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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1988 AT&T */
/* All Rights Reserved */
#pragma weak _makecontext = makecontext
#pragma weak ___makecontext_v2 = __makecontext_v2
#include "lint.h"
#include <stdarg.h>
#include <strings.h>
/* Can't just use <ucontext.h> due to redefine_extname stuff. */
#include <sys/ucontext.h>
#include <sys/regset.h>
#include <sys/stack.h>
#include <sys/frame.h>
/*
* The ucontext_t that the user passes in must have been primed with a
* call to getcontext(2), have the uc_stack member set to reflect the
* stack which this context will use, and have the uc_link member set
* to the context which should be resumed when this context returns.
* When makecontext() returns, the ucontext_t will be set to run the
* given function with the given parameters on the stack specified by
* uc_stack, and which will return to the ucontext_t specified by uc_link.
*/
static void resumecontext(void);
void
makecontext(ucontext_t *ucp, void (*func)(), int argc, ...)
{
greg_t *reg;
long *tsp;
char *sp;
int argno;
va_list ap;
size_t size;
reg = ucp->uc_mcontext.gregs;
reg[REG_PC] = (greg_t)func;
reg[REG_nPC] = reg[REG_PC] + 0x4;
/*
* Reserve enough space for a frame and the arguments beyond the
* sixth; round to stack alignment.
*/
size = sizeof (struct frame);
size += (argc > 6 ? argc - 6 : 0) * sizeof (long);
/*
* The legacy implemenation of makecontext() on sparc has been to
* interpret the uc_stack.ss_sp member incorrectly as the top of the
* stack rather than the base. We preserve this behavior here, but
* provide the correct semantics in __makecontext_v2().
*/
sp = (char *)(((uintptr_t)ucp->uc_stack.ss_sp - size) &
~(STACK_ALIGN - 1));
/*
* Copy all args to the stack, and put the first 6 args into the
* ucontext_t. Zero the other fields of the frame.
*/
/* LINTED pointer cast may result in improper alignment */
tsp = &((struct frame *)sp)->fr_argd[0];
bzero(sp, sizeof (struct frame));
va_start(ap, argc);
for (argno = 0; argno < argc; argno++) {
if (argno < 6)
*tsp++ = reg[REG_O0 + argno] = va_arg(ap, long);
else
*tsp++ = va_arg(ap, long);
}
va_end(ap);
reg[REG_SP] = (greg_t)sp - STACK_BIAS; /* sp (when done) */
reg[REG_O7] = (greg_t)resumecontext - 8; /* return pc */
}
void
__makecontext_v2(ucontext_t *ucp, void (*func)(), int argc, ...)
{
greg_t *reg;
long *tsp;
char *sp;
int argno;
va_list ap;
size_t size;
reg = ucp->uc_mcontext.gregs;
reg[REG_PC] = (greg_t)func;
reg[REG_nPC] = reg[REG_PC] + 0x4;
/*
* Reserve enough space for a frame and the arguments beyond the
* sixth; round to stack alignment.
*/
size = sizeof (struct frame);
size += (argc > 6 ? argc - 6 : 0) * sizeof (long);
sp = (char *)(((uintptr_t)ucp->uc_stack.ss_sp +
ucp->uc_stack.ss_size - size) & ~(STACK_ALIGN - 1));
/*
* Copy all args to the stack, and put the first 6 args into the
* ucontext_t. Zero the other fields of the frame.
*/
/* LINTED pointer cast may result in improper alignment */
tsp = &((struct frame *)sp)->fr_argd[0];
bzero(sp, sizeof (struct frame));
va_start(ap, argc);
for (argno = 0; argno < argc; argno++) {
if (argno < 6)
*tsp++ = reg[REG_O0 + argno] = va_arg(ap, long);
else
*tsp++ = va_arg(ap, long);
}
va_end(ap);
reg[REG_SP] = (greg_t)sp - STACK_BIAS; /* sp (when done) */
reg[REG_O7] = (greg_t)resumecontext - 8; /* return pc */
}
static void
resumecontext(void)
{
/*
* We can't include ucontext.h (where these functions are defined)
* because it remaps the symbol makecontext.
*/
extern int getcontext(ucontext_t *);
extern int setcontext(const ucontext_t *);
ucontext_t uc;
(void) getcontext(&uc);
(void) setcontext(uc.uc_link);
}
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