292 lines
6.5 KiB
C
292 lines
6.5 KiB
C
/* $NetBSD: kern_ras.c,v 1.42 2022/08/08 22:31:45 riastradh Exp $ */
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/*-
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* Copyright (c) 2002, 2006, 2007, 2008 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Gregory McGarry, and by Andrew Doran.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_ras.c,v 1.42 2022/08/08 22:31:45 riastradh Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/kmem.h>
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#include <sys/proc.h>
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#include <sys/ras.h>
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#include <sys/xcall.h>
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#include <sys/syscallargs.h>
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#include <uvm/uvm_extern.h>
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#define MAX_RAS_PER_PROC 16
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u_int ras_per_proc = MAX_RAS_PER_PROC;
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#ifdef DEBUG
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int ras_debug = 0;
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#define DPRINTF(x) if (ras_debug) printf x
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#else
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#define DPRINTF(x) /* nothing */
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#endif
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/*
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* Force all CPUs through cpu_switchto(), waiting until complete.
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* Context switching will drain the write buffer on the calling
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* CPU.
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*/
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static void
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ras_sync(void)
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{
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/* No need to sync if exiting or single threaded. */
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if (curproc->p_nlwps > 1 && ncpu > 1) {
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xc_barrier(0);
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}
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}
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/*
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* Check the specified address to see if it is within the
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* sequence. If it is found, we return the restart address,
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* otherwise we return -1. If we do perform a restart, we
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* mark the sequence as hit.
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*
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* No locking required: we disable preemption and ras_sync()
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* guarantees that individual entries are valid while we still
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* have visibility of them.
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*/
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void *
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ras_lookup(struct proc *p, void *addr)
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{
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struct ras *rp;
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void *startaddr;
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lwp_t *l;
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startaddr = (void *)-1;
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l = curlwp;
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KPREEMPT_DISABLE(l);
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for (rp = p->p_raslist; rp != NULL; rp = rp->ras_next) {
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if (addr > rp->ras_startaddr && addr < rp->ras_endaddr) {
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startaddr = rp->ras_startaddr;
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DPRINTF(("RAS hit: p=%p %p\n", p, addr));
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break;
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}
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}
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KPREEMPT_ENABLE(l);
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return startaddr;
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}
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/*
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* During a fork, we copy all of the sequences from parent p1 to
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* the child p2.
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*
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* No locking required as the parent must be paused.
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*/
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int
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ras_fork(struct proc *p1, struct proc *p2)
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{
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struct ras *rp, *nrp;
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for (rp = p1->p_raslist; rp != NULL; rp = rp->ras_next) {
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nrp = kmem_alloc(sizeof(*nrp), KM_SLEEP);
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nrp->ras_startaddr = rp->ras_startaddr;
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nrp->ras_endaddr = rp->ras_endaddr;
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nrp->ras_next = p2->p_raslist;
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p2->p_raslist = nrp;
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}
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DPRINTF(("ras_fork: p1=%p, p2=%p\n", p1, p2));
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return 0;
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}
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/*
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* Nuke all sequences for this process.
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*/
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int
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ras_purgeall(void)
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{
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struct ras *rp, *nrp;
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proc_t *p;
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p = curproc;
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if (p->p_raslist == NULL)
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return 0;
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mutex_enter(&p->p_auxlock);
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if ((rp = p->p_raslist) != NULL) {
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p->p_raslist = NULL;
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ras_sync();
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for(; rp != NULL; rp = nrp) {
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nrp = rp->ras_next;
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kmem_free(rp, sizeof(*rp));
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}
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}
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mutex_exit(&p->p_auxlock);
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return 0;
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}
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#if defined(__HAVE_RAS)
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/*
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* Install the new sequence. If it already exists, return
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* an error.
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*/
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static int
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ras_install(void *addr, size_t len)
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{
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struct ras *rp;
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struct ras *newrp;
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void *endaddr;
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int nras, error;
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proc_t *p;
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if (len == 0)
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return EINVAL;
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if ((uintptr_t)addr < VM_MIN_ADDRESS ||
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(uintptr_t)addr > VM_MAXUSER_ADDRESS)
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return EINVAL;
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if (len > VM_MAXUSER_ADDRESS - (uintptr_t)addr)
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return EINVAL;
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endaddr = (char *)addr + len;
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newrp = kmem_alloc(sizeof(*newrp), KM_SLEEP);
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newrp->ras_startaddr = addr;
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newrp->ras_endaddr = endaddr;
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error = 0;
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nras = 0;
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p = curproc;
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mutex_enter(&p->p_auxlock);
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for (rp = p->p_raslist; rp != NULL; rp = rp->ras_next) {
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if (++nras >= ras_per_proc) {
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error = EINVAL;
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break;
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}
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if (addr < rp->ras_endaddr && endaddr > rp->ras_startaddr) {
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error = EEXIST;
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break;
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}
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}
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if (rp == NULL) {
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newrp->ras_next = p->p_raslist;
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p->p_raslist = newrp;
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ras_sync();
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mutex_exit(&p->p_auxlock);
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} else {
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mutex_exit(&p->p_auxlock);
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kmem_free(newrp, sizeof(*newrp));
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}
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return error;
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}
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/*
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* Nuke the specified sequence. Both address and len must
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* match, otherwise we return an error.
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*/
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static int
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ras_purge(void *addr, size_t len)
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{
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struct ras *rp, **link;
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proc_t *p;
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p = curproc;
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mutex_enter(&p->p_auxlock);
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link = &p->p_raslist;
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for (rp = *link; rp != NULL; link = &rp->ras_next, rp = *link) {
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if (addr == rp->ras_startaddr &&
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(char *)rp->ras_endaddr - (char *)rp->ras_startaddr == len)
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break;
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}
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if (rp != NULL) {
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*link = rp->ras_next;
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ras_sync();
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mutex_exit(&p->p_auxlock);
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kmem_free(rp, sizeof(*rp));
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return 0;
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} else {
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mutex_exit(&p->p_auxlock);
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return ESRCH;
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}
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}
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#endif /* defined(__HAVE_RAS) */
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/*ARGSUSED*/
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int
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sys_rasctl(struct lwp *l, const struct sys_rasctl_args *uap, register_t *retval)
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{
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#if defined(__HAVE_RAS)
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/* {
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syscallarg(void *) addr;
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syscallarg(size_t) len;
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syscallarg(int) op;
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} */
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void *addr;
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size_t len;
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int op;
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int error;
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/*
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* first, extract syscall args from the uap.
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*/
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addr = (void *)SCARG(uap, addr);
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len = (size_t)SCARG(uap, len);
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op = SCARG(uap, op);
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DPRINTF(("sys_rasctl: p=%p addr=%p, len=%ld, op=0x%x\n",
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curproc, addr, (long)len, op));
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switch (op) {
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case RAS_INSTALL:
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error = ras_install(addr, len);
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break;
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case RAS_PURGE:
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error = ras_purge(addr, len);
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break;
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case RAS_PURGE_ALL:
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error = ras_purgeall();
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break;
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default:
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error = EINVAL;
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break;
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}
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return (error);
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#else
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return (EOPNOTSUPP);
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#endif
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}
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