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/* $NetBSD: makecontext.c,v 1.5 2009/12/14 01:07:42 matt Exp $ */
/*-
* Copyright (c) 2001 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Klaus Klein.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: makecontext.c,v 1.5 2009/12/14 01:07:42 matt Exp $");
#endif
#include <sys/param.h>
#include <machine/regnum.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <ucontext.h>
__weak_reference(__makecontext, makecontext);
void _ctx_done(ucontext_t *);
void _ctx_start(void);
void
__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
{
mcontext_t *mc;
register_t *sp;
int i;
va_list ap;
/*
* XXX/juli
* We need an mc_len or mc_flags like other architectures
* so that we can mark a context as invalid. Store it in
* mc->mc_regs[ZERO] perhaps?
*/
if (argc < 0 || argc > 6 || ucp == NULL ||
ucp->uc_stack.ss_sp == NULL ||
ucp->uc_stack.ss_size < MINSIGSTKSZ)
return;
mc = &ucp->uc_mcontext;
sp = (register_t *)
((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
#if defined(__mips_o32) || defined(__mips_o64)
sp -= (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */
sp = (register_t *)
((uintptr_t)sp & ~0x7); /* Align on double-word boundary. */
#elif defined(__mips_n32) || defined(__mips_n64)
sp -= (argc > 8 ? argc - 8 : 0); /* Make room for > 8 arguments. */
sp = (register_t *)
((uintptr_t)sp & ~0xf); /* Align on quad-word boundary. */
#endif
mc->mc_regs[SP] = (intptr_t)sp;
mc->mc_regs[S0] = (intptr_t)ucp;
mc->mc_regs[T9] = (intptr_t)func;
mc->mc_pc = (intptr_t)_ctx_start;
/* Construct argument list. */
va_start(ap, argc);
#if defined(__mips_o32) || defined(__mips_o64)
/* Up to the first four arguments are passed in $a0-3. */
for (i = 0; i < argc && i < 4; i++)
/* LINTED register_t is safe */
mc->mc_regs[A0 + i] = va_arg(ap, register_t);
/* Pass remaining arguments on the stack above the $a0-3 gap. */
sp += i;
#endif
#if defined(__mips_n32) || defined(__mips_n64)
/* Up to the first 8 arguments are passed in $a0-7. */
for (i = 0; i < argc && i < 8; i++)
/* LINTED register_t is safe */
mc->mc_regs[A0 + i] = va_arg(ap, register_t);
/* Pass remaining arguments on the stack above the $a0-3 gap. */
#endif
/* Pass remaining arguments on the stack above the $a0-3 gap. */
for (; i < argc; i++)
/* LINTED uintptr_t is safe */
*sp++ = va_arg(ap, register_t);
va_end(ap);
}
void
_ctx_done(ucontext_t *ucp)
{
if (ucp->uc_link == NULL)
exit(0);
else {
setcontext((const ucontext_t *)ucp->uc_link);
abort();
}
}
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