arm64: Create a Linux view of the ID registers

When adding support for new hardware extensions we may not want to
enable support for the FreeBSD and Linux ABIs at the same time. To
support this split the Linux ID register and hwcaps so they can be
configured separately.

Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D42372

sys: Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

arm64: add swapueword8/32

Much like casueword*, except just a plain old swap. Maintains a similar
interface to casu(9)- return value -1 (fault), 0 (success), or 1 (fail),
and also both ll/sc and LSE variants are implemented.

These will be used to implement 32-bit swp/swpb emulation on aarch64.

Reveiwed by: andrew
Sponsored by: Stormshield
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D39837

Simplify swi for bus_dma.

When a DMA request using bounce pages completes, a swi is triggered to
schedule pending DMA requests using the just-freed bounce pages. For
a long time this bus_dma swi has been tied to a "virtual memory" swi
(swi_vm). However, all of the swi_vm implementations are the same and
consist of checking a flag (busdma_swi_pending) which is always true
and if set calling busdma_swi. I suspect this dates back to the
pre-SMPng days and that the intention was for swi_vm to serve as a
mux. However, in the current scheme there's no need for the mux.

Instead, remove swi_vm and vm_ih. Each bus_dma implementation that
uses bounce pages is responsible for creating its own swi (busdma_ih)
which it now schedules directly. This swi invokes busdma_swi directly
removing the need for busdma_swi_pending.

One consequence is that the swi now works on RISC-V which had previously
failed to invoke busdma_swi from swi_vm.

Reviewed by: imp, kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D33447

minidump: Parameterize minidumpsys()

The minidump code is written assuming that certain global state will not
change, and rightly so, since it executes from a kernel debugger
context. In order to support taking minidumps of a live system, we
should allow copies of relevant global state that is likely to change to
be passed as parameters to the minidumpsys() function.

This patch does the work of parameterizing this function, by adding a
struct minidumpstate argument. For now, this struct allows for copies of
the kernel message buffer, and the bitset that tracks which pages should
be dumped (vm_page_dump). Follow-up changes will actually make use of
these arguments.

Notably, dump_avail[] does not need a snapshot, since it is not expected
to change after system initialization.

The existing minidumpsys() definitions are renamed, and a thin MI
wrapper is added to kern_dump.c, which handles the construction of
the state struct. Thus, calling minidumpsys() remains as simple as
before.

Reviewed by: kib, markj, jhb
Sponsored by: Juniper Networks, Inc.
Sponsored by: Klara, Inc.
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D31989

arm64: HWCAP/HWCAP2 aux args support for 32-bit ARM binaries.

This fixes build/run of golang under COMPAT32 emulation.

PR: 256897
Reviewed by: andrew, mmel, manu, jhb, cognet, Robert Clausecker
Tested by: brd, andrew, Robert Clausecker
MFC after: 3 weeks
Relnotes: yes
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D31175

Replace the arm64 initial_fpcr with a macro

This value was never changed from its default value. Replace it with a
macro.

Sponsored by: Innovate UK

arm64: Initialize VFP control register.

The RW fields in this register reset to architecturally unknown values,
so initialize these to the proper rounding and denormal mode.
MFC after: 1 week

Move vm_page_dump bitset array definition to MI code

These definitions were repeated by all architectures, with small
variations. Consolidate the common definitons in machine
independent code and use bitset(9) macros for manipulation. Many
opportunities for deduplication remain in the machine dependent
minidump logic. The only intended functional change is increasing
the bit index type to vm_pindex_t, allowing the indexing of pages
with address of 8 TiB and greater.

Reviewed by: kib, markj
Approved by: scottl (implicit)
MFC after: 1 week
Sponsored by: Ampere Computing, Inc.
Differential Revision: https://reviews.freebsd.org/D26129

Add NetBSD compatible bus_space_peek_N() and bus_space_poke_N() functions.
One problem with the bus_space_read_N() and bus_space_write_N() family of
functions is that they provide no protection against exceptions which can
occur when no physical hardware or device responds to the read or write
cycles. In such a situation, the system typically would panic due to a
kernel-mode bus error. The bus_space_peek_N() and bus_space_poke_N() family
of functions provide a mechanism to handle these exceptions gracefully
without the risk of crashing the system.

Typical example is access to PCI(e) configuration space in bus enumeration
function on badly implemented PCI(e) root complexes (RK3399 or Neoverse
N1 N1SDP and/or access to PCI(e) register when device is in deep sleep state.

This commit adds a real implementation for arm64 only. The remaining
architectures have bus_space_peek()/bus_space_poke() emulated by using
bus_space_read()/bus_space_write() (without exception handling).

MFC after: 1 month
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D25371

arm64: export new HWCAP features

Expose some of the new HWCAP features added in r65304. This includes the
addition of elf_hwcap2 into the sysvec, and a separate function to parse
for those features.

This only exposes features which require no further configuration, e.g.
indicating the presence of certain instructions. Larger features (SVE)
will not be advertised until we actually support them. The exact list of
features/extensions this patch exposes is:
- ARMv8.0-DGH
- ARMv8.0-SB
- ARMv8.2-BF16
- ARMv8.2-DCCVADP
- ARMv8.2-I8MM
- ARMv8.4-LRCPC
- ARMv8.5-CondM
- ARMv8.5-FRINT
- ARMv8.5-RNG
- PSTATE.SSBS

While here, annotate elf_hwcap and elf_hwcap2 as __read_frequently, and
move the declarations to the machine/md_var.h header.

Submitted by: mikael@ (D22314 portion)
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D26031
Differential Revision: https://reviews.freebsd.org/D22314

Implement userspace gettimeofday(2) with HPET timecounter.

Right now, userspace (fast) gettimeofday(2) on x86 only works for
RDTSC. For older machines, like Core2, where RDTSC is not C2/C3
invariant, and which fall to HPET hardware, this means that the call
has both the penalty of the syscall and of the uncached hw behind the
QPI or PCIe connection to the sought bridge. Nothing can me done
against the access latency, but the syscall overhead can be removed.
System already provides mappable /dev/hpetX devices, which gives
straight access to the HPET registers page.

Add yet another algorithm to the x86 'vdso' timehands. Libc is updated
to handle both RDTSC and HPET. For HPET, the index of the hpet device
to mmap is passed from kernel to userspace, index might be changed and
libc invalidates its mapping as needed.

Remove cpu_fill_vdso_timehands() KPI, instead require that
timecounters which can be used from userspace, to provide
tc_fill_vdso_timehands{,32}() methods. Merge i386 and amd64
libc/<arch>/sys/__vdso_gettc.c into one source file in the new
libc/x86/sys location. __vdso_gettc() internal interface is changed
to move timecounter algorithm detection into the MD code.

Measurements show that RDTSC even with the syscall overhead is faster
than userspace HPET access. But still, userspace HPET is three-four
times faster than syscall HPET on several Core2 and SandyBridge
machines.

Tested by: Howard Su <howard0su@gmail.com>
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
Differential revision: https://reviews.freebsd.org/D7473

Call busdma_swi from swi_vm as is done from other architectures.

Obtained from: ABT Systems Ltd
Sponsored by: The FreeBSD Foundation

Add support for usermode (vdso-like) gettimeofday(2) and
clock_gettime(2) on ARMv7 and ARMv8 systems which have architectural
generic timer hardware. It is similar how the RDTSC timer is used in
userspace on x86.

Fix a permission problem where generic timer access from EL0 (or
userspace on v7) was not properly initialized on APs.

For ARMv7, mark the stack non-executable. The shared page is added for
all arms (including ARMv8 64bit), and the signal trampoline code is
moved to the page.

Reviewed by: andrew
Discussed with: emaste, mmel
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D4209

Remove pmap_kenter from pmap.h, the function doesn't exist.

Bring in the start of the arm64 kernel.

This is only the minimum set of files needed to boot in qemu. As such it is
missing a few things.

The bus_dma code is currently only stub functions with a full implementation
from the development tree to follow.

The gic driver has been copied as the interrupt framework is different. It
is expected the two drivers will be merged by the arm intrng project,
however this will need to be imported into the tree and support for arm64
would need to be added.

This includes code developed by myself, SemiHalf, Ed Maste, and Robin
Randhawa from ARM. This has been funded by the FreeBSD Foundation, with
early development by myself in my spare time with assistance from Robin.

Differential Revision: https://reviews.freebsd.org/D2199
Reviewed by: emaste, imp
Relnotes: yes
Sponsored by: The FreeBSD Foundation