Commit Graph

53 Commits

Author SHA1 Message Date
John Baldwin
70d12a18f2 Export 'struct pcpu' to userland w/o requiring _KERNEL. A few ports
already define _KERNEL to get to this and I'm about to add hooks to
libkvm to access per-CPU data.

MFC after:	1 week
2008-08-19 19:53:52 +00:00
Kip Macy
93ee134a24 Integrate support for xen in to i386 common code.
MFC after:	1 month
2008-08-15 20:51:31 +00:00
Jeff Roberson
6c47aaae12 - Add an integer argument to idle to indicate how likely we are to wake
from idle over the next tick.
 - Add a new MD routine, cpu_wake_idle() to wakeup idle threads who are
   suspended in cpu specific states.  This function can fail and cause the
   scheduler to fall back to another mechanism (ipi).
 - Implement support for mwait in cpu_idle() on i386/amd64 machines that
   support it.  mwait is a higher performance way to synchronize cpus
   as compared to hlt & ipis.
 - Allow selecting the idle routine by name via sysctl machdep.idle.  This
   replaces machdep.cpu_idle_hlt.  Only idle routines supported by the
   current machine are permitted.

Sponsored by:	Nokia
2008-04-25 05:18:50 +00:00
Attilio Rao
6759608248 Rework the PCPU_* (MD) interface:
- Rename PCPU_LAZY_INC into PCPU_INC
- Add the PCPU_ADD interface which just does an add on the pcpu member
  given a specific value.

Note that for most architectures PCPU_INC and PCPU_ADD are not safe.
This is a point that needs some discussions/work in the next days.

Reviewed by: alc, bde
Approved by: jeff (mentor)
2007-06-04 21:38:48 +00:00
Alan Cox
c640357f04 Push down the implementation of PCPU_LAZY_INC() into the machine-dependent
header file.  Reimplement PCPU_LAZY_INC() on amd64 and i386 making it
atomic with respect to interrupts.

Reviewed by: bde, jhb
2007-03-11 05:54:29 +00:00
Bruce Evans
1300fd67f3 Fixed some style bugs. Routine except:
- don't use __GNUCLIKE___OFFSETOF, since __offsetof() is a standard
  FreeBSD implementaion detail which has nothing to do with GNUC.
2007-02-06 18:04:02 +00:00
Bruce Evans
3764a82377 Simplified PCPU_GET() and PCPU_SET(). We must copy through a temporary
variable to avoid invalid constraints in dead code.  Use an array of
u_char's (inside a struct) instead of a char/short/int/long variable so
that the variable and its accesses can be spelled in the same way in all
cases and code doesn't need to be cloned just to hold the spelling
differences.

Fixed strict-aliasing errors in PCPU_SET() and in the amd64 PCPU_GET().
Cast to (void *) as in rev.1.37 of the i386 version where the errors
were fixed for the i386 PCPU_GET() only.  It would be more correct to
copy to and from the temp. variable using memcpy(), but then an
ifdef tangle would be required to ensure using the builtin memcpy().
We depend on fairly aggressive optimization to put the temp. variable
only in a register despite it being copied using
*(type *)(void *)&anothertype and could depend on this when using
memcpy() too.  This seems to work right even for -O0, but the -O0 case
has not been completely tested.

This change gives identical object code for all object files in LINT
on amd64 (except for one file with a __TIME__ stamp).  For LINT on
i386 it gives unimportant differences in instruction order and padding
in a few object files.  This was only tested for -O.

This change (actually a previous version of it) gives the following
reductions in the number of object files in LINT that fail to compile
with -O2 but without the -fno-strict-aliasing kludge:
- amd64: 29 (down from 211)
- i386: 36 (down from 47)

gcc-3.4.6 actually allows the invalid constraints that result from not
using the temp. variable, at least with -O[1-2], but gcc-3.3.3 crashes
on them and I don't want to depend on compiler bugs.
2007-02-06 16:21:09 +00:00
Peter Wemm
374757c7cb Test commit after repoman upgrade. Remove one of my many email addresses
from a copyright message.
2006-05-12 22:41:58 +00:00
David Xu
1bfa910843 Move global variable private_tss into per-cpu area.
Reviewed by: jhb
2005-12-26 00:07:19 +00:00
Peter Wemm
e0ab2c6d10 Change the segment limits to 4GB, we set the user accessible bit on all
of the kernel address space already.  Intel recommend this anyway, because
using a non-4GB limit adds an additional clock cycle to address generation.
We were able to install 4GB segments into the LDT, so any limits we imposed
on %cs and %ds were academic anyway.  More importantly, this allows us to
make a page in the kernel readable to user applications, for holding things
like the signal trampoline and other fun things.

Move the user %cs/%ds segments from the LDT to the GDT.  There was no good
reason for them to be there anyway.  The old LDT entries are still there
but we can now relax the restriction that prevented users from emptying
the default LDT entries.

Putting user and kernel %cs and %ds together allows us to access the fast
sysenter/sysexit/syscall/sysret instructions.  syscall/sysret in particular
require that the user/kernel segments be laid out this way.  Reserve a slot
specifically for NDIS while here.

Create two user controllable slots in the GDT that are context switched
with the (kernel) thread.  This allows user applications to set two
user privilige selectors to arbitary values.  Create
i386_set_fsbase(void *base) and friends. (get/set, fs/gs).  For i386,
%gs is used by tls and the thread libraries and this means that user
processes no longer have to have the cost of having a custom LDT, and
we will no longer to do a ldt switch when activating a kthread/ithread in
the usual case any more.

In other words, we can now set the base address for %fs and %gs to arbitary
addresses without the pain of messing with ldt segments.
2005-04-13 22:57:17 +00:00
Joerg Wunsch
a5f50ef9e4 netchild's mega-patch to isolate compiler dependencies into a central
place.

This moves the dependency on GCC's and other compiler's features into
the central sys/cdefs.h file, while the individual source files can
then refer to #ifdef __COMPILER_FEATURE_FOO where they by now used to
refer to #if __GNUC__ > 3.1415 && __BARC__ <= 42.

By now, GCC and ICC (the Intel compiler) have been actively tested on
IA32 platforms by netchild.  Extension to other compilers is supposed
to be possible, of course.

Submitted by:	netchild
Reviewed by:	various developers on arch@, some time ago
2005-03-02 21:33:29 +00:00
Tom Rhodes
a122cca953 These are changes to allow to use the Intel C/C++ compiler (lang/icc)
to build the kernel. It doesn't affect the operation if gcc.

Most of the changes are just adding __INTEL_COMPILER to #ifdef's, as
icc v8 may define __GNUC__ some parts may look strange but are
necessary.

Additional changes:
 - in_cksum.[ch]:
   * use a generic C version instead of the assembly version in the !gcc
     case (ASM code breaks with the optimizations icc does)
     -> no bad checksums with an icc compiled kernel
     Help from:		andre, grehan, das
     Stolen from: 	alpha version via ppc version
     The entire checksum code should IMHO be replaced with the DragonFly
     version (because it isn't guaranteed future revisions of gcc will
     include similar optimizations) as in:
        ---snip---
          Revision  Changes    Path
          1.12      +1 -0      src/sys/conf/files.i386
          1.4       +142 -558  src/sys/i386/i386/in_cksum.c
          1.5       +33 -69    src/sys/i386/include/in_cksum.h
          1.5       +2 -0      src/sys/netinet/igmp.c
          1.6       +0 -1      src/sys/netinet/in.h
          1.6       +2 -0      src/sys/netinet/ip_icmp.c

          1.4       +3 -4      src/contrib/ipfilter/ip_compat.h
          1.3       +1 -2      src/sbin/natd/icmp.c
          1.4       +0 -1      src/sbin/natd/natd.c
          1.48      +1 -0      src/sys/conf/files
          1.2       +0 -1      src/sys/conf/files.amd64
          1.13      +0 -1      src/sys/conf/files.i386
          1.5       +0 -1      src/sys/conf/files.pc98
          1.7       +1 -1      src/sys/contrib/ipfilter/netinet/fil.c
          1.10      +2 -3      src/sys/contrib/ipfilter/netinet/ip_compat.h
          1.10      +1 -1      src/sys/contrib/ipfilter/netinet/ip_fil.c
          1.7       +1 -1      src/sys/dev/netif/txp/if_txp.c
          1.7       +1 -1      src/sys/net/ip_mroute/ip_mroute.c
          1.7       +1 -2      src/sys/net/ipfw/ip_fw2.c
          1.6       +1 -2      src/sys/netinet/igmp.c
          1.4       +158 -116  src/sys/netinet/in_cksum.c
          1.6       +1 -1      src/sys/netinet/ip_gre.c
          1.7       +1 -2      src/sys/netinet/ip_icmp.c
          1.10      +1 -1      src/sys/netinet/ip_input.c
          1.10      +1 -2      src/sys/netinet/ip_output.c
          1.13      +1 -2      src/sys/netinet/tcp_input.c
          1.9       +1 -2      src/sys/netinet/tcp_output.c
          1.10      +1 -1      src/sys/netinet/tcp_subr.c
          1.10      +1 -1      src/sys/netinet/tcp_syncache.c
          1.9       +1 -2      src/sys/netinet/udp_usrreq.c

          1.5       +1 -2      src/sys/netinet6/ipsec.c
          1.5       +1 -2      src/sys/netproto/ipsec/ipsec.c
          1.5       +1 -1      src/sys/netproto/ipsec/ipsec_input.c
          1.4       +1 -2      src/sys/netproto/ipsec/ipsec_output.c

          and finally remove
            sys/i386/i386        in_cksum.c
            sys/i386/include     in_cksum.h
        ---snip---
 - endian.h:
   * DTRT in C++ mode
 - quad.h:
   * we don't use gcc v1 anymore, remove support for it
   Suggested by:	bde (long ago)
 - assym.h:
   * avoid zero-length arrays (remove dependency on a gcc specific
     feature)
     This change changes the contents of the object file, but as it's
     only used to generate some values for a header, and the generator
     knows how to handle this, there's no impact in the gcc case.
   Explained by:	bde
   Submitted by:	Marius Strobl <marius@alchemy.franken.de>
 - aicasm.c:
   * minor change to teach it about the way icc spells "-nostdinc"
   Not approved by:	gibbs (no reply to my mail)
 - bump __FreeBSD_version (lang/icc needs to know about the changes)

Incarnations of this patch survive gcc compiles since a loooong time,
I use it on my desktop. An icc compiled kernel works since Nov. 2003
(exceptions: snd_* if used as modules), it survives a build of the
entire ports collection with icc.

Parts of this commit contains suggestions or submissions from
Marius Strobl <marius@alchemy.franken.de>.

Reviewed by:	-arch
Submitted by:	netchild
2004-03-12 21:45:33 +00:00
Peter Wemm
c287f723c4 MFamd64: use a less compiler-intensive MD implementation of 'curthread'
so that the compiler doesn't have to do so much work.

Approved by:  re (jhb)
2003-11-20 23:23:22 +00:00
Bruce Evans
6a0d1abc5d Fixed pedantic warnings for statement-expressions using __extension__
and by not using a statement-expression for the non-expression
__PCPU_SET().
2003-11-17 04:40:58 +00:00
Bruce Evans
81bbee5996 Fixed a pedantic syntax error (a stray semicolon at the end of
PCPU_MD_FIELDS).
2003-11-17 03:40:41 +00:00
John Baldwin
6f92bdd0c1 New APIC support code:
- The apic interrupt entry points have been rewritten so that each entry
  point can serve 32 different vectors.  When the entry is executed, it
  uses one of the 32-bit ISR registers to determine which vector in its
  assigned range was triggered.  Thus, the apic code can support 159
  different interrupt vectors with only 5 entry points.
- We now always to disable the local APIC to work around an errata in
  certain PPros and then re-enable it again if we decide to use the APICs
  to route interrupts.
- We no longer map IO APICs or local APICs using special page table
  entries.  Instead, we just use pmap_mapdev().  We also no longer
  export the virtual address of the local APIC as a global symbol to
  the rest of the system, but only in local_apic.c.  To aid this, the
  APIC ID of each CPU is exported as a per-CPU variable.
- Interrupt sources are provided for each intpin on each IO APIC.
  Currently, each source is given a unique interrupt vector meaning that
  PCI interrupts are not shared on most machines with an I/O APIC.
  That mapping for interrupt sources to interrupt vectors is up to the
  APIC enumerator driver however.
- We no longer probe to see if we need to use mixed mode to route IRQ 0,
  instead we always use mixed mode to route IRQ 0 for now.  This can be
  disabled via the 'NO_MIXED_MODE' kernel option.
- The npx(4) driver now always probes to see if a built-in FPU is present
  since this test can now be performed with the new APIC code.  However,
  an SMP kernel will panic if there is more than one CPU and a built-in
  FPU is not found.
- PCI interrupts are now properly routed when using APICs to route
  interrupts, so remove the hack to psuedo-route interrupts when the
  intpin register was read.
- The apic.h header was moved to apicreg.h and a new apicvar.h header
  that declares the APIs used by the new APIC code was added.
2003-11-03 21:53:38 +00:00
Peter Wemm
f3d3771beb Detour via (void *) to defeat gcc's strict-aliasing warnings when using
-O2 or -Os (such as 'make release').

This commit brought to you by the warning:
  dereferencing type-punned pointer will break strict-aliasing rules
2003-07-30 00:04:58 +00:00
Peter Wemm
b50953ccfa Fix the false IPIs on smp when using LAZY_SWITCH caused by pmap_activate()
not releasing the pm_active bit in the old pmap.
2003-06-27 21:50:52 +00:00
Poul-Henning Kamp
7e9bac35e2 A more lint friendly #ifdef lint section. 2002-10-01 14:01:58 +00:00
Mark Murray
80a0ead4fe Wrap GNU specific code in ifdefs, and help lint out by providing
some alternative definitions.
2002-07-15 13:29:40 +00:00
Matthew Dillon
d74ac6819b Compromise for critical*()/cpu_critical*() recommit. Cleanup the interrupt
disablement assumptions in kern_fork.c by adding another API call,
cpu_critical_fork_exit().  Cleanup the td_savecrit field by moving it
from MI to MD.  Temporarily move cpu_critical*() from <arch>/include/cpufunc.h
to <arch>/<arch>/critical.c (stage-2 will clean this up).

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

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

Reviewed by:	core
Approved by:	core
2002-03-27 05:39:23 +00:00
John Baldwin
0bbc882680 Overhaul the per-CPU support a bit:
- The MI portions of struct globaldata have been consolidated into a MI
  struct pcpu.  The MD per-CPU data are specified via a macro defined in
  machine/pcpu.h.  A macro was chosen over a struct mdpcpu so that the
  interface would be cleaner (PCPU_GET(my_md_field) vs.
  PCPU_GET(md.md_my_md_field)).
- All references to globaldata are changed to pcpu instead.  In a UP kernel,
  this data was stored as global variables which is where the original name
  came from.  In an SMP world this data is per-CPU and ideally private to each
  CPU outside of the context of debuggers.  This also included combining
  machine/globaldata.h and machine/globals.h into machine/pcpu.h.
- The pointer to the thread using the FPU on i386 was renamed from
  npxthread to fpcurthread to be identical with other architectures.
- Make the show pcpu ddb command MI with a MD callout to display MD
  fields.
- The globaldata_register() function was renamed to pcpu_init() and now
  init's MI fields of a struct pcpu in addition to registering it with
  the internal array and list.
- A pcpu_destroy() function was added to remove a struct pcpu from the
  internal array and list.

Tested on:	alpha, i386
Reviewed by:	peter, jake
2001-12-11 23:33:44 +00:00
John Baldwin
fd54558a83 - If we ever do the per-cpu KTR stuff, the index won't be volatile as it
will be private to each CPU.
- Re-style(9) the globaldata structures.  There really needs to be a MI
  struct pcpu that has a MD struct mdpcpu member at some point.
2001-09-18 21:46:26 +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
Peter Wemm
268bdb43f9 Optionize UPAGES for the i386. As part of this I split some of the low
level implementation stuff out of machine/globaldata.h to avoid exposing
UPAGES to lots more places.  The end result is that we can double
the kernel stack size with 'options UPAGES=4' etc.

This is mainly being done for the benefit of a MFC to RELENG_4 at some
point.  -current doesn't really need this so much since each interrupt
runs on its own kstack.
2001-08-25 02:20:02 +00:00
David E. O'Brien
589278dbae style(9) and make consistent across platforms 2001-08-16 09:29:35 +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
ae60f36f19 Axe the per-cpu variable witness_spin_check as it was replaced by the
per-cpu spinlocks list.
2001-04-06 07:20:27 +00:00
John Baldwin
192846463a Rework the witness code to work with sx locks as well as mutexes.
- 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.
2001-03-28 09:03:24 +00:00
Peter Wemm
f1532aadee Activate USER_LDT by default. The new thread libraries are going to
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
2001-02-23 01:25:02 +00:00
John Baldwin
142ba5f3d7 - Make astpending and need_resched process attributes rather than CPU
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.
2001-02-10 02:20:34 +00:00
John Baldwin
7f918b0230 Axe gd_cpu_lockid as it is no longer used. 2001-02-09 14:25:22 +00:00
Peter Wemm
aa0b4c590f Remove some leftovers from the CMAP* stuff in globaldata and the
BSP and AP startup.
2001-01-30 04:02:28 +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
Jake Burkholder
3e899e1063 Remove the per-cpu pages used for copy and zero-ing pages of memory
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.
2001-01-21 06:50:03 +00:00
Jake Burkholder
7586909279 Remove unused per-cpu variables inside_intr and ss_eflags. 2001-01-12 07:47:54 +00:00
Jake Burkholder
f8761e53a7 Implement accessors for per-cpu variables which don't depend on the
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.
2001-01-06 19:55:42 +00:00
Jake Burkholder
41ed17bfec Use %fs to access per-cpu variables in uni-processor kernels the same
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
2001-01-06 17:40:04 +00:00
John Baldwin
6c56727456 - Change fast interrupts on x86 to push a full interrupt frame and to
return through doreti to handle ast's.  This is necessary for the
  clock interrupts to work properly.
- Change the clock interrupts on the x86 to be fast instead of threaded.
  This is needed because both hardclock() and statclock() need to run in
  the context of the current process, not in a separate thread context.
- Kill the prevproc hack as it is no longer needed.
- We really need Giant when we call psignal(), but we don't want to block
  during the clock interrupt.  Instead, use two p_flag's in the proc struct
  to mark the current process as having a pending SIGVTALRM or a SIGPROF
  and let them be delivered during ast() when hardclock() has finished
  running.
- Remove CLKF_BASEPRI, which was #ifdef'd out on the x86 anyways.  It was
  broken on the x86 if it was turned on since cpl is gone.  It's only use
  was to bogusly run softclock() directly during hardclock() rather than
  scheduling an SWI.
- Remove the COM_LOCK simplelock and replace it with a clock_lock spin
  mutex.  Since the spin mutex already handles disabling/restoring
  interrupts appropriately, this also lets us axe all the *_intr() fu.
- Back out the hacks in the APIC_IO x86 cpu_initclocks() code to use
  temporary fast interrupts for the APIC trial.
- Add two new process flags P_ALRMPEND and P_PROFPEND to mark the pending
  signals in hardclock() that are to be delivered in ast().

Submitted by:	jakeb (making statclock safe in a fast interrupt)
Submitted by:	cp (concept of delaying signals until ast())
2000-10-06 02:20:21 +00:00
John Baldwin
d238b83315 Make the gd_currentldt member in struct globaldata unconditional so
that this header doesn't depend on USER_LDT.  This fixes the USER_LDT
breakage with SMP kernels.
2000-10-05 20:30:36 +00:00
Jason Evans
0384fff8c5 Major update to the way synchronization is done in the kernel. Highlights
include:

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

* Per-CPU idle processes.

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

Partially contributed by:	BSDi (BSD/OS)
Submissions by (at least):	cp, dfr, dillon, grog, jake, jhb, sheldonh
2000-09-07 01:33:02 +00:00
Matthew Dillon
36e9f877df Commit major SMP cleanups and move the BGL (big giant lock) in the
syscall path inward.  A system call may select whether it needs the MP
    lock or not (the default being that it does need it).

    A great deal of conditional SMP code for various deadended experiments
    has been removed.  'cil' and 'cml' have been removed entirely, and the
    locking around the cpl has been removed.  The conditional
    separately-locked fast-interrupt code has been removed, meaning that
    interrupts must hold the CPL now (but they pretty much had to anyway).
    Another reason for doing this is that the original separate-lock for
    interrupts just doesn't apply to the interrupt thread mechanism being
    contemplated.

    Modifications to the cpl may now ONLY occur while holding the MP
    lock.  For example, if an otherwise MP safe syscall needs to mess with
    the cpl, it must hold the MP lock for the duration and must (as usual)
    save/restore the cpl in a nested fashion.

    This is precursor work for the real meat coming later: avoiding having
    to hold the MP lock for common syscalls and I/O's and interrupt threads.
    It is expected that the spl mechanisms and new interrupt threading
    mechanisms will be able to run in tandem, allowing a slow piecemeal
    transition to occur.

    This patch should result in a moderate performance improvement due to
    the considerable amount of code that has been removed from the critical
    path, especially the simplification of the spl*() calls.  The real
    performance gains will come later.

Approved by: jkh
Reviewed by: current, bde (exception.s)
Some work taken from: luoqi's patch
2000-03-28 07:16:37 +00:00
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
Jonathan Lemon
eb9d435ae7 Unifdef VM86.
Reviewed by:	silence on on -current
1999-06-01 18:20:36 +00:00
Luoqi Chen
0f0fe5a4c5 Unbreak VESA on SMP. 1999-05-12 21:39:07 +00:00
Luoqi Chen
5206bca10a Enable vmspace sharing on SMP. Major changes are,
- %fs register is added to trapframe and saved/restored upon kernel entry/exit.
- Per-cpu pages are no longer mapped at the same virtual address.
- Each cpu now has a separate gdt selector table. A new segment selector
  is added to point to per-cpu pages, per-cpu global variables are now
  accessed through this new selector (%fs). The selectors in gdt table are
  rearranged for cache line optimization.
- fask_vfork is now on as default for both UP and SMP.
- Some aio code cleanup.

Reviewed by:	Alan Cox	<alc@cs.rice.edu>
		John Dyson	<dyson@iquest.net>
		Julian Elischer	<julian@whistel.com>
		Bruce Evans	<bde@zeta.org.au>
		David Greenman	<dg@root.com>
1999-04-28 01:04:33 +00:00
Bruce Evans
025a06fd58 Added a per-cpu variable `switchticks' for use in scheduling. 1999-02-22 15:13:34 +00:00
Mike Smith
287e61c39f Presently there is only one `currentldt' variable for all cpus
in a SMP system. Unexpected things could happen if each cpu
        has a different ldt setting and one cpu tries to use value
        of currentldt set by another cpu.

        The fix is to move currentldt to the per-cpu area. It includes
        patches I filed in PR i386/6219 which are also user ldt related.

PR:		i386/7591, i386/6219
Submitted by:	Luoqi Chen <luoqi@watermarkgroup.com>
1998-08-18 07:47:12 +00:00
Poul-Henning Kamp
e796e00de3 Some cleanups related to timecounters and weird ifdefs in <sys/time.h>.
Clean up (or if antipodic: down) some of the msgbuf stuff.

Use an inline function rather than a macro for timecounter delta.

Maintain process "on-cpu" time as 64 bits of microseconds to avoid
needless second rollover overhead.

Avoid calling microuptime the second time in mi_switch() if we do
not pass through _idle in cpu_switch()

This should reduce our context-switch overhead a bit, in particular
on pre-P5 and SMP systems.

WARNING:  Programs which muck about with struct proc in userland
will have to be fixed.

Reviewed, but found imperfect by:       bde
1998-05-28 09:30:28 +00:00
Tor Egge
5d183e9691 Change simple lock handling to not depend upon having a local apic
available.  The per-cpu variable ss_tpr has been replaced by ss_eflags.
This reduced the number of interrupts sent to the wrong CPU, due to
the cpu having the global lock being inside a critical region.

Remove some unneeded manipulation of tpr register in mplock.s.

Adjust code in mplock.s to be aware of variables on the stack being
destroyed by MPgetlock if GRAB_LOPRIO is defined.
1998-05-17 23:08:04 +00:00