Commit Graph

185 Commits

Author SHA1 Message Date
Poul-Henning Kamp
2266fe776e Don't export timecounter structures under debug. with sysctl, they
contain no truly interesting data anymore.
2002-04-30 19:34:31 +00:00
Poul-Henning Kamp
7e2d76ff05 Remove the tc_update() function. Any frequency change to the
timecounter will be used starting at the next second, which is
good enough for sysctl purposes.  If better adjustment is needed
the NTP PLL should be used.
2002-04-26 10:06:26 +00:00
Matthew Dillon
d74ac6819b Compromise for critical*()/cpu_critical*() recommit. Cleanup the interrupt
disablement assumptions in kern_fork.c by adding another API call,
cpu_critical_fork_exit().  Cleanup the td_savecrit field by moving it
from MI to MD.  Temporarily move cpu_critical*() from <arch>/include/cpufunc.h
to <arch>/<arch>/critical.c (stage-2 will clean this up).

Implement interrupt deferral for i386 that allows interrupts to remain
enabled inside critical sections.  This also fixes an IPI interlock bug,
and requires uses of icu_lock to be enclosed in a true interrupt disablement.

This is the stage-1 commit.  Stage-2 will occur after stage-1 has stabilized,
and will move cpu_critical*() into its own header file(s) + other things.
This commit may break non-i386 architectures in trivial ways.  This should
be temporary.

Reviewed by:	core
Approved by:	core
2002-03-27 05:39:23 +00:00
Alfred Perlstein
89c9a48352 Remove __P. 2002-03-20 07:51:46 +00:00
Matthew Dillon
181df8c9d4 revert last commit temporarily due to whining on the lists. 2002-02-26 20:33:41 +00:00
Matthew Dillon
f96ad4c223 STAGE-1 of 3 commit - allow (but do not require) interrupts to remain
enabled in critical sections and streamline critical_enter() and
critical_exit().

This commit allows an architecture to leave interrupts enabled inside
critical sections if it so wishes.  Architectures that do not wish to do
this are not effected by this change.

This commit implements the feature for the I386 architecture and provides
a sysctl, debug.critical_mode, which defaults to 1 (use the feature).  For
now you can turn the sysctl on and off at any time in order to test the
architectural changes or track down bugs.

This commit is just the first stage.  Some areas of the code, specifically
the MACHINE_CRITICAL_ENTER #ifdef'd code, is strictly temporary and will
be cleaned up in the STAGE-2 commit when the critical_*() functions are
moved entirely into MD files.

The following changes have been made:

	* critical_enter() and critical_exit() for I386 now simply increment
	  and decrement curthread->td_critnest.  They no longer disable
	  hard interrupts.  When critical_exit() decrements the counter to
	  0 it effectively calls a routine to deal with whatever interrupts
	  were deferred during the time the code was operating in a critical
	  section.

	  Other architectures are unaffected.

	* fork_exit() has been conditionalized to remove MD assumptions for
	  the new code.  Old code will still use the old MD assumptions
	  in regards to hard interrupt disablement.  In STAGE-2 this will
	  be turned into a subroutine call into MD code rather then hardcoded
	  in MI code.

	  The new code places the burden of entering the critical section
	  in the trampoline code where it belongs.

	* I386: interrupts are now enabled while we are in a critical section.
	  The interrupt vector code has been adjusted to deal with the fact.
	  If it detects that we are in a critical section it currently defers
	  the interrupt by adding the appropriate bit to an interrupt mask.

	* In order to accomplish the deferral, icu_lock is required.  This
	  is i386-specific.  Thus icu_lock can only be obtained by mainline
	  i386 code while interrupts are hard disabled.  This change has been
	  made.

	* Because interrupts may or may not be hard disabled during a
	  context switch, cpu_switch() can no longer simply assume that
	  PSL_I will be in a consistent state.  Therefore, it now saves and
	  restores eflags.

	* FAST INTERRUPT PROVISION.  Fast interrupts are currently deferred.
	  The intention is to eventually allow them to operate either while
	  we are in a critical section or, if we are able to restrict the
	  use of sched_lock, while we are not holding the sched_lock.

	* ICU and APIC vector assembly for I386 cleaned up.  The ICU code
	  has been cleaned up to match the APIC code in regards to format
	  and macro availability.  Additionally, the code has been adjusted
	  to deal with deferred interrupts.

	* Deferred interrupts use a per-cpu boolean int_pending, and
	  masks ipending, spending, and fpending.  Being per-cpu variables
	  it is not currently necessary to lock; bus cycles modifying them.

	  Note that the same mechanism will enable preemption to be
	  incorporated as a true software interrupt without having to
	  further hack up the critical nesting code.

	* Note: the old critical_enter() code in kern/kern_switch.c is
	  currently #ifdef to be compatible with both the old and new
	  methodology.  In STAGE-2 it will be moved entirely to MD code.

Performance issues:

	One of the purposes of this commit is to enhance critical section
	performance, specifically to greatly reduce bus overhead to allow
	the critical section code to be used to protect per-cpu caches.
	These caches, such as Jeff's slab allocator work, can potentially
	operate very quickly making the effective savings of the new
	critical section code's performance very significant.

	The second purpose of this commit is to allow architectures to
	enable certain interrupts while in a critical section.  Specifically,
	the intention is to eventually allow certain FAST interrupts to
	operate rather then defer.

	The third purpose of this commit is to begin to clean up the
	critical_enter()/critical_exit()/cpu_critical_enter()/
	cpu_critical_exit() API which currently has serious cross pollution
	in MI code (in fork_exit() and ast() for example).

	The fourth purpose of this commit is to provide a framework that
	allows kernel-preempting software interrupts to be implemented
	cleanly.  This is currently used for two forward interrupts in I386.
	Other architectures will have the choice of using this infrastructure
	or building the functionality directly into critical_enter()/
	critical_exit().

	Finally, this commit is designed to greatly improve the flexibility
	of various architectures to manage critical section handling,
	software interrupts, preemption, and other highly integrated
	architecture-specific details.
2002-02-26 17:06:21 +00:00
Bruce Evans
586079cc26 Don't include <isa/isavar.h> or compile code depending on it when isa
is not configured.  Including <isa/isavar.h> when it is not used is
harmful as well as bogus, since it includes "isa_if.h" which is not
generated when isa is not configured.

This was fixed in 1999 but was broken by unconditionalizing PNPBIOS.
2002-01-30 12:41:12 +00:00
John Baldwin
98f9879242 Introduce a standard name for the lock protecting an interrupt controller
and it's associated state variables: icu_lock with the name "icu".  This
renames the imen_mtx for x86 SMP, but also uses the lock to protect
access to the 8259 PIC on x86 UP.  This also adds an appropriate lock to
the various Alpha chipsets which fixes problems with Alpha SMP machines
dropping interrupts with an SMP kernel.
2001-12-20 23:48:31 +00:00
Mitsuru IWASAKI
f9390180fe Some fix for the recent apm module changes.
- Now that apm loadable module can inform its existence to other kernel
   components  (e.g. i386/isa/clock.c:startrtclock()'s TCS hack).
 - Exchange priority of SI_SUB_CPU and SI_SUB_KLD for above purpose.
 - Add simple arbitration mechanism for APM vs. ACPI.  This prevents
   the kernel enables both of them.
 - Remove obsolete `#ifdef DEV_APM' related code.
 - Add abstracted interface for Powermanagement operations.  Public apm(4)
   functions, such as apm_suspend(), should be replaced new interfaces.
   Currently only power_pm_suspend (successor of apm_suspend) is implemented.

Reviewed by:	peter, arch@ and audit@
2001-11-01 16:34:07 +00:00
Robert Drehmel
1e8ff53804 Remove an unneeded variable declaration and statement.
Approved by:	jake
2001-10-09 16:06:28 +00:00
Mitsuru IWASAKI
db2077f8e1 Reenable RTC interrupts after wakeup. Some laptops have a problem
with system statistics monitoring tools (such as systat, vmstat...)
because of stopping RTC interrupts generation.
Restore all the timers (RTC and i8254) atomically.

Reviewed by:	bde
MFC after:	1 week
2001-09-04 16:02:06 +00:00
Mike Smith
5f063c7b09 Add ACPI attachments. 2001-08-30 09:17:03 +00:00
John Baldwin
8bd57f8fc2 Remove unneeded includes of sys/ipl.h and machine/ipl.h. 2001-05-15 23:22:29 +00:00
John Baldwin
4d4bc9acc6 Add in a missing call to forward_hardclock() in the SMP case.
Submitted by:	bde
2001-04-28 01:37:44 +00:00
John Baldwin
6caa8a1501 Overhaul of the SMP code. Several portions of the SMP kernel support have
been made machine independent and various other adjustments have been made
to support Alpha SMP.

- It splits the per-process portions of hardclock() and statclock() off
  into hardclock_process() and statclock_process() respectively.  hardclock()
  and statclock() call the *_process() functions for the current process so
  that UP systems will run as before.  For SMP systems, it is simply necessary
  to ensure that all other processors execute the *_process() functions when the
  main clock functions are triggered on one CPU by an interrupt.  For the alpha
  4100, clock interrupts are delievered in a staggered broadcast fashion, so
  we simply call hardclock/statclock on the boot CPU and call the *_process()
  functions on the secondaries.  For x86, we call statclock and hardclock as
  usual and then call forward_hardclock/statclock in the MD code to send an IPI
  to cause the AP's to execute forwared_hardclock/statclock which then call the
  *_process() functions.
- forward_signal() and forward_roundrobin() have been reworked to be MI and to
  involve less hackery.  Now the cpu doing the forward sets any flags, etc. and
  sends a very simple IPI_AST to the other cpu(s).  AST IPIs now just basically
  return so that they can execute ast() and don't bother with setting the
  astpending or needresched flags themselves.  This also removes the loop in
  forward_signal() as sched_lock closes the race condition that the loop worked
  around.
- need_resched(), resched_wanted() and clear_resched() have been changed to take
  a process to act on rather than assuming curproc so that they can be used to
  implement forward_roundrobin() as described above.
- Various other SMP variables have been moved to a MI subr_smp.c and a new
  header sys/smp.h declares MI SMP variables and API's.   The IPI API's from
  machine/ipl.h have moved to machine/smp.h which is included by sys/smp.h.
- The globaldata_register() and globaldata_find() functions as well as the
  SLIST of globaldata structures has become MI and moved into subr_smp.c.
  Also, the globaldata list is only available if SMP support is compiled in.

Reviewed by:	jake, peter
Looked over by:	eivind
2001-04-27 19:28:25 +00:00
John Baldwin
f34fa851e0 Catch up to header include changes:
- <sys/mutex.h> now requires <sys/systm.h>
- <sys/mutex.h> and <sys/sx.h> now require <sys/lock.h>
2001-03-28 09:17:56 +00:00
Bruce Evans
12a586bbda Fixed style bugs in clock.c rev.1.164 and cpu.h rev.1.52-1.53 -- declare
tsc_present in the right places (together with other variables of the
same linkage), and don't use messy ifdefs just to avoid exporting it in
some cases.
2001-02-19 03:00:34 +00:00
John Baldwin
5781f5419e Catch up to changes to inthand_add(). 2001-02-09 17:48:33 +00:00
Bosko Milekic
9ed346bab0 Change and clean the mutex lock interface.
mtx_enter(lock, type) becomes:

mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)

similarily, for releasing a lock, we now have:

mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.

The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.

Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:

MTX_QUIET and MTX_NOSWITCH

The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:

mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.

Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.

Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.

Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.

Finally, caught up to the interface changes in all sys code.

Contributors: jake, jhb, jasone (in no particular order)
2001-02-09 06:11:45 +00:00
Peter Wemm
f444a0efe9 Convert mca (microchannel bus support) from something that we count
(bogus) to something that we test for the presence of.
2001-01-29 11:57:27 +00:00
Jason Evans
d1c1b8413e Remove MUTEX_DECLARE() and MTX_COLD. Instead, postpone full mutex
initialization until after malloc() is safe to call, then iterate through
all mutexes and complete their initialization.

This change is necessary in order to avoid some circular bootstrapping
dependencies.
2001-01-21 07:52:20 +00:00
Peter Wemm
1467a651ab Convert apm from a bogus 'count' into a plain option. Clean out some
other cruft from the files.alpha and files.ia64 that were related to this.
2001-01-19 14:09:54 +00:00
Mark Murray
4a3a2f0704 Namespace cleanup. Remove some #includes in favour of an explicit
declaration.

Asked for by:	bde
2000-12-02 17:59:41 +00:00
Poul-Henning Kamp
54b1161b73 Revert two experimental changes which escaped from my devel machine. 2000-10-28 06:55:12 +00:00
Poul-Henning Kamp
46aa3347cb Convert all users of fldoff() to offsetof(). fldoff() is bad
because it only takes a struct tag which makes it impossible to
use unions, typedefs etc.

Define __offsetof() in <machine/ansi.h>

Define offsetof() in terms of __offsetof() in <stddef.h> and <sys/types.h>

Remove myriad of local offsetof() definitions.

Remove includes of <stddef.h> in kernel code.

NB: Kernelcode should *never* include from /usr/include !

Make <sys/queue.h> include <machine/ansi.h> to avoid polluting the API.

Deprecate <struct.h> with a warning.  The warning turns into an error on
01-12-2000 and the file gets removed entirely on 01-01-2001.

Paritials reviews by:   various.
Significant brucifications by:  bde
2000-10-27 11:45:49 +00:00
John Baldwin
8088699f79 - Overhaul the software interrupt code to use interrupt threads for each
type of software interrupt.  Roughly, what used to be a bit in spending
  now maps to a swi thread.  Each thread can have multiple handlers, just
  like a hardware interrupt thread.
- Instead of using a bitmask of pending interrupts, we schedule the specific
  software interrupt thread to run, so spending, NSWI, and the shandlers
  array are no longer needed.  We can now have an arbitrary number of
  software interrupt threads.  When you register a software interrupt
  thread via sinthand_add(), you get back a struct intrhand that you pass
  to sched_swi() when you wish to schedule your swi thread to run.
- Convert the name of 'struct intrec' to 'struct intrhand' as it is a bit
  more intuitive.  Also, prefix all the members of struct intrhand with
  'ih_'.
- Make swi_net() a MI function since there is now no point in it being
  MD.

Submitted by:	cp
2000-10-25 05:19:40 +00:00
John Baldwin
02660e29a8 - machine/mutex.h -> sys/mutex.h
- machine/ipl.h -> sys/ipl.h
- Use MUTEX_DECLARE() for clock_lock
2000-10-20 07:31:00 +00:00
John Baldwin
6c56727456 - Change fast interrupts on x86 to push a full interrupt frame and to
return through doreti to handle ast's.  This is necessary for the
  clock interrupts to work properly.
- Change the clock interrupts on the x86 to be fast instead of threaded.
  This is needed because both hardclock() and statclock() need to run in
  the context of the current process, not in a separate thread context.
- Kill the prevproc hack as it is no longer needed.
- We really need Giant when we call psignal(), but we don't want to block
  during the clock interrupt.  Instead, use two p_flag's in the proc struct
  to mark the current process as having a pending SIGVTALRM or a SIGPROF
  and let them be delivered during ast() when hardclock() has finished
  running.
- Remove CLKF_BASEPRI, which was #ifdef'd out on the x86 anyways.  It was
  broken on the x86 if it was turned on since cpl is gone.  It's only use
  was to bogusly run softclock() directly during hardclock() rather than
  scheduling an SWI.
- Remove the COM_LOCK simplelock and replace it with a clock_lock spin
  mutex.  Since the spin mutex already handles disabling/restoring
  interrupts appropriately, this also lets us axe all the *_intr() fu.
- Back out the hacks in the APIC_IO x86 cpu_initclocks() code to use
  temporary fast interrupts for the APIC trial.
- Add two new process flags P_ALRMPEND and P_PROFPEND to mark the pending
  signals in hardclock() that are to be delivered in ast().

Submitted by:	jakeb (making statclock safe in a fast interrupt)
Submitted by:	cp (concept of delaying signals until ast())
2000-10-06 02:20:21 +00:00
John Baldwin
1931cf940a - Heavyweight interrupt threads on the alpha for device I/O interrupts.
- Make softinterrupts (SWI's) almost completely MI, and divorce them
  completely from the x86 hardware interrupt code.
  - The ihandlers array is now gone.  Instead, there is a MI shandlers array
    that just contains SWI handlers.
  - Most of the former machine/ipl.h files have moved to a new sys/ipl.h.
- Stub out all the spl*() functions on all architectures.

Submitted by:	dfr
2000-10-05 23:09:57 +00:00
John Baldwin
9a94c9c5c3 - Remove the inthand2_t type and use the equivalent driver_intr_t type from
newbus for referencing device interrupt handlers.
- Move the 'struct intrec' type which describes interrupt sources into
  sys/interrupt.h instead of making it just be a x86 structure.
- Don't create 'ithd' and 'intrec' typedefs, instead, just use 'struct ithd'
  and 'struct intrec'
- Move the code to translate new-bus interrupt flags into an interrupt thread
  priority out of the x86 nexus code and into a MI ithread_priority()
  function in sys/kern/kern_intr.c.
- Remove now-uneeded x86-specific headers from sys/dev/ata/ata-all.c and
  sys/pci/pci_compat.c.
2000-09-13 18:33:25 +00:00
Jason Evans
0384fff8c5 Major update to the way synchronization is done in the kernel. Highlights
include:

* Mutual exclusion is used instead of spl*().  See mutex(9).  (Note: The
  alpha port is still in transition and currently uses both.)

* Per-CPU idle processes.

* Interrupts are run in their own separate kernel threads and can be
  preempted (i386 only).

Partially contributed by:	BSDi (BSD/OS)
Submissions by (at least):	cp, dfr, dillon, grog, jake, jhb, sheldonh
2000-09-07 01:33:02 +00:00
Poul-Henning Kamp
0825a8a33f Allow use of TSC even if APM is compiled in but disabled. 2000-07-30 21:05:22 +00:00
Poul-Henning Kamp
77978ab8bc Previous commit changing SYSCTL_HANDLER_ARGS violated KNF.
Pointed out by:	bde
2000-07-04 11:25:35 +00:00
Poul-Henning Kamp
82d9ae4e32 Style police catches up with rev 1.26 of src/sys/sys/sysctl.h:
Sanitize SYSCTL_HANDLER_ARGS so that simplistic tools can grog our
sources:

        -sysctl_vm_zone SYSCTL_HANDLER_ARGS
        +sysctl_vm_zone (SYSCTL_HANDLER_ARGS)
2000-07-03 09:35:31 +00:00
Mike Smith
2a50a6d730 Add PnP probe methods to some common AT hardware drivers. In each case,
the PnP probe is merely a stub as we make assumptions about some of this
hardware before we have probed it.

Since these devices (with the exception of the speaker) are 'standard',
suppress output in the !bootverbose case to clean up the probe messages
somewhat.
2000-06-23 07:44:33 +00:00
Bruce Evans
5f582114dd Add SWI_TQ_MASK to all interrupt masks except SWI_CLOCK_MASK. Use a
new macro SWI_LOW_MASK to give the mask for low priority SWIs instead
of hard-coding this mask as SWI_CLOCK_MASK.

Reviewed by:	dfr
2000-05-31 13:32:28 +00:00
Poul-Henning Kamp
91266b96c4 Isolate the Timecounter internals in their own two files.
Make the public interface more systematically named.

Remove the alternate method, it doesn't do any good, only ruins performance.

Add counters to profile the usage of the 8 access functions.

Apply the beer-ware to my code.

The weird +/- counts are caused by two repocopies behind the scenes:
	kern/kern_clock.c -> kern/kern_tc.c
	sys/time.h -> sys/timetc.h
(thanks peter!)
2000-03-20 14:09:06 +00:00
Tor Egge
82916a1126 ISA device drivers use the ISA source interrupt number in locations where
the low level interrupt handler number should be used.  Change
setup_apic_irq_mapping() to allocate low level interrupt handler X (Xintr${X})
for any ISA interrupt X mentioned in the MP table.

Remove an assumption in the driver for the system clock (clock.c) that
interrupts mentioned in the MP table as delivered to IOAPIC #0 intpin Y
is handled by low level interrupt handler Y (Xintr${Y}) but don't assume
that low level interrupt handler 0 (Xintr0) is used.

Don't allocate two low level interrupt handlers for the system clock.
Reviewed by:	NOKUBI Hirotaka <hnokubi@yyy.or.jp>
2000-01-04 22:24:59 +00:00
Bruce Evans
0f19e631e2 Fixed races accessing the RTC. The races apparently caused
apm_default_resume() to sometimes set a very wrong time.
(1) Accesses to the RTC index and data registers were not atomic enough.
    Interrupts were not masked.  This was only good enough until an
    interrupt handler (rtcintr()) started accessing the RTC in FreeBSD-2.0.
(2) Access to the block of time registers in inittodr() was not atomic
    enough.  inittodr() has 244us to read the time registers.  Interrupts
    were not masked.  This was only good enough until something (apm)
    started calling inittodr() after boot time in FreeBSD-2.0.
The fix for (2) also makes the timecounter update more atomic, although
this is currently unimportant due to the low resolution of the RTC.

Problem reported by:	mckay
1999-12-25 15:30:31 +00:00
Peter Wemm
ec6e462d78 Remove references to register_intr() etc in comments. 1999-12-20 15:11:31 +00:00
Mitsuru IWASAKI
29803c2003 i8254_restore is called from apm_default_resume() to reload
the countdown register.
this should not be necessary but there are broken laptops that
do not restore the countdown register on resume.
when it happnes, it messes up the hardclock interval and system clock,
which leads to the infamous "calcru: negative time" problem.

Submitted by:	kjc, iwasaki
Reviewed by:	Steve O'Hara-Smith <steveo@eircom.net> and committers.
Obtained from:	PAO3
1999-10-30 14:56:01 +00:00
Matthew N. Dodd
7612e4c122 This adds the i386 specific support for systems with a MicroChannel
Architecture bus.

Reviewed by: msmith
1999-09-03 02:04:28 +00:00
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
Poul-Henning Kamp
ce9edcf5b5 Merge the cons.c and cons.h to the best of my ability. alpha may or
may not compile, I can't test it.
1999-08-09 10:35:05 +00:00
Brian Feldman
8799702cbc Remove XXX from the headers (broke the build, I'm betting.) 1999-07-29 01:20:47 +00:00
Mike Smith
e33bfde398 We're called too early to have any idea whether APM is going to be
active or not.  The only sane thing we can do here is assume that if
APM is supported it might be active at some point, and bail.

In reality, even this isn't good enough; regardless of whether we support
APM or not, the system may well futz with the CPU's clock speed and throw
the TSC off.  We need to stop using it for timekeeping except under
controlled circumstances.  Curse the lack of a dependable high-resolution
timer.
1999-07-28 20:22:30 +00:00
Bruce Evans
e9ecccf8cb Updated acquire_timer2()'s state machine to work when the i8254 is
being used for timecounting.  Fixed a race or two in it.  Undisabled
it.

PR:		10455
1999-07-18 18:32:42 +00:00
Bruce Evans
ab64b6dc3c Don't let the machdep.tsc_freq sysctl proceed if the TSC is present
but broken, since tsc_timecounter is not initialised in that case,
and updating an uninitialised timecounter is fatal.

Fixed style bugs in the machdep.i8254_freq and machdep.tsc_freq
sysctls.

Reviewed by:	phk
1999-07-18 15:19:29 +00:00
Peter Wemm
e66b7bac41 Shut up gcc. 1999-06-27 09:08:48 +00:00
Brian Feldman
9840e7cb5a This commit gives support for the Rise mP6 CPU. It has two changes:
1. Rise is recognized in identdcpu.c.
	2. The TSC is not written to. A workaround for the CPU bug is being
	   applied to clock.c (the bug being that the mP6 has TSC enabled
	   in its CPUID-capabilities, but it only supports reading it. If we
	   try to write to it (MSR 16), a GPF occurs.) The new behavior is that
	   FreeBSD will _not_ zero the TSC. Instead, we do a bit of 64-bit
	   arithmetic.

Reviewed by:	msmith
Obtained from:	unfurl & msmith
1999-06-24 03:48:25 +00:00