1/* Copyright (C) 2001-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <libintl.h>
19#include <stdarg.h>
20#include <stdio.h>
21#include <stdlib.h>
22#include <ucontext.h>
23#include <sys/rse.h>
24#include <link.h>
25#include <dl-fptr.h>
26
27
28#define PUSH(val) \
29do { \
30 if (ia64_rse_is_rnat_slot (rbs)) \
31 *rbs++ = 0; \
32 *rbs++ = (val); \
33} while (0)
34
35
36/* This implementation can handle an ARGC value of at most 8 and
37 values can be passed only in integer registers (r32-r39). */
38
39void
40__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
41{
42 mcontext_t *sc = &ucp->uc_mcontext;
43 extern void __start_context (ucontext_t *link, long gp, ...);
44 unsigned long stack_start, stack_end;
45 va_list ap;
46 unsigned long *rbs;
47 int i;
48
49 stack_start = (long) sc->sc_stack.ss_sp;
50 stack_end = (long) sc->sc_stack.ss_sp + sc->sc_stack.ss_size;
51
52 stack_start = (stack_start + 7) & -8;
53 stack_end = stack_end & -16;
54
55 if (argc > 8)
56 {
57 fprintf (stderr, _("\
58makecontext: does not know how to handle more than 8 arguments\n"));
59 exit (-1);
60 }
61
62 /* set the entry point and global pointer: */
63 sc->sc_br[0] = ELF_PTR_TO_FDESC (&__start_context)->ip;
64 sc->sc_br[1] = ELF_PTR_TO_FDESC (func)->ip;
65 sc->sc_gr[1] = ELF_PTR_TO_FDESC (func)->gp;
66
67 /* set up the call frame: */
68 sc->sc_ar_pfs = ((sc->sc_ar_pfs & ~0x3fffffffffUL)
69 | (argc + 2) | ((argc + 2) << 7));
70 rbs = (unsigned long *) stack_start;
71 PUSH((long) ucp->uc_link);
72 PUSH(ELF_PTR_TO_FDESC (&__start_context)->gp);
73 va_start (ap, argc);
74 for (i = 0; i < argc; ++i)
75 PUSH(va_arg (ap, long));
76 va_end (ap);
77
78 /* set the memory and register stack pointers: */
79 sc->sc_ar_bsp = (long) rbs;
80 sc->sc_gr[12] = stack_end - 16;
81
82 /* clear the NaT bits for r1 and r12: */
83 sc->sc_nat &= ~((1 << 1) | (1 << 12));
84 sc->sc_ar_rnat = 0;
85}
86
87weak_alias (__makecontext, makecontext)
88

source code of glibc/sysdeps/unix/sysv/linux/ia64/makecontext.c