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freebsd/sys/powerpc/include/critical.h
Peter Grehan e796443d47 Remove race condition between reading of MSR, setting md_savecrit,
and setting MSR. This was most evident with the idle proc running
with interrupts disabled and causing a lockup. Switch over to the
i386 style which does things in the right order.

debug assisted by:  gallatin, and the invaluable KTR option.
2004-08-03 04:14:55 +00:00

91 lines
2.7 KiB
C

/*-
* Copyright (c) 2002 Matthew Dillon. 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* This file contains prototypes and high-level inlines related to
* machine-level critical function support:
*
* cpu_critical_enter() - inlined
* cpu_critical_exit() - inlined
* cpu_critical_fork_exit() - prototyped
* related support functions residing
* in <arch>/<arch>/critical.c - prototyped
*
* $FreeBSD$
*/
#ifndef _MACHINE_CRITICAL_H_
#define _MACHINE_CRITICAL_H_
__BEGIN_DECLS
/*
* Prototypes - see <arch>/<arch>/critical.c
*/
void cpu_critical_fork_exit(void);
#ifdef __GNUC__
/*
* cpu_critical_enter:
*
* This routine is called from critical_enter() on the 0->1 transition
* of td_critnest, prior to it being incremented to 1.
*/
static __inline void
cpu_critical_enter(struct thread *td)
{
td->td_md.md_savecrit = intr_disable();
}
/*
* cpu_critical_exit:
*
* This routine is called from critical_exit() on a 1->0 transition
* of td_critnest, after it has been decremented to 0. We are
* exiting the last critical section.
*/
static __inline void
cpu_critical_exit(struct thread *td)
{
intr_restore(td->td_md.md_savecrit);
}
#else /* !__GNUC__ */
void cpu_critical_enter(struct thread *td);
void cpu_critical_exit(struct thread *td);
#endif /* __GNUC__ */
__END_DECLS
#endif /* !_MACHINE_CRITICAL_H_ */