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

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

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

msgbuf: Allow microsecond granularity timestamps

Today, kern.msgbuf_show_timestamp=1 will give 1 second granularity
timestamps on dmesg lines. When kern.msgbuf_show_timestamp=2, we'll
produce microsecond level graunlarity.
For example:
old (== 1):
[13] Dual Console: Video Primary, Serial Secondary
[14] lo0: link state changed to UP
[15] bxe0: NIC Link is Up, 10000 Mbps full duplex, Flow control: ON - receive & transmit
[15] bxe0: link state changed to UP
new (== 2):
[13.807015] Dual Console: Video Primary, Serial Secondary
[14.544150] lo0: link state changed to UP
[15.272044] bxe0: NIC Link is Up, 10000 Mbps full duplex, Flow control: ON - receive & transmit
[15.272052] bxe0: link state changed to UP

Sponsored by: Netflix

Make msgbuf_peekbytes() not return leading zeroes.

Introduce new MSGBUF_WRAP flag, indicating that buffer has wrapped
at least once and does not keep zeroes from the last msgbuf_clear().
It allows msgbuf_peekbytes() to return only real data, not requiring
every consumer to trim the leading zeroes after doing pointless copy.
The most visible effect is that kern.msgbuf sysctl now always returns
proper zero-terminated string, not only after the first buffer wrap.

MFC after: 1 week
Sponsored by: iXsystems, Inc.

Allow minidumps to be performed on the live system

Add a boolean parameter to minidumpsys(), to indicate a live dump. When
requested, take a snapshot of important global state, and pass this to
the machine-dependent minidump function. For now this includes the
kernel message buffer, and the bitset of pages to be dumped. Beyond
this, we don't take much action to protect the integrity of the dump
from changes in the running system.

A new function msgbuf_duplicate() is added for snapshotting the message
buffer. msgbuf_copy() is insufficient for this purpose since it marks
any new characters it finds as read.

For now, nothing can actually trigger a live minidump. A future patch
will add the mechanism for this. For simplicity and safety, live dumps
are disallowed for mips.

Reviewed by: markj, jhb
MFC after: 2 weeks
Sponsored by: Juniper Networks, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D31993

kern: clean up empty lines in .c and .h files

msgbuf: Light detailing (const'ify and bool'itize)

Do pass removing some write-only variables from the kernel.

This reduces noise when kernel is compiled by newer GCC versions,
such as one used by external toolchain ports.

Reviewed by: kib, andrew(sys/arm and sys/arm64), emaste(partial), erj(partial)
Reviewed by: jhb (sys/dev/pci/* sys/kern/vfs_aio.c and sys/kern/kern_synch.c)
Differential Revision: https://reviews.freebsd.org/D10385

sys/kern: adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

sys/kern: spelling fixes in comments.

No functional change.

Pull in r267961 and r267973 again. Fix for issues reported will follow.

Revert r267961, r267973:

These changes prevent sysctl(8) from returning proper output,
such as:

1) no output from sysctl(8)
2) erroneously returning ENOMEM with tools like truss(1)
or uname(1)
truss: can not get etype: Cannot allocate memory

Extend the meaning of the CTLFLAG_TUN flag to automatically check if
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.

Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.

MFC after: 2 weeks
Sponsored by: Mellanox Technologies

- Clean up timestamps in msgbuf code. The timestamps should now be
inserted after the priority token thus cleaning up the output.
- Remove the needless double internal do_add_char function.
- Resolve a possible deadlock if interrupts are
disabled and getnanotime is called

Reviewed by: bde kmacy, avg, sbruno (various versions)
Approved by: cperciva
MFC after: 2 weeks

Add a timestamp to the msgbuf output in order to determine when when
messages were printed.

This can be enabled with the kern.msgbuf_show_timestamp sysctl

PR: kern/161553
Reviewed by: avg
Submitted by: Arnaud Lacombe <lacombar@gmail.com>
Approved by: cperciva
MFC after: 1 month

Fix a bug introduced in revision 222537.

In msgbuf_reinit() and msgbuf_init(), we weren't initializing the mutex.
Depending on the contents of memory, the LO_INITIALIZED flag might be
set on the mutex (either due to a warm reboot, and the message buffer
remaining in place, or due to garbage in memory) and in that case, with
INVARIANTS turned on, we would trigger an assertion that the mutex had
already been initialized.

Fix this by bzeroing the message buffer mutex for the _init() and _reinit()
paths.

Reported by: mdf

Fix apparent garbage in the message buffer.

While we have had a fix in place (options PRINTF_BUFR_SIZE=128) to fix
scrambled console output, the message buffer and syslog were still getting
log messages one character at a time. While all of the characters still
made it into the log (courtesy of atomic operations), they were often
interleaved when there were multiple threads writing to the buffer at the
same time.

This fixes message buffer accesses to use buffering logic as well, so that
strings that are less than PRINTF_BUFR_SIZE will be put into the message
buffer atomically. So now dmesg output should look the same as console
output.

subr_msgbuf.c: Convert most message buffer calls to use a new spin
lock instead of atomic variables in some places.

Add a new routine, msgbuf_addstr(), that adds a
NUL-terminated string to a message buffer. This
takes a priority argument, which allows us to
eliminate some races (at least in the the string
at a time case) that are present in the
implementation of msglogchar(). (dangling and
lastpri are static variables, and are subject to
races when multiple callers are present.)

msgbuf_addstr() also allows the caller to request
that carriage returns be stripped out of the
string. This matches the behavior of msglogchar(),
but in testing so far it doesn't appear that any
newlines are being stripped out. So the carriage
return removal functionality may be a candidate
for removal later on if further analysis shows
that it isn't necessary.

subr_prf.c: Add a new msglogstr() routine that calls
msgbuf_logstr().

Rename putcons() to putbuf(). This now handles
buffered output to the message log as well as
the console. Also, remove the logic in putcons()
(now putbuf()) that added a carriage return before
a newline. The console path was the only path that
needed it, and cnputc() (called by cnputs())
already adds a carriage return. So this
duplication resulted in kernel-generated console
output lines ending in '\r''\r''\n'.

Refactor putchar() to handle the new buffering
scheme.

Add buffering to log().

Change log_console() to use msglogstr() instead of
msglogchar(). Don't add extra newlines by default
in log_console(). Hide that behavior behind a
tunable/sysctl (kern.log_console_add_linefeed) for
those who would like the old behavior. The old
behavior led to the insertion of extra newlines
for log output for programs that print out a
string, and then a trailing newline on a separate
write. (This is visible with dmesg -a.)

msgbuf.h: Add a prototype for msgbuf_addstr().

Add three new fields to struct msgbuf, msg_needsnl,
msg_lastpri and msg_lock. The first two are needed
for log message functionality previously handled
by msglogchar(). (Which is still active if
buffering isn't enabled.)

Include sys/lock.h and sys/mutex.h for the new
mutex.

Reviewed by: gibbs

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

- Import the HEAD csup code which is the basis for the cvsmode work.

/* -> /*- for copyright notices, minor format tweaks as necessary

Put the message about msgbuf cksum mismatch under bootverbose and tell
people what the consequence is.

Replace the code for reading and writing the kernel message buffer
with a new implementation that has a mostly reentrant "addchar"
routine, supports multiple message buffers in the kernel, and hides
the implementation details from callers.

The new code uses a kind of sequence number to represend the current
read and write positions in the buffer. This approach (suggested
mainly by bde) permits the read and write pointers to be maintained
separately, which reduces the number of atomic operations that are
required. The "mostly reentrant" above refers to the way that while
it is now always safe to have any number of concurrent writers,
readers could see the message buffer after a writer has advanced
the pointers but before it has witten the new character.

Discussed on: freebsd-arch