free-run and doing a subtract in microtime() rather than resetting the
counter to zero at every clock tick. In combination with the changes to
kern_clock.c, this should eliminate all the immediately obvious sources
of systematic jitter in timekeeping on Pentium machines.
the first one in the config has priority. They can be switched using
userconfig().
i386/i386/conf.c:
Initialize the shared syscons/pcvt cdevsw entry to `nx'.
Add cdevsw registration functions.
Use devsw functions of the correct type if they exist.
i386/i386/cons.c:
Add renamed syscons entry points to constab.
i386/i386/cons.h:
Declare the renamed syscons entry points.
i386/i386/machdep.c:
Repeat console initialization after userconfig() in case the current
console has become wrong. This depends on cn functions not wiring down
anything important.
sys/conf.h:
Declare new functions.
i386/isa/isa.[ch]:
Add a function to decide which display driver has priority. Should be
done better.
i386/isa/syscons.c:
Rename pccn* -> sccn*.
Initialize CRTC start address in case the previous driver has moved it.
i386/isa/syscons.c, i386/isa/pcvt/*
Initialize the bogusly shared variable Crtat dynamically in case the
stored value was changed by the previous driver.
Initialize cdevsw table from a template.
Don't grab the console if another display driver has priority.
i386/isa/syscons.h, i386/isa/pcvt/pcvt_hdr.h:
Don't externally declare now-static cdevsw functions.
i386/isa/pcvt/pcvt_hdr.h:
Set the sensitive hardware flag so that pcvt doesn't always have lower
priority than syscons. This also fixes the "stupid" detection of the
display after filling the display with text.
i386/isa/pcvt/pcvt_out.c:
Don't be confused the off-screen cursor offset 0xffff set by syscons.
kern/subr_xxx.c:
Add enough nxio/nodev/null devsw functions of the correct type for syscons
and pcvt.
Fix one such THING in code to match comment.
Sort IO_GSC* into numeric order and update comments about the gaps.
Sort common SCSI addresses into alphabetical order.
Remove bogus comments about com ports having i/o size 4.
Uniformize whitespace.
Uniformize case in hex digits.
This file is very incomplete. In particular, it doesn't mention any
network cards. This doesn't matter much for the base addresses, but
it means that the comments about which addresses are free are mostly
bogus. The i/o sizes are unreliable because of split address ranges
for many devices (VGA, wd). The i/o sizes are incomplete. In
particular, there are no sizes for SCSI controllers. The bt driver
still returns a truth value instead of a size.
A phone call from Manfred quickly pointed up the fact that I got the conflict
check backwards. NOW we implement the conflict checking correctly! Wheesh!
to access it. setdelayed() actually ORs the bits in `idelayed' into
`ipending' and clears `idelayed'.
Call setdelayed() every (normal) clock tick to convert delayed
interrupts into pending ones.
Drivers can set bits in `idelayed' at any time to schedule an interrupt
at the next clock tick. This is more efficient than calling timeout().
Currently only software interrupts can be scheduled.
Previously, this worked right if both AUTO_EOI_1 and AUTO_EOI_2 are
defined, but not if AUTO_EOI_1 is defined and AUTO_EOI_2 is not defined.
The latter case should be the default. DUMMY_NOPS should be the default
too. Currently there are only two NOPs slowing down rtcin() (although
there are no delays in writertc()) and several FASTER_NOPs slowing down
interrupt handling in vector.s.
Fix stack offsets for the (previously) unused untested
FAST_INTR_HANDLER_USES_ES case.
For those where it was easy, drivers were also fixed to call
dev_attach() during probe rather than attach (in keeping with the
new design articulated in a mail message five months ago). For
a few that were really easy, correct state tracking was added as well.
The `fd' driver was fixed to correctly fill in the description.
The CPU identify code was fixed to attach a `cpu' device. The code
was also massively reordered to fill in cpu_model with somethingremotely
resembling what identifycpu() prints out. A few bytes saved by using
%b to format the features list rather than lots of ifs.
messages like this:
wdc0 at 0x1f0-0x1f7 irq 14 on isa
wdc0: unit 0 (wd0): <ST506>
wd0: size unknown, using BIOS values: 615 cyl, 4 head, 17 sec, bytes/sec 512
npx0 at 0xf0-0xff irq 13 on motherboard
npx0: changing root device to wd0a
^^^^^^
The spurious 'npx0: ' pops up if you have a 386 with a 387 FPU.
briefly over it, and see some serious architectural issues in this stuff.
On the other hand, I doubt that we will have any solution to these issues
before 2.1, so we might as well leave this in.
Most of the stuff is bracketed by #ifdef's so it shouldn't matter too much
in the normal case.
Reviewed by: phk
Submitted by: HOSOKAWA, Tatsumi <hosokawa@mt.cs.keio.ac.jp>
Put in the much shorter and cleaner version for the calibrate_cycle_counter
for the Pentium that Bruce suggested. Tested here on my Pentium and
it works okay.
shifting. Also correct the original code as Garrett noticed it in mail.
Leave the mishandled code in to use it later if future versions of gcc
are correct. The code was part of the calibrate_cyclecounter routine to
get the speed of the pentium chip.
Remove bogus input operands for fnsave(), fnstcw() and fnstsw().
Change all fwait's to fnop's. This might help avoid hardware bugs.
Wait after fninit with an fnop. This should be safer now.
Fix some spelling and formatting errors.
Use natural sizes for control and status words (u_short, promotes to int).
Don't clobber the SWI_CLOCK_MASK bits in npx0_imask when using IRQ13.
Set the devconf state correctly (always busy, if configured). Improve
code for npx_registerdev() a little (gcc can't keep id->id_unit in a
register for some reason). Don't register a nonexistent npx device.
Print a useful message in npxattach() again (delete references to errors
and not the whole message). Don't print "387 emulator" if there is no
emulator in the kernel.
Use %p for pointers in error messages.
Don't clobber the FPU state when there is an FPU exception. Just clear
the exception flags (after saving the flags as before). This allows
debuggers and SIGFPE handlers to look at the full exception state.
SIGFPE handlers should normally return via longjmp(), which restores a
good FPU state (as before). Returning from a SIGFPE handler may leave
the FPU in the wrong state (as before).
Clear the busy latch _after_ clearing the exception flags so that there
is less chance of getting a bogus h/w interrupt for a control operation.
Clear the saved exception status word when the next FPU instruction is
excuted so that it doesn't stick around until the next exception.
Clear the busy latch after fnsave() in npxsave() in case it was set when
npxsave() was called.
Move definition of `stat_imask' to clock.c.
clock.c:
Rename `rtcmask' to `stat_imask' and export it. Rename `clkmask' to
`clk_imask' for consistency.
Only calculate TIMER_DIV(hz) once.
Merge debugging and "garbage" code to produce debugging code and format the
output better.
Make writertc() static inline and use it everywhere. Now all accesses to
the clock registers go through rtcin() and writertc().
Move rtc initialization to cpu_initclocks().
Merge enablertclock() with cpu_initclocks() and remove enablertclock().
The extra entry point was just a leftover from 1.1.5.
Keep track of interrupt nesting level. It is normally 0
for syscalls and traps, but is fudged to 1 for their exit
processing in case they metamorphose into an interrupt
handler.
i386/genassym.c;
Remove support for the obsolete pcb_iml and pcb_cmap2.
Add support for pcb_inl.
i386/swtch.s:
Fudge the interrupt nesting level across context switches and in
the idle loop so that the work for preemptive context switches
gets counted as interrupt time, the work for voluntary context
switches gets counted mostly as system time (the part when
curproc == 0 gets counted as interrupt time), and only truly idle
time gets counted as idle time.
Remove obsolete support (commented out and otherwise) for pcb_iml.
Load curpcb just before curproc instead of just after so that
curpcb is always valid if curproc is. A few more changes like
this may fix tracing through context switches.
Remove obsolete function swtch_to_inactive().
include/cpu.h:
Use the new interrupt nesting level variable to implement a
non-fake CLF_INTR() so that accounting for the interrupt state
works.
You can use top, iostat or (best) an up to date systat to see
interrupt overheads. I see the expected huge interrupt overheads
for ISA devices (on a 486DX/33, about 55% for an IDE drive
transferring 1250K/sec and the same for a WD8013EBT network card
transferring 1100K/sec). The huge interrupt overheads for serial
devices are unfortunately normally invisible.
include/pcb.h:
Remove the obsolete pcb_iml and pcb_cmap2. Replace them by
padding to preserve binary compatibility.
Use part of the new padding for pcb_inl.
isa/icu.s:
isa/vector.s:
Keep track of interrupt nesting level.
with the current default exception (un)mask. There should be no such
processes unless you change the mask. Someday the mask should be
changed to the IEEE default of everything masked. The npx state
gets saved so that it can be checked and this may have the side effect
of fixing a bug that was reported for 1.1.5. (npx exceptions may
sometimes leak across exits and clobber another process. I can't see
how this can happen.)
Get some missing/wrong declarations from headers now that the headers
have them.
doesn't have to calculate it every call.
Rename `timer0_prescale' to `timer0_prescaler_count' and maintain it
correctly. Previously we lost a few 8253 cycles for every "prescaled"
clock interrupt, and the lossage grows rapidly at 16 KHz. Now we
only lose a few cycles for every standard clock interrupt.
Rename `*_divisor' to `*_max_count'.
Do the calculation of TIMER_DIV(rate) only once instead of 3 times each
time the rate is changed.
Don't allow preposterously large interrupt rates. Bug fixes elsewhere
should allow the system to survive rates that saturate the system, however.
Clean up declarations.
Include <machine/clock.h> to check our own declarations.
