glibc/sysdeps/unix/sysv/linux/ia64/makecontext.c

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/* Copyright (C) 2001-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by David Mosberger-Tang <davidm@hpl.hp.com>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <libintl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <ucontext.h>
#include <sys/rse.h>
#include <link.h>
#include <dl-fptr.h>
#define PUSH(val) \
do { \
if (ia64_rse_is_rnat_slot (rbs)) \
*rbs++ = 0; \
*rbs++ = (val); \
} while (0)
/* This implementation can handle an ARGC value of at most 8 and
values can be passed only in integer registers (r32-r39). */
void
__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
{
struct sigcontext *sc = &ucp->uc_mcontext;
extern void __start_context (ucontext_t *link, long gp, ...);
unsigned long stack_start, stack_end;
va_list ap;
unsigned long *rbs;
int i;
stack_start = (long) sc->sc_stack.ss_sp;
stack_end = (long) sc->sc_stack.ss_sp + sc->sc_stack.ss_size;
stack_start = (stack_start + 7) & -8;
stack_end = stack_end & -16;
if (argc > 8)
{
fprintf (stderr, _("\
makecontext: does not know how to handle more than 8 arguments\n"));
exit (-1);
}
/* set the entry point and global pointer: */
sc->sc_br[0] = ELF_PTR_TO_FDESC (&__start_context)->ip;
sc->sc_br[1] = ELF_PTR_TO_FDESC (func)->ip;
sc->sc_gr[1] = ELF_PTR_TO_FDESC (func)->gp;
/* set up the call frame: */
sc->sc_ar_pfs = ((sc->sc_ar_pfs & ~0x3fffffffffUL)
| (argc + 2) | ((argc + 2) << 7));
rbs = (unsigned long *) stack_start;
PUSH((long) ucp->uc_link);
PUSH(ELF_PTR_TO_FDESC (&__start_context)->gp);
va_start (ap, argc);
for (i = 0; i < argc; ++i)
PUSH(va_arg (ap, long));
va_end (ap);
/* set the memory and register stack pointers: */
sc->sc_ar_bsp = (long) rbs;
sc->sc_gr[12] = stack_end - 16;
/* clear the NaT bits for r1 and r12: */
sc->sc_nat &= ~((1 << 1) | (1 << 12));
sc->sc_ar_rnat = 0;
}
weak_alias (__makecontext, makecontext)