Commit Graph

11186 Commits

Author SHA1 Message Date
Konstantin Belousov
50ad4fc65c Regenerate 2008-04-08 09:51:19 +00:00
Konstantin Belousov
48b05c3f82 Implement the linux syscalls
openat, mkdirat, mknodat, fchownat, futimesat, fstatat, unlinkat,
    renameat, linkat, symlinkat, readlinkat, fchmodat, faccessat.

Submitted by:	rdivacky
Sponsored by:	Google Summer of Code 2007
Tested by:	pho
2008-04-08 09:45:49 +00:00
Alan Cox
109d493230 Update pmap_page_wired_mappings() so that it counts 2/4MB page mappings. 2008-04-07 07:38:02 +00:00
John Baldwin
1ee1b68792 Add a MI intr_event_handle() routine for the non-INTR_FILTER case. This
allows all the INTR_FILTER #ifdef's to be removed from the MD interrupt
code.
- Rename the intr_event 'eoi', 'disable', and 'enable' hooks to
  'post_filter', 'pre_ithread', and 'post_ithread' to be less x86-centric.
  Also, add a comment describe what the MI code expects them to do.
- On amd64, i386, and powerpc this is effectively a NOP.
- On arm, don't bother masking the interrupt unless the ithread is
  scheduled in the non-INTR_FILTER case to match what INTR_FILTER did.
  Also, don't bother unmasking the interrupt in the post_filter case if
  we never masked it.  The INTR_FILTER case had been doing this by having
  arm_unmask_irq for the post_filter (formerly 'eoi') hook.
- On ia64, stray interrupts are now masked for the non-INTR_FILTER case.
  They were already masked in the INTR_FILTER case.
- On sparc64, use the a NULL pre_ithread hook and use intr_enable_eoi() for
  both the 'post_filter' and 'post_ithread' hooks to match what the
  non-INTR_FILTER code did.
- On sun4v, retire the ithread wrapper hack by using an appropriate
  'post_ithread' hook instead (it's what 'post_ithread'/'enable' was
  designed to do even in 5.x).

Glanced at by:	piso
Reviewed by:	marius
Requested by:	marius [1], [5]
Tested on:	amd64, i386, arm, sparc64
2008-04-05 19:58:30 +00:00
Alan Cox
7630c26507 Reintroduce UMA_SLAB_KMAP; however, change its spelling to
UMA_SLAB_KERNEL for consistency with its sibling UMA_SLAB_KMEM.
(UMA_SLAB_KMAP met its original demise in revision 1.30 of
vm/uma_core.c.)  UMA_SLAB_KERNEL is now required by the jumbo frame
allocators.  Without it, UMA cannot correctly return pages from the
jumbo frame zones to the VM system because it resets the pages' object
field to NULL instead of the kernel object.  In more detail, the jumbo
frame zones are created with the option UMA_ZONE_REFCNT.  This causes
UMA to overwrite the pages' object field with the address of the slab.
However, when UMA wants to release these pages, it doesn't know how to
restore the object field, so it sets it to NULL.  This change teaches
UMA how to reset the object field to the kernel object.

Crashes reported by: kris
Fix tested by: kris
Fix discussed with: jeff
MFC after: 6 weeks
2008-04-04 18:41:12 +00:00
Konstantin Belousov
57b4252e45 Add the support for the AT_FDCWD and fd-relative name lookups to the
namei(9).

Based on the submission by rdivacky,
	sponsored by Google Summer of Code 2007
Reviewed by:	rwatson, rdivacky
Tested by:	pho
2008-03-31 12:01:21 +00:00
Alan Cox
4ae6e47432 Eliminate an #if 0/#endif that was unintentionally introduced
by the previous revision.
2008-03-29 04:29:50 +00:00
Ed Maste
064fb2d184 If we're returning successfully from bus_dmamem_alloc, don't record a KTR
of error = ENOMEM.
2008-03-28 15:28:20 +00:00
Brooks Davis
96a6e6e6ca Use ; instead of : to end a line.
Submitted by:	Niclas Zeising <niclas dot zeising at gmail dot com>
2008-03-28 08:19:03 +00:00
Paul Saab
6e7534b8c8 Add support to mincore for detecting whether a page is part of a
"super" page or not.

Reviewed by:	alc, ups
2008-03-28 04:29:27 +00:00
Doug Rabson
fa9d9930ca Add kernel module support for nfslockd and krpc. Use the module system
to detect (or load) kernel NLM support in rpc.lockd. Remove the '-k'
option to rpc.lockd and make kernel NLM the default. A user can still
force the use of the old user NLM by building a kernel without NFSLOCKD
and/or removing the nfslockd.ko module.
2008-03-27 11:54:20 +00:00
John Birrell
e483943791 When building a kernel module, define MAXCPU the same as SMP so
that modules work with and without SMP.
2008-03-27 05:03:26 +00:00
Alan Cox
97dbe5e48e MFamd64 with few changes:
1. Add support for automatic promotion of 4KB page mappings to 2MB page
   mappings.  Automatic promotion can be enabled by setting the tunable
   "vm.pmap.pg_ps_enabled" to a non-zero value.  By default, automatic
   promotion is disabled.  Tested by: kris

2. To date, we have assumed that the TLB will only set the PG_M bit in a
   PTE if that PTE has the PG_RW bit set.  However, this assumption does
   not hold on recent processors from Intel.  For example, consider a PTE
   that has the PG_RW bit set but the PG_M bit clear.  Suppose this PTE
   is cached in the TLB and later the PG_RW bit is cleared in the PTE,
   but the corresponding TLB entry is not (yet) invalidated.
   Historically, upon a write access using this (stale) TLB entry, the
   TLB would observe that the PG_RW bit had been cleared and initiate a
   page fault, aborting the setting of the PG_M bit in the PTE.  Now,
   however, P4- and Core2-family processors will set the PG_M bit before
   observing that the PG_RW bit is clear and initiating a page fault.  In
   other words, the write does not occur but the PG_M bit is still set.

   The real impact of this difference is not that great.  Specifically,
   we should no longer assert that any PTE with the PG_M bit set must
   also have the PG_RW bit set, and we should ignore the state of the
   PG_M bit unless the PG_RW bit is set.
2008-03-27 04:34:17 +00:00
Poul-Henning Kamp
dad3b6c6fd Back in the good old days, PC's had random pieces of rock for
frequency generation and what frequency the generated was anyones
guess.

In general the 32.768kHz RTC clock x-tal was the best, because that
was a regular wrist-watch Xtal, whereas the X-tal generating the
ISA bus frequency was much lower quality, often costing as much as
several cents a piece, so it made good sense to check the ISA bus
frequency against the RTC clock.

The other relevant property of those machines, is that they
typically had no more than 16MB RAM.

These days, CPU chips croak if their clocks are not tightly within
specs and all necessary frequencies are derived from the master
crystal by means if PLL's.

Considering that it takes on average 1.5 second to calibrate the
frequency of the i8254 counter, that more likely than not, we will
not actually use the result of the calibration, and as the final
clincher, we seldom use the i8254 for anything besides BEL in
syscons anyway, it has become time to drop the calibration code.

If you need to tell the system what frequency your i8254 runs,
you can do so from the loader using hw.i8254.freq or using the
sysctl kern.timecounter.tc.i8254.frequency.
2008-03-26 22:12:00 +00:00
Poul-Henning Kamp
e465985885 The "free-lance" timer in the i8254 is only used for the speaker
these days, so de-generalize the acquire_timer/release_timer api
to just deal with speakers.

The new (optional) MD functions are:
	timer_spkr_acquire()
	timer_spkr_release()
and
	timer_spkr_setfreq()

the last of which configures the timer to generate a tone of a given
frequency, in Hz instead of 1/1193182th of seconds.

Drop entirely timer2 on pc98, it is not used anywhere at all.

Move sysbeep() to kern/tty_cons.c and use the timer_spkr*() if
they exist, and do nothing otherwise.

Remove prototypes and empty acquire-/release-timer() and sysbeep()
functions from the non-beeping archs.

This eliminate the need for the speaker driver to know about
i8254frequency at all.  In theory this makes the speaker driver MI,
contingent on the timer_spkr_*() functions existing but the driver
does not know this yet and still attaches to the ISA bus.

Syscons is more tricky, in one function, sc_tone(), it knows the hz
and things are just fine.

In the other function, sc_bell() it seems to get the period from
the KDMKTONE ioctl in terms if 1/1193182th second, so we hardcode
the 1193182 and leave it at that.  It's probably not important.

Change a few other sysbeep() uses which obviously knew that the
argument was in terms of i8254 frequency, and leave alone those
that look like people thought sysbeep() took frequency in hertz.

This eliminates the knowledge of i8254_freq from all but the actual
clock.c code and the prof_machdep.c on amd64 and i386, where I think
it would be smart to ask for help from the timecounters anyway [TBD].
2008-03-26 20:09:21 +00:00
Doug Rabson
dfdcada31e Add the new kernel-mode NFS Lock Manager. To use it instead of the
user-mode lock manager, build a kernel with the NFSLOCKD option and
add '-k' to 'rpc_lockd_flags' in rc.conf.

Highlights include:

* Thread-safe kernel RPC client - many threads can use the same RPC
  client handle safely with replies being de-multiplexed at the socket
  upcall (typically driven directly by the NIC interrupt) and handed
  off to whichever thread matches the reply. For UDP sockets, many RPC
  clients can share the same socket. This allows the use of a single
  privileged UDP port number to talk to an arbitrary number of remote
  hosts.

* Single-threaded kernel RPC server. Adding support for multi-threaded
  server would be relatively straightforward and would follow
  approximately the Solaris KPI. A single thread should be sufficient
  for the NLM since it should rarely block in normal operation.

* Kernel mode NLM server supporting cancel requests and granted
  callbacks. I've tested the NLM server reasonably extensively - it
  passes both my own tests and the NFS Connectathon locking tests
  running on Solaris, Mac OS X and Ubuntu Linux.

* Userland NLM client supported. While the NLM server doesn't have
  support for the local NFS client's locking needs, it does have to
  field async replies and granted callbacks from remote NLMs that the
  local client has contacted. We relay these replies to the userland
  rpc.lockd over a local domain RPC socket.

* Robust deadlock detection for the local lock manager. In particular
  it will detect deadlocks caused by a lock request that covers more
  than one blocking request. As required by the NLM protocol, all
  deadlock detection happens synchronously - a user is guaranteed that
  if a lock request isn't rejected immediately, the lock will
  eventually be granted. The old system allowed for a 'deferred
  deadlock' condition where a blocked lock request could wake up and
  find that some other deadlock-causing lock owner had beaten them to
  the lock.

* Since both local and remote locks are managed by the same kernel
  locking code, local and remote processes can safely use file locks
  for mutual exclusion. Local processes have no fairness advantage
  compared to remote processes when contending to lock a region that
  has just been unlocked - the local lock manager enforces a strict
  first-come first-served model for both local and remote lockers.

Sponsored by:	Isilon Systems
PR:		95247 107555 115524 116679
MFC after:	2 weeks
2008-03-26 15:23:12 +00:00
Poul-Henning Kamp
ebfbcd612a Rename timer0_max_count to i8254_max_count.
Rename timer0_real_max_count to i8254_real_max_count and make it static.
Rename timer_freq to i8254_freq and make it a loader tunable.
2008-03-26 15:03:24 +00:00
Poul-Henning Kamp
f168bfa529 The RTC related pscnt and psdiv variables have no business being public. 2008-03-26 13:25:27 +00:00
Christian Brueffer
662cac9f23 Fix some "in in" typos in comments.
PR:		121490
Submitted by:	Anatoly Borodin <anatoly.borodin@gmail.com>
Approved by:	rwatson (mentor), jkoshy
MFC after:	3 days
2008-03-26 07:32:08 +00:00
Alan Cox
fdcd29b52b Enable the automatic creation of superpage reservations. 2008-03-26 03:12:00 +00:00
Jung-uk Kim
cb7d38abf2 Belatedly add BPF_JITTER in NOTES for supported architectures. 2008-03-24 22:23:22 +00:00
Konstantin Belousov
3f7905d29c Prevent the overflow in the calculation of the next page directory.
The overflow causes the wraparound with consequent corruption of the
(almost) whole address space mapping.

As Alan noted, pmap_copy() does not require the wrap-around checks
because it cannot be applied to the kernel's pmap. The checks there are
included for consistency.

Reported and tested by:	kris (i386/pmap.c:pmap_remove() part)
Reviewed by:	alc
MFC after:	1 week
2008-03-23 07:07:27 +00:00
John Baldwin
eb2b0540e5 Explicitly use spinlock_enter/exit rather than locking the icu_lock spin
lock in the 8259A drivers as these drivers are only used on UP systems.
This slightly reduces the penalty of an SMP kernel (such as GENERIC) on
a UP x86 machine.
2008-03-20 21:53:27 +00:00
John Baldwin
dcc8106854 Implement a BUS_BIND_INTR() method in the bus interface to bind an IRQ
resource to a CPU.  The default method is to pass the request up to the
parent similar to BUS_CONFIG_INTR() so that all busses don't have to
explicitly implement bus_bind_intr.  A bus_bind_intr(9) wrapper routine
similar to bus_setup/teardown_intr() is added for device drivers to use.
Unbinding an interrupt is done by binding it to NOCPU.  The IRQ resource
must be allocated, but it can happen in any order with respect to
bus_setup_intr().  Currently it is only supported on amd64 and i386 via
nexus(4) methods that simply call the intr_bind() routine.

Tested by:	gallatin
2008-03-20 21:24:32 +00:00
John Baldwin
6d2d1c044f Simplify the interrupt code a bit:
- Always include the ie_disable and ie_eoi methods in 'struct intr_event'
  and collapse down to one intr_event_create() routine.  The disable and
  eoi hooks simply aren't used currently in the !INTR_FILTER case.
- Expand 'disab' to 'disable' in a few places.
- Use function casts for arm and i386:intr_eoi_src() instead of wrapper
  routines since to trim one extra indirection.

Compiled on:	{arm,amd64,i386,ia64,ppc,sparc64} x {FILTER, !FILTER}
Tested on:	{amd64,i386} x {FILTER, !FILTER}
2008-03-17 22:42:01 +00:00
Poul-Henning Kamp
272870cf7b A cautionary XXX comment about seemingly bogus errata checks. 2008-03-17 09:05:15 +00:00
Poul-Henning Kamp
462302db47 Increase time we wait for things to settle to 1 millisecond,
10 microseconds is too short.

Always set the cpu to the highest frequency so that we get through
boot and don't handicap cpus where powerd(8) is not used.
2008-03-17 09:01:43 +00:00
Poul-Henning Kamp
68b84e73e3 Revert last commit and stop committing before morning tea. 2008-03-17 09:00:59 +00:00
Poul-Henning Kamp
5d306f44cc Increase time we wait for things to settle to 1 millisecond,
10 microseconds is too short.

Always set the cpu to the highest frequency so that we get through
boot and don't handicap cpus where powerd(8) is not used.
2008-03-17 08:38:38 +00:00
Poul-Henning Kamp
29cc138cdf Use correct bitmask for identifying chip family. 2008-03-17 00:36:16 +00:00
Pawel Jakub Dawidek
6eb4157ffc Implement atomic_fetchadd_long() for all architectures and document it.
Reviewed by:	attilio, jhb, jeff, kris (as a part of the uidinfo_waitfree.patch)
2008-03-16 21:20:50 +00:00
Roman Divacky
d8653dd986 Regen. 2008-03-16 16:29:37 +00:00
Roman Divacky
5dfb688191 Implement sched_setaffinity and get_setaffinity using
real cpu affinity setting primitives.

Reviewed by:	jeff
Approved by:	kib (mentor)
2008-03-16 16:27:44 +00:00
Robert Watson
237fdd787b In keeping with style(9)'s recommendations on macros, use a ';'
after each SYSINIT() macro invocation.  This makes a number of
lightweight C parsers much happier with the FreeBSD kernel
source, including cflow's prcc and lxr.

MFC after:	1 month
Discussed with:	imp, rink
2008-03-16 10:58:09 +00:00
John Baldwin
eaf86d1678 Add preliminary support for binding interrupts to CPUs:
- Add a new intr_event method ie_assign_cpu() that is invoked when the MI
  code wishes to bind an interrupt source to an individual CPU.  The MD
  code may reject the binding with an error.  If an assign_cpu function
  is not provided, then the kernel assumes the platform does not support
  binding interrupts to CPUs and fails all requests to do so.
- Bind ithreads to CPUs on their next execution loop once an interrupt
  event is bound to a CPU.  Only shared ithreads are bound.  We currently
  leave private ithreads for drivers using filters + ithreads in the
  INTR_FILTER case unbound.
- A new intr_event_bind() routine is used to bind an interrupt event to
  a CPU.
- Implement binding on amd64 and i386 by way of the existing pic_assign_cpu
  PIC method.
- For x86, provide a 'intr_bind(IRQ, cpu)' wrapper routine that looks up
  an interrupt source and binds its interrupt event to the specified CPU.
  MI code can currently (ab)use this by doing:

	intr_bind(rman_get_start(irq_res), cpu);

  however, I plan to add a truly MI interface (probably a bus_bind_intr(9))
  where the implementation in the x86 nexus(4) driver would end up calling
  intr_bind() internally.

Requested by:	kmacy, gallatin, jeff
Tested on:	{amd64, i386} x {regular, INTR_FILTER}
2008-03-14 19:41:48 +00:00
John Baldwin
c9107e85d9 Fix a silly bogon which prevented all the CPUs that are tagged as interrupt
receivers from being given interrupts if any CPUs in the system were not
tagged as interrupt receivers that I introduced when switching the x86
interrupt code to track CPUs via FreeBSD CPU IDs rather than local APIC
IDs.  In practice this only affects systems with Hyperthreading (though
disabling HTT in the BIOS would workaround the issue) as that is the only
case currently where one can have CPUs that aren't tagged as interrupt
receivers.  On a Dell SC1425 test box with 2 x Xeon w/ HTT (so 4 logical
CPUs of which 2 were interrupt receivers) the result was that all
device interrupts were sent to CPU 0.

MFC after:	1 week
Pointy hat to:	jhb
2008-03-14 03:44:42 +00:00
John Baldwin
5217af301c Rework how the nexus(4) device works on x86 to better handle the idea of
different "platforms" on x86 machines.  The existing code already handles
having two platforms: ACPI and legacy.  However, the existing approach was
rather hardcoded and difficult to extend.  These changes take the approach
that each x86 hardware platform should provide its own nexus(4) driver (it
can inherit most of its behavior from the default legacy nexus(4) driver)
which is responsible for probing for the platform and performing
appropriate platform-specific setup during attach (such as adding a
platform-specific bus device).  This does mean changing the x86 platform
busses to no longer use an identify routine for probing, but to move that
logic into their matching nexus(4) driver instead.
- Make the default nexus(4) driver in nexus.c on i386 and amd64 handle the
  legacy platform.  It's probe routine now returns BUS_PROBE_GENERIC so it
  can be overriden.
- Expose a nexus_init_resources() routine which initializes the various
  resource managers so that subclassed nexus(4) drivers can invoke it from
  their attach routine.
- The legacy nexus(4) driver explicitly adds a legacy0 device in its
  attach routine.
- The ACPI driver no longer contains an new-bus identify method.  Instead
  it exposes a public function (acpi_identify()) which is a probe routine
  that the MD nexus(4) drivers can use to probe for ACPI.  All of the
  probe logic in acpi_probe() is now moved into acpi_identify() and
  acpi_probe() is just a stub.
- On i386 and amd64, an ACPI-specific nexus(4) driver checks for ACPI via
  acpi_identify() and claims the nexus0 device if the probe succeeds.  It
  then explicitly adds an acpi0 device in its attach routine.
- The legacy(4) driver no longer knows anything about the acpi0 device.
- On ia64 if acpi_identify() fails you basically end up with no devices.
  This matches the previous behavior where the old acpi_identify() would
  fail to add an acpi0 device again leaving you with no devices.

Discussed with:	imp
Silence on:	arch@
2008-03-13 20:39:04 +00:00
John Baldwin
d0234f752f Use the SMAP data from the loader if it is provided instead of using
virtual 86 mode to query the BIOS directly.  This is needed for certain
HP machines whose BIOS only provide an SMAP when invoked from real mode.
On such machines the loader will be able to query the SMAP successfully
due to the recent BTX changes, but the kernel will not.

One thing I'm not sure of is if we can skip the INT 12h probe altogether
if we have the SMAP from the loader as it seems that we do the INT 12h
probe to setup enough state so we can use vm86 to call the BIOS.

MFC after:	1 week
2008-03-13 18:56:53 +00:00
Konstantin Belousov
22eca0bf45 Since version 4.3, gcc changed its behaviour concerning the i386/amd64
ABI and the direction flag, that is it now assumes that the direction
flag is cleared at the entry of a function and it doesn't clear once
more if needed. This new behaviour conforms to the i386/amd64 ABI.

Modify the signal handler frame setup code to clear the DF {e,r}flags
bit on the amd64/i386 for the signal handlers.

jhb@ noted that it might break old apps if they assumed DF == 1 would be
preserved in the signal handlers, but that such apps should be rare and
that older versions of gcc would not generate such apps.

Submitted by:	Aurelien Jarno <aurelien aurel32 net>
PR:	121422
Reviewed by:	jhb
MFC after:	2 weeks
2008-03-13 10:54:38 +00:00
Konstantin Belousov
ea39de9f93 Add missed parentheses 2008-03-13 09:52:48 +00:00
John Baldwin
391664b110 The variable MTRR registers actually have variable-sized PhysBase and
PhysMask fields based on the number of physical address bits supported
by the current CPU.  The old code assumed 36 bits on i386 and 40 bits on
amd64.  In truth, all Intel CPUs up until recently used 36 bits (a newer
Intel CPU uses 38 bits) and all the Opteron CPUs used 40 bits.

In at least one case (the new Intel CPU) having the size of the mask field
wrong resulted in writing questionable values into the MTRR registers on
the application processors (BSP as well if you modify the MTRRs via
memcontrol or running X, etc.).  The result of the questionable physmask
was that all of memory was apparently treated as uncached rather than
write-back resulting in a very significant performance hit.

Fix this by constructing a run-time mask for the PhysBase and PhysMask
fields based on the number of physical address bits supported by the CPU.
All 64-bit capable CPUs provide a count of PA bits supported via the
0x80000008 extended CPUID feature, so use that if it is available.  If that
feature is not available, then assume 36 PA bits.

While I'm here, expand the (now-unused) macros for the PhysBase and
PhysMask fields to the current largest possible value (52 PA bits).

MFC after:	1 week
PR:		i386/120516
Reported by:	Nokia
2008-03-12 22:09:19 +00:00
John Baldwin
4cbd0e8984 MFamd64: Break up the probe logic in the mem_drvinit routines so it's
a bit easier to parse.
2008-03-12 21:44:46 +00:00
Jeff Roberson
6617724c5f Remove kernel support for M:N threading.
While the KSE project was quite successful in bringing threading to
FreeBSD, the M:N approach taken by the kse library was never developed
to its full potential.  Backwards compatibility will be provided via
libmap.conf for dynamically linked binaries and static binaries will
be broken.
2008-03-12 10:12:01 +00:00
John Baldwin
1b085fde87 Style(9) these files. No changes in the compiled code. (Verified by
diff'ing objdump -d output).
2008-03-11 21:41:36 +00:00
John Baldwin
336d8e5536 Add constants for the various fields in MTRR registers.
MFC after:	1 week
Verified by:	md5(1)
2008-03-11 20:10:37 +00:00
John Baldwin
463e0f91cb Probe CPUs after the PCI hierarchy on i386, amd64, and ia64. This allows
the cpufreq drivers to reliably use properties of PCI devices for quirks,
etc.
- For the legacy drivers, add CPU devices via an identify routine in the
  CPU driver itself rather than in the legacy driver's attach routine.
- Add CPU devices after Host-PCI bridges in the acpi bus driver.
- Change the ichss(4) driver to use pci_find_bsf() to locate the ICH and
  check its device ID rather than having a bogus PCI attachment that only
  checked for the ID in probe and always failed.  As a side effect, you
  can now kldload ichss after boot.
- Fix the ichss(4) driver to use the correct device_t for the ICH (and not
  for ichss0) when doing PCI config space operations to enable SpeedStep.

MFC after:	2 weeks
Reviewed by:	njl, Andriy Gapon  avg of icyb.net.ua
2008-03-10 22:18:07 +00:00
John Baldwin
c3cefed5eb - Don't execute cpuid to fetch the features. We already have the features
present in cpu_feature2.  Also, use CPUID2_EST rather than a magic
  number.
- Don't free the ACPI settings list in detach if we are going to fail the
  request.  Otherwise an attempt to kldunload est would free the array
  but the driver would keep trying to use it.

MFC after:	1 week
2008-03-10 22:00:35 +00:00
Jeff Roberson
32c9d3a767 - Rather than repeating the same preemption code everywhere call the scheduler
specific sched_preempt() routine.
2008-03-10 01:32:48 +00:00
Rink Springer
2e7328e7cc Import uslcom(4) from OpenBSD - this is a driver for Silicon Laboratories
CP2101/CP2102 based USB serial adapters.

Reviewed by:		imp, emaste
Obtained from:		OpenBSD
MFC after:		2 weeks
2008-03-05 14:13:30 +00:00
Bruce Evans
f3d2db418f Change float_t and double_t to long double on i386. All floating point
expressions on i386 are evaluated in the range of the long double type,
so this is wrong in a different but hopefully less worse way than
before.  Since expressions are evaluated in long double registers,
there is no runtime cost to using long double instead of double to
declare intermediate values (except in cases where this avoids compiler
bugs), and by careful use of float_t or double_t it is possible to
avoid some of the compiler bugs in this area, provided these types are
declared as long double.

I was going to change float.h to be less broken and more usable in
combination with the change here (in particular, it is more necessary
to know the effective number of bits in a double_t when double_t !=
double, since DBL_MANT_DIG no longer logically gives this, and
LDBL_MANT_DIG doesn't give it either with FreeBSD-i386's default
rounding precision.  However, this was too hard for now.  In particular,
LDBL_MANT_DIG is used a lot in libm, so it cannot be changed.  One
thing that is completely broken now is LDBL_MAX.  This may have sort
of worked when it was changed from DBL_MAX in 2002 (adding 0 to it at
runtime gave +Inf, but you could at least compare with it), but starting
with gcc-3.3.1 in 2003, it is always +Inf due to evaluating it at
compile time in the default rounding precision.
2008-03-05 11:21:14 +00:00