Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

MFC r317055,r317056 (glebius): Include sys/vmmeter.h as included

r317055: All these files need sys/vmmeter.h, but now they got it implicitly
included via sys/pcpu.h.

r317056: Typo!

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

MFC r306262, r306267, r310021: (needed to avoid conflicts on later merges)

Remove bus_dma_get_range and bus_dma_get_range_nb on armv6. We only need
this on a few earlier arm SoCs.

Restrict where we need to define fdt_fixup_table to just PowerPC and
Marvell.

Add the missing void to function signatures in much of the arm code.

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

Move the check to see if we are tracing a function with the DTrace Function
Boundary Trace to assembly to reduce the overhead of these checks.

Submitted by: Howard Su <howard0su@gmail.com>
Relnotes: Yes
Differential Revision: https://reviews.freebsd.org/D4266

Add the kernel support for Thumb-2. It is only supported on ARMv7 as the
main ARMv6 target, the Raspberry Pi, doesn't support Thumb-2.

This as been tested with a Thumb-2 userland, however building one is
currently unsupported as there are known toolchain issues breaking some
binaries. Further work will also be needed to decide on the method of
selecting which instruction set to build for, and to benchmark both to
find how building everything as Thumb-2 will affect performance.

Relnotes: yes

Add the MD parts of dtrace needed to use fbt on ARM. For this we need to
emulate the instructions used in function entry and exit.

For function entry ARM will use a push instruction to push up to 16
registers to the stack. While we don't expect all 16 to be used we need to
handle any combination the compiler may generate, even if it doesn't make
sense (e.g. pushing the program counter).

On function return we will either have a pop or branch instruction. The
former is similar to the push instruction, but with care to make sure we
update the stack pointer and program counter correctly in the cases they
are either in the list of registers or not. For branch we need to take the
24-bit offset, sign-extend it, and add that number of 4-byte words to the
program counter. Care needs to be taken as, due to historical reasons, the
address the branch is relative to is not the current instruction, but 8
bytes later.

This allows us to use the following probes on ARM boards:
dtrace -n 'fbt::malloc:entry { stack() }'
and
dtrace -n 'fbt::free:return { stack() }'

Differential Revision: https://reviews.freebsd.org/D2007
Reviewed by: gnn, rpaulo
Sponsored by: ABT Systems Ltd

Unify interrupts bit definition and usage. While here remove PSR_C_bit.

Submitted by: Svatopluk Kraus <onwahe at gmail.com>,
Michal Meloun <meloun at miracle.cz>
Differential Revision: https://reviews.freebsd.org/D754

Make undefined exception entry MPSAFE.

The old code used static storage to preserve a couple registers while
setting up the trapframe for the main handler. Doing so was the last
leftover crumbs from the days when a low-level debugger was hooked into
the exception entry code.

Now the exception entry sequence is essentially the same as for the
other exceptions, which still involves needlessly indirecting through
a function pointer which points to the same code on every platform.
Removing that indirection will be handled as a separate cleanup.

This work is based on an analysis by Juergen Weiss.

Remove the last dregs of trapframe_t. It turns out only arm was using
this type, so remove it to make arm code more consistant with other
platforms. Thanks to bde@ for pointing out only arm used trapframe_t.

Rename device vfp to option VFP and retire the ARM_VFP_SUPPORT option. This
simplifies enabling as previously both options were required to be enabled,
now we only need a single option.

While here enable VFP on the PandaBoard.

Remove unused FPE code. This is not enabled anywhere as it is the only
file I can find containing FAST_FPE. It appears this would not work as
want_resched is not defined anywhere.

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

Final whitespace trim.

KDB needs <machine/db_machdep.h>, so move it under #ifdef KDB.
While I'm there, remove dead code, we will never support acorn26.

Retire the MALLOC and FREE macros. They are an abomination unto style(9).

MFC after: 3 months

Rework the PCPU_* (MD) interface:
- Rename PCPU_LAZY_INC into PCPU_INC
- Add the PCPU_ADD interface which just does an add on the pcpu member
given a specific value.

Note that for most architectures PCPU_INC and PCPU_ADD are not safe.
This is a point that needs some discussions/work in the next days.

Reviewed by: alc, bde
Approved by: jeff (mentor)

style(9) cleanup.

Approved by: cognet

Not only disable/enable interrupts, do it for FIQs as well, when needed.

userret() now only takes 2 parameters.

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

Merge from p4: minor formatting nits.

1. Change prototype of trapsignal and sendsig to use ksiginfo_t *, most
changes in MD code are trivial, before this change, trapsignal and
sendsig use discrete parameters, now they uses member fields of
ksiginfo_t structure. For sendsig, this change allows us to pass
POSIX realtime signal value to user code.

2. Remove cpu_thread_siginfo, it is no longer needed because we now always
generate ksiginfo_t data and feed it to libpthread.

3. Add p_sigqueue to proc structure to hold shared signals which were
blocked by all threads in the proc.

4. Add td_sigqueue to thread structure to hold all signals delivered to
thread.

5. i386 and amd64 now return POSIX standard si_code, other arches will
be fixed.

6. In this sigqueue implementation, pending signal set is kept as before,
an extra siginfo list holds additional siginfo_t data for signals.
kernel code uses psignal() still behavior as before, it won't be failed
even under memory pressure, only exception is when deleting a signal,
we should call sigqueue_delete to remove signal from sigqueue but
not SIGDELSET. Current there is no kernel code will deliver a signal
with additional data, so kernel should be as stable as before,
a ksiginfo can carry more information, for example, allow signal to
be delivered but throw away siginfo data if memory is not enough.
SIGKILL and SIGSTOP have fast path in sigqueue_add, because they can
not be caught or masked.
The sigqueue() syscall allows user code to queue a signal to target
process, if resource is unavailable, EAGAIN will be returned as
specification said.
Just before thread exits, signal queue memory will be freed by
sigqueue_flush.
Current, all signals are allowed to be queued, not only realtime signals.

Earlier patch reviewed by: jhb, deischen
Tested on: i386, amd64

Use PCPU_LAZY_INC() for cnt.v_{intr,trap,syscalls} rather than atomic
operations in some places and simple non-per CPU math in others.

Add support for ptrace() and gdb breakpoints.

Start all license statements with /*-

Include <sys/signalvar.h> for trapsignal().

Don't include sys/user.h merely for its side-effect of recursively
including other headers.

Implement breakpoints and single stepping on arm.

Obtained from: NetBSD

Implement enough to be able to enter and leave DDB.

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.