__builtin_unreachable doesn't raise any compile-time warnings/errors on its
own, so problems with its usage can't be easily detected. While it would be
nice for this situation to change and compilers to at least add a warning
for trivial cases where local state means the instruction can't be reached,
this isn't the case at the moment and likely will not happen.
This commit adds an __assert_unreachable, whose intent is incredibly clear:
it asserts that this instruction is unreachable. On INVARIANTS builds, it's
a panic(), and on non-INVARIANTS it expands to __unreachable().
Existing users of __unreachable() are converted to __assert_unreachable,
to improve debuggability if this assumption is violated.
Reviewed by: mjg
Differential Revision: https://reviews.freebsd.org/D23793
r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.
This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.
Mark all obvious cases as MPSAFE. All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT
Approved by: kib (mentor, blanket)
Commented by: kib, gallatin, melifaro
Differential Revision: https://reviews.freebsd.org/D23718
o Remove All Rights Reserved from my notices
o imp@FreeBSD.org everywhere
o regularize punctiation, eliminate date ranges
o Make sure that it's clear that I don't claim All Rights reserved by listing
All Rights Reserved on same line as other copyright holders (but not
me). Other such holders are also listed last where it's clear.
I limited potentially infinite timings by 960 us based on a footnote on
page 38 of Maxim Integrated Application Note 937, Book of iButton
Standards: "In order not to mask interrupt signalling by other devices
on the 1–Wire bus, tRSTL + tR should always be less than 960 us."
MFC after: 3 weeks
Previously we used the minimal value of 1 us and it was really tight.
Application Note 3829 has a table describing recommended t_rec values
for various bus voltages, temperature conditions and numbers of slave
devices. The new value decreases the maximum possible data rate from
16.3 Kbit/s to 13.3 Kbit/s, but it allows for up to four slaves on a
3.3V bus (under room temperature).
References:
- Maxim Integrated Application Note 3829
Determining the Recovery Time for Multiple-Slave 1-Wire(R) Networks
- Maxim Integrated Application Note 937
Book of iButton Standards
Discussed with: imp (D22108)
MFC after: 3 weeks
This allows replacing "sys/eventfilter.h" includes with "sys/_eventfilter.h"
in other header files (e.g., sys/{bus,conf,cpu}.h) and reduces header
pollution substantially.
EVENTHANDLER_DECLARE and EVENTHANDLER_LIST_DECLAREs were moved out of .c
files into appropriate headers (e.g., sys/proc.h, powernv/opal.h).
As a side effect of reduced header pollution, many .c files and headers no
longer contain needed definitions. The remainder of the patch addresses
adding appropriate includes to fix those files.
LOCK_DEBUG and LOCK_FILE_LINE_ARG are moved to sys/_lock.h, as required by
sys/mutex.h since r326106 (but silently protected by header pollution prior
to this change).
No functional change (intended). Of course, any out of tree modules that
relied on header pollution for sys/eventhandler.h, sys/lock.h, or
sys/mutex.h inclusion need to be fixed. __FreeBSD_version has been bumped.
Coverity reports an uninitialized "dir" in case the switch defaults
without hitting any case. Respect the original intent and quell the
false positive with the relatively new __unreachable() builtin.
CID: 1331566
only gpiobus configured via FDT is supported. Bus enumeration is
supported. Devices are created for each device found. 1-Wire
temperature controllers are supported, but other drivers could be
written. Temperatures are polled and reported via a sysctl. Errors
are reported via sysctl counters. Mis-wired bus detection is included
for more trouble shooting. See ow(4), owc(4) and ow_temp(4) for
details of what's supported and known issues.
This has been tested on Raspberry Pi-B, Pi2 and Beagle Bone Black
with up to 7 devices.
Differential Revision: https://reviews.freebsd.org/D2956
Relnotes: yes
MFC after: 2 weeks
Reviewed by: loos@ (with many insightful comments)
