1993-06-12 14:58:17 +00:00
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/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* William Jolitz.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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1993-10-08 20:51:00 +00:00
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* from: @(#)pcb.h 5.10 (Berkeley) 5/12/91
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1999-08-28 01:08:13 +00:00
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* $FreeBSD$
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1993-06-12 14:58:17 +00:00
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*/
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1993-10-08 20:51:00 +00:00
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#ifndef _I386_PCB_H_
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#define _I386_PCB_H_
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1993-06-12 14:58:17 +00:00
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/*
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* Intel 386 process control block
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*/
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1994-08-13 03:50:34 +00:00
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#include <machine/npx.h>
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1993-06-12 14:58:17 +00:00
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struct pcb {
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1997-04-07 06:45:18 +00:00
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int pcb_cr3;
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int pcb_edi;
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int pcb_esi;
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int pcb_ebp;
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int pcb_esp;
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int pcb_ebx;
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int pcb_eip;
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1999-07-09 04:16:00 +00:00
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int pcb_dr0;
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int pcb_dr1;
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int pcb_dr2;
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int pcb_dr3;
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int pcb_dr6;
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int pcb_dr7;
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2001-07-12 06:32:51 +00:00
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union savefpu pcb_save;
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2002-01-17 17:49:23 +00:00
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u_int pcb_flags;
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1995-08-17 11:30:03 +00:00
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#define FP_SOFTFP 0x01 /* process using software fltng pnt emulator */
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1999-07-09 04:16:00 +00:00
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#define PCB_DBREGS 0x02 /* process using debug registers */
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2001-05-22 21:20:49 +00:00
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#define PCB_NPXTRAP 0x04 /* npx trap pending */
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1993-06-12 14:58:17 +00:00
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caddr_t pcb_onfault; /* copyin/out fault recovery */
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1997-06-07 04:36:10 +00:00
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int pcb_gs;
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1997-08-09 00:04:06 +00:00
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struct pcb_ext *pcb_ext; /* optional pcb extension */
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STAGE-1 of 3 commit - allow (but do not require) interrupts to remain
enabled in critical sections and streamline critical_enter() and
critical_exit().
This commit allows an architecture to leave interrupts enabled inside
critical sections if it so wishes. Architectures that do not wish to do
this are not effected by this change.
This commit implements the feature for the I386 architecture and provides
a sysctl, debug.critical_mode, which defaults to 1 (use the feature). For
now you can turn the sysctl on and off at any time in order to test the
architectural changes or track down bugs.
This commit is just the first stage. Some areas of the code, specifically
the MACHINE_CRITICAL_ENTER #ifdef'd code, is strictly temporary and will
be cleaned up in the STAGE-2 commit when the critical_*() functions are
moved entirely into MD files.
The following changes have been made:
* critical_enter() and critical_exit() for I386 now simply increment
and decrement curthread->td_critnest. They no longer disable
hard interrupts. When critical_exit() decrements the counter to
0 it effectively calls a routine to deal with whatever interrupts
were deferred during the time the code was operating in a critical
section.
Other architectures are unaffected.
* fork_exit() has been conditionalized to remove MD assumptions for
the new code. Old code will still use the old MD assumptions
in regards to hard interrupt disablement. In STAGE-2 this will
be turned into a subroutine call into MD code rather then hardcoded
in MI code.
The new code places the burden of entering the critical section
in the trampoline code where it belongs.
* I386: interrupts are now enabled while we are in a critical section.
The interrupt vector code has been adjusted to deal with the fact.
If it detects that we are in a critical section it currently defers
the interrupt by adding the appropriate bit to an interrupt mask.
* In order to accomplish the deferral, icu_lock is required. This
is i386-specific. Thus icu_lock can only be obtained by mainline
i386 code while interrupts are hard disabled. This change has been
made.
* Because interrupts may or may not be hard disabled during a
context switch, cpu_switch() can no longer simply assume that
PSL_I will be in a consistent state. Therefore, it now saves and
restores eflags.
* FAST INTERRUPT PROVISION. Fast interrupts are currently deferred.
The intention is to eventually allow them to operate either while
we are in a critical section or, if we are able to restrict the
use of sched_lock, while we are not holding the sched_lock.
* ICU and APIC vector assembly for I386 cleaned up. The ICU code
has been cleaned up to match the APIC code in regards to format
and macro availability. Additionally, the code has been adjusted
to deal with deferred interrupts.
* Deferred interrupts use a per-cpu boolean int_pending, and
masks ipending, spending, and fpending. Being per-cpu variables
it is not currently necessary to lock; bus cycles modifying them.
Note that the same mechanism will enable preemption to be
incorporated as a true software interrupt without having to
further hack up the critical nesting code.
* Note: the old critical_enter() code in kern/kern_switch.c is
currently #ifdef to be compatible with both the old and new
methodology. In STAGE-2 it will be moved entirely to MD code.
Performance issues:
One of the purposes of this commit is to enhance critical section
performance, specifically to greatly reduce bus overhead to allow
the critical section code to be used to protect per-cpu caches.
These caches, such as Jeff's slab allocator work, can potentially
operate very quickly making the effective savings of the new
critical section code's performance very significant.
The second purpose of this commit is to allow architectures to
enable certain interrupts while in a critical section. Specifically,
the intention is to eventually allow certain FAST interrupts to
operate rather then defer.
The third purpose of this commit is to begin to clean up the
critical_enter()/critical_exit()/cpu_critical_enter()/
cpu_critical_exit() API which currently has serious cross pollution
in MI code (in fork_exit() and ast() for example).
The fourth purpose of this commit is to provide a framework that
allows kernel-preempting software interrupts to be implemented
cleanly. This is currently used for two forward interrupts in I386.
Other architectures will have the choice of using this infrastructure
or building the functionality directly into critical_enter()/
critical_exit().
Finally, this commit is designed to greatly improve the flexibility
of various architectures to manage critical section handling,
software interrupts, preemption, and other highly integrated
architecture-specific details.
2002-02-26 17:06:21 +00:00
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int pcb_psl; /* process status long */
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u_long __pcb_spare[2]; /* adjust to avoid core dump size changes */
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1993-06-12 14:58:17 +00:00
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};
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1994-05-25 09:21:21 +00:00
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/*
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* The pcb is augmented with machine-dependent additional data for
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* core dumps. For the i386: ???
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*/
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struct md_coredump {
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};
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1999-12-29 04:46:21 +00:00
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#ifdef _KERNEL
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1997-10-10 12:40:09 +00:00
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void savectx __P((struct pcb *));
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1993-06-12 14:58:17 +00:00
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#endif
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1993-10-08 20:51:00 +00:00
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#endif /* _I386_PCB_H_ */
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