Commit Graph

46 Commits

Author SHA1 Message Date
Warner Losh
86cb007f9f /* -> /*- for copyright notices, minor format tweaks as necessary 2005-01-06 22:18:23 +00:00
Marcel Moolenaar
f0556e70bb Make profiling actually work. The gcc compiler emits a call to the
_mcount() stub when profiling is enabled. Emit this code sequence
for assembly routines as welli (MCOUNT definition in <machine/asm.h>.
We do not pass the GOT entry however as the 4th argument, because it's
not used. The _mcount() stub calls __mcount(), which does the actual
work. Define _MCOUNT_DECL to define __mcount. We do not have an
implementation of mcount(), so we define MCOUNT as empty, but have a
weak alias to _mcount() in _mcount.S.
Note that the _mcount() stub in the kernel is slightly different from
the stub in userland. This is because we do not have to worry about
nested routines in the kernel.
2004-08-25 07:42:34 +00:00
Maxime Henrion
9f1b87f106 Instead of calling ia32_pause() conditionally on __i386__ or __amd64__
being defined, define and use a new MD macro, cpu_spinwait().  It only
expands to something on i386 and amd64, so the compiled code should be
identical.

Name of the macro found by:	jhb
Reviewed by:	jhb
2004-08-03 18:44:27 +00:00
Bruce Evans
4c5f10a672 Backed out previous commit. Blind substitution of dev_t by `struct cdev *'
was just wrong here because the dev_t's are user dev_t's.
2004-06-20 03:52:50 +00:00
Poul-Henning Kamp
89c9c53da0 Do the dreaded s/dev_t/struct cdev */
Bump __FreeBSD_version accordingly.
2004-06-16 09:47:26 +00:00
Warner Losh
f36cfd49ad Remove advertising clause from University of California Regent's
license, per letter dated July 22, 1999 and email from Peter Wemm,
Alan Cox and Robert Watson.

Approved by: core, peter, alc, rwatson
2004-04-07 20:46:16 +00:00
Marcel Moolenaar
d6c3e38bb2 Change TRAPF_USERMODE and CLOCKF_USERMODE to not test for CPL == 3,
but for CPL != 0. For some reason yet unknown it is possible for the
CPL to be 2. This would previously be counted as kernel mode, which
resulted in nasty panics. By changing the test it is now treated as
user mode, which is more correct. We still need to figure out how it
is possible that the privilege level can be 2 (or 1 for that matter),
because it's not used by us. We only use 3 (user mode) and 0 (kernel
mode).
2003-09-19 07:48:22 +00:00
Marcel Moolenaar
4a98d8b095 Undo the mistake made in revision 1.77 of trap.c and which was the
ultimate trigger for the follow-up fixes in revisions 1.78, 1.80,
1.81 and 1.82 of trap.c. I was simply too pre-occupied with the
gateway page and how it blurs kernel space with user space and
vice versa that I couldn't see that it was all a load of bollocks.

It's not the IP address that matters, it's the privilege level that
counts. We never run in user space with lifted permissions and we
sure can not run in kernel space without it. Sure, the gateway page
is the exception, but not if you look at the privilege level. It's
user space if you run with user permissions and kernel space otherwise.

So, we're back to looking at the privilege level like it should be.
There's no other way.

Pointy hat: marcel
2003-08-20 05:30:35 +00:00
Marcel Moolenaar
26502503e5 Further cleanup <machine/cpu.h> and <machine/md_var.h>: move the MI
prototypes of cpu_halt(), cpu_reset() and swi_vm() from md_var.h to
cpu.h. This affects db_command.c and kern_shutdown.c.

ia64: move all MD prototypes from cpu.h to md_var.h. This affects
madt.c, interrupt.c and mp_machdep.c. Remove is_physical_memory().
It's not used (vm_machdep.c).

alpha: the MD prototypes have been left in cpu.h with a comment
that they should be there. Moving them is left for later. It was
expected that the impact would be significant enough to be done in
a seperate commit.

powerpc: MD prototypes left in cpu.h. Comment added.

Suggested by: bde
Tested with: make universe (pc98 incomplete)
2003-08-16 16:57:57 +00:00
Marcel Moolenaar
e57196b3db Cleanup prototypes in cpu.h, including fswintrberr and any references
to it. Sort the remaining prototypes in cpu.h.

No functional change.
2003-08-12 03:51:53 +00:00
John Baldwin
8b149b5131 Consistently use the BSD u_int and u_short instead of the SYSV uint and
ushort.  In most of these files, there was a mixture of both styles and
this change just makes them self-consistent.

Requested by:	bde (kern_ktrace.c)
2003-08-07 15:04:27 +00:00
Marcel Moolenaar
46e31b2612 Cleanup the clock code. This includes:
o  Remove alpha specific timer code (mc146818A) and compiled-out
   calibration of said timer.
o  Remove i386 inherited timer code (i8253) and related acquire and
   release functions.
o  Move sysbeep() from clock.c to machdep.c and have it return
   ENODEV. Console beeps should be implemented using ACPI or if no
   such device is described, using the sound driver.
o  Move the sysctls related to adjkerntz, disable_rtc_set and
   wall_cmos_clock from machdep.c to clock.c, where the variables
   are.
o  Don't hardcode a hz value of 1024 in cpu_initclocks() and don't
   bother faking a stathz that's 1/8 of that. Keep it simple: hz
   defaults to HZ and stathz equals hz. This is also how it's done
   for sparc64.
o  Keep a per-CPU ITC counter (pc_clock) and adjustment (pc_clockadj)
   to calculate ITC skew and corrections. On average, we adjust the
   ITC match register once every ~1500 interrupts for a duration of
   2 consequtive interruprs. This is to correct the non-deterministic
   behaviour of the ITC interrupt (there's a delay between the match
   and the raising of the interrupt).
o  Add 4 debugging sysctls to monitor clock behaviour. Those are
   debug.clock_adjust_edges, debug.clock_adjust_excess,
   debug.clock_adjust_lost and debug.clock_adjust_ticks. The first
   counts the individual adjustment cycles (when the skew first
   crosses the threshold), the second counts the number of times the
   adjustment was excessive (any non-zero value is to be considered
   a bug), the third counts lost clock interrupts and the last counts
   the number of interrupts for which we applied an adjustment
   (debug.clock_adjust_ticks / debug.clock_adjust_edges gives the
   avarage duration of an individual adjustment -- should be ~2).

While here, remove some nearby (trivial) left-overs from alpha and
other cleanups.
2003-08-04 05:13:18 +00:00
Marcel Moolenaar
e2fe99a2e0 Remove prototype of ia64_pa_access(). The function has been moved to
mem.c where it's been made static.
2003-07-26 10:13:30 +00:00
Marcel Moolenaar
eaa7bda4a5 Have TRAPF_USERMODE() take into account that the gateway page is not
always kernel space. It should be treated as user space when run with
user privileges (which is the case for the signal trampolines). This
fixes its only use in a KASSERT in subr_trap.c.
2003-06-06 23:27:18 +00:00
Marcel Moolenaar
3a8c4f9f9c Move the sysctls of the misalignment handler to where they belong
and use OID_AUTO instead of fixed IDs.

Approved by: re@ (blanket)
2003-05-29 06:30:36 +00:00
Marcel Moolenaar
95f2dbba40 Consistently us the same metric to differentiate between kernel mode
and user mode. We need to take into account that the EPC syscall path
introduces a grey area in which one can argue either way, including a
third: neither.

We now use the region in which the IP address lies. Regions 5, 6 and 7
are kernel VA regions and if the IP lies any any of those regions we
assume we're in kernel mode. Hence, we can be in kernel mode even if
we're not on the kernel stack and/or have user privileges. There're
gremlins living in the twilight zone :-)

For the EPC syscall path this particularly means that the process
leaves user mode the moment it calls into the gateway page. This
makes the most sense because from a process' point of view the call
represents a request to the kernel for some service and that service
has been performed if the call returns. With the metric we picked,
this also means that we're back in user mode IFF the call returns.

Approved by: re@ (blanket)
2003-05-24 21:16:19 +00:00
Marcel Moolenaar
d1d7df1905 Fix an alpha inheritance bug:
On alpha, PAL is involved in context management and after wiring
the CPU (in alpha_init()) a context switch was performed to tell
PAL about the context. This was bogusly brought over to ia64
where it introduced bugs, because we restored the context from
a mostly uninitialized PCB.

The cleanup constitutes:
o  Remove the unused arguments from ia64_init().
o  Don't return from ia64_init(), but instead call mi_startup()
   directly. This reduces the amount of muckery in assembly and
   also allows for the next bullet:
o  Save our currect context prior to calling mi_startup(). The
   reason for this is that many threads are created from thread0
   by cloning the PCB. By saving our context in the PCB, we have
   something sane to clone. It also ensures that a cloned thread
   that does not alter the context in any way will return to
   the saved context, where we're ready for the eventuality with
   a nice, user unfriendly panic().

The cleanup fixes at least the following bugs:
o  Entering mi_startup() with the RSE in enforced lazy mode.
o  Re-execution of ia64_init() in certain "lab" conditions.

While here, add proper unwind directives to __start() so that
the unwind knows it has reached the bottom of the (call) stack.

Approved by: re@ (blanket)
2003-05-24 00:17:34 +00:00
Marcel Moolenaar
f2c49dd248 Revamp of the syscall path, exception and context handling. The
prime objectives are:
o  Implement a syscall path based on the epc inststruction (see
   sys/ia64/ia64/syscall.s).
o  Revisit the places were we need to save and restore registers
   and define those contexts in terms of the register sets (see
   sys/ia64/include/_regset.h).

Secundairy objectives:
o  Remove the requirement to use contigmalloc for kernel stacks.
o  Better handling of the high FP registers for SMP systems.
o  Switch to the new cpu_switch() and cpu_throw() semantics.
o  Add a good unwinder to reconstruct contexts for the rare
   cases we need to (see sys/contrib/ia64/libuwx)

Many files are affected by this change. Functionally it boils
down to:
o  The EPC syscall doesn't preserve registers it does not need
   to preserve and places the arguments differently on the stack.
   This affects libc and truss.
o  The address of the kernel page directory (kptdir) had to
   be unstaticized for use by the nested TLB fault handler.
   The name has been changed to ia64_kptdir to avoid conflicts.
   The renaming affects libkvm.
o  The trapframe only contains the special registers and the
   scratch registers. For syscalls using the EPC syscall path
   no scratch registers are saved. This affects all places where
   the trapframe is accessed. Most notably the unaligned access
   handler, the signal delivery code and the debugger.
o  Context switching only partly saves the special registers
   and the preserved registers. This affects cpu_switch() and
   triggered the move to the new semantics, which additionally
   affects cpu_throw().
o  The high FP registers are either in the PCB or on some
   CPU. context switching for them is done lazily. This affects
   trap().
o  The mcontext has room for all registers, but not all of them
   have to be defined in all cases. This mostly affects signal
   delivery code now. The *context syscalls are as of yet still
   unimplemented.

Many details went into the removal of the requirement to use
contigmalloc for kernel stacks. The details are mostly CPU
specific and limited to exception_save() and exception_restore().
The few places where we create, destroy or switch stacks were
mostly simplified by not having to construct physical addresses
and additionally saving the virtual addresses for later use.

Besides more efficient context saving and restoring, which of
course yields a noticable speedup, this also fixes the dreaded
SMP bootup problem as a side-effect. The details of which are
still not fully understood.

This change includes all the necessary backward compatibility
code to have it handle older userland binaries that use the
break instruction for syscalls. Support for break-based syscalls
has been pessimized in favor of a clean implementation. Due to
the overall better performance of the kernel, this will still
be notived as an improvement if it's noticed at all.

Approved by: re@ (jhb)
2003-05-16 21:26:42 +00:00
Marcel Moolenaar
53efb27fc5 MFp4:
Add function map_port_space() to map the memory mapped I/O port
range as uncacheable virtual memory and call it prior to probing
for a console. This removes the dependency on the loader to have
done this for us. Note that this change does not include doing
the same for APs.

Approved by: re (blanket)
2002-11-24 20:15:08 +00:00
David E. O'Brien
39b9b6a43f It appears CPU_MAXID should be 1 more than the number of CPU_* defines. 2002-10-06 05:25:10 +00:00
Marcel Moolenaar
55f50d95f7 o Move prototypes for restorectx and savectx from cpu.h to pcb.h,
o  Remove Alpha specific contents of struct md_coredump.
2002-05-19 04:14:42 +00:00
Marcel Moolenaar
f5b454cf25 o Rename ia64_count_aps to ia64_count_cpus and reimplement the
function to return the total number of CPUs and not the highest
   CPU id.
o  Define mp_maxid based on the minimum of the actual number of
   CPUs in the system and MAXCPU.
o  In cpu_mp_add, when the CPU id of the CPU we're trying to add
   is larger than mp_maxid, don't add the CPU. Formerly this was
   based on MAXCPU. Don't count CPUs when we add them. We already
   know how many CPUs exist.
o  Replace MAXCPU with mp_maxid when used in loops that iterate
   over the id space. This avoids a couple of useless iterations.
o  In cpu_mp_unleash, use the number of CPUs to determine if we
   need to launch the CPUs.
o  Remove mp_hardware as it's not used anymore.
o  Move the IPI vector array from mp_machdep.c to sal.c. We use
   the array as a centralized place to collect vector assignments.
   Note that we still assign vectors to SMP specific IPIs in
   non-SMP configurations. Rename the array from mp_ipi_vector to
   ipi_vector.
o  Add IPI_MCA_RENDEZ and IPI_MCA_CMCV. These are used by MCA.
   Note that IPI_MCA_CMCV is not SMP specific.
o  Initialize the ipi_vector array so that we place the IPIs in
   sensible priority classes. The classes are relative to where
   the AP wake-up vector is located to guarantee that it's the
   highest priority (external) interrupt. Class assignment is
   as follows:
	class	IPI		notes
	x	AP wake-up	(normally x=15)
	x-1	MCA rendezvous
	x-2	AST, Rendezvous, stop
	x-3	CMCV, test
2002-05-12 05:54:21 +00:00
Alfred Perlstein
e41ed5da90 Remove __P.
Reviewd by: peter
2002-03-20 23:30:31 +00:00
Peter Wemm
12adcbdf35 Move a couple of prototypes together instead of being incompletely
scattered around.
2002-03-19 11:14:52 +00:00
Doug Rabson
f17bd83f5f Add a couple of arguments to ia64_init. I'll use them later to improve
the method of passing bootinfo from the loader.
2001-09-29 11:44:35 +00:00
Julian Elischer
b40ce4165d KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after:    ha ha ha ha
2001-09-12 08:38:13 +00:00
John Baldwin
688ebe120c - Close races with signals and other AST's being triggered while we are in
the process of exiting the kernel.  The ast() function now loops as long
  as the PS_ASTPENDING or PS_NEEDRESCHED flags are set.  It returns with
  preemption disabled so that any further AST's that arrive via an
  interrupt will be delayed until the low-level MD code returns to user
  mode.
- Use u_int's to store the tick counts for profiling purposes so that we
  do not need sched_lock just to read p_sticks.  This also closes a
  problem where the call to addupc_task() could screw up the arithmetic
  due to non-atomic reads of p_sticks.
- Axe need_proftick(), aston(), astoff(), astpending(), need_resched(),
  clear_resched(), and resched_wanted() in favor of direct bit operations
  on p_sflag.
- Fix up locking with sched_lock some.  In addupc_intr(), use sched_lock
  to ensure pr_addr and pr_ticks are updated atomically with setting
  PS_OWEUPC.  In ast() we clear pr_ticks atomically with clearing
  PS_OWEUPC.  We also do not grab the lock just to test a flag.
- Simplify the handling of Giant in ast() slightly.

Reviewed by:	bde (mostly)
2001-08-10 22:53:32 +00:00
John Baldwin
7aa7260e4a Move ast() and userret() to sys/kern/subr_trap.c now that they are MI. 2001-06-29 19:51:37 +00:00
John Baldwin
6be523bca7 Add a new MI pointer to the process' trapframe p_frame instead of using
various differently named pointers buried under p_md.

Reviewed by:	jake (in principle)
2001-06-29 11:10:41 +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
7b4a30b689 Clockframes have a trapframe stored in a cf_tf member, not ct_tf. 2001-02-24 18:57:34 +00:00
John Baldwin
7182d6578d Whitespace nits. 2001-02-24 18:41:38 +00:00
John Baldwin
ad0a541a9e Pass in process to mark ast on to aston(). 2001-02-24 18:41:17 +00:00
John Baldwin
938f15c7c4 Rename switch_trampoline() to fork_trampoline() on the alpha and ia64.
Suggested by:	dfr
2001-02-22 16:56:53 +00:00
John Baldwin
3e68dabf19 Add TRAPF_PC() and TRAPF_USERMODE() macros and redefine CLKF_PC() and
CLKF_USERMODE() in terms of them.
2001-02-22 15:35:04 +00:00
John Baldwin
de0e830e6d Catch up to new MI astpending and need_resched handling. 2001-02-22 13:29:22 +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
John Baldwin
a8a3dd2bb5 - Proc locking.
- P_OWEUPC -> PS_OWEUPC.
2001-01-24 10:38:58 +00:00
Jake Burkholder
a448b62ac9 Make intr_nesting_level per-process, rather than per-cpu. Setup
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
2001-01-21 19:25:07 +00:00
Marcel Moolenaar
d034d459da Don't use p->p_sigstk.ss_flags to keep state of whether the
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
2000-11-30 05:23:49 +00:00
Mark Murray
5855006767 Add a consistent API to a feature that most modern CPUs have; a fast
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
2000-11-21 19:55:21 +00:00
Doug Rabson
7fcf71bc40 * Correct some of my misunderstandings about how best to switch to the
kernel backing store.
* Implement syscalls via break instructions.
* Fix backing store copying in cpu_fork() so that the child gets the right
  register values.

This thing is actually starting to work now. This set of changes takes me
up to the second execve (the one which runs the first shell). Next stop
single-user mode :-).
2000-10-16 08:54:40 +00:00
Doug Rabson
61e1efff8a Implement a rudimentary interrupt handling system which should be good
enough for clock interrupts in SKI.
2000-10-12 17:47:01 +00:00
Doug Rabson
5596cfd09a * Fix exception handling so that it actually works. We can now handle
exceptions from both kernel and user mode.
* Fix context switching so that we can switch back to a proc which we
  switched away from (we were saving the state in the wrong place).
* Implement lazy switching of the high-fp state. This needs to be looked
  at again for SMP to cope with the case of a process migrating from one
  processor to another while it has the high-fp state.
* Make setregs() work properly. I still think this should be called
  cpu_exec() or something.
* Various other minor fixes.

With this lot, we can execve() /sbin/init and we get all the way up to its
first syscall. At that point, we stop because syscall handling is not done
yet.
2000-10-12 14:36:39 +00:00
Doug Rabson
ec502c357d * Add rudimentary DDB support (no kgdb, no backtrace, no single step).
* Track recent changes to SWI code.
* Allocate RIDs for pmaps (untested).
* Implement assembler version of cpu_switch - its cleaner that way.
2000-10-10 14:57:10 +00:00
Doug Rabson
1ebcad5720 This is the first snapshot of the FreeBSD/ia64 kernel. This kernel will
not work on any real hardware (or fully work on any simulator). Much more
needs to happen before this is actually functional but its nice to see
the FreeBSD copyright message appear in the ia64 simulator.
2000-09-29 13:46:07 +00:00