67 lines
2.6 KiB
ArmAsm
67 lines
2.6 KiB
ArmAsm
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/* $NetBSD: __vfork14.S,v 1.5 2008/04/28 20:22:56 martin Exp $ */
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/*-
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* Copyright (c) 2001 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 Matt Fredette.
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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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#include <sys/errno.h>
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#include "SYS.h"
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ENTRY(__vfork14, 0)
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/*
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* NB: __vfork14 is a tricky syscall. We can't save
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* any values on the stack, because the stack will be
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* trashed by the child, leaving garbage for when the
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* parent returns.
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*
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* So we must save values in registers, specifically,
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* registers that the kernel is willing to preserve
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* across the syscall. Normally, this would be callee-
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* saved registers, with the kernel being the callee,
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* but the problem is that we, too, are a callee, and
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* would have to save that very same register somewhere,
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* because *our* caller is counting on us to do so.
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*
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* What we need is a normally caller-saved register,
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* that the kernel is willing to save for us. The
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* syscall entry code in locore.S has been modified
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* to do just this for the t4 register.
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*/
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.import __cerror, code
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copy %rp, %t4
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ldil L%SYSCALLGATE, %r1
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ble 4(%sr7, %r1)
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ldi SYS___vfork14, %t1
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comb,<> %r0, %t1, __cerror
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copy %t4, %rp
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addi -1, %ret1, %ret1
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bv %r0(%rp)
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and %ret0, %ret1, %ret0
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EXIT(__vfork14)
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