Add two new routines to libkvm for working with per-CPU data:
kvm_getmaxcpu() and kvm_getpcpu(). MFC after: 1 week
This commit is contained in:
John Baldwin
parent
70d12a18f2
commit
794a9a6c96
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=181876
@ -10,15 +10,16 @@ CFLAGS+=-DSUN4V
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.endif
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SRCS= kvm.c kvm_${MACHINE_ARCH}.c kvm_file.c kvm_getloadavg.c \
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kvm_getswapinfo.c kvm_proc.c
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kvm_getswapinfo.c kvm_pcpu.c kvm_proc.c
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.if ${MACHINE_ARCH} == "amd64" || ${MACHINE_ARCH} == "i386"
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SRCS+= kvm_minidump_${MACHINE_ARCH}.c
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.endif
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INCS= kvm.h
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MAN= kvm.3 kvm_geterr.3 kvm_getfiles.3 kvm_getloadavg.3 kvm_getprocs.3 \
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kvm_getswapinfo.3 kvm_nlist.3 kvm_open.3 kvm_read.3
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MAN= kvm.3 kvm_geterr.3 kvm_getfiles.3 kvm_getloadavg.3 kvm_getpcpu.3 \
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kvm_getprocs.3 kvm_getswapinfo.3 kvm_nlist.3 kvm_open.3
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MLINKS+=kvm_getpcpu.3 kvm_getmaxcpu.3
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MLINKS+=kvm_getprocs.3 kvm_getargv.3 kvm_getprocs.3 kvm_getenvv.3
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MLINKS+=kvm_open.3 kvm_close.3 kvm_open.3 kvm_openfiles.3
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MLINKS+=kvm_read.3 kvm_write.3
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@ -74,6 +74,8 @@ char **kvm_getenvv(kvm_t *, const struct kinfo_proc *, int);
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char *kvm_geterr(kvm_t *);
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char *kvm_getfiles(kvm_t *, int, int, int *);
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int kvm_getloadavg(kvm_t *, double [], int);
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int kvm_getmaxcpu(kvm_t *);
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void *kvm_getpcpu(kvm_t *, int);
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struct kinfo_proc *
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kvm_getprocs(kvm_t *, int, int, int *);
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int kvm_getswapinfo(kvm_t *, struct kvm_swap *, int, int);
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93
lib/libkvm/kvm_getpcpu.3
Normal file
93
lib/libkvm/kvm_getpcpu.3
Normal file
@ -0,0 +1,93 @@
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.\" Copyright (c) 2008 Yahoo!, Inc.
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.\" All rights reserved.
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.\" Written by: John Baldwin <jhb@FreeBSD.org>
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the author nor the names of any co-contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd August 19, 2008
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.Dt KVM_GETPCPU 3
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.Os
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.Sh NAME
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.Nm kvm_getmaxcpu ,
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.Nm kvm_getpcpu
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.Nd access per-CPU data
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.Sh LIBRARY
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.Lb libkvm
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/pcpu.h
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.In sys/sysctl.h
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.In kvm.h
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.Ft int
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.Fn kvm_getmaxcpu "kvm_t *kd"
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.Ft void *
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.Fn kvm_getpcpu "kvm_t *kd" "int cpu"
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.Sh DESCRIPTION
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The
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.Fn kvm_getmaxcpu
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and
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.Fn kvm_getpcpu
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functions are used to access the per-CPU data of active processors in the
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kernel indicated by
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.Fa kd .
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The
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.Fn kvm_getmaxcpu
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function returns the maximum number of CPUs supported by the kernel.
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The
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.Fn kvm_getpcpu
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function returns a buffer holding the per-CPU data for a single CPU.
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This buffer is described by the
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.Vt "struct pcpu"
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type.
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The caller is responsible for releasing the buffer via a call to
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.Xr free 3
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when it is no longer needed.
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If
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.Fa cpu
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is not active, then
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.Dv NULL
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is returned instead.
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.Sh RETURN VALUES
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On success, the
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.Fn kvm_getmaxcpu
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function returns the maximum number of CPUs supported by the kernel.
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If an error occurs,
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it returns -1 instead.
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.Pp
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On success, the
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.Fn kvm_getpcpu
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function returns a pointer to an allocated buffer or
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.Dv NULL.
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If an error occurs,
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it returns -1 instead.
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.Pp
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If either function encounters an error,
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then an error message may be retrieved via
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.Xr kvm_geterr 3.
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.Sh SEE ALSO
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.Xr free 3 ,
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.Xr kvm 3
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152
lib/libkvm/kvm_pcpu.c
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152
lib/libkvm/kvm_pcpu.c
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@ -0,0 +1,152 @@
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/*-
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* Copyright (c) 2008 Yahoo!, Inc.
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* All rights reserved.
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* Written by: John Baldwin <jhb@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/pcpu.h>
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#include <sys/sysctl.h>
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#include <kvm.h>
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#include <limits.h>
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#include <stdlib.h>
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#include "kvm_private.h"
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static struct nlist kvm_pcpu_nl[] = {
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{ "_cpuid_to_pcpu" },
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{ "_mp_maxcpus" },
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{ NULL },
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};
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/*
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* Kernel per-CPU data state. We cache this stuff on the first
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* access.
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*/
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static void **pcpu_data;
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static int maxcpu;
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#define NL_CPUID_TO_PCPU 0
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#define NL_MP_MAXCPUS 1
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static int
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_kvm_pcpu_init(kvm_t *kd)
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{
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size_t len;
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int max;
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void *data;
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if (kvm_nlist(kd, kvm_pcpu_nl) < 0)
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return (-1);
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if (kvm_pcpu_nl[NL_CPUID_TO_PCPU].n_value == 0) {
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_kvm_err(kd, kd->program, "unable to find cpuid_to_pcpu");
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return (-1);
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}
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if (kvm_pcpu_nl[NL_MP_MAXCPUS].n_value == 0) {
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_kvm_err(kd, kd->program, "unable to find mp_maxcpus");
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return (-1);
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}
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if (kvm_read(kd, kvm_pcpu_nl[NL_MP_MAXCPUS].n_value, &max,
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sizeof(max)) != sizeof(max)) {
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_kvm_err(kd, kd->program, "cannot read mp_maxcpus");
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return (-1);
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}
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len = max * sizeof(void *);
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data = malloc(len);
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if (data == NULL) {
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_kvm_err(kd, kd->program, "out of memory");
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return (-1);
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}
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if (kvm_read(kd, kvm_pcpu_nl[NL_CPUID_TO_PCPU].n_value, data, len) !=
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len) {
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_kvm_err(kd, kd->program, "cannot read cpuid_to_pcpu array");
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free(data);
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return (-1);
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}
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pcpu_data = data;
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maxcpu = max;
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return (0);
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}
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static void
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_kvm_pcpu_clear(void)
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{
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maxcpu = 0;
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free(pcpu_data);
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pcpu_data = NULL;
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}
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void *
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kvm_getpcpu(kvm_t *kd, int cpu)
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{
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char *buf;
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int i;
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if (kd == NULL) {
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_kvm_pcpu_clear();
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return (NULL);
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}
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if (maxcpu == 0)
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if (_kvm_pcpu_init(kd) < 0)
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return ((void *)-1);
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if (cpu >= maxcpu || pcpu_data[cpu] == NULL)
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return (NULL);
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buf = malloc(sizeof(struct pcpu));
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if (buf == NULL) {
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_kvm_err(kd, kd->program, "out of memory");
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return ((void *)-1);
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}
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if (kvm_read(kd, (uintptr_t)pcpu_data[cpu], buf, sizeof(struct pcpu)) !=
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sizeof(struct pcpu)) {
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_kvm_err(kd, kd->program, "unable to read per-CPU data");
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free(buf);
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return ((void *)-1);
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}
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return (buf);
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}
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int
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kvm_getmaxcpu(kvm_t *kd)
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{
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if (kd == NULL) {
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_kvm_pcpu_clear();
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return (0);
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}
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if (maxcpu == 0)
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if (_kvm_pcpu_init(kd) < 0)
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return (-1);
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return (maxcpu);
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}
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