freebsd-skq/lib/libc/aarch64/gen/makecontext.c
andrew 87fffd8ba1 Add support for makecontext. This supports up to 8 arguments as this
simplifies the code, these can be passed in registers.

Obtained from:	ABT Systems Ltd
Sponsored by:	The FreeBSD Foundation
2015-07-10 08:36:22 +00:00

87 lines
2.6 KiB
C

/*-
* Copyright (c) 2015 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Andrew Turner under
* sponsorship from the FreeBSD Foundation.
*
* 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 <machine/armreg.h>
#include <inttypes.h>
#include <stdarg.h>
#include <stdlib.h>
#include <ucontext.h>
void _ctx_start(void);
void
ctx_done(ucontext_t *ucp)
{
if (ucp->uc_link == NULL) {
exit(0);
} else {
setcontext((const ucontext_t *)ucp->uc_link);
abort();
}
}
__weak_reference(__makecontext, makecontext);
void
__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
{
struct gpregs *gp;
va_list ap;
int i;
/* A valid context is required. */
if (ucp == NULL)
return;
if ((argc < 0) || (argc > 8))
return;
gp = &ucp->uc_mcontext.mc_gpregs;
va_start(ap, argc);
/* Pass up to eight arguments in x0-7. */
for (i = 0; i < argc && i < 8; i++)
gp->gp_x[i] = va_arg(ap, uint64_t);
va_end(ap);
/* Set the stack */
gp->gp_sp = STACKALIGN(ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
/* Arrange for return via the trampoline code. */
gp->gp_elr = (__register_t)_ctx_start;
gp->gp_x[19] = (__register_t)func;
gp->gp_x[20] = (__register_t)ucp;
}