glibc/sysdeps/mach/hurd/mips/trampoline.c

85 lines
2.7 KiB
C

/* Set thread_state for sighandler, and sigcontext to recover. MIPS version.
Copyright (C) 1994 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <hurd/signal.h>
#include <mach/thread_status.h>
static void
trampoline (void (*handler) (int signo, int sigcode, struct sigcontext *scp),
int signo, int sigcode, struct sigcontext *scp)
{
(*handler) (signo, sigcode, scp);
(void) __sigreturn (scp); /* Does not return. */
while (1)
LOSE; /* Firewall. */
}
struct sigcontext *
_hurd_setup_sighandler (int flags,
__sighandler_t handler,
struct sigaltstack *sigaltstack,
int signo, int sigcode,
void *state)
{
struct mips_thread_state *ts;
void *sigsp;
struct sigcontext *scp;
ts = state;
if ((flags & SA_ONSTACK) &&
!(sigaltstack->ss_flags & (SA_DISABLE|SA_ONSTACK)))
{
sigsp = sigaltstack->ss_sp + sigaltstack->ss_size;
sigaltstack->ss_flags |= SA_ONSTACK;
/* XXX need to set up base of new stack for
per-thread variables, cthreads. */
}
else
sigsp = (char *) ts->r29;
/* Set up the sigcontext structure on the stack. This is all the stack
needs, since the args are passed in registers (below). */
sigsp -= sizeof (*scp);
scp = sigsp;
/* Set up the sigcontext from the current state of the thread. */
scp->sc_onstack = sigaltstack->ss_flags & SA_ONSTACK ? 1 : 0;
/* struct sigcontext is laid out so that starting at sc_gpr
mimics a struct mips_thread_state. */
memcpy (scp->sc_gpr, &ts, sizeof ts);
/* Modify the thread state to call `trampoline' on the new stack. */
/* These registers are used for passing the first four arguments to a
function (the rest go on the stack). Fortunately `trampoline' takes
just four arguments, so they all fit in registers. */
ts->r4 = (int) handler;
ts->r5 = signo;
ts->r6 = sigcode;
ts->r7 = (int) scp;
ts->r29 = (int) sigsp; /* r29 is the stack pointer register. */
ts->pc = (int) &trampoline;
return scp;
}