108 lines
3.4 KiB
Groff
108 lines
3.4 KiB
Groff
.\" $NetBSD: curproc.9,v 1.6 2022/09/22 14:02:24 riastradh Exp $
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.\"
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.\" Copyright (c) 2002 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Gregory McGarry.
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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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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd July 1, 2010
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.Dt CURPROC 9
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.Os
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.Sh NAME
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.Nm curproc ,
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.Nm curcpu ,
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.Nm curlwp
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.Nd current process, processor, and
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.Tn LWP
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.Sh SYNOPSIS
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.In sys/proc.h
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.Ft struct cpu_info *
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.Fn curcpu "void"
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.Vt struct proc *curproc ;
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.Vt struct lwp *curlwp ;
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.Sh DESCRIPTION
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The following macros retrieve
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the current CPU, process, and thread
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.Pq lightweight process, or Tn LWP ,
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respectively:
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.Bl -tag -width Dv
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.It Fn curcpu
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Returns a pointer to the
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.Vt "struct cpu_info"
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structure representing the CPU that the code calling it is running on.
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.Pp
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The value of
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.Fn curcpu
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is unstable and may be stale as soon as it is read unless the caller
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prevents preemption by raising the IPL
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.Pq Xr spl 9 , Xr mutex 9 ,
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by disabling preemption
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.Pq Xr kpreempt_disable 9 ,
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or by binding the thread to its CPU
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.Pq Xr curlwp_bind 9 .
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.It Dv curproc
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Yields a pointer to the
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.Vt "struct proc"
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structure representing the currently running process.
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.Pp
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The value of
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.Dv curproc
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is stable and does not change during execution except in
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machine-dependent logic to perform context switches, so it works like a
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global constant, not like a stateful procedure.
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.It Dv curlwp
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Yields a pointer to the
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.Vt "struct lwp"
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structure representing the currently running thread.
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.Pp
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The value of
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.Dv curlwp
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is stable and does not change during execution except in
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machine-dependent logic to perform context switches, so it works like a
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global constant, not like a stateful procedure.
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.El
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.Sh SOURCE REFERENCES
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The
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.Fn curcpu
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macro is defined in the machine-independent
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.Pa machine/cpu.h .
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.Pp
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The
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.Dv curproc
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macro is defined in
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.Pa sys/lwp.h .
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.Pp
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The
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.Dv curlwp
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macro has a machine-independent definition in
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.Pa sys/lwp.h ,
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but it may be overridden by
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.Pa machine/cpu.h ,
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and must be overridden on architectures supporting multiprocessing and
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kernel preemption.
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.Sh SEE ALSO
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.Xr cpu_number 9 ,
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.Xr proc_find 9
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