lock until after grabbing the sched_lock to avoid CURSIG racing with
psignal.
- Don't grab Giant for addupc_task() as it isn't needed.
Reported by: tegge (signal race), bde (addupc_task a while back)
startup routine more closely matches that of alpha and ia64. At some
point the common mutexes shared across all platforms probably should move
into sys/kern_mutex.c.
trace code that was brought over from NetBSD.)
- Check for "syscall_with_err_pushed" as the label prior to a syscall trap
frame rather than "Xlcall_syscall" and "Xint0x80_syscall". We don't
have a valid trapframe during the short range of code that those two
symbols now cover.
- Simplify db_next_frame() to avoid duplicating the code for the different
trap frame types.
- Don't try to trace a swapped-out process. (Brought over from NetBSD via
the new alpha trace code.)
- Replace some very poorly thought out API hacks that should have been
fixed a long while ago.
- Provide some much more flexible search functions (resource_find_*())
- Use strings for storage instead of an outgrowth of the rather
inconvenient temporary ioconf table from config(). We already had a
fallback to using strings before malloc/vm was running anyway.
- move the sysctl code to kern_intr.c
- do not use INTRCNT_COUNT, but rather eintrcnt - intrcnt to determine
the length of the intrcnt array
- move the declarations of intrnames, eintrnames, intrcnt and eintrcnt
from machine-dependent include files to sys/interrupt.h
- remove the hw.nintr sysctl, it is not needed.
- fix various style bugs
Requested by: bde
Reviewed by: bde (some time ago)
from cpu_switch(), curproc has been changed, but the sched_lock owner will
not be updated until we return to mi_switch(), thus we deadlock against
ourselves. As a workaround, push the acquire and release of sched_lock out
to the callers of set_user_ldt(). Note that we can't use a mtx_assert() in
set_user_ldt for the same reason.
Sleuting by: tmm
Tested by: tmm, dougb
simpler for npx exceptions that start as traps (no assembly required...)
and works better for npx exceptions that start as interrupts (there is
no longer a problem for nested interrupts).
Submitted by: original (pre-SMPng) version by luoqi
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.
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.
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.
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.
API for IPI's that isn't tied to the Intel APIC. MD code can still use
the apic_ipi() function or dink with the apic directly if needed to send
MD IPI's.
because:
- it used a better namespace (smp_ipi_* rather than *_ipi),
- it used better constant names for the IPI's (IPI_* rather than
X*_OFFSET), and
- this API also somewhat exists for both alpha and ia64 already.
Since pid's are not in the kernel address space, this doesn't conflict
with the funcionality of specifying an arbitrary frame pointer to the
trace command.
- If the first function of a backtrace maps to fork_trampoline, then this
is a newly fork'd process that has not been executed yet, so just print
out the first frame and then return for that case.
- Lower the default count from 65535 to 1024. ddb doesn't trace into
userland, and if the stack gets hosed and starts looping it's less
annoying.
Specifically, the cpuid, curproc, curpcb, npxproc, and idleproc members.
Also, if witness is compiled into the kernel, then a list of all the spin
locks held by this CPU is displayed. By default the information for the
current CPU is displayed, but a decimal cpu id may be specified as a
parameter to obtain information on a specific CPU.
stylistic.
# Yes, this break K&R, but this file already used so many gcc extensions
# keeping K&R support seemed too anachronistic for me.
Didn't fix the bug where functions that can only be used in the kernel
are exported to userland.
that people use from userland in C++ programs. I've had this in my
tree for ages and just got bit by it not being in the real tree again.
This is a MFC candidate.
- Introduce lock classes and lock objects. Each lock class specifies a
name and set of flags (or properties) shared by all locks of a given
type. Currently there are three lock classes: spin mutexes, sleep
mutexes, and sx locks. A lock object specifies properties of an
additional lock along with a lock name and all of the extra stuff needed
to make witness work with a given lock. This abstract lock stuff is
defined in sys/lock.h. The lockmgr constants, types, and prototypes have
been moved to sys/lockmgr.h. For temporary backwards compatability,
sys/lock.h includes sys/lockmgr.h.
- Replace proc->p_spinlocks with a per-CPU list, PCPU(spinlocks), of spin
locks held. By making this per-cpu, we do not have to jump through
magic hoops to deal with sched_lock changing ownership during context
switches.
- Replace proc->p_heldmtx, formerly a list of held sleep mutexes, with
proc->p_sleeplocks, which is a list of held sleep locks including sleep
mutexes and sx locks.
- Add helper macros for logging lock events via the KTR_LOCK KTR logging
level so that the log messages are consistent.
- Add some new flags that can be passed to mtx_init():
- MTX_NOWITNESS - specifies that this lock should be ignored by witness.
This is used for the mutex that blocks a sx lock for example.
- MTX_QUIET - this is not new, but you can pass this to mtx_init() now
and no events will be logged for this lock, so that one doesn't have
to change all the individual mtx_lock/unlock() operations.
- All lock objects maintain an initialized flag. Use this flag to export
a mtx_initialized() macro that can be safely called from drivers. Also,
we on longer walk the all_mtx list if MUTEX_DEBUG is defined as witness
performs the corresponding checks using the initialized flag.
- The lock order reversal messages have been improved to output slightly
more accurate file and line numbers.
and change the u_int mtx_saveintr member of struct mtx to a critical_t
mtx_savecrit.
- On the alpha we no longer need a custom _get_spin_lock() macro to avoid
an extra PAL call, so remove it.
- Partially fix using mutexes with WITNESS in modules. Change all the
_mtx_{un,}lock_{spin,}_flags() macros to accept explicit file and line
parameters and rename them to use a prefix of two underscores. Inside
of kern_mutex.c, generate wrapper functions for
_mtx_{un,}lock_{spin,}_flags() (only using a prefix of one underscore)
that are called from modules. The macros mtx_{un,}lock_{spin,}_flags()
are mapped to the __mtx_* macros inside of the kernel to inline the
usual case of mutex operations and map to the internal _mtx_* functions
in the module case so that modules will use WITNESS and KTR logging if
the kernel is compiled with support for it.
sections.
- Add implementations of the critical_enter() and critical_exit() functions
and remove restore_intr() and save_intr().
- Remove the somewhat bogus disable_intr() and enable_intr() functions on
the alpha as the alpha actually uses a priority level and not simple bit
flag on the CPU.
running in process context in order to run interrupt handlers. This
caused a big smashing of the stack on AMD K6, K5 and Intel Pentium (ie, P5)
processors because we are using npxproc as a flag to indicate whether
the state has been pushed onto the stack.
Submitted by: bde
of long and int64_t; and print the result as an unsigned long. This should
make the output from the bzero() test more readable, and avoid printing a
negative bandwidth. Note that this doesn't change the decision process,
since that is based on time elapsed, not on computed bandwidth.
For UP, we were using $tmp_stk as a stack from the data section. If the
kernel text section grew beyond ~3MB, the data section would be pushed
beyond the temporary 4MB P==V mapping. This would cause the trampoline
up to high memory to fault. The hack workaround I did was to use all of
the page table pages that we already have while preparing the initial
P==V mapping, instead of just the first one.
For SMP, the AP bootstrap process suffered the same sort of problem and
got the same treatment.
MFC candidate - this breaks on 4.x just the same..
Thanks to: Richard Todd <rmtodd@ichotolot.servalan.com>
if we hold a spin mutex, since we can trivially get into deadlocks if we
start switching out of processes that hold spinlocks. Checking to see if
interrupts were disabled was a sort of cheap way of doing this since most
of the time interrupts were only disabled when holding a spin lock. At
least on the i386. To fix this properly, use a per-process counter
p_spinlocks that counts the number of spin locks currently held, and
instead of checking to see if interrupts are disabled in the witness code,
check to see if we hold any spin locks. Since child processes always
start up with the sched lock magically held in fork_exit(), we initialize
p_spinlocks to 1 for child processes. Note that proc0 doesn't go through
fork_exit(), so it starts with no spin locks held.
Consulting from: cp
- Don't try to grab Giant before postsig() in userret() as it is no longer
needed.
- Don't grab Giant before psignal() in ast() but get the proc lock instead.
supported architectures such as the alpha. This allows us to save
on kernel virtual address space, TLB entries, and (on the ia64) VHPT
entries. pmap_map() now modifies the passed in virtual address on
architectures that do not support direct-mapped segments to point to
the next available virtual address. It also returns the actual
address that the request was mapped to.
- On the IA64 don't use a special zone of PV entries needed for early
calls to pmap_kenter() during pmap_init(). This gets us in trouble
because we end up trying to use the zone allocator before it is
initialized. Instead, with the pmap_map() change, the number of needed
PV entries is small enough that we can get by with a static pool that is
used until pmap_init() is complete.
Submitted by: dfr
Debugging help: peter
Tested by: me
bolted to a ne-2000 chip. This is necessary for the NetGear FA-410TX
and other cards.
This also requires you add mii to your kernel if you have an ed driver
configured.
This code will result in a couple of timeout messages for ed on the
impacted cards. Additional work will be needed, but this does work
right now, and many people need these cards.
Submitted by: Ian Dowse <iedowse@maths.tcd.ie>
with egcs-1.1.1. bus_space_write_multi_2() had an extra operation that
should have been removed.
Remove it.
This fixes the panic when bus_space_write_multi_2() is used.
Obtained from: jake
gcc -aout -mno-underscores. The bioscall.s tweak is not an a.out
requirement really, but to work around the bugs in the antique version of
gas that used for a.out. Makefile hacks are all that is needed to
get an a.out kernel. There is no telling if it will work though.
This is little more than an academic curiosity anyway since all it is
good for is situations where the boot code is hard wired, eg: rom
bootstraps (such as the gnat box).
GENERIC:
...
size -aout kernel ; chmod 755 kernel
text data bss dec hex
3051520 368640 198688 3618848 373820
and used in C or vice versa. The elf compiler uses the same names
for both. Remove asnames.h with great prejudice; it has served its
purpose.
Note that this does not affect the ability to generate an aout kernel
due to gcc's -mno-underscores option.
moral support from: peter, jhb
to be more like Xint0x80_syscall and less like c function syscall().
- Reduce code duplication between the int0x80 and lcall handlers by
shuffling the elfags into the right place, saving the sizeof the
instruction in tf_err and jumping into the common int0x80 code.
Reviewed by: peter
depend on this. The linux ABI emulator tries to use it for some linux
binaries too. VM86 had a bigger cost than this and it was made default
a while ago.
Reviewed by: jhb, imp
the the original trapframe of the syscall, trap, or interrupt that entered
the kernel. Before SMPng, ast's were handled via a psuedo trap at the
end of doerti. With the SMPng commit, ast's were broken out into a
separate ast() function that was called from doreti to match the behavior
of other architectures. Unfortunately, when this was done, the
p_md.md_regs member of curproc was not updateda in ast(), thus when
signals are handled by userret() after an interrupt that returns to
userland, we end up using a stale trapframe that will result in the
registers from the old trapframe overwriting the real trapframe and
smashing all the registers right before we return to usermode. The saved
%cs:%eip from where we were in usermode are saved in the trapframe for
example.
- Don't use an atomic operation to update cnt.v_soft in ast(). This is
the only place the variable is written to, and sched_lock is always
held when it is written, so it is already protected and the mutex release
of sched_lock asserts a memory barrier that ensures the value will be
updated in a timely fashion.
- Don't hold sched_lock around addupc_task() as this apparently breaks
profiling badly due to sched_lock being held across copyin().
Reported by: bde (2)
scheduling an interrupt thread to run when needed. This has the side
effect of enabling support for entropy gathering from interrupts on
all architectures.
- Change the software interrupt and x86 and alpha hardware interrupt code
to use ithread_schedule() for most of their processing when scheduling
an interrupt to run.
- Remove the pesky Warning message about interrupt threads having entropy
enabled. I'm not sure why I put that in there in the first place.
- Add more error checking for parameters and change some cases that
returned EINVAL to panic on failure instead via KASSERT().
- Instead of doing a documented evil hack of setting the P_NOLOAD flag
on every interrupt thread whose pri was SWI_CLOCK, set the flag
explicity for clk_ithd's proc during start_softintr().
in mi_switch() just before calling cpu_switch() so that the first switch
after a resched request will satisfy the request.
- While I'm at it, move a few things into mi_switch() and out of
cpu_switch(), specifically set the p_oncpu and p_lastcpu members of
proc in mi_switch(), and handle the sched_lock state change across a
context switch in mi_switch().
- Since cpu_switch() no longer handles the sched_lock state change, we
have to setup an initial state for sched_lock in fork_exit() before we
release it.
always on curproc. This is needed to implement signal delivery properly
(see a future log message for kern_sig.c).
Debogotified the definition of aston(). aston() was defined in terms
of signotify() (perhaps because only the latter already operated on
a specified process), but aston() is the primitive.
Similar changes are needed in the ia64 versions of cpu.h and trap.c.
I didn't make them because the ia64 is missing the prerequisite changes
to make astpending and need_resched per-process and those changes are
too large to make without testing.
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.
- All processes go into the same array of queues, with different
scheduling classes using different portions of the array. This
allows user processes to have their priorities propogated up into
interrupt thread range if need be.
- I chose 64 run queues as an arbitrary number that is greater than
32. We used to have 4 separate arrays of 32 queues each, so this
may not be optimal. The new run queue code was written with this
in mind; changing the number of run queues only requires changing
constants in runq.h and adjusting the priority levels.
- The new run queue code takes the run queue as a parameter. This
is intended to be used to create per-cpu run queues. Implement
wrappers for compatibility with the old interface which pass in
the global run queue structure.
- Group the priority level, user priority, native priority (before
propogation) and the scheduling class into a struct priority.
- Change any hard coded priority levels that I found to use
symbolic constants (TTIPRI and TTOPRI).
- Remove the curpriority global variable and use that of curproc.
This was used to detect when a process' priority had lowered and
it should yield. We now effectively yield on every interrupt.
- Activate propogate_priority(). It should now have the desired
effect without needing to also propogate the scheduling class.
- Temporarily comment out the call to vm_page_zero_idle() in the
idle loop. It interfered with propogate_priority() because
the idle process needed to do a non-blocking acquire of Giant
and then other processes would try to propogate their priority
onto it. The idle process should not do anything except idle.
vm_page_zero_idle() will return in the form of an idle priority
kernel thread which is woken up at apprioriate times by the vm
system.
- Update struct kinfo_proc to the new priority interface. Deliberately
change its size by adjusting the spare fields. It remained the same
size, but the layout has changed, so userland processes that use it
would parse the data incorrectly. The size constraint should really
be changed to an arbitrary version number. Also add a debug.sizeof
sysctl node for struct kinfo_proc.
Some things needed bits of <i386/include/lock.h> - cy.c now has its
own (only) copy of the COM_(UN)LOCK() macros, and IMASK_(UN)LOCK()
has been moved to <i386/include/apic.h> (AKA <machine/apic.h>).
Reviewed by: jhb
attributes. This is needed for AST's to be properly posted in a preemptive
kernel. They are backed by two new flags in p_sflag: PS_ASTPENDING and
PS_NEEDRESCHED. They are still accesssed by their old macros:
aston(), astoff(), etc. For completeness, an astpending() macro has been
added to check for a pending AST, and clear_resched() has been added to
clear need_resched().
- Rename syscall2() on the x86 back to syscall() to be consistent with
other architectures.
- Use swi_* function names.
- Use void * to hold cookies to handlers instead of struct intrhand *.
- In sio.c, use 'driver_name' instead of "sio" as the name of the driver
lock to minimize diffs with cy(4).
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)
by myself. It solves a serious vm_map corruption problem that can occur
with the buffer cache when block sizes > 64K are used. This code has been
heavily tested in -stable but only tested somewhat on -current. An MFC
will occur in a few days. My additions include the vm_map_simplify_entry()
and minor buffer cache boundry case fix.
Make the buffer cache use a system map for buffer cache KVM rather then a
normal map.
Ensure that VM objects are not allocated for system maps. There were cases
where a buffer map could wind up with a backing VM object -- normally
harmless, but this could also result in the buffer cache blocking in places
where it assumes no blocking will occur, possibly resulting in corrupted
maps.
Fix a minor boundry case in the buffer cache size limit is reached that
could result in non-optimal code.
Add vm_map_simplify_entry() calls to prevent 'creeping proliferation'
of vm_map_entry's in the buffer cache's vm_map. Previously only a simple
linear optimization was made. (The buffer vm_map typically has only a
handful of vm_map_entry's. This stabilizes it at that level permanently).
PR: 20609
Submitted by: (Tor Egge) tegge
- If possible, context switch to the thread directly in sched_ithd(),
rather than triggering a delayed ast reschedule.
- Disable interrupts while restoring fpu state in the trap handler,
in order to ensure that we are not preempted in the middle, which
could cause migration to another cpu.
Reviewed by: peter
Tested by: peter (alpha)
problem is that a mutex lock, prior to this change, is acquired before
the curproc is set to idleproc, so we mess ourselves up by calling
the mutex lock routine with curproc == NULL.
Moving it up after the aps_ready spin-wait has us hopefully setting it
after idleproc is setup.
Solved by: jake (the allmighty) :-)
instead of a trapframe directly. (Requested by bde.)
- Convert the alpha switch_trampoline to call fork_exit() and use the MI
fork_return() instead of child_return().
- Axe child_return().
that name as a variable. Use mtx_owned(&Giant) where appropriate
instead.
- Proc locking.
- P_FOO -> PS_FOO.
- Update comments about enable interrupts during trap and why this may be
bad if we trap while holding a spin mutex.
- Don't bother resetting p to curproc in syscall() in case we are the child
returning from fork. The child hasn't returned from fork through syscall
in a while.
- Remove fork_return() as it has been superseded by the MI version.
the alpha mp_machdep.c.
- Proc locking.
- Catch up to the P_FOO -> PS_FOO proc flags changes.
- Stick ap_init()'s prototype with the other prototypes.
- Remove the Xforwardirq IPI.
- Remove unused simplelocks.
- Don't try to psignal() from forward_statclock(), but set the appropriate
signal pending flag in p_sflag instead.
- Add in KTR_SMP tracepoints for various SMP functions. (Brought over
from the alpha port)
- Setup proc0.p_heldmtx, proc0.contested, and curproc earlier so that we
can use mutexes.
- Initialize sched_lock and Giant earlier and enter Giant during init386.
- Use suser(9) instead of checking cr_uid directly.
inline functions non-inlined. Hide parts of the mutex implementation that
should not be exposed.
Make sure that WITNESS code is not executed during boot until the mutexes
are fully initialized by SI_SUB_MUTEX (the original motivation for this
commit).
Submitted by: peter
interrupt threads to run with it always >= 1, so that malloc can
detect M_WAITOK from "interrupt" context. This is also necessary
in order to context switch from sched_ithd() directly.
Reviewed By: peter
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.
for SMP; just use the same ones as UP. These weren't used without
holding Giant anyway, and the routines that use them would have to
be protected from pre-emption to avoid migrating cpus.
appropriate function, rather than doing a horse-and-buggy
acquire. They now take the mutex type as an arg and can be
used with sleep as well as spin mutexes.
All calls to mtx_init() for mutexes that recurse must now include
the MTX_RECURSE bit in the flag argument variable. This change is in
preparation for an upcoming (further) mutex API cleanup.
The witness code will call panic() if a lock is found to recurse but
the MTX_RECURSE bit was not set during the lock's initialization.
The old MTX_RECURSE "state" bit (in mtx_lock) has been renamed to
MTX_RECURSED, which is more appropriate given its meaning.
The following locks have been made "recursive," thus far:
eventhandler, Giant, callout, sched_lock, possibly some others declared
in the architecture-specific code, all of the network card driver locks
in pci/, as well as some other locks in dev/ stuff that I've found to
be recursive.
Reviewed by: jhb
non-386 atomic_load_acq(). %eax is an input since its value is used in
the cmpxchg instruction, but we don't care what value it is, so setting
it to a specific value is just wasteful. Thus, it is being used without
being initialized as the warning stated, but it is ok for it to be used
because its value isn't important. Thus, we are only sort of lying when
we say it is an output only operand.
- Add "cc" to the clobber list for atomic_load_acq() since the cmpxchgl
changes ZF.
slow enough as it is, without having to constantly check that it really
is an i386 still. It was possible to compile out the conditionals for
faster cpus by leaving out 'I386_CPU', but it was not possible to
unconditionally compile for the i386. You got the runtime checking whether
you wanted it or not. This makes I386_CPU mutually exclusive with the
other cpu types, and tidies things up a little in the process.
Reviewed by: alfred, markm, phk, benno, jlemon, jhb, jake, grog, msmith,
jasone, dcs, des (and a bunch more people who encouraged it)
compiling errors where gcc would run out of registers.
- Add "cc" to the list of clobbers for micro-ops where we perform
instructions that alter %eflags.
- Use xchgl instead of cmpxchgl to release a spin lock. This could allow
for more efficient register allocation as we no longer mandate that %eax
be used.
- Reenable the optimized mutex micro-ops in the non-i386 case.
that modules can call.
- Remove the old gcc <= 2.8 versions of the atomic ops.
- Resort the order of some things in the file so that there is only
one #ifdef for KLD_MODULE, and so that all WANT_FUNCTIONS stuff is
moved to the bottom of the file.
- Remove ATOMIC_ACQ_REL() and just use explicit macros instead.
time I tinkered around here. Since INTREN is called from the interrupt
critical path now, it should not be too expensive. In this case, we
look at the bits being changed to decide which 8 bit IO port to write to
rather than unconditionally writing to both. I could probably have gone
further and only done the write if the bits actually changed, but that
seemed overkill for the usual case in interrupt threads.
[an outb is rather expensive when it has to cross the ISA bus]
exactly the same functionality via a sysctl, making this feature
a run-time option.
The default is 1(ON), which means that /dev/random device will
NOT block at startup.
setting kern.random.sys.seeded to 0(OFF) will cause /dev/random
to block until the next reseed, at which stage the sysctl
will be changed back to 1(ON).
While I'm here, clean up the sysctls, and make them dynamic.
Reviewed by: des
Tested on Alpha by: obrien
implement memory fences for the 486+. The 386 still uses versions w/o
memory fences as all operations on the 386 are not program ordered.
The 386 versions are not MP safe.
declarations of a variable of the same name. The one in the outer block
was unused and probably just slipped in at one point or another. This
silences a compiler warning.
__FreeBSD_version 500015 can be used to detect their disappearance.
- Move the symbols for SMP_prvspace and lapic from globals.s to
locore.s.
- Remove globals.s with extreme prejudice.
symbols in globals.s.
PCPU_GET(name) returns the value of the per-cpu variable
PCPU_PTR(name) returns a pointer to the per-cpu variable
PCPU_SET(name, val) sets the value of the per-cpu variable
In general these are not yet used, compatibility macros remain.
Unifdef SMP struct globaldata, this makes variables such as cpuid
available for UP as well.
Rebuilding modules is probably a good idea, but I believe old
modules will still work, as most of the old infrastructure
remains.
as multi-processor kernels. The old way made it difficult for kernel
modules to be portable between uni-processor and multi-processor
kernels. It is no longer necessary to jump through hoops.
- always load %fs with the private segment on entry to the kernel
- change the type of the self referntial pointer from struct privatespace
to struct globaldata
- make the globaldata symbol have value 0 in all cases, so the symbols
in globals.s are always offsets, not aliases for fields in globaldata
- define the globaldata space used for uniprocessor kernels in C, rather
than assembler
- change the assmebly language accessors to use %fs, add a macro
PCPU_ADDR(member, reg), which loads the register reg with the address
of the per-cpu variable member
vm86_trap() to return to the calling program directly. vm86_trap()
doesn't return, thus it was never returning to trap() to release
Giant. Thus, release Giant before calling vm86_trap().
struct swblock entries by dividing the number of the entries by 2
until the swap metadata fits.
- Reject swapon(2) upon failure of swap_zone allocation.
This is just a temporary fix. Better solutions include:
(suggested by: dillon)
o reserving swap in SWAP_META_PAGES chunks, and
o swapping the swblock structures themselves.
Reviewed by: alfred, dillon
variables from i386 assembly language. The syntax is PCPU(member)
where member is the capitalized name of the per-cpu variable, without
the gd_ prefix. Example: movl %eax,PCPU(CURPROC). The capitalization
is due to using the offsets generated by genassym rather than the symbols
provided by linking with globals.o. asmacros.h is the wrong place for
this but it seemed as good a place as any for now. The old implementation
in asnames.h has not been removed because it is still used to de-mangle
the symbols used by the C variables for the UP case.
of explicit calls to lockmgr. Also provides macros for the flags
pased to specify shared, exclusive or release which map to the
lockmgr flags. This is so that the use of lockmgr can be easily
replaced with optimized reader-writer locks.
- Add some locking that I missed the first time.
the witness code is compiled in. Without this, the witness code doesn't
notice that sched_lock is released by fork_trampoline() and thus gets all
confused about spin lock order later on.
held and panic if so (conditional on witness).
- Change witness_list to return the number of locks held so this is easier.
- Add kern/syscalls.c to the kernel build if witness is defined so that the
panic message can contain the name of the offending system call.
- Add assertions that Giant and sched_lock are not held when returning from
a system call, which were missing for alpha and ia64.
- Move PCI core code to dev/pci.
- Split bridge code out into separate modules.
- Remove the descriptive strings from the bridge drivers. If you
want to know what a device is, use pciconf. Add support for
broadly identifying devices based on class/subclass, and for
parsing a preloaded device identification database so that if
you want to waste the memory, you can identify *anything* we know
about.
- Remove machine-dependant code from the core PCI code. APIC interrupt
mapping is performed by shadowing the intline register in machine-
dependant code.
- Bring interrupt routing support to the Alpha
(although many platforms don't yet support routing or mapping
interrupts entirely correctly). This resulted in spamming
<sys/bus.h> into more places than it really should have gone.
- Put sys/dev on the kernel/modules include path. This avoids
having to change *all* the pci*.h includes.
calling the C functions mtx_enter_hard() and mtx_exit_hard() clobbers them.
Note that %eax is also not call safe, but it is already clobbered due to
cmpxchg. However, now we are back to not compiling again, so these macros
are still left disabled for now.
that of MTX_EXIT. Don't assume that the reg parameter to MTX_ENTER
holds curproc, load it explicitly. Put semi-colons at the end of
the macros to be more consistent and so its harder to forget them
when these change.
SMP problem. Compaq, in their infinite wisdom, forgot to put the IO apic
intpin #0 connection to the 8259 PIC into the mptable. This hack is to
look and see if intpin #0 has *no* table entry and adds a fake ExtInt
entry for the remap routines to use. isa/clock.c will still test the
interrupts. This entry is only ever used on an already broken system.
mpapic.c. This gives us the benefit of C type checking. These functions
are not called in any critical paths and are not used by the interrupt
routines.
spending, which was unused now that all software interrupts have
their own thread. Make the legacy schednetisr use an atomic op
for setting bits in the netisr mask.
Reviewed by: jhb
Also, while here, run up to 32 interrupt sources on APIC systems.
Normalize INTREN/INTRDIS so they are the same on both UP and SMP systems
rather than sometimes a macro, and sometimes a function.
Reviewed by: jhb, jakeb
MPLOCKED macro
(2) Use decimal 12 rather than hex 0xc in an addl
(3) Implement MTX_ENTER for the I386_CPU case
(4) Use semi-colons between instructions to allow MTX_ENTER
and MTX_ENTER_WITH_RECURSION to be assembled
(5) Use incl instead of incw to increment the recusion count
(6) 10 is not a valid label, use 7, 8 and 9 rather than 8, 9 and 10
(7) Sort numeric labels
Submitted by: bde (2, 4, and 5)
pushl that of the new process, rather than doing a movl (%esp) and
assuming that the stack has been setup right. This make the initial
stack setup slightly more sane, and will make it easier to stick
an interrupted process onto the run queue without its knowing.
process is on the alternate stack or not. For compatibility
with sigstack(2) state is being updated if such is needed.
We now determine whether the process is on the alternate
stack by looking at its stack pointer. This allows a process
to siglongjmp from a signal handler on the alternate stack
to the place of the sigsetjmp on the normal stack. When
maintaining state, this would have invalidated the state
information and causing a subsequent signal to be delivered
on the normal stack instead of the alternate stack.
PR: 22286
-current and RELENG_4 with GENERIC.
NKPT is the number of initial bootstrap page table pages we create for
the kernel during startup. Once VM is up, we resize it as needed, but
with 4G ram, the size of the vm_page_t structures was pushing it over
the limit. The fact that trimmed down kernels boot on 4G ram machines
suggests that we were pretty close to the edge.
The "30" is arbitary, but smaller than the 'nkpt' variable on all
machines that I checked.
timeout. If DIAGNOSTIC is turned on, then display a message to the console
with a map of which CPUs failed to stop or restart. This gives an SMP box
at least a fighting chance of getting into DDB if one of the other CPUs has
interrupts disabled.
counter register in-CPU.
This is to be used as a fast "timer", where linearity is more important
than time, and multiple lines in the linearity caused by multiple CPUs
in an SMP machine is not a problem.
This adds no code whatsoever to the FreeBSD kernel until it is actually
used, and then as a single-instruction inline routine (except for the
80386 and 80486 where it is some more inline code around nanotime(9).
Reviewed by: bde, kris, jhb
- Use the mutex in hardclock to ensure no races between it and
softclock.
- Make softclock be INTR_MPSAFE and provide a flag,
CALLOUT_MPSAFE, which specifies that a callout handler does not
need giant. There is still no way to set this flag when
regstering a callout.
Reviewed by: -smp@, jlemon
may block on a mutex while on the sleep queue without corrupting
it.
- Move dropping of Giant to after the acquire of sched_lock.
Tested by: John Hay <jhay@icomtek.csir.co.za>
jhb
instead of DIAGNOSTIC.
- Remove the p_wchan check as it no longer applies since a process may be
switched out during CURSIG() within msleep() or mawait().
- Remove an extra sanity check only needed during the early SMPng work.
acquire Giant as needed in functions that call mi_switch(). The releases
need to be done outside of the sched_lock to avoid potential deadlocks
from trying to acquire Giant while interrupts are disabled.
Submitted by: witness
sched_lock. This is needed for kernel threads that are created before
interrupts are enabled. kthreads created by kld's that are created at
SI_SUB_KLD such as the random kthread.
Tested by: phk
