Dividing by 0 in order to check for irq13/exception16 delivery apparently
always causes an irq13 even if we have configured for exception16 (by
setting CR0_NE). This was expected, but the timing of the irq13 was
unexpected. Without CR0_NE, the irq13 is delivered synchronously at
least on my test machine, but with CR0_NE it is delivered a little
later (about 250 nsec) in PIC mode and much later (5000-10000 nsec)
in APIC mode. So especially in APIC mode, the irq13 may arrive after
it is supposed to be shut down. It should then be masked, but the
shutdown is incomplete, so the irq goes to a null handler that just
reports it as stray. The fix is to wait a bit after dividing by 0 to
give a good chance of the irq13 being handled by its proper handler.
Removed the hack that was supposed to recover from the incomplete shutdown
of irq13. The shutdown is now even more incomplete, or perhaps just
incomplete in a different way, but the hack now has no effect because
irq13 is edge triggered and handling of edge triggered interrupts is
now optimized by skipping their masking. The hack only worked due
to it accidentally not losing races.
The incomplete shutdown of irq13 still allows unprivileged users to
generate a stray irq13 (except on systems where irq13 is actually used)
by unmasking an npx exception and causing one. The exception gets
handled properly by the exception 16 handler. A spurious irq13 is
delivered asynchronously but is harmless (as in the probe) because it
is almost perfectly not handled by the null interrupt handler.
Perfectly not handling it involves mainly not resetting the npx busy
latch. This prevents further irq13's despite them not being masked in
the [A]PIC.
Removed paragraph about "new experimental feature" the hw.ata.tags
which sysctl -a knows nothing about.
Fix typos while I'm here.
PR: docs/66493
Submitted by: Julien Gabel <jpeg@thilelli.net>
It does not appear to be possible to cross-build arm from i386 at the
moment, and I have no ARM hardware anyway. Thus, I'm sure there are
bugs. I will gladly fix these when the arm port is more mature.
Reviewed by: standards@
features appear to work, subject to the caveat that you tell gcc you
want standard rather than recklessly fast behavior
(-mieee-with-inexact -mfp-rounding-mode=d).
The non-standard feature of delivering a SIGFPE when an application
raises an unmasked exception does not work, presumably due to a kernel
bug. This isn't so bad given that floating-point exceptions on the
Alpha architecture are not precise, so making them useful in userland
requires a significant amount of wizardry.
Reviewed by: standards@
with an ASUS A7N8X-E motherboard in APIC mode, since storming interrupts
don't repeat immediately. Use DELAY(1) to wait a bit for them to repeat.
This affects all systems. Only delay for the first
(10 * intr_storm_threshold) interrupts (per interrupt handler) so that
this is only a pessimization while warming up. Throttle after calling
the sub-handlers instead of before so that the long delay given by
throttling can be used instead of the DELAY(1) to detect storms after
warming up.
Reduced the throttling period from 1/10 second to 1/hz seconds so that
throttling doesn't destroy performance so much. Interrupts that are
detected as storming are effectively handled by polling at a frequency
of hz Hz. On A7N8X-E's there is another hardware or configuration bug
that makes the throttled frequency closer to 2*hz Hz.
Remove references to termcap@berkeley.edu and uunet!ucbvax!termcap in
favor of send-pr(1).
Add comment about how to use cap_mkdb to build a new termcap db.
Submitted by: Ted Mittelstaedt <tedm@toybox.placo.com>
MFC After: 2 weeks
tree, output an empty string instead of "?". This is already what
happened with DEVICE_SYSCTL_LOCATION and DEVICE_SYSCTL_PNPINFO. This
makes the output of "sysctl dev" much nicer (it won't display those
empty sysctls).
Reviewed by: des
"stray irq 9" messages on my Thinkpad. It may also help with general
reboot consistency although the recent hang on reboot was solved by
acpi_cpu.c rev 1.39.
after. Unify the paths for all Cx states. Remove cpu_idle_busy and
instead do the little profiling we need before re-enabling interrupts.
Use 1 quantum as estimate for C1 sleep duration since the timer interrupt
is the main reason we wake.
While here, change the cx_history sysctl to cx_usage and report statistics
for which idle states were used in terms of percent. This seems more
intuitive than counters. Remove the cx_stats structure since it's no
longer used. Update the man page.
Change various types which do not need explicit size.
