80 lines
2.6 KiB
ArmAsm
80 lines
2.6 KiB
ArmAsm
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/* $NetBSD: resumecontext.S,v 1.4 2008/04/28 20:22:58 martin Exp $ */
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/*-
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* Copyright (c) 1999 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 Klaus Klein.
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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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* Modified for x86-64 by fvdl@wasabisystems.com
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*/
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#include <machine/asm.h>
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#include "SYS.h"
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#if defined(LIBC_SCCS) && !defined(lint)
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RCSID("$NetBSD: resumecontext.S,v 1.4 2008/04/28 20:22:58 martin Exp $")
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#endif /* LIBC_SCCS && !lint */
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/*
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* This assembly-language implementation differs from the (obvious)
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* C-language implementation only in not clobbering the previous
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* function's return address (us), which is the point of the exercise.
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*/
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NENTRY(_resumecontext) /* profiling prologue would clobber TOS */
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leaq -(8 + 784)(%rsp),%rdi /* retaddr + sizeof (ucontext_t) */
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andq $~15,%rdi /* align on _UC_UCONTEXT_ALIGN */
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movq %rdi,%rsp
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#ifdef PIC
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call PIC_PLT(_C_LABEL(_getcontext))
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#else
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call _C_LABEL(_getcontext)
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#endif
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movq 8(%rsp),%rdi /* uc_link */
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testq %rdi,%rdi /* link end? */
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jnz 9f
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/* normal exit */
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#ifdef PIC
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call PIC_PLT(_C_LABEL(exit))
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#else
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call _C_LABEL(exit)
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#endif
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9:
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#ifdef PIC
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call PIC_PLT(_C_LABEL(setcontext))
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#else
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call _C_LABEL(setcontext)
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#endif
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/* NOTREACHED */
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/* something is wrong, pull the brake */
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movq $-1,%rdi
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movq $SYS_exit,%rax
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syscall
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/* NOTREACHED */
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