NetBSD/sys/kern/kern_ras.c

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/* $NetBSD: kern_ras.c,v 1.34 2008/10/15 06:51:20 wrstuden Exp $ */
/*-
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* Copyright (c) 2002, 2006, 2007, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
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* by Gregory McGarry, and by Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_ras.c,v 1.34 2008/10/15 06:51:20 wrstuden Exp $");
#include <sys/param.h>
#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/kmem.h>
#include <sys/proc.h>
#include <sys/ras.h>
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#include <sys/sa.h>
#include <sys/savar.h>
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#include <sys/xcall.h>
#include <sys/syscallargs.h>
#include <uvm/uvm_extern.h>
#define MAX_RAS_PER_PROC 16
u_int ras_per_proc = MAX_RAS_PER_PROC;
#ifdef DEBUG
int ras_debug = 0;
#define DPRINTF(x) if (ras_debug) printf x
#else
#define DPRINTF(x) /* nothing */
#endif
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/*
* Force all CPUs through cpu_switchto(), waiting until complete.
* Context switching will drain the write buffer on the calling
* CPU.
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*/
static void
ras_sync(void)
{
/* No need to sync if exiting or single threaded. */
if (curproc->p_nlwps > 1 && ncpu > 1) {
#ifdef NO_SOFTWARE_PATENTS
uint64_t where;
where = xc_broadcast(0, (xcfunc_t)nullop, NULL, NULL);
xc_wait(where);
#else
/*
* Assumptions:
*
* o preemption is disabled by the thread in
* ras_lookup().
* o proc::p_raslist is only inspected with
* preemption disabled.
* o ras_lookup() plus loads reordered in advance
* will take no longer than 1/8s to complete.
*/
const int delta = hz >> 3;
int target = hardclock_ticks + delta;
do {
kpause("ras", false, delta, NULL);
} while (hardclock_ticks < target);
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#endif
}
}
/*
* Check the specified address to see if it is within the
* sequence. If it is found, we return the restart address,
* otherwise we return -1. If we do perform a restart, we
* mark the sequence as hit.
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*
* No locking required: we disable preemption and ras_sync()
* guarantees that individual entries are valid while we still
* have visibility of them.
*/
void *
ras_lookup(struct proc *p, void *addr)
{
struct ras *rp;
void *startaddr;
lwp_t *l;
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startaddr = (void *)-1;
l = curlwp;
KPREEMPT_DISABLE(l);
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for (rp = p->p_raslist; rp != NULL; rp = rp->ras_next) {
if (addr > rp->ras_startaddr && addr < rp->ras_endaddr) {
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startaddr = rp->ras_startaddr;
DPRINTF(("RAS hit: p=%p %p\n", p, addr));
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break;
}
}
KPREEMPT_ENABLE(l);
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return startaddr;
}
/*
* During a fork, we copy all of the sequences from parent p1 to
* the child p2.
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*
* No locking required as the parent must be paused.
*/
int
ras_fork(struct proc *p1, struct proc *p2)
{
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);
nrp->ras_startaddr = rp->ras_startaddr;
nrp->ras_endaddr = rp->ras_endaddr;
nrp->ras_next = p2->p_raslist;
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p2->p_raslist = nrp;
}
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DPRINTF(("ras_fork: p1=%p, p2=%p\n", p1, p2));
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return 0;
}
/*
* Nuke all sequences for this process.
*/
int
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ras_purgeall(void)
{
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struct ras *rp, *nrp;
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) {
p->p_raslist = NULL;
ras_sync();
for(; rp != NULL; rp = nrp) {
nrp = rp->ras_next;
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kmem_free(rp, sizeof(*rp));
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}
}
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mutex_exit(&p->p_auxlock);
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return 0;
}
#if defined(__HAVE_RAS)
/*
* Install the new sequence. If it already exists, return
* an error.
*/
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static int
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ras_install(void *addr, size_t len)
{
struct ras *rp;
struct ras *newrp;
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void *endaddr;
int nras, error;
proc_t *p;
endaddr = (char *)addr + len;
if (addr < (void *)VM_MIN_ADDRESS ||
endaddr > (void *)VM_MAXUSER_ADDRESS)
return (EINVAL);
if (len <= 0)
return (EINVAL);
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newrp = kmem_alloc(sizeof(*newrp), KM_SLEEP);
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newrp->ras_startaddr = addr;
newrp->ras_endaddr = endaddr;
error = 0;
nras = 0;
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) {
if (++nras >= ras_per_proc) {
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error = EINVAL;
break;
}
if (addr < rp->ras_endaddr && endaddr > rp->ras_startaddr) {
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error = EEXIST;
break;
}
}
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if (rp == NULL) {
newrp->ras_next = p->p_raslist;
p->p_raslist = newrp;
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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return error;
}
/*
* Nuke the specified sequence. Both address and len must
* match, otherwise we return an error.
*/
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static int
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ras_purge(void *addr, size_t len)
{
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struct ras *rp, **link;
void *endaddr;
proc_t *p;
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endaddr = (char *)addr + len;
p = curproc;
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mutex_enter(&p->p_auxlock);
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link = &p->p_raslist;
for (rp = *link; rp != NULL; link = &rp->ras_next, rp = *link) {
if (addr == rp->ras_startaddr && endaddr == rp->ras_endaddr)
break;
}
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if (rp != NULL) {
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*link = rp->ras_next;
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;
} else {
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mutex_exit(&p->p_auxlock);
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return ESRCH;
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}
}
#endif /* defined(__HAVE_RAS) */
/*ARGSUSED*/
int
sys_rasctl(struct lwp *l, const struct sys_rasctl_args *uap, register_t *retval)
{
#if defined(__HAVE_RAS)
/* {
syscallarg(void *) addr;
syscallarg(size_t) len;
syscallarg(int) op;
} */
void *addr;
size_t len;
int op;
int error;
/*
* first, extract syscall args from the uap.
*/
addr = (void *)SCARG(uap, addr);
len = (size_t)SCARG(uap, len);
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));
switch (op) {
case RAS_INSTALL:
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error = ras_install(addr, len);
break;
case RAS_PURGE:
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error = ras_purge(addr, len);
break;
case RAS_PURGE_ALL:
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error = ras_purgeall();
break;
default:
error = EINVAL;
break;
}
return (error);
#else
return (EOPNOTSUPP);
#endif
}