Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

- 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

Increase MSGBUF_SIZE.
The previous size lead to truncated /var/run/dmesg.boot when booted with "-v".

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

Make MSGBUF_SIZE kernel option a loader tunable kern.msgbufsize.

Submitted by: perryh pluto.rain.com (previous version)
Reviewed by: jhb
Approved by: kib (mentor)
Tested by: universe

Make /dev/klog and kern.msgbuf* MPSAFE.

Normally msgbufp is locked using Giant. Switch it to use the
msgbuf_lock. Instead of changing the tsleep() calls to msleep(), just
convert it to condvar(9).

In my opinion the locking around msgbuf_peekbytes() still remains
questionable. It looks like locks are dropped while performing copies of
multiple blocks to userspace, which may cause the msgbuf to be reset in
the mean time. At least getting it underneath from Giant should make it
a little easier for us to figure out how to solve that.

Reminded by: rdivacky

up the default msgbuf limit to 64k.. a verbose boot on i386 on modern
hardware returns almost 48k of data... to change the default per platform,
it should be done in DEFAULTS, not here...

Discussed on: -arch

/* -> /*- for license, minor formatting changes

Increase the message buffer size on AMD64. Such machines can have a lot
of devices in them, and aren't run with only 64MB of RAM.

Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core

Fixed some style bugs (spaces instead of tabs in macro definitions ...).

Backed out previous commit since it just causes panics unless a special
value for MSGBUF_SIZE is configured. MSGBUF_SIZE =
(32768 * bootverbose ? 2 : 1) is always 1 or 2, so there is not enough space
in the buffer for metadata, and blindly using the nonexistent space tends
to cause fatal pagefaults. I think
MSGBUF_SIZE = (32768 * (bootverbose ? 2 : 1)) would be always 32768 since
bootverbose is only statically initialized to 0 early when MSGBUF_SIZE is
used. MSGBUF_SIZE = (32768 * ((boothowto & RB_VERBOSE) ? 2 : 1)) should
work, but this belongs in <sys/msgbuf.h> even less than previous versions.
MSGBUF_SIZE shouldn't be a macro.

Increase the size of MSGBUF_SIZE if booted with -v.

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

Add a checksum to the kernel message buffer, and update it every
time a character is written. Use this at boot time to reject the
existing buffer contents if they are corrupt. This fixes a problem
seen on some hardware (especially laptops) where the message buffer
gets partially corrupted during a short power cycle or reset, but
the msgbuf structure is left intact so it gets reused, resulting
in random junk and control characters appearing in dmesg and
/var/log/messages.

PR: kern/28497

Make the msg_size, msg_bufx and msg_bufr memebers of struct msgbuf
signed, since they describe a ring buffer and signed arithmetic is
performed on them. This avoids some evilish casts.

Since this changes all but two members of this structure, style(9)
those remaining ones, too.

Requested by: bde
Reviewed by: bde (earlier version)

Fixed some style bugs in the removal of __P(()). The main ones were
not removing tabs before "__P((", and not outdenting continuation lines
to preserve non-KNF lining up of code with parentheses. Switch to KNF
formatting and/or rewrap the whole prototype in some cases.

Remove __P

style(9) the structure definitions.

Replace logwakeup() with "int msgbuftrigger". There is little
point in calling a function just to set a flag.

Keep better track of the syslog FAC/PRI code and try to DTRT if
they mingle.

Log all writes to /dev/console to syslog with <console.info>
priority. The formatting is not preserved, there is no robust,
way of doing it. (Ideas with patches welcome).

Increase the default msgbuf size from 8k to 32k. Boot -v easily
overflows the default buffer making it too hard to get a dmesg from
a verbose boot. It's still changeable via an option, so if picobsd
needs to set it to something else they still can.

Reviewed by: phk, alfred

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

$Id$ -> $FreeBSD$

Some cleanups related to timecounters and weird ifdefs in <sys/time.h>.

Clean up (or if antipodic: down) some of the msgbuf stuff.

Use an inline function rather than a macro for timecounter delta.

Maintain process "on-cpu" time as 64 bits of microseconds to avoid
needless second rollover overhead.

Avoid calling microuptime the second time in mi_switch() if we do
not pass through _idle in cpu_switch()

This should reduce our context-switch overhead a bit, in particular
on pre-P5 and SMP systems.

WARNING: Programs which muck about with struct proc in userland
will have to be fixed.

Reviewed, but found imperfect by: bde

Make the size of the msgbuf (dmesg) a "normal" option.

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Increase default msgbuf to 8k.

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Made msgbuf range checking more robust and clean.

Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) and most of the warnings from
`gcc -Wnested-externs'. Fix all the bugs found. There were no serious
ones.

Made them all idempotent.
Reviewed by:
Submitted by:

Fix up some sloppy coding practices:

- Delete redundant declarations.
- Add -Wredundant-declarations to Makefile.i386 so they don't come back.
- Delete sloppy COMMON-style declarations of uninitialized data in
header files.
- Add a few prototypes.
- Clean up warnings resulting from the above.

NB: ioconf.c will still generate a redundant-declaration warning, which
is unavoidable unless somebody volunteers to make `config' smarter.

Added $Id$

This commit was generated by cvs2svn to compensate for changes in r1541,
which included commits to RCS files with non-trunk default branches.

BSD 4.4 Lite Kernel Sources