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/*
* Copyright (c) 2011-2015 Richard Braun.
* 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 ``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.
*
*
* Upstream site with license notes :
* http://git.sceen.net/rbraun/librbraun.git/
*/
#ifndef _CPU_H
#define _CPU_H
#include <sched.h>
#include "macros.h"
/*
* Maximum number of supported processors.
*/
#define NR_CPUS CONFIG_NR_CPUS
/*
* Filter invalid values.
*
* The maximum number of processors must be a power-of-two in order to avoid
* divisions.
*/
#if (NR_CPUS < 1) || !ISP2(NR_CPUS)
#error "invalid number of configured processors"
#endif
/*
* L1 cache line shift and size.
*/
#define CPU_L1_SHIFT CONFIG_CPU_L1_SHIFT
#define CPU_L1_SIZE (1 << CPU_L1_SHIFT)
/*
* Return the ID of the currently running CPU.
*
* This implementation uses a glibc-specific function that relies on a
* Linux-specific system call to obtain the CPU ID. If this function fails
* (e.g. when run in valgrind), 0 is returned.
*
* The returned CPU ID cannot be greater than the maximum number of supported
* processors.
*/
static inline int
cpu_id(void)
{
#if NR_CPUS == 1
return 0;
#else
int id;
id = sched_getcpu();
if (id == -1) {
return 0;
} else if (id >= NR_CPUS) {
id &= (NR_CPUS - 1);
}
return id;
#endif
}
#endif /* _CPU_H */
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