npxsave() went to great lengths to excecute fnsave with interrupts
enabled in case executing it froze the CPU. This case can't happen,
at least for Intel CPU/NPX's. Spurious IRQ13's don't imply spurious
freezes. Anyway, the complications were usually no-ops because IRQ13
is not used on i486's and newer CPUs, and because SMPng broke them in
rev.1.84. Forcible enabling of interrupts was changed to
write_eflags(old_eflags), but since SMPng usually calls npxsave() from
cpu_switch() with interrupts disabled, write_eflags() usually just
kept interrupts disabled.
npxinit() didn't have the usual race because it doesn't save to curpcb,
but it may have had a worse form of it since it uses the npx when it
doesn't "own" it. I'm not sure if locking prevented this. npxinit()
is normally caled with the proc lock but not sched_lock.
Use a critical region to protect pushing of curproc's npx state to
curpcb in npxexit(). Not doing so was harmless since it at worst
saved a wrong state to a dieing pcb.
Not doing this was fairly harmless because savectx() is only called
for panic dumps and the bug could at worse reset the state.
savectx() is still missing saving of (volatile) debug registers, and
still isn't called for core dumps.
vm_mtx does not recurse and is required for most low level
vm operations.
faults can not be taken without holding Giant.
Memory subsystems can now call the base page allocators safely.
Almost all atomic ops were removed as they are covered under the
vm mutex.
Alpha and ia64 now need to catch up to i386's trap handlers.
FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).
Reviewed (partially) by: jake, jhb
- Attach a writable sysctl to bootverbose (debug.bootverbose) so it can be
toggled after boot.
- Move the printf of the version string to a SI_SUB_COPYRIGHT SYSINIT just
afer the display of the copyright message instead of doing it by hand in
three MD places.
registers better. Hold sched_lock not only for checking the flag but
also while performing the actual operation to ensure the process doesn't
get swapped out by another CPU while we the operation is being performed.
. FD_CLRERR clears the error counter, thus re-enables kernel error
printf()s,
. FD_GSTAT obtains the last FDC operation state, if any,
. FDOPT_NOERRLOG (temporarily) turns off kernel printf() floppy
error logging,
. FDOPT_NOERROR makes the kernel ignore an FDC error, thus can
enable the transfer of an erroneous sector to the user application
All options are being cleared on (last) close.
Prime consumer of the last features will be fdread(1), to be committed
shortly.
(FD_CLRERR should be wired into fdcontrol(8), but then fdcontrol(8)
needs a major rewrite anyway.)
If for some reason DEVFS is undesired, the "NODEVFS" option is
needed now.
Pending any significant issues, DEVFS will be made mandatory in
-current on july 1st so that we can start reaping the full
benefits of having it.
pcb for fork(). It was possible for the state to be saved twice when an
interrupt handler saved it concurrently. This corrupted (reset) the state
because fnsave has the (in)convenient side effect of doing an implicit
fninit. Mundane null pointer bugs were not possible, because we save to
an "arbitrary" process's pcb and not to the "right" place (npxproc).
Push the parent's %gs to the pcb for fork(). Changes to %gs before
fork() were not preserved in the child unless an accidental context
switch did the pushing. Updated the list of pcb contents which is
supposed to inhibit bugs like this. pcb_dr*, pcb_gs and pcb_ext were
missing. Copying is correct for pcb_dr*, and pcb_ext is already
handled specially (although XXX'ly).
Reducing the savectx() call to an npxsave() call in rev.1.80 was a
mistake. The above bugs are duplicated in many places, including in
savectx() itself.
The arbitraryness of the parent process pointer for the fork()
subroutines, the pcb pointer for savectx(), and the save87 pointer
for npxsave(), is illusory. These functions don't work "right" unless
the pointers are precisely curproc, curpcb, and the address of npxproc's
save87 area, respectively, although the special context in which they
are called allows savectx(&dumppcb) to sort of work and npxsave(&dummy)
to work. cpu_fork() just doesn't work unless the parent process
pointer is curproc, or the caller has pushed %gs to the pcb, or %gs
happens to already be in the pcb.
follow Linux' convention and use %gs. This adds back the setting of
%fs to a sane value in sendsig(). The value of %gs remains preserved
to whatever it was in user context.
handler in Linux emulation. According to bde, this is what Linux
does.
Recent versions of linuxthreads use %gs for thread-specific data,
while FreeBSD uses %fs (mostly because WINE uses %gs).
Tested by: drew
and DP83821 gigabit ethernet MAC chips and the NatSemi DP83861 10/100/1000
copper PHY. There are a whole bunch of very low cost cards available with
this chipset selling for $150USD or less. This includes the SMC9462TX,
D-Link DGE-500T, Asante GigaNIX 1000TA and 1000TPC, and a couple cards
from Addtron.
This chip supports TCP/IP checksum offload, VLAN tagging/insertion.
2048-bit multicast filter, jumbograms and has 8K TX and 32K RX FIFOs.
I have not done serious performance testing with this driver. I know
it works, and I want it under CVS control so I can keep tabs on it.
Note that there's no serious mutex stuff in here yet either: I need
to talk more with jhb to figure out the right way to do this. That
said, I don't think there will be any problems.
This driver should also work on the alpha. It's not turned on in
GENERIC.
safe from preemption and concurrent access to the LDT.
- Move the prototype for i386_extend_pcb() to <machine/pcb_ext.h>.
Reviewed by: silence on -hackers
%fs and %gs registers instead of setting them to known sane values.
%fs is going to be used for thread/KSE specific data by the new
threads library; we'll want it to be valid inside of signal handlers.
According to bde, Linux preserves the state of %fs and %gs when setting
up signal handlers, so there is precedent for doing this.
The same changes should be made in the Linux emulator, but when made,
they seem to break (at least one version of) the IBM JDK for Linux
(reported by drew).
Approved by: bde
handling, SMPng always switches the npx context away from curproc
before calling the handler, so the handler always paniced. When using
exception 16 exception handling, SMPng sometimes switches the npx
context away from curproc before calling the handler, so the handler
sometimes paniced. Also, we didn't lock the context while using it,
so we sometimes didn't detect the switch and then paniced in a less
controlled way.
Just lock the context while using it, and return without doing anything
except clearing the busy latch if the context is not for curproc. This
fixes the exception 16 case and makes the IRQ13 case harmless. In both
cases, the instruction that caused the exception is restarted and the
exception repeats. In the exception 16 case, we soon get an exception
that can be handled without doing anything special. In the IRQ13 case,
we get an easy to kill hung process.
This driver supports PCI Xr-based and ISA Xem Digiboard cards.
dgm will go away soon if there are no problems reported. For now,
configuring dgm into your kernel warns that you should be using
digi. This driver is probably close to supporting Xi, Xe and Xeve
cards, but I wouldn't expect them to work properly (hardware
donations welcome).
The digi_* pseudo-drivers are not drivers themselves but contain
the BIOS and FEP/OS binaries for various digiboard cards and are
auto-loaded and auto-unloaded by the digi driver at initialisation
time. They *may* be configured into the kernel, but waste a lot
of space if they are. They're intended to be left as modules.
The digictl program is (mainly) used to re-initialise cards that
have external port modules attached such as the PC/Xem.
other "system" header files.
Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.
Sort sys/*.h includes where possible in affected files.
OK'ed by: bde (with reservations)
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
panic_cpu shared variable. I used a simple atomic operation here instead
of a spin lock as it seemed to be excessive overhead. Also, this can avoid
recursive panics if, for example, witness is broken.
are some good reasons for not doing this, even if the linting of
the code breaks.
1) If lint were ever to understand the stuff inside the macros,
that would break the checks.
2) There are ways to use __GNUC__ to exclude overly specific
code.
3) (Not yet practical) Lint(1) needs to properlyu understand
all of te code we actually run.
Complained about by: bde
Education by: jake, jhb, eivind
interfaces and functionality intended for use during correctness and
regression testing. Features enabled by "options REGRESSION" may
in and of themselves introduce security or correctness problems if
used improperly, and so are not intended for use in production
systems, only in testing environments.
Obtained from: TrustedBSD Project
