506 lines
13 KiB
C
506 lines
13 KiB
C
/*-
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* Copyright (c) 1982, 1986 The Regents of the University of California.
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* Copyright (c) 1989, 1990 William Jolitz
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* Copyright (c) 1994 John Dyson
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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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* the Systems Programming Group of the University of Utah Computer
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* Science Department, and 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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* from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
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* Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
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* $FreeBSD$
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*/
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/*
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* Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Author: Chris G. Demetriou
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/malloc.h>
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#include <sys/bio.h>
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#include <sys/buf.h>
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#include <sys/mutex.h>
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#include <sys/vnode.h>
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#include <sys/vmmeter.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/unistd.h>
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#include <machine/clock.h>
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#include <machine/cpu.h>
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#include <machine/fpu.h>
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#include <machine/md_var.h>
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#include <machine/prom.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <sys/lock.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_page.h>
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#include <vm/vm_map.h>
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#include <vm/vm_extern.h>
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#include <sys/user.h>
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/*
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* quick version of vm_fault
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*/
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int
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vm_fault_quick(v, prot)
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caddr_t v;
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int prot;
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{
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int r;
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if (prot & VM_PROT_WRITE)
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r = subyte(v, fubyte(v));
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else
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r = fubyte(v);
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return(r);
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}
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/*
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* Finish a fork operation, with process p2 nearly set up.
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* Copy and update the pcb, set up the stack so that the child
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* ready to run and return to user mode.
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*/
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void
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cpu_fork(p1, p2, flags)
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register struct proc *p1, *p2;
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int flags;
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{
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if ((flags & RFPROC) == 0)
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return;
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p2->p_md.md_tf = p1->p_md.md_tf;
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p2->p_md.md_flags = p1->p_md.md_flags & (MDP_FPUSED | MDP_UAC_MASK);
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/*
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* Cache the physical address of the pcb, so we can
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* swap to it easily.
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*/
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p2->p_md.md_pcbpaddr = (void*)vtophys((vm_offset_t)&p2->p_addr->u_pcb);
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/*
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* Copy floating point state from the FP chip to the PCB
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* if this process has state stored there.
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*/
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alpha_fpstate_save(p1, 0);
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/*
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* Copy pcb and stack from proc p1 to p2. We do this as
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* cheaply as possible, copying only the active part of the
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* stack. The stack and pcb need to agree. Make sure that the
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* new process has FEN disabled.
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*/
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p2->p_addr->u_pcb = p1->p_addr->u_pcb;
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p2->p_addr->u_pcb.pcb_hw.apcb_usp = alpha_pal_rdusp();
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p2->p_addr->u_pcb.pcb_hw.apcb_flags &= ~ALPHA_PCB_FLAGS_FEN;
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/*
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* Set the floating point state.
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*/
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if ((p2->p_addr->u_pcb.pcb_fp_control & IEEE_INHERIT) == 0) {
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p2->p_addr->u_pcb.pcb_fp_control = 0;
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p2->p_addr->u_pcb.pcb_fp.fpr_cr = (FPCR_DYN_NORMAL
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| FPCR_INVD | FPCR_DZED
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| FPCR_OVFD | FPCR_INED
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| FPCR_UNFD);
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}
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/*
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* Arrange for a non-local goto when the new process
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* is started, to resume here, returning nonzero from setjmp.
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*/
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#ifdef DIAGNOSTIC
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alpha_fpstate_check(p1);
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#endif
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/*
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* create the child's kernel stack, from scratch.
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*/
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{
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struct user *up = p2->p_addr;
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struct trapframe *p2tf;
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/*
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* Pick a stack pointer, leaving room for a trapframe;
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* copy trapframe from parent so return to user mode
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* will be to right address, with correct registers.
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*/
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p2tf = p2->p_md.md_tf = (struct trapframe *)
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((char *)p2->p_addr + USPACE - sizeof(struct trapframe));
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bcopy(p1->p_md.md_tf, p2->p_md.md_tf,
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sizeof(struct trapframe));
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/*
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* Set up return-value registers as fork() libc stub expects.
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*/
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p2tf->tf_regs[FRAME_V0] = 0; /* child's pid (linux) */
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p2tf->tf_regs[FRAME_A3] = 0; /* no error */
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p2tf->tf_regs[FRAME_A4] = 1; /* is child (FreeBSD) */
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/*
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* Arrange for continuation at fork_return(), which
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* will return to exception_return(). Note that the child
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* process doesn't stay in the kernel for long!
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*
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* This is an inlined version of cpu_set_kpc.
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*/
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up->u_pcb.pcb_hw.apcb_ksp = (u_int64_t)p2tf;
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up->u_pcb.pcb_context[0] =
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(u_int64_t)fork_return; /* s0: a0 */
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up->u_pcb.pcb_context[1] =
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(u_int64_t)exception_return; /* s1: ra */
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up->u_pcb.pcb_context[2] = (u_long) p2; /* s2: a1 */
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up->u_pcb.pcb_context[7] =
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(u_int64_t)fork_trampoline; /* ra: assembly magic */
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#ifdef SMP
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/*
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* We start off at a nesting level of 1 within the kernel.
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*/
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p2->p_md.md_kernnest = 1;
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#endif
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}
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}
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/*
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* Intercept the return address from a freshly forked process that has NOT
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* been scheduled yet.
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*
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* This is needed to make kernel threads stay in kernel mode.
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*/
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void
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cpu_set_fork_handler(p, func, arg)
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struct proc *p;
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void (*func) __P((void *));
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void *arg;
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{
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/*
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* Note that the trap frame follows the args, so the function
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* is really called like this: func(arg, frame);
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*/
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p->p_addr->u_pcb.pcb_context[0] = (u_long) func;
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p->p_addr->u_pcb.pcb_context[2] = (u_long) arg;
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}
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/*
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* cpu_exit is called as the last action during exit.
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* We release the address space of the process, block interrupts,
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* and call switch_exit. switch_exit switches to proc0's PCB and stack,
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* then jumps into the middle of cpu_switch, as if it were switching
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* from proc0.
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*/
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void
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cpu_exit(p)
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register struct proc *p;
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{
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alpha_fpstate_drop(p);
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PROC_LOCK(p);
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mtx_lock_spin(&sched_lock);
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mtx_unlock_flags(&Giant, MTX_NOSWITCH);
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mtx_assert(&Giant, MA_NOTOWNED);
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/*
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* We have to wait until after releasing all locks before
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* changing p_stat. If we block on a mutex then we will be
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* back at SRUN when we resume and our parent will never
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* harvest us.
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*/
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p->p_stat = SZOMB;
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wakeup(p->p_pptr);
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PROC_UNLOCK_NOSWITCH(p);
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cnt.v_swtch++;
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cpu_switch();
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panic("cpu_exit");
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}
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void
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cpu_wait(p)
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struct proc *p;
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{
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mtx_lock(&vm_mtx);
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/* drop per-process resources */
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pmap_dispose_proc(p);
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/* and clean-out the vmspace */
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vmspace_free(p->p_vmspace);
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mtx_unlock(&vm_mtx);
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}
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/*
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* Dump the machine specific header information at the start of a core dump.
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*/
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int
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cpu_coredump(p, vp, cred)
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struct proc *p;
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struct vnode *vp;
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struct ucred *cred;
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{
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return (vn_rdwr(UIO_WRITE, vp, (caddr_t) p->p_addr, ctob(UPAGES),
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(off_t)0, UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, (int *)NULL,
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p));
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}
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#ifdef notyet
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static void
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setredzone(pte, vaddr)
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u_short *pte;
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caddr_t vaddr;
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{
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/* eventually do this by setting up an expand-down stack segment
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for ss0: selector, allowing stack access down to top of u.
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this means though that protection violations need to be handled
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thru a double fault exception that must do an integral task
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switch to a known good context, within which a dump can be
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taken. a sensible scheme might be to save the initial context
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used by sched (that has physical memory mapped 1:1 at bottom)
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and take the dump while still in mapped mode */
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}
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#endif
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/*
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* Map an IO request into kernel virtual address space.
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*
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* All requests are (re)mapped into kernel VA space.
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* Notice that we use b_bufsize for the size of the buffer
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* to be mapped. b_bcount might be modified by the driver.
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*/
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void
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vmapbuf(bp)
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register struct buf *bp;
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{
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register caddr_t addr, v, kva;
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vm_offset_t pa;
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if ((bp->b_flags & B_PHYS) == 0)
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panic("vmapbuf");
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mtx_lock(&vm_mtx);
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for (v = bp->b_saveaddr, addr = (caddr_t)trunc_page(bp->b_data);
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addr < bp->b_data + bp->b_bufsize;
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addr += PAGE_SIZE, v += PAGE_SIZE) {
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/*
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* Do the vm_fault if needed; do the copy-on-write thing
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* when reading stuff off device into memory.
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*/
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vm_fault_quick(addr,
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(bp->b_iocmd == BIO_READ)?(VM_PROT_READ|VM_PROT_WRITE):VM_PROT_READ);
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pa = trunc_page(pmap_kextract((vm_offset_t) addr));
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if (pa == 0)
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panic("vmapbuf: page not present");
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vm_page_hold(PHYS_TO_VM_PAGE(pa));
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pmap_kenter((vm_offset_t) v, pa);
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}
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mtx_unlock(&vm_mtx);
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kva = bp->b_saveaddr;
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bp->b_saveaddr = bp->b_data;
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bp->b_data = kva + (((vm_offset_t) bp->b_data) & PAGE_MASK);
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}
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/*
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* Free the io map PTEs associated with this IO operation.
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* We also invalidate the TLB entries and restore the original b_addr.
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*/
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void
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vunmapbuf(bp)
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register struct buf *bp;
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{
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register caddr_t addr;
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vm_offset_t pa;
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if ((bp->b_flags & B_PHYS) == 0)
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panic("vunmapbuf");
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mtx_lock(&vm_mtx);
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for (addr = (caddr_t)trunc_page(bp->b_data);
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addr < bp->b_data + bp->b_bufsize;
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addr += PAGE_SIZE) {
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pa = trunc_page(pmap_kextract((vm_offset_t) addr));
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pmap_kremove((vm_offset_t) addr);
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vm_page_unhold(PHYS_TO_VM_PAGE(pa));
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}
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mtx_unlock(&vm_mtx);
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bp->b_data = bp->b_saveaddr;
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}
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/*
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* Reset back to firmware.
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*/
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void
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cpu_reset()
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{
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prom_halt(0);
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}
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int
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grow_stack(p, sp)
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struct proc *p;
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size_t sp;
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{
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int rv;
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rv = vm_map_growstack (p, sp);
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if (rv != KERN_SUCCESS)
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return (0);
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return (1);
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}
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static int cnt_prezero;
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SYSCTL_INT(_machdep, OID_AUTO, cnt_prezero, CTLFLAG_RD, &cnt_prezero, 0, "");
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/*
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* Implement the pre-zeroed page mechanism.
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* This routine is called from the idle loop.
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*/
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#define ZIDLE_LO(v) ((v) * 2 / 3)
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#define ZIDLE_HI(v) ((v) * 4 / 5)
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int
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vm_page_zero_idle()
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{
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static int free_rover;
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static int zero_state;
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vm_page_t m;
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int s;
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/*
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* Attempt to maintain approximately 1/2 of our free pages in a
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* PG_ZERO'd state. Add some hysteresis to (attempt to) avoid
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* generally zeroing a page when the system is near steady-state.
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* Otherwise we might get 'flutter' during disk I/O / IPC or
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* fast sleeps. We also do not want to be continuously zeroing
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* pages because doing so may flush our L1 and L2 caches too much.
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*/
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if (mtx_trylock(&vm_mtx) == 0)
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return (0);
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if (zero_state && vm_page_zero_count >= ZIDLE_LO(cnt.v_free_count)) {
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mtx_unlock(&vm_mtx);
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return(0);
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}
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if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count)) {
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mtx_unlock(&vm_mtx);
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return(0);
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}
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s = splvm();
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m = vm_page_list_find(PQ_FREE, free_rover, FALSE);
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zero_state = 0;
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if (m != NULL && (m->flags & PG_ZERO) == 0) {
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vm_page_queues[m->queue].lcnt--;
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TAILQ_REMOVE(&vm_page_queues[m->queue].pl, m, pageq);
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m->queue = PQ_NONE;
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splx(s);
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pmap_zero_page(VM_PAGE_TO_PHYS(m));
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(void)splvm();
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vm_page_flag_set(m, PG_ZERO);
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m->queue = PQ_FREE + m->pc;
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vm_page_queues[m->queue].lcnt++;
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TAILQ_INSERT_TAIL(&vm_page_queues[m->queue].pl, m,
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pageq);
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++vm_page_zero_count;
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++cnt_prezero;
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if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count))
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zero_state = 1;
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}
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free_rover = (free_rover + PQ_PRIME2) & PQ_L2_MASK;
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splx(s);
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mtx_unlock(&vm_mtx);
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return (1);
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}
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/*
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* Software interrupt handler for queued VM system processing.
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*/
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void
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swi_vm(void *dummy)
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{
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if (busdma_swi_pending != 0)
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busdma_swi();
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}
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/*
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* Tell whether this address is in some physical memory region.
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* Currently used by the kernel coredump code in order to avoid
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* dumping the ``ISA memory hole'' which could cause indefinite hangs,
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* or other unpredictable behaviour.
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*/
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int
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is_physical_memory(addr)
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vm_offset_t addr;
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{
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/*
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* stuff other tests for known memory-mapped devices (PCI?)
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* here
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*/
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return 1;
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}
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