initial import

1 files changed, 258 insertions, 0 deletions

diff --git a/sysdeps/mach/hurd/hppa/trampoline.c b/sysdeps/mach/hurd/hppa/trampoline.c
new file mode 100644
index 0000000000..09ab71e88d
--- /dev/null
+++ b/sysdeps/mach/hurd/hppa/trampoline.c
@@ -0,0 +1,258 @@
+/* Set thread_state for sighandler, and sigcontext to recover.  HPPA version.
+Copyright (C) 1995 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 "thread_state.h"
+#include <assert.h>
+#include <errno.h>
+#include "hurdfault.h"
+
+     
+struct mach_msg_trap_regargs
+  {
+    /* These first four arguments are in registers 26..23.  */
+    mach_msg_size_t rcv_size;	/* arg3 */
+    mach_msg_size_t send_size;	/* arg2 */
+    mach_msg_option_t option;	/* arg1 */
+    mach_msg_header_t *msg;	/* arg0 */
+  };
+
+struct sigcontext *
+_hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
+			int signo, long int sigcode,
+			volatile int rpc_wait,
+			struct machine_thread_all_state *state)
+{
+  __label__ trampoline, rpc_wait_trampoline;
+  void *volatile sigsp;
+  struct sigcontext *scp;
+
+  if (ss->context)
+    {
+      /* We have a previous sigcontext that sigreturn was about
+	 to restore when another signal arrived.  We will just base
+	 our setup on that.  */
+      if (_hurdsig_catch_fault (SIGSEGV))
+	assert (_hurdsig_fault_sigcode >= (long int) ss->context &&
+		_hurdsig_fault_sigcode < (long int) (ss->context + 1));
+      else
+	{
+	  memcpy (&state->basic, &ss->context->sc_parisc_thread_state,
+		  sizeof (state->basic));
+	  state->set = (1 << PARISC_THREAD_STATE);
+	  assert (! rpc_wait);
+	  /* The intr_port slot was cleared before sigreturn sent us the
+	     sig_post that made us notice this pending signal, so
+	     _hurd_internal_post_signal wouldn't do interrupt_operation.
+	     After we return, our caller will set SCP->sc_intr_port (in the
+	     new context) from SS->intr_port and clear SS->intr_port.  Now
+	     that we are restoring this old context recorded by sigreturn,
+	     we want to restore its intr_port too; so store it in
+	     SS->intr_port now, so it will end up in SCP->sc_intr_port
+	     later.  */
+	  ss->intr_port = ss->context->sc_intr_port;
+	}
+      /* If the sigreturn context was bogus, just ignore it.  */
+      ss->context = NULL;
+    }
+  else if (! machine_get_basic_state (ss->thread, state))
+    return NULL;
+
+  if ((ss->actions[signo].sa_flags & SA_ONSTACK) &&
+      !(ss->sigaltstack.ss_flags & (SA_DISABLE|SA_ONSTACK)))
+    {
+      sigsp = ss->sigaltstack.ss_sp + ss->sigaltstack.ss_size;
+      ss->sigaltstack.ss_flags |= SA_ONSTACK;
+      /* XXX need to set up base of new stack for
+	 per-thread variables, cthreads.  */
+    }
+  else
+    sigsp = (char *) state->basic.uesp;
+
+  /* Push the signal context on the stack.  */
+  sigsp -= sizeof (*scp);
+  scp = sigsp;
+
+  if (_hurdsig_catch_fault (SIGSEGV))
+    {
+      assert (_hurdsig_fault_sigcode >= (long int) scp &&
+	      _hurdsig_fault_sigcode <= (long int) (scp + 1));
+      /* We got a fault trying to write the stack frame.
+	 We cannot set up the signal handler.
+	 Returning NULL tells our caller, who will nuke us with a SIGILL.  */
+      return NULL;
+    }
+  else
+    {
+      int ok;
+
+      /* Set up the sigcontext from the current state of the thread.  */
+
+      scp->sc_onstack = ss->sigaltstack.ss_flags & SA_ONSTACK ? 1 : 0;
+
+      /* struct sigcontext is laid out so that starting at sc_regs mimics a
+	 struct parisc_thread_state.  */
+      memcpy (&scp->sc_parisc_thread_state,
+	      &state->basic, sizeof (state->basic));
+
+      _hurdsig_end_catch_fault ();
+
+      if (! ok)
+	return NULL;
+    }
+
+  /* Modify the thread state to call the trampoline code on the new stack.  */
+  if (rpc_wait)
+    {
+      /* The signalee thread was blocked in a mach_msg_trap system call,
+	 still waiting for a reply.  We will have it run the special
+	 trampoline code which retries the message receive before running
+	 the signal handler.
+	 
+	 To do this we change the OPTION argument on its stack to enable only
+	 message reception, since the request message has already been
+	 sent.  */
+
+      struct mach_msg_trap_regargs *args = (void *) &state->basic.r23;
+
+      if (_hurdsig_catch_fault (SIGSEGV))
+	{
+	  assert (_hurdsig_fault_sigcode >= (long int) args &&
+		  _hurdsig_fault_sigcode < (long int) (args + 1));
+	  /* Faulted accessing ARGS.  Bomb.  */
+	  return NULL;
+	}
+
+      assert (args->option & MACH_RCV_MSG);
+      /* Disable the message-send, since it has already completed.  The
+	 calls we retry need only wait to receive the reply message.  */
+      args->option &= ~MACH_SEND_MSG;
+
+      _hurdsig_end_catch_fault ();
+
+      MACHINE_THREAD_STATE_SET_PC (&state->basic, &&rpc_wait_trampoline);
+      /* The reply-receiving trampoline code runs initially on the original
+	 user stack.  We pass it the signal stack pointer in %r5.  */
+      state->basic.r5 = (int) sigsp;
+      /* After doing the message receive, the trampoline code will need to
+	 update the %r28 value to be restored by sigreturn.  To simplify
+	 the assembly code, we pass the address of its slot in SCP to the
+	 trampoline code in %r4.  */
+      state->basic.r4 = (unsigned int) &scp->sc_regs[27];
+      /* Set up the arguments for the handler function in callee-saved
+	 registers that we will move to the argument registers after
+	 mach_msg_trap returns.  */
+      state->basic.r6 = signo;
+      state->basic.r7 = sigcode;
+      state->basic.r8 = (unsigned int) scp;
+    }
+  else
+    {
+      MACHINE_THREAD_STATE_SET_PC (&state->basic, &&trampoline);
+      state->basic.r20 = (unsigned int) sigsp;
+      /* Set up the arguments for the handler function.  */
+      state->basic.r26 = signo;
+      state->basic.r25 = sigcode;
+      state->basic.r24 = (unsigned int) scp;
+    }
+
+  /* We pass the handler function to the trampoline code in %r9.  */
+  state->basic.r9 = (unsigned int) handler;
+  /* For convenience, we pass the address of __sigreturn in %r10.  */
+  state->basic.r10 = (unsigned int) &__sigreturn;
+  /* The extra copy of SCP for the __sigreturn arg goes in %r8.  */
+  state->basic.r10 = (unsigned int) scp;
+
+  return scp;
+
+  /* The trampoline code follows.  This is not actually executed as part of
+     this function, it is just convenient to write it that way.  */
+
+ rpc_wait_trampoline:
+  /* This is the entry point when we have an RPC reply message to receive
+     before running the handler.  The MACH_MSG_SEND bit has already been
+     cleared in the OPTION argument on our stack.  The interrupted user
+     stack pointer has not been changed, so the system call can find its
+     arguments; the signal stack pointer is in %ebx.  For our convenience,
+     %ecx points to the sc_eax member of the sigcontext.  */
+  asm volatile
+    (/* Retry the interrupted mach_msg system call.  */
+     "ldil L%0xC0000000,%r1\nble 4(%sr7,%r1)\n"
+     "ldi -25, %r22\n"		/* mach_msg_trap */
+     /* When the sigcontext was saved, %r28 was MACH_RCV_INTERRUPTED.  But
+	now the message receive has completed and the original caller of
+	the RPC (i.e. the code running when the signal arrived) needs to
+	see the final return value of the message receive in %r28.  So
+	store the new %r28 value into the sc_regs[27] member of the sigcontext
+	(whose address is in %r4 to make this code simpler).  */
+     "stw (%r4), %r28\n"
+     /* Switch to the signal stack.  */
+     "copy %r5, %r30\n"
+     /* Copy the handler arguments to the argument registers.  */
+     "copy %r6, %r26\n"
+     "copy %r7, %r25\n"
+     "copy %r8, %r24\n"
+     );
+
+ trampoline:
+  /* Entry point for running the handler normally.  The arguments to the
+     handler function are already in the argument registers.  */
+  asm volatile
+    ("bv (%r9); nop"		/* Call the handler function.  */
+     "bv (%r10)\n"		/* Call __sigreturn (SCP); never returns.  */
+     "copy %r8, %r26"		/* Set up arg in delay slot.  */
+     : : "i" (&__sigreturn));
+
+  /* NOTREACHED */
+  return NULL;
+}
+
+/* STATE describes a thread that had intr_port set (meaning it was inside
+   HURD_EINTR_RPC), after it has been thread_abort'd.  It it looks to have
+   just completed a mach_msg_trap system call that returned
+   MACH_RCV_INTERRUPTED, return nonzero and set *PORT to the receive right
+   being waited on.  */
+int
+_hurdsig_rcv_interrupted_p (struct machine_thread_all_state *state,
+			    mach_port_t *port)
+{
+  const unsigned int *volatile pc
+    = MACHINE_THREAD_STATE_PC (&state->basic);
+  const mach_port_t *rcv_name
+    = (void *) state->r30 -32-20; /* VA_ARG4 from <mach/machine/asm.h>.  */
+
+  if (_hurdsig_catch_fault (SIGSEGV))
+    assert (_hurdsig_fault_sigcode == (long int) pc ||
+	    _hurdsig_fault_sigcode == (long int) rcv_name);
+  else
+    {
+      int rcving = (state->basic.r28 == MACH_RCV_INTERRUPTED &&
+		    pc == ???unfinished???);
+      if (rcving)
+	/* We did just return from a mach_msg_trap system call
+	   doing a message receive that was interrupted.
+	   Examine the parameters to find the receive right.  */
+	*port = *rcv_name;
+      _hurdsig_end_catch_fault ();
+      if (rcving)
+	return 1;
+    }
+
+  return 0;
+}