Commit Graph

25 Commits

Author SHA1 Message Date
John Baldwin
c6a37e8413 Divorce critical sections from spinlocks. Critical sections as denoted by
critical_enter() and critical_exit() are now solely a mechanism for
deferring kernel preemptions.  They no longer have any affect on
interrupts.  This means that standalone critical sections are now very
cheap as they are simply unlocked integer increments and decrements for the
common case.

Spin mutexes now use a separate KPI implemented in MD code: spinlock_enter()
and spinlock_exit().  This KPI is responsible for providing whatever MD
guarantees are needed to ensure that a thread holding a spin lock won't
be preempted by any other code that will try to lock the same lock.  For
now all archs continue to block interrupts in a "spinlock section" as they
did formerly in all critical sections.  Note that I've also taken this
opportunity to push a few things into MD code rather than MI.  For example,
critical_fork_exit() no longer exists.  Instead, MD code ensures that new
threads have the correct state when they are created.  Also, we no longer
try to fixup the idlethreads for APs in MI code.  Instead, each arch sets
the initial curthread and adjusts the state of the idle thread it borrows
in order to perform the initial context switch.

This change is largely a big NOP, but the cleaner separation it provides
will allow for more efficient alternative locking schemes in other parts
of the kernel (bare critical sections rather than per-CPU spin mutexes
for per-CPU data for example).

Reviewed by:	grehan, cognet, arch@, others
Tested on:	i386, alpha, sparc64, powerpc, arm, possibly more
2005-04-04 21:53:56 +00:00
Warner Losh
86cb007f9f /* -> /*- for copyright notices, minor format tweaks as necessary 2005-01-06 22:18:23 +00:00
Warner Losh
dc7949f45f bde points out that this can't do anything useful. The full patch has
other parts that I can't locat at the moment, so back it out until I can.
2004-06-28 05:37:22 +00:00
Warner Losh
f465e257e2 When opening /dev/io, preserve iopl properly. Otherwise, if you open
/dev/io multiple times, the first close remove the privs.
2004-06-28 03:16:32 +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
John Baldwin
a8084030ad Add a per-thread variable for saving the state of eflags to support the
critical section code.
2003-11-03 21:30:00 +00:00
John Baldwin
ab79480392 Note that the sched_lock protects md_ldt of struct mdproc. 2002-10-25 20:06:16 +00:00
Poul-Henning Kamp
c2b6013026 It is too much work convincing lint why we would want empty structures,
so make the non-empty #ifdef lint.
2002-10-01 14:08:08 +00:00
Matthew Dillon
50b6a55512 Remove the critmode sysctl - the new method for critical_enter/exit (already
the default) is now the only method for i386.

Remove the paraphanalia that supported critmode.  Remove td_critnest, clean
up the assembly, and clean up (mostly remove) the old junk from
cpu_critical_enter() and cpu_critical_exit().
2002-07-10 20:15:58 +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
Alfred Perlstein
b63dc6ad47 Remove __P. 2002-03-20 05:48:58 +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
24db04598b Split the per-process Local Descriptor Table out of the PCB and into
struct mdproc.

Submitted by:	Andrew R. Reiter <arr@watson.org>
Silence on:	-current
2001-10-25 00:53:43 +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
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
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +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
Peter Wemm
6f486a5552 Convert md_regs from an int[] to a struct trapframe *. It simplifies
some code.
1997-05-07 19:55:13 +00:00
Peter Wemm
6875d25465 Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.
1997-02-22 09:48:43 +00:00
Jordan K. Hubbard
1130b656e5 Make the long-awaited change from $Id$ to $FreeBSD$
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore.  This update would have been
insane otherwise.
1997-01-14 07:20:47 +00:00
Nate Williams
9368fc2012 hp300 -> i386 1996-04-10 05:27:11 +00:00
Rodney W. Grimes
26f9a76710 The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.
Reviewed by:	Rodney W. Grimes
Submitted by:	John Dyson and David Greenman
1994-05-25 09:21:21 +00:00
Garrett Wollman
6e393973f5 Made all header files idempotent and moved incorrect common data from
headers into a related source file.  Added cons.h as first step towards
moving i386/i386/cons.h to machine/cons.h where it belongs.
1993-11-07 17:43:17 +00:00
Rodney W. Grimes
34a8ed1be1 Removed all patch kit headers, sccsid and rcsid strings, put $Id$ in, some
minor cleanup.  Added $Id$ to files that did not have any version info, etc
1993-10-16 14:40:57 +00:00
Rodney W. Grimes
5b81b6b301 Initial import, 0.1 + pk 0.2.4-B1 1993-06-12 14:58:17 +00:00