was converted to use Mach VM for Net2/4.4BSD. The user segment table
pointer was originally stored in the PCB. When Mach VM came along,
however, it was also stored in the pmap, and loaded into the PCB in
pmap_activate(). pmap_activate() would then note that the PCB's USTP
was now in sync with the pmap's USTP, and the low-level context switch
code would use the value from the PCB.
However, pmap_activate() would also load the hardware MMU context if
the pmap was the current pmap (or, in the case where pmaps can be shared,
such as in NetBSD, if the proc was the current proc). The low-level
context switch code would then reload the hardware _again_ using the
USTP from the PCB.
However, the optimization of not calling pmap_activate() if "stchanged"
was false ended up causing some processes to use stale USTP values from
the PCB when the low-level context switch code reloaded the hardware!
This was noticed by using a real vfork(2) (which worked for some time
before failing, surprisingly!)
Since I'm hard pressed to find any real optimization here (since the
hardware was always reloaded once, sometimes twice!), the code now always
calls pmap_activate(), which uses the correct USTP value (the one in the
pmap). The PCB's USTP is now ignored, and should eventually be g/c'd.
Another optimization can actually be performed, and I have added a comment
describing what it is, but have not yet implemented it.
Also note that most of the loadustp() functions where actually incomplete.
This has been corrected. These functions should probably be split up into
MMU-specific operations, and called indirectly, rather than doing constant
run-time decision making based on values that will never change during the
course of a boot's lifetime.
pseudo-device rnd # /dev/random and in-kernel generator
in config files.
o Add declaration to all architectures.
o Clean up copyright message in rnd.c, rnd.h, and rndpool.c to include
that this code is derived in part from Ted Tyso's linux code.
msgbuf. Note that old 'dmesg' and 'syslogd' binaries will continue running,
though old 'dmesg' binaries will output a few bytes of junk at the start of
the buffer, and will miss a few bytes at the end of the buffer.
port, which is lifted from amiga port, plus some changes from me:
- Add support for the HP MMU to the 020/030 bus/address error handler
(mostly lifted wholesale from the old code).
- Rename addrerr and buserr to busaddrerr2030. The new name reflects that
these functions are specific to the 68020 and 68030, and that the same
handler function is used for both vectors.
The vector table is patched once we know our CPU type, before the MMU
is enabled. In the event that we're running on a CPU that we're not
configured for, simply invoke the PROM's "reboot request"; we have no
hope of running in the event of a config botch, since we need working
a working bus error handler for console initialization.
These new functions optimze for common-case page faults, eliminate
many run-time checks, and are sharable.
Correct handling for Trap #2 in SunOS executables,
now that we know it is supposed to flush the cache.
(Was thought to be "some obscure FPU operation".)
Frodo ASIC, originally contributed by Mike Smith
<mike@pressed.spam.frisbee.net.au>, but reworked by me to:
- Essentially duplicate the dca driver, modifiying where necessary
to work with the APCI.
- Deal with the different Frodo autoconfiguration model.
- Don't attach a tty to the 0th UART - it's not really useful for much
more than the Domain keyboard.
- Added a routine to check for the existence of a DCA at select code 9.
On most models, the 1'th UART is mapped to select code 9 by the PROM,
and on these models, we do _NOT_ want to attach the device as an APCI.
However, on the 425e, this mapping does not take place, so we attach
as an APCI. The 2'th and 3'th UARTs always get tty instances.
- Add console support which will only be invoked on the 425e (i.e. check
for DCA at 9, and defer console to it if it exists).
