stand/lua: always allow overriding with local config files

Loader now also read configuration files listed in local_loader_conf_files.
Files listed here are the last ones read. And /boot/loader.conf.local was
moved from loader_conf_files to local_loader_conf_files leaving only
loader.conf and device.hints in loader_conf_files by default.

The idea is to ensure local_loader_conf_files, i.e., /boot/loader.conf.local,
can always be used to override other user defined settings.

So the sequencing is now as follow:

1. Bootstrap:
/boot/defaults/loader.conf

2. Read loader_conf_files files:
/boot/device.hints
/boot/loader.conf

3. Read loader_conf_dirs files:
/boot/loader.conf.d/*.conf

4. And finally, rread local_loader_conf_files files:
/boot/loader.conf.local

Reviewed by: imp, kevans
Pull Request: https://github.com/freebsd/freebsd-src/pull/759

Revert "stand/lua: always allow overriding with local config files"

This reverts commit d3d0b735571d9562812ce5b343a6e91f7a795dbe. no mail
sent out, and the commit message was wrong.

Sponsored by: Netflix

stand/lua: always allow overriding with local config files

Loader now also read configuration files listed in local_loader_conf_files.
Files listed here are the last ones read. And /boot/loader.conf.local was
moved from loader_conf_files to local_loader_conf_files leaving only
loader.conf and device.hints in loader_conf_files by default.

The idea is to ensure local_loader_conf_files, i.e., /boot/loader.conf.local,
can always be used to override other user defined settings.

So the sequencing is now as follow:

1. Bootstrap:
/boot/defaults/loader.conf

2. Read loader_conf_files files:
/boot/device.hints
/boot/loader.conf

3. Read loader_conf_dirs files:
/boot/loader.conf.d/*.conf

4. And finally, rread local_loader_conf_files files:
/boot/loader.conf.local

stand: Add 1440p to the list of known resolutions.

MFC after: 1 week
Reviewed by: manu, kevans, imp
Differential Revision: https://reviews.freebsd.org/D43391

Use 115200 bps by default for serial communication

9600 was a standard baud rate decades ago, but 115200 is now more common
so choose defaults that are useful to the largest number of users.

Note that boot0sio does not support rates above 9600 so it remains
unchanged.

Reviewed by: bz, imp, manu
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D36295

Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Add support for getting early entropy from UEFI

UEFI provides a protocol for accessing randomness. This is a good way
to gather early entropy, especially when there's no driver for the RNG
on the platform (as is the case on the Marvell Armada8k (MACCHIATObin)
for now).

If the entropy_efi_seed option is enabled in loader.conf (default: YES)
obtain 2048 bytes of entropy from UEFI and pass is to the kernel as a
"module" of name "efi_rng_seed" and type "boot_entropy_platform"; if
present, ingest it into the kernel RNG.

Submitted by: Greg V
Reviewed by: markm, kevans
Approved by: csprng (markm)
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D20780

loader: Set twiddle globaldiv to 16 by default

Booting FreeBSD on an EC2 c5.xlarge instance, the loader "twiddles"
810 times over the course of 510 ms, a rate of 1.59 kHz. Even accepting
that many systems are slower than this particular VM and will take
longer to boot (especially if using spinning-rust disks), this seems
like an unhelpfully large amount of twiddling when compared to the
~60 Hz frame rate of many displays; printing the twiddles also consumes
roughly 10% of the boot time on the aforementioned VM.

Setting the default globaldiv to 16 dramatically reduces the time spent
printing twiddles to the console while still twiddling at roughly 100
Hz; this should be ample even for systems which take longer to boot and
consequently twiddle slower.

Note that this can adjusted via the twiddle_divisor variable in
loader.conf, but that file is not processed until nearly halfway
through the loader's runtime.

Reviewed by: allanjude, jrtc27, kevans
MFC after: 1 week
Sponsored by: https://www.patreon.com/cperciva
Differential Revision: <https://reviews.freebsd.org/D32163>

lualoader: add loader_conf_dirs support (loader.conf.d)

loader_conf_dirs is the supporting mechanism for the included
/boot/loader.conf.d directory. When lualoader finishes processing all of
the loader_conf_files it finds after walking /boot/defaults/loader.conf,
it will now check any and all loader_conf_dirs and process files ending
in ".conf" as if they were a loader.conf.

Note that loader_conf_files may be specified in a loader.conf.d config
file, but loader_conf_dirs may *not*. It will only be processed as specified
in /boot/defaults/loader.conf and any loader_conf_files that were loaded
from there.

Reviewed by: allanjude, freqlabs, rpokala, tsoome
Includes suggestion from: imp
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D25608

loader: zfs should support bootonce an nextboot

bootonce feature is temporary, one time boot, activated by
"bectl activate -t BE", "bectl activate -T BE" will reset the bootonce flag.

By default, the bootonce setting is reset on attempt to boot and the next
boot will use previously active BE.

By setting zfs_bootonce_activate="YES" in rc.conf, the bootonce BE will
be set permanently active.

bootonce dataset name is recorded in boot pool labels, bootenv area.

in case of nextboot, the nextboot_enable boolean variable is recorded in
freebsd:nvstore nvlist, also stored in boot pool label bootenv area.
On boot, the loader will process /boot/nextboot.conf if nextboot_enable
is "YES", and will set nextboot_enable to "NO", preventing /boot/nextboot.conf
processing on next boot.

bootonce and nextboot features are usable in both UEFI and BIOS boot.

To use bootonce/nextboot features, the boot loader needs to be updated on disk;
if loader.efi is stored on ESP, then ESP needs to be updated and
for BIOS boot, stage2 (zfsboot or gptzfsboot) needs to be updated
(gpart or other tools).

At this time, only lua loader is updated.

Sponsored by: Netflix, Klara Inc.
Differential Revision: https://reviews.freebsd.org/D25512

Properly backout r362998

Correct a small mistake in r363060's backaout of r362998 by reverse-applying
r362998 by hand to loader.conf.

Differential Revision: https://reviews.freebsd.org/D25606

Revert r362998, r326999 while a better compatibility strategy is devised.

Fix a example/docs typo from r362998, no functional change.

Migrate the feature of excluding RAM pages to use "excludelist"
as its nomenclature.

MFC after: 1 week

Preload hostuuid for early-boot use

prison0's hostuuid will get set by the hostid rc script, either after
generating it and saving it to /etc/hostid or by simply reading /etc/hostid.

Some things (e.g. arbitrary MAC address generation) may use the hostuuid as
a factor in early boot, so providing a way to read /etc/hostid (if it's
available) and using it before userland starts up is desirable. The code is
written such that the preload doesn't *have* to be /etc/hostid, thus not
assuming that there will be newline at the end of the buffer or even the
exact shape of the newline. White trailing whitespace/non-printables
trimmed, the result will be validated as a valid uuid before it's used for
early boot purposes.

The preload can be turned off with hostuuid_load="NO" in /boot/loader.conf,
just as other preloads; it's worth noting that this is a 37-byte file, the
overhead is believed to be generally minimal.

It doesn't seem necessary at this time to be concerned with kern.hostid.

One does wonder if we should consider validating hostuuids coming in
via jail_set(2); some bits seem to care about uuid form and we bother
validating format of smbios-provided uuid and in-fact whatever uuid comes
from /etc/hostid.

Reviewed by: karels, delphij, jamie
MFC after: 1 week (don't preload by default, probably)
Differential Revision: https://reviews.freebsd.org/D24288

Enable lualoader's kernel autodetection, disabled on install media

As documented in loader.conf(5), kernels_autodetect="YES" will cause the
Lua scripts to effectively scan /boot for directories with a "kernel" file
inside, to be listed in the loader menu.

Approved by: re (kib)

lualoader: Create a module blacklist, add DRM modules to it

This is a step in the process of easing migration into the new world order
of DRM drivers. Strongly encourage users towards loading DRM modules via
rc.conf(5) instead of loader.conf(5) by failing the load from loader(8).
Users so inclined may wipe out the blacklist via module_blacklist="" in
loader.conf(5), and it is expected that these modules will eventually be
removed from the blacklist. They may still be loaded as dependencies of
other modules or explicitly via the loader prompt, but this should not be a
major problem.

Approved by: re (rgrimes)
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D16914

The kernel DTrace audit provider (dtaudit) relies on auditd(8) to load
/etc/security/audit_event to provide a list of audit event-number <->
name mappings. However, this occurs too late for anonymous tracing.
With this change, adding 'audit_event_load="YES"' to /boot/loader.conf
will cause the boot loader to preload the file, and then the kernel
audit code will parse it to register an initial set of audit event-number
<-> name mappings. Those mappings can later be updated by auditd(8) if
the configuration file changes.

Reviewed by: gnn, asomers, markj, allanjude
Discussed with: jhb
Approved by: re (kib)
MFC after: 1 week
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D16589

Add microcode update configuration to the default loader.conf.

MFC after: 6 weeks
Sponsored by: The FreeBSD Foundation

Default loader.conf: Drop efi_max_resolution to 1x1

Effectively disabling the mode changing bits in the loader. No matter which
way we go with it, it seems to be wrong- either the firmware doesn't change
the resolution and reports the resolution we requested, or the firmware
changes the resolution and doesn't report the resolution we requested. It
some cases, it does the right thing, but the bad cases outweight those.

Interested individuals can still set efi_max_resolution to 1080p or whatnot
in loader.conf(5) to restore the new behavior, but the new behavior does not
work out well for many cases.

Discussed with: imp

efi loader: Respect efi_max_resolution in loader.conf(5)

Default the max resolution to 1080p, we'll accept Width x Height
specifications along with the following presets:

- 480p
- 720p
- 1080p
- 2160p or 4k
- 5k

PR: 224825
Differential Revision: https://reviews.freebsd.org/D14801

Move /boot/overlays to /boot/dtb/overlays

The former is fairly vague; these are FDT overlays to be applied to the
running system, so /boot/dtb is a sensible location to put it without
cluttering up /boot/dtb even further if desired.

Fix a typo: "now" -> "no".

Take a meat cleaver to defaults/loader.conf

Remove almost all of the _load=XXX options (kept only those relevant
to splash screens, since there were other settings).
Remove the excessively cutesy comment blocks.
Remove excessive comments and replace with similar content
Remove gratuitous blank lines (while leaving some)

We have too many modules to list them all here. There's no purpose in
doing so and it's a giant hassle to maintain. In addition the extra
~500 lines slow this down on small platforms. It slowed it down
so much small platforms forked, which caused other issues...
This is a compromise between those two extremes.

Go back to one loader.conf

We really only need one loader.conf. The other loader.conf was created
because the current one took forever to parse in FORTH. That will be
fixed in the next commit.