sysdeps/mach/hurd/mips/sigreturn.c

   1 /* Copyright (C) 1991, 1992, 1994, 1995 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <hurd.h>
  20 #include <hurd/signal.h>
  21 #include <hurd/threadvar.h>
  22 #include <stdlib.h>
  23
  24 int
  25 __sigreturn (struct sigcontext *scp)
  26 {
  27   struct hurd_sigstate *ss;
  28   mach_port_t *reply_port;
  29
  30   if (scp == NULL || (scp->sc_mask & _SIG_CANT_MASK))
  31     {
  32       errno = EINVAL;
  33       return -1;
  34     }
  35
  36   ss = _hurd_self_sigstate ();
  37   __spin_lock (&ss->lock);
  38
  39   /* Restore the set of blocked signals, and the intr_port slot.  */
  40   ss->blocked = scp->sc_mask;
  41   ss->intr_port = scp->sc_intr_port;
  42
  43   /* Check for pending signals that were blocked by the old set.  */
  44   if (ss->pending & ~ss->blocked)
  45     {
  46       /* There are pending signals that just became unblocked.  Wake up the
  47          signal thread to deliver them.  But first, squirrel away SCP where
  48          the signal thread will notice it if it runs another handler, and
  49          arrange to have us called over again in the new reality.  */
  50       ss->context = scp;
  51       /* Clear the intr_port slot, since we are not in fact doing
  52          an interruptible RPC right now.  If SS->intr_port is not null,
  53          the SCP context is doing an interruptible RPC, but the signal
  54          thread will examine us while we are blocked in the sig_post RPC.  */
  55       ss->intr_port = MACH_PORT_NULL;
  56       __spin_unlock (&ss->lock);
  57       __msg_sig_post (_hurd_msgport, 0, __mach_task_self ());
  58       /* If a pending signal was handled, sig_post never returned.  */
  59       __spin_lock (&ss->lock);
  60     }
  61
  62   if (scp->sc_onstack)
  63     {
  64       ss->sigaltstack.ss_flags &= ~SA_ONSTACK; /* XXX threadvars */
  65       /* XXX cannot unlock until off sigstack */
  66       abort ();
  67     }
  68   else
  69     __spin_unlock (&ss->lock);
  70
  71   /* Destroy the MiG reply port used by the signal handler, and restore the
  72      reply port in use by the thread when interrupted.  */
  73   reply_port =
  74     (mach_port_t *) __hurd_threadvar_location (_HURD_THREADVAR_MIG_REPLY);
  75   if (*reply_port)
  76     __mach_port_destroy (__mach_task_self (), *reply_port);
  77   *reply_port = scp->sc_reply_port;
  78
  79   if (scp->sc_coproc_used & SC_COPROC_USE_FPU)
  80     {
  81       /* Restore FPU state.  */
  82 #define restore_fpr(n) \
  83   asm volatile ("l.d $f" #n ",%0" : : "m" (scp->sc_fpr[n]))
  84
  85       /* Restore floating-point registers. */
  86       restore_fpr (0);
  87       restore_fpr (2);
  88       restore_fpr (4);
  89       restore_fpr (6);
  90       restore_fpr (8);
  91       restore_fpr (10);
  92       restore_fpr (12);
  93       restore_fpr (14);
  94       restore_fpr (16);
  95       restore_fpr (18);
  96       restore_fpr (20);
  97       restore_fpr (22);
  98       restore_fpr (24);
  99       restore_fpr (26);
 100       restore_fpr (28);
 101       restore_fpr (30);
 102
 103       /* Restore the floating-point control/status register ($f31).  */
 104       asm volatile ("ctc1 %0,$f31" : : "r" (scp->sc_fpcsr));
 105     }
 106
 107   /* Load all the registers from the sigcontext.  */
 108 #define restore_gpr(n) \
 109   asm volatile ("lw $" #n ",%0" : : "m" (scpreg->sc_gpr[n - 1]))
 110
 111   {
 112     register const struct sigcontext *const scpreg asm ("$1") = scp;
 113     register int *at asm ("$1");
 114
 115     /* First restore the multiplication result registers.  The compiler
 116        will use some temporary registers, so we do this before restoring
 117        the general registers.  */
 118     asm volatile ("mtlo %0" : : "r" (scpreg->sc_mdlo));
 119     asm volatile ("mthi %0" : : "r" (scpreg->sc_mdhi));
 120
 121     /* In the word after the saved PC, store the saved $1 value.  */
 122     (&scpreg->sc_pc)[1] = scpreg->sc_gpr[0];
 123
 124     asm volatile (".set noreorder; .set noat;");
 125
 126     /* Restore the normal registers.  */
 127     restore_gpr (2);
 128     restore_gpr (3);
 129     restore_gpr (4);
 130     restore_gpr (5);
 131     restore_gpr (6);
 132     restore_gpr (7);
 133     restore_gpr (8);
 134     restore_gpr (9);
 135     restore_gpr (10);
 136     restore_gpr (11);
 137     restore_gpr (12);
 138     restore_gpr (13);
 139     restore_gpr (14);
 140     restore_gpr (15);
 141     restore_gpr (16);
 142     restore_gpr (17);
 143     restore_gpr (18);
 144     restore_gpr (19);
 145     restore_gpr (20);
 146     restore_gpr (21);
 147     restore_gpr (22);
 148     restore_gpr (23);
 149     restore_gpr (24);
 150     restore_gpr (25);
 151     /* Registers 26-27 are kernel-only.  */
 152     restore_gpr (28);
 153     restore_gpr (29);           /* Stack pointer.  */
 154     restore_gpr (30);           /* Frame pointer.  */
 155     restore_gpr (31);           /* Return address.  */
 156
 157     at = &scpreg->sc_pc;
 158     /* This is an emulated instruction that will find at the address in $1
 159        two words: the PC value to restore, and the $1 value to restore.  */
 160     asm volatile (".word op_sigreturn");
 161
 162     asm volatile (".set reorder; .set at;");
 163   }
 164
 165   /* NOTREACHED */
 166   return -1;
 167 }
 168
 169 weak_alias (__sigreturn, sigreturn)