freebsd-skq/sys/amd64/include/counter.h
nwhitehorn 89d01c24d1 Replace a number of conflations of mp_ncpus and mp_maxid with either
mp_maxid or CPU_FOREACH() as appropriate. This fixes a number of places in
the kernel that assumed CPU IDs are dense in [0, mp_ncpus) and would try,
for example, to run tasks on CPUs that did not exist or to allocate too
few buffers on systems with sparse CPU IDs in which there are holes in the
range and mp_maxid > mp_ncpus. Such circumstances generally occur on
systems with SMT, but on which SMT is disabled. This patch restores system
operation at least on POWER8 systems configured in this way.

There are a number of other places in the kernel with potential problems
in these situations, but where sparse CPU IDs are not currently known
to occur, mostly in the ARM machine-dependent code. These will be fixed
in a follow-up commit after the stable/11 branch.

PR:		kern/210106
Reviewed by:	jhb
Approved by:	re (glebius)
2016-07-06 14:09:49 +00:00

90 lines
2.5 KiB
C

/*-
* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
* 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 THE 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.
*
* $FreeBSD$
*/
#ifndef __MACHINE_COUNTER_H__
#define __MACHINE_COUNTER_H__
#include <sys/pcpu.h>
extern struct pcpu __pcpu[1];
#define counter_enter() do {} while (0)
#define counter_exit() do {} while (0)
#ifdef IN_SUBR_COUNTER_C
static inline uint64_t
counter_u64_read_one(uint64_t *p, int cpu)
{
return (*(uint64_t *)((char *)p + sizeof(struct pcpu) * cpu));
}
static inline uint64_t
counter_u64_fetch_inline(uint64_t *p)
{
uint64_t r;
int i;
r = 0;
CPU_FOREACH(i)
r += counter_u64_read_one((uint64_t *)p, i);
return (r);
}
static void
counter_u64_zero_one_cpu(void *arg)
{
*((uint64_t *)((char *)arg + sizeof(struct pcpu) *
PCPU_GET(cpuid))) = 0;
}
static inline void
counter_u64_zero_inline(counter_u64_t c)
{
smp_rendezvous(smp_no_rendevous_barrier, counter_u64_zero_one_cpu,
smp_no_rendevous_barrier, c);
}
#endif
#define counter_u64_add_protected(c, i) counter_u64_add(c, i)
static inline void
counter_u64_add(counter_u64_t c, int64_t inc)
{
__asm __volatile("addq\t%1,%%gs:(%0)"
:
: "r" ((char *)c - (char *)&__pcpu[0]), "ri" (inc)
: "memory", "cc");
}
#endif /* ! __MACHINE_COUNTER_H__ */