Interrupt Controller driver
- Simplification of startup code for all platforms

o Add keyword volatile for user mutex owner field.
o Fix type consistent problem by using type long for old
umtx and wait channel.
o Rename casuptr to casuword.

Use ENTRY_NP for alternate entry points instead of ENTRY to avoid calling
mcount twice when profiling.

Spotted out by: bde

Use ENTRY instead of ALTENTRY, it doesn't exist on arm.

Implement casuword32, compare and set user integer, thank Marcel Moolenarr
who wrote the IA64 version of casuword32.

Don't use fusufault in casuptr(), as it assumes the current PCB will be
stored in r2, which can't be easily done with casuptr(). Introduce
casuptrfault instead.

Make sure casuptr() reset pcb->pcb_onfault when returning.

Start all license statements with /*-

Use the RET macro.

Implement casuptr.

Calling fuword from fuword32 with bl and without returning after is really a bad
idea.
Any way I get a customized CVS template with "Pointy hat to: cognet"
pre-filled ?

Import FreeBSD/arm kernel bits.
It only supports sa1110 (on simics) right now, but xscale support should come
soon.
Some of the initial work has been provided by :
Stephane Potvin <sepotvin at videotron.ca>
Most of this comes from NetBSD.