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2001-07-06 Paul Eggert <eggert@twinsun.com> * manual/argp.texi: Remove ignored LGPL copyright notice; it's not appropriate for documentation anyway. * manual/libc-texinfo.sh: "Library General Public License" -> "Lesser General Public License". 2001-07-06 Andreas Jaeger <aj@suse.de> * All files under GPL/LGPL version 2: Place under LGPL version 2.1.
101 lines
3.2 KiB
C
101 lines
3.2 KiB
C
/* Copyright (C) 2001 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <libintl.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <ucontext.h>
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/* This implementation can handle any ARGC value but only
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normal integer type parameters. Parameters of type float,
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double, complex and structure with sizes 0, 2, 4 or 8
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won't work.
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makecontext sets up a stack and the registers for the
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user context. The stack looks like this:
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size offset
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%r15 -> +-----------------------+
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8 | back chain (zero) | 0
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8 | reserved | 8
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144 | save area for (*func) | 16
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+-----------------------+
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n | overflow parameters | 160
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+-----------------------+
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8 | trampoline | 160+n
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+-----------------------+
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The registers are set up like this:
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%r2-%r6: parameters 1 to 5
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%r7 : (*func) pointer
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%r8 : uc_link from ucontext structure
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%r9 : address of setcontext
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%r14 : return address to uc_link trampoline
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%r15 : stack pointer.
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The trampoline looks like this:
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basr %r14,%r7
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lgr %r2,%r8
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br %r9. */
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void
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__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
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{
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unsigned long *sp;
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va_list ap;
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int i;
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sp = (long *) (((long) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size) & -8L);
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/* Setup the trampoline. */
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*--sp = 0x0de7b904002807f9;
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/* Set the return address to trampoline. */
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ucp->uc_mcontext.gregs[14] = (long) sp;
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/* Set register parameters. */
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va_start (ap, argc);
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for (i = 0; (i < argc) && (i < 5); i++)
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ucp->uc_mcontext.gregs[2+i] = va_arg (ap, long);
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/* The remaining arguments go to the overflow area. */
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if (argc > 5) {
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sp -= argc - 5;
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for (i = 5; i < argc; i++)
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sp[i] = va_arg(ap, long);
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}
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va_end (ap);
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/* Make room for the save area and set the backchain. */
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sp -= 20;
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*sp = 0;
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/* Pass (*func) to __start_context in %r7. */
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ucp->uc_mcontext.gregs[7] = (long) func;
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/* Pass ucp->uc_link to __start_context in %r8. */
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ucp->uc_mcontext.gregs[8] = (long) ucp->uc_link;
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/* Pass address of setcontext in %r9. */
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ucp->uc_mcontext.gregs[9] = (long) &setcontext;
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/* Set stack pointer. */
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ucp->uc_mcontext.gregs[15] = (long) sp;
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}
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weak_alias (__makecontext, makecontext)
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