1d3c0fa7b2
preserve the ABI and API for applications. It was removed in the port to amd64, but was remained as garbage giving a micro-pessimization and spurious single-step traps on i386. pcb_psl was intended to be used just to do a context switch of PSL_I, but this context switch was null in most or all versions, and mis-switching of PSL_T was done instead. Some history: - in 386BSD-0.0, cpu_switch() ran at splhigh() and splhigh() did too much interrupt disabling, so interrupts were hard-disabled across cpu_switch() and too many other places - in 386BSD-0.0-patchkit through FreeBSD-4 and FreeBSD-5 before SMPng, splhigh() did soft interrupt masking, and cpu_switch() was excessively cautious and did a cli at the start and a sti at the end to hard-disable interrupts across the switch - SMPng replaced the spl's and cli's by spinlocks (just sched_lock?), so interrupts were hard-disabled across cpu_switch() and too many other places again - initial attempts to fix this intended to restore some soft interrupt disabling, but to support variations in this cpu_switch() used pushfl/popfl into pcb_psl to avoid hard-coding the assumption that the initial and final states have PSL_I enabled. But the version with soft interrupt disabling wasn't used for long, or was never committed, (except I always used my different version of it for UP) so the pushfl/popl and pcb_psl to hold them have been doing less than nothing for about 14 years.
116 lines
3.4 KiB
C
116 lines
3.4 KiB
C
/*-
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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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* 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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* from: @(#)pcb.h 5.10 (Berkeley) 5/12/91
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* $FreeBSD$
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*/
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#ifndef _I386_PCB_H_
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#define _I386_PCB_H_
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/*
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* Intel 386 process control block
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*/
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#ifndef _KERNEL
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#include <machine/segments.h>
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#endif
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#include <machine/npx.h>
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/*
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* NB: The fields marked with (*) are used by kernel debuggers. Their
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* ABI should be preserved.
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*/
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struct pcb {
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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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struct segment_descriptor pcb_fsd;
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struct segment_descriptor pcb_gsd;
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int pcb_ds;
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int pcb_es;
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int pcb_fs;
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int pcb_gs;
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int pcb_ss;
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int pcb_cr0;
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int pcb_cr2;
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int pcb_cr3;
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int pcb_cr4;
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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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struct region_descriptor pcb_gdt;
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struct region_descriptor pcb_idt;
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uint16_t pcb_ldt;
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uint16_t pcb_tr;
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u_int pcb_flags;
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#define PCB_DBREGS 0x02 /* process using debug registers */
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#define PCB_NPXINITDONE 0x08 /* fpu state is initialized */
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#define PCB_VM86CALL 0x10 /* in vm86 call */
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#define PCB_NPXUSERINITDONE 0x20 /* user fpu state is initialized */
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#define PCB_KERNNPX 0x40 /* kernel uses npx */
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uint16_t pcb_initial_npxcw;
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caddr_t pcb_onfault; /* copyin/out fault recovery */
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struct pcb_ext *pcb_ext; /* optional pcb extension */
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int pcb_waspsl; /* unused padding for ABI and API compat */
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u_long pcb_vm86[2]; /* vm86bios scratch space */
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union savefpu *pcb_save;
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uint32_t pcb_pad[10];
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};
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/* Per-CPU state saved during suspend and resume. */
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struct susppcb {
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struct pcb sp_pcb;
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/* fpu context for suspend/resume */
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void *sp_fpususpend;
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};
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#ifdef _KERNEL
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struct trapframe;
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void makectx(struct trapframe *, struct pcb *);
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int savectx(struct pcb *) __returns_twice;
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void resumectx(struct pcb *) __fastcall;
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#endif
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#endif /* _I386_PCB_H_ */
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