critical_enter() and critical_exit() are now solely a mechanism for
deferring kernel preemptions. They no longer have any affect on
interrupts. This means that standalone critical sections are now very
cheap as they are simply unlocked integer increments and decrements for the
common case.
Spin mutexes now use a separate KPI implemented in MD code: spinlock_enter()
and spinlock_exit(). This KPI is responsible for providing whatever MD
guarantees are needed to ensure that a thread holding a spin lock won't
be preempted by any other code that will try to lock the same lock. For
now all archs continue to block interrupts in a "spinlock section" as they
did formerly in all critical sections. Note that I've also taken this
opportunity to push a few things into MD code rather than MI. For example,
critical_fork_exit() no longer exists. Instead, MD code ensures that new
threads have the correct state when they are created. Also, we no longer
try to fixup the idlethreads for APs in MI code. Instead, each arch sets
the initial curthread and adjusts the state of the idle thread it borrows
in order to perform the initial context switch.
This change is largely a big NOP, but the cleaner separation it provides
will allow for more efficient alternative locking schemes in other parts
of the kernel (bare critical sections rather than per-CPU spin mutexes
for per-CPU data for example).
Reviewed by: grehan, cognet, arch@, others
Tested on: i386, alpha, sparc64, powerpc, arm, possibly more
this problem put these lines back in. While they should be
unnecessary, they appear to be sometimes necessary.
Reviewed in concept: dfr
Approved by: re (scottl@)
to the pci attachment. Cardbus is a derived class of pci so all pci
drivers are automatically available for matching against cardbus devices.
Reviewed by: imp
Wearing said pointy hat, correct the oversight and hope nobody
notices.
# this should make xircom modems happier to detach once other bugs with
# the cardbus layer are fixed.
Noticed by: scottl
Conical Hat to: imp
to put the device into 8 bit mode a second time. This appears to have
no ill effects on other devices, and appears to be necessary for the
xircom modem.
Submitted by: gwk@sgi.com, many others that found his patch in the archives.
allows us to move the sio softc data structure back into sio.c and
reduce the complexity of the non sio.c sio files.
Submitted by: bde
# I didn't fix the locking issues that bruce also submitted.
sio_pccard_detach to use new siodetach. Add an extra arg to sioprobe
to tell driver to probe/not probe the device for IRQs.
This incorporates most of Bruce's review material. I'm at a good
checkpoint, but there will be more to come based on bde's further
reviews.
Reviewed by: bde
