freebsd-skq/sys/powerpc/booke/copyinout.c
nwhitehorn 1d215b1285 Use the ABI-mandated thread pointer register (r2 for ppc32, r13 for ppc64)
instead of a PCPU field for curthread. This averts a race on SMP systems
with a high interrupt rate where the thread looking up the value of
curthread could be preempted and migrated between obtaining the PCPU
pointer and reading the value of pc_curthread, resulting in curthread being
observed to be the current thread on the thread's original CPU. This played
merry havoc with the system, in particular with mutexes. Many thanks to
jhb for helping me work this one out.

Note that Book-E is in principle susceptible to the same problem, but has
not been modified yet due to lack of Book-E hardware.

MFC after:	2 weeks
2011-06-23 22:21:28 +00:00

316 lines
6.7 KiB
C

/*-
* Copyright (C) 2002 Benno Rice
* All rights reserved.
*
* 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 Benno Rice ``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 TOOLS GMBH 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.
*/
/*-
* Copyright (C) 1993 Wolfgang Solfrank.
* Copyright (C) 1993 TooLs GmbH.
* All rights reserved.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by TooLs GmbH.
* 4. The name of TooLs GmbH may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <machine/pcb.h>
#include <machine/vmparam.h>
int setfault(faultbuf); /* defined in locore.S */
static int
is_uaddr(const void *addr)
{
int rv = ((vm_offset_t)addr <= VM_MAXUSER_ADDRESS) ? 1 : 0;
return rv;
}
int
copyout(const void *kaddr, void *udaddr, size_t len)
{
struct thread *td;
faultbuf env;
if (!is_uaddr(udaddr))
return (EFAULT);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
return (EFAULT);
}
bcopy(kaddr, udaddr, len);
td->td_pcb->pcb_onfault = NULL;
return (0);
}
int
copyin(const void *udaddr, void *kaddr, size_t len)
{
struct thread *td;
faultbuf env;
if (!is_uaddr(udaddr) || is_uaddr(kaddr))
return (EFAULT);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
return (EFAULT);
}
bcopy(udaddr, kaddr, len);
td->td_pcb->pcb_onfault = NULL;
return (0);
}
int
copyinstr(const void *udaddr, void *kaddr, size_t len, size_t *done)
{
struct thread *td;
faultbuf env;
const char *up;
char *kp;
size_t l;
int rv, c;
if (!is_uaddr(udaddr) || is_uaddr(kaddr))
return (EFAULT);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
return (EFAULT);
}
kp = kaddr;
up = udaddr;
rv = ENAMETOOLONG;
for (l = 0; len-- > 0; l++) {
c = *up++;
if (!(*kp++ = c)) {
l++;
rv = 0;
break;
}
}
if (done != NULL) {
*done = l;
}
td->td_pcb->pcb_onfault = NULL;
return (rv);
}
int
subyte(void *addr, int byte)
{
struct thread *td;
faultbuf env;
if (!is_uaddr(addr))
return (EFAULT);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
return (EFAULT);
}
*(char *)addr = (char)byte;
td->td_pcb->pcb_onfault = NULL;
return (0);
}
int
suword(void *addr, long word)
{
struct thread *td;
faultbuf env;
if (!is_uaddr(addr))
return (EFAULT);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
return (EFAULT);
}
*(long *)addr = word;
td->td_pcb->pcb_onfault = NULL;
return (0);
}
int
suword32(void *addr, int32_t word)
{
return (suword(addr, (long)word));
}
int
fubyte(const void *addr)
{
struct thread *td;
faultbuf env;
int val;
if (!is_uaddr(addr))
return (EFAULT);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
return (EFAULT);
}
val = *(const u_char *)addr;
td->td_pcb->pcb_onfault = NULL;
return (val);
}
long
fuword(const void *addr)
{
struct thread *td;
faultbuf env;
long val;
if (!is_uaddr(addr))
return (EFAULT);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
return (EFAULT);
}
val = *(const long *)addr;
td->td_pcb->pcb_onfault = NULL;
return (val);
}
int32_t
fuword32(const void *addr)
{
return ((int32_t)fuword(addr));
}
uint32_t
casuword32(volatile uint32_t *base, uint32_t oldval, uint32_t newval)
{
return (casuword((volatile u_long *)base, oldval, newval));
}
u_long
casuword(volatile u_long *addr, u_long old, u_long new)
{
struct thread *td;
faultbuf env;
u_long val;
if (!((vm_offset_t)addr <= VM_MAXUSER_ADDRESS))
return (EFAULT);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
return (EFAULT);
}
__asm __volatile (
"1:\tlwarx %0, 0, %2\n\t" /* load old value */
"cmplw %3, %0\n\t" /* compare */
"bne 2f\n\t" /* exit if not equal */
"stwcx. %4, 0, %2\n\t" /* attempt to store */
"bne- 1b\n\t" /* spin if failed */
"b 3f\n\t" /* we've succeeded */
"2:\n\t"
"stwcx. %0, 0, %2\n\t" /* clear reservation (74xx) */
"3:\n\t"
: "=&r" (val), "=m" (*addr)
: "r" (addr), "r" (old), "r" (new), "m" (*addr)
: "cc", "memory");
td->td_pcb->pcb_onfault = NULL;
return (val);
}