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

   1 /* Copyright (C) 2001 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by David Mosberger-Tang <davidm@hpl.hp.com>.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <libintl.h>
  21 #include <stdarg.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <ucontext.h>
  25 #include <sys/rse.h>
  26
  27
  28 struct fdesc
  29   {
  30     unsigned long ip;
  31     unsigned long gp;
  32   };
  33
  34 #define PUSH(val)                               \
  35 do {                                            \
  36   if (ia64_rse_is_rnat_slot (rbs))              \
  37     *rbs++ = 0;                                 \
  38   *rbs++ = (val);                               \
  39 } while (0)
  40
  41
  42 /* This implementation can handle an ARGC value of at most 8 and
  43    values can be passed only in integer registers (r32-r39).  */
  44
  45 void
  46 __makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
  47 {
  48   struct sigcontext *sc = &ucp->uc_mcontext;
  49   extern void __start_context (ucontext_t *link, long gp, ...);
  50   unsigned long stack_start, stack_end;
  51   va_list ap;
  52   long *rbs;
  53   int i;
  54
  55   stack_start = (long) sc->sc_stack.ss_sp;
  56   stack_end = (long) sc->sc_stack.ss_sp + sc->sc_stack.ss_size;
  57
  58   stack_start = (stack_start + 7) & -8;
  59   stack_end = stack_end & -16;
  60
  61   if (argc > 8)
  62     {
  63       fprintf (stderr, _("\
  64 makecontext: does not know how to handle more than 8 arguments\n"));
  65       exit (-1);
  66     }
  67
  68   /* set the entry point and global pointer: */
  69   sc->sc_br[0] = ((struct fdesc *) &__start_context)->ip;
  70   sc->sc_br[1] = ((struct fdesc *) func)->ip;
  71   sc->sc_gr[1] = ((struct fdesc *) func)->gp;
  72
  73   /* set up the call frame: */
  74   sc->sc_ar_pfs = ((sc->sc_ar_pfs & ~0x3fffffffffUL)
  75                    | (argc + 2) | ((argc + 2) << 7));
  76   rbs = (long *) stack_start;
  77   PUSH((long) ucp->uc_link);
  78   PUSH(((struct fdesc *) &__start_context)->gp);
  79   va_start (ap, argc);
  80   for (i = 0; i < argc; ++i)
  81     PUSH(va_arg (ap, long));
  82   va_end (ap);
  83
  84   /* set the memory and register stack pointers: */
  85   sc->sc_ar_bsp = (long) rbs;
  86   sc->sc_gr[12] = stack_end - 16;
  87
  88   /* clear the NaT bits for r1 and r12: */
  89   sc->sc_nat &= ~((1 << 1) | (1 << 12));
  90   sc->sc_ar_rnat = 0;
  91 }
  92
  93 weak_alias (__makecontext, makecontext)