507 lines
14 KiB
C
507 lines
14 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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* $Id: vm_machdep.c,v 1.3 1998/07/12 16:30:58 dfr Exp $
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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/buf.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 <machine/clock.h>
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#include <machine/cpu.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 <vm/vm_prot.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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void
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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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if (prot & VM_PROT_WRITE)
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subyte(v, fubyte(v));
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else
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fubyte(v);
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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)
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register struct proc *p1, *p2;
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{
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struct user *up = p2->p_addr;
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int i;
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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;
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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) &up->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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if (p1 == fpcurproc) {
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alpha_pal_wrfen(1);
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savefpstate(&fpcurproc->p_addr->u_pcb.pcb_fp);
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alpha_pal_wrfen(0);
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}
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/*
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* Copy pcb and stack from proc p1 to p2.
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* We do this as cheaply as possible, copying only the active
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* part of the stack. The stack and pcb need to agree;
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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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/*
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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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if (p1 != curproc)
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panic("cpu_fork: curproc");
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if ((up->u_pcb.pcb_hw.apcb_flags & ALPHA_PCB_FLAGS_FEN) != 0)
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printf("DANGER WILL ROBINSON: FEN SET IN cpu_fork!\n");
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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 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] = p1->p_pid; /* parent's pid */
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p2tf->tf_regs[FRAME_A3] = 0; /* no error */
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p2tf->tf_regs[FRAME_A4] = 1; /* is child */
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/*
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* Arrange for continuation at child_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)child_return; /* s0: pc */
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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: a0 */
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up->u_pcb.pcb_context[7] =
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(u_int64_t)switch_trampoline; /* ra: assembly magic */
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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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if (p == fpcurproc)
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fpcurproc = NULL;
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(void) splhigh();
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cnt.v_swtch++;
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cpu_switch(p);
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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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/* 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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}
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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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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_flags&B_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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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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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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bp->b_data = bp->b_saveaddr;
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}
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/*
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* Force reset the processor by invalidating the entire address space!
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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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/*
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* Grow the user stack to allow for 'sp'. This version grows the stack in
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* chunks of SGROWSIZ.
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*/
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int
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grow(p, sp)
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struct proc *p;
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size_t sp;
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{
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unsigned int nss;
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caddr_t v;
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struct vmspace *vm = p->p_vmspace;
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if ((caddr_t)sp <= vm->vm_maxsaddr || sp >= (size_t) USRSTACK)
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return (1);
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nss = roundup(USRSTACK - (vm_offset_t)sp, PAGE_SIZE);
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if (nss > p->p_rlimit[RLIMIT_STACK].rlim_cur)
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return (0);
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if (vm->vm_ssize && roundup(vm->vm_ssize << PAGE_SHIFT,
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SGROWSIZ) < nss) {
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int grow_amount;
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/*
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* If necessary, grow the VM that the stack occupies
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* to allow for the rlimit. This allows us to not have
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* to allocate all of the VM up-front in execve (which
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* is expensive).
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* Grow the VM by the amount requested rounded up to
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* the nearest SGROWSIZ to provide for some hysteresis.
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*/
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grow_amount = roundup((nss - (vm->vm_ssize << PAGE_SHIFT)), SGROWSIZ);
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v = (char *)USRSTACK - roundup(vm->vm_ssize << PAGE_SHIFT,
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SGROWSIZ) - grow_amount;
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/*
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* If there isn't enough room to extend by SGROWSIZ, then
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* just extend to the maximum size
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*/
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if (v < vm->vm_maxsaddr) {
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v = vm->vm_maxsaddr;
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grow_amount = MAXSSIZ - (vm->vm_ssize << PAGE_SHIFT);
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}
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if ((grow_amount == 0) || (vm_map_find(&vm->vm_map, NULL, 0, (vm_offset_t *)&v,
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grow_amount, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0) != KERN_SUCCESS)) {
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return (0);
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}
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vm->vm_ssize += grow_amount >> PAGE_SHIFT;
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}
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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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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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vm_page_t m;
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int s;
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/*
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* XXX
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* We stop zeroing pages when there are sufficent prezeroed pages.
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* This threshold isn't really needed, except we want to
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* bypass unneeded calls to vm_page_list_find, and the
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* associated cache flush and latency. The pre-zero will
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* still be called when there are significantly more
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* non-prezeroed pages than zeroed pages. The threshold
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* of half the number of reserved pages is arbitrary, but
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* approximately the right amount. Eventually, we should
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* perhaps interrupt the zero operation when a process
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* is found to be ready to run.
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*/
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if (cnt.v_free_count - vm_page_zero_count <= cnt.v_free_reserved / 2)
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return (0);
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#ifdef SMP
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if (try_mplock()) {
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#endif
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s = splvm();
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m = vm_page_list_find(PQ_FREE, free_rover);
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if (m != NULL) {
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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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#if 0
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rel_mplock();
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#endif
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pmap_zero_page(VM_PAGE_TO_PHYS(m));
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#if 0
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get_mplock();
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#endif
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(void)splvm();
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m->queue = PQ_ZERO + m->pc;
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++(*vm_page_queues[m->queue].lcnt);
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TAILQ_INSERT_HEAD(vm_page_queues[m->queue].pl, m,
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pageq);
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free_rover = (free_rover + PQ_PRIME3) & PQ_L2_MASK;
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++vm_page_zero_count;
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++cnt_prezero;
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}
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splx(s);
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#ifdef SMP
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rel_mplock();
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#endif
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return (1);
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#ifdef SMP
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}
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#endif
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return (0);
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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()
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{
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#if 0
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if (busdma_swi_pending != 0)
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busdma_swi();
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#endif
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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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