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231 lines
8.5 KiB
C
231 lines
8.5 KiB
C
/* Set thread_state for sighandler, and sigcontext to recover. HPPA version.
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Copyright (C) 1995 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <hurd/signal.h>
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#include "thread_state.h"
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#include <assert.h>
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#include <errno.h>
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#include "hurdfault.h"
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struct mach_msg_trap_regargs
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{
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/* These first four arguments are in registers 26..23. */
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mach_msg_size_t rcv_size; /* arg3 */
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mach_msg_size_t send_size; /* arg2 */
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mach_msg_option_t option; /* arg1 */
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mach_msg_header_t *msg; /* arg0 */
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};
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struct sigcontext *
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_hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
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int signo, long int sigcode,
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volatile int rpc_wait,
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struct machine_thread_all_state *state)
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{
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__label__ trampoline, rpc_wait_trampoline;
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void *volatile sigsp;
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struct sigcontext *scp;
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if (ss->context)
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{
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/* We have a previous sigcontext that sigreturn was about
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to restore when another signal arrived. We will just base
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our setup on that. */
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if (_hurdsig_catch_fault (SIGSEGV))
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assert (_hurdsig_fault_sigcode >= (long int) ss->context &&
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_hurdsig_fault_sigcode < (long int) (ss->context + 1));
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else
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{
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memcpy (&state->basic, &ss->context->sc_parisc_thread_state,
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sizeof (state->basic));
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state->set = (1 << PARISC_THREAD_STATE);
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assert (! rpc_wait);
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/* The intr_port slot was cleared before sigreturn sent us the
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sig_post that made us notice this pending signal, so
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_hurd_internal_post_signal wouldn't do interrupt_operation.
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After we return, our caller will set SCP->sc_intr_port (in the
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new context) from SS->intr_port and clear SS->intr_port. Now
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that we are restoring this old context recorded by sigreturn,
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we want to restore its intr_port too; so store it in
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SS->intr_port now, so it will end up in SCP->sc_intr_port
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later. */
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ss->intr_port = ss->context->sc_intr_port;
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}
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/* If the sigreturn context was bogus, just ignore it. */
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ss->context = NULL;
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}
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else if (! machine_get_basic_state (ss->thread, state))
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return NULL;
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if ((ss->actions[signo].sa_flags & SA_ONSTACK) &&
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!(ss->sigaltstack.ss_flags & (SA_DISABLE|SA_ONSTACK)))
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{
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sigsp = ss->sigaltstack.ss_sp + ss->sigaltstack.ss_size;
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ss->sigaltstack.ss_flags |= SA_ONSTACK;
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/* XXX need to set up base of new stack for
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per-thread variables, cthreads. */
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}
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else
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sigsp = (char *) state->basic.uesp;
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/* Push the signal context on the stack. */
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sigsp -= sizeof (*scp);
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scp = sigsp;
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if (_hurdsig_catch_fault (SIGSEGV))
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{
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assert (_hurdsig_fault_sigcode >= (long int) scp &&
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_hurdsig_fault_sigcode <= (long int) (scp + 1));
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/* We got a fault trying to write the stack frame.
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We cannot set up the signal handler.
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Returning NULL tells our caller, who will nuke us with a SIGILL. */
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return NULL;
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}
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else
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{
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int ok;
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/* Set up the sigcontext from the current state of the thread. */
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scp->sc_onstack = ss->sigaltstack.ss_flags & SA_ONSTACK ? 1 : 0;
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/* struct sigcontext is laid out so that starting at sc_regs mimics a
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struct parisc_thread_state. */
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memcpy (&scp->sc_parisc_thread_state,
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&state->basic, sizeof (state->basic));
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_hurdsig_end_catch_fault ();
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if (! ok)
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return NULL;
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}
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/* Modify the thread state to call the trampoline code on the new stack. */
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if (rpc_wait)
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{
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/* The signalee thread was blocked in a mach_msg_trap system call,
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still waiting for a reply. We will have it run the special
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trampoline code which retries the message receive before running
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the signal handler.
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To do this we change the OPTION argument on its stack to enable only
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message reception, since the request message has already been
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sent. */
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struct mach_msg_trap_regargs *args = (void *) &state->basic.r23;
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if (_hurdsig_catch_fault (SIGSEGV))
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{
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assert (_hurdsig_fault_sigcode >= (long int) args &&
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_hurdsig_fault_sigcode < (long int) (args + 1));
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/* Faulted accessing ARGS. Bomb. */
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return NULL;
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}
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assert (args->option & MACH_RCV_MSG);
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/* Disable the message-send, since it has already completed. The
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calls we retry need only wait to receive the reply message. */
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args->option &= ~MACH_SEND_MSG;
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/* Limit the time to receive the reply message, in case the server
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claimed that `interrupt_operation' succeeded but in fact the RPC
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is hung. */
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args->option |= MACH_RCV_TIMEOUT;
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args->timeout = _hurd_interrupted_rpc_timeout;
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_hurdsig_end_catch_fault ();
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MACHINE_THREAD_STATE_SET_PC (&state->basic, &&rpc_wait_trampoline);
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/* The reply-receiving trampoline code runs initially on the original
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user stack. We pass it the signal stack pointer in %r5. */
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state->basic.r5 = (int) sigsp;
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/* After doing the message receive, the trampoline code will need to
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update the %r28 value to be restored by sigreturn. To simplify
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the assembly code, we pass the address of its slot in SCP to the
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trampoline code in %r4. */
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state->basic.r4 = (unsigned int) &scp->sc_regs[27];
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/* Set up the arguments for the handler function in callee-saved
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registers that we will move to the argument registers after
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mach_msg_trap returns. */
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state->basic.r6 = signo;
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state->basic.r7 = sigcode;
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state->basic.r8 = (unsigned int) scp;
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}
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else
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{
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MACHINE_THREAD_STATE_SET_PC (&state->basic, &&trampoline);
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state->basic.r20 = (unsigned int) sigsp;
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/* Set up the arguments for the handler function. */
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state->basic.r26 = signo;
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state->basic.r25 = sigcode;
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state->basic.r24 = (unsigned int) scp;
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}
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/* We pass the handler function to the trampoline code in %r9. */
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state->basic.r9 = (unsigned int) handler;
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/* For convenience, we pass the address of __sigreturn in %r10. */
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state->basic.r10 = (unsigned int) &__sigreturn;
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/* The extra copy of SCP for the __sigreturn arg goes in %r8. */
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state->basic.r10 = (unsigned int) scp;
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return scp;
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/* The trampoline code follows. This is not actually executed as part of
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this function, it is just convenient to write it that way. */
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rpc_wait_trampoline:
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/* This is the entry point when we have an RPC reply message to receive
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before running the handler. The MACH_MSG_SEND bit has already been
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cleared in the OPTION argument on our stack. The interrupted user
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stack pointer has not been changed, so the system call can find its
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arguments; the signal stack pointer is in %ebx. For our convenience,
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%ecx points to the sc_eax member of the sigcontext. */
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asm volatile
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(/* Retry the interrupted mach_msg system call. */
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"ldil L%0xC0000000,%r1\nble 4(%sr7,%r1)\n"
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"ldi -25, %r22\n" /* mach_msg_trap */
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/* When the sigcontext was saved, %r28 was MACH_RCV_INTERRUPTED. But
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now the message receive has completed and the original caller of
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the RPC (i.e. the code running when the signal arrived) needs to
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see the final return value of the message receive in %r28. So
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store the new %r28 value into the sc_regs[27] member of the sigcontext
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(whose address is in %r4 to make this code simpler). */
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"stw (%r4), %r28\n"
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/* Switch to the signal stack. */
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"copy %r5, %r30\n"
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/* Copy the handler arguments to the argument registers. */
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"copy %r6, %r26\n"
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"copy %r7, %r25\n"
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"copy %r8, %r24\n"
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);
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trampoline:
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/* Entry point for running the handler normally. The arguments to the
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handler function are already in the argument registers. */
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asm volatile
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("bv (%r9); nop" /* Call the handler function. */
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"bv (%r10)\n" /* Call __sigreturn (SCP); never returns. */
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"copy %r8, %r26" /* Set up arg in delay slot. */
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: : "i" (&__sigreturn));
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/* NOTREACHED */
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return NULL;
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}
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