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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2004 Suleiman Souhlal
* All rights reserved.
*
* 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 AUTHOR 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 AUTHOR 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("$FreeBSD$");
#include <sys/param.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 *ucp);
void _ctx_start(void);
void
_ctx_done(ucontext_t *ucp)
{
if (ucp->uc_link == NULL)
exit(0);
else {
/* invalidate context */
ucp->uc_mcontext.mc_len = 0;
setcontext((const ucontext_t *)ucp->uc_link);
abort(); /* should never return from above call */
}
}
void
__makecontext(ucontext_t *ucp, void (*start)(void), int argc, ...)
{
mcontext_t *mc;
char *sp;
va_list ap;
int i, regargs, stackargs;
/* Sanity checks */
if ((ucp == NULL) || (argc < 0)
|| (ucp->uc_stack.ss_sp == NULL)
|| (ucp->uc_stack.ss_size < MINSIGSTKSZ)) {
/* invalidate context */
ucp->uc_mcontext.mc_len = 0;
return;
}
/*
* The stack must have space for the frame pointer, saved
* link register, overflow arguments, and be 16-byte
* aligned.
*/
stackargs = (argc > 8) ? argc - 8 : 0;
sp = (char *) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size
- sizeof(uint32_t)*(stackargs + 2);
sp = (char *)((uint32_t)sp & ~0x1f);
mc = &ucp->uc_mcontext;
/*
* Up to 8 register args. Assumes all args are 32-bit and
* integer only. Not sure how to cater for floating point,
* although 64-bit args will work if aligned correctly
* in the arg list.
*/
regargs = (argc > 8) ? 8 : argc;
va_start(ap, argc);
for (i = 0; i < regargs; i++)
mc->mc_gpr[3 + i] = va_arg(ap, uint32_t);
/*
* Overflow args go onto the stack
*/
if (argc > 8) {
uint32_t *argp;
/* Skip past frame pointer and saved LR */
argp = (uint32_t *)sp + 2;
for (i = 0; i < stackargs; i++)
*argp++ = va_arg(ap, uint32_t);
}
va_end(ap);
/*
* Use caller-saved regs 14/15 to hold params that _ctx_start
* will use to invoke the user-supplied func
*/
mc->mc_srr0 = (uint32_t) _ctx_start;
mc->mc_gpr[1] = (uint32_t) sp; /* new stack pointer */
mc->mc_gpr[14] = (uint32_t) start; /* r14 <- start */
mc->mc_gpr[15] = (uint32_t) ucp; /* r15 <- ucp */
}
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