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Add a lockless uniprocessor version of atomic_cas_generic.c, which

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is currently used by all the archs that previously used cas_generic.
This commit is contained in:
pooka 2010-11-21 21:46:43 +00:00
parent d0e5481abd
commit 566f7922d9
2 changed files with 65 additions and 3 deletions
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8
sys/rump/librump/rumpkern/Makefile.rumpkern
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@ -1,4 +1,4 @@
# $NetBSD: Makefile.rumpkern,v 1.99 2010/11/21 17:34:11 pooka Exp $
# $NetBSD: Makefile.rumpkern,v 1.100 2010/11/21 21:46:43 pooka Exp $
#
.include "${RUMPTOP}/Makefile.rump"
@ -167,13 +167,15 @@ KERNMISCCPPFLAGS+= -D_RUMPKERNEL
# Some architectures require a little special massage with atomic
# compare-and-swap. This is because the kernel version is using
# instructions or routines unavailable to us in userspace. We
# use effectively the multiprocessor version of the userspace ops.
# use a very simple CAS routine which (correctly) assumes non-SMP
# and no preemption. If some of these archs later develop MP
# support, switch them to use atomic_cas_generic.c
#
.if ${MACHINE_CPU} == "arm" || ${MACHINE_CPU} == "hppa" \
|| ${MACHINE_CPU} == "mips" || ${MACHINE_CPU} == "sh3" \
|| ${MACHINE_CPU} == "vax" || ${MACHINE_ARCH} == "m68000"
CPPFLAGS+= -I${RUMPTOP}/../../common/lib/libc/atomic
SRCS+= atomic_cas_generic.c
SRCS+= atomic_cas_up.c
.endif
.include <bsd.lib.mk>

60
sys/rump/librump/rumpkern/atomic_cas_up.c Normal file
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@ -0,0 +1,60 @@
/* $NetBSD: atomic_cas_up.c,v 1.1 2010/11/21 21:46:43 pooka Exp $ */
/*-
* Copyright (c) 2010 Antti Kantee. 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 THE AUTHOR 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 AUTHOR 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>
__KERNEL_RCSID(0, "$NetBSD: atomic_cas_up.c,v 1.1 2010/11/21 21:46:43 pooka Exp $");
/*
* Uniprocessor version of atomic CAS. Since there is no preemption
* in rump, this is a piece of cake.
*/
#include <sys/types.h>
uint32_t rumpup_cas_32_up(volatile uint32_t *ptr, uint32_t, uint32_t);
uint32_t
rumpup_cas_32_up(volatile uint32_t *ptr, uint32_t old, uint32_t new)
{
uint32_t ret;
ret = *ptr;
if (__predict_true(ret == old)) {
*ptr = new;
}
return ret;
}
__strong_alias(atomic_cas_32,rumpup_cas_32_up)
__strong_alias(atomic_cas_uint,rumpup_cas_32_up)
__strong_alias(atomic_cas_ulong,rumpup_cas_32_up)
__strong_alias(atomic_cas_ptr,rumpup_cas_32_up)
__strong_alias(atomic_cas_32_ni,rumpup_cas_32_up)
__strong_alias(atomic_cas_uint_ni,rumpup_cas_32_up)
__strong_alias(atomic_cas_ulong_ni,rumpup_cas_32_up)
__strong_alias(atomic_cas_ptr_ni,rumpup_cas_32_up)