summaryrefslogtreecommitdiff
path: root/sysdeps/mach/hurd/mips/sigreturn.c
blob: fe38fac1df256be5bf0f6aaf6365e90510ee9956 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
/* Copyright (C) 1996, 1997 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., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <hurd.h>
#include <hurd/signal.h>
#include <hurd/threadvar.h>
#include <stdlib.h>
#include <mach/mips/mips_instruction.h>

int
__sigreturn (struct sigcontext *scp)
{
  struct hurd_sigstate *ss;
  struct hurd_userlink *link = (void *) &scp[1];
  mach_port_t *reply_port;

  if (scp == NULL || (scp->sc_mask & _SIG_CANT_MASK))
    {
      errno = EINVAL;
      return -1;
    }

  ss = _hurd_self_sigstate ();
  __spin_lock (&ss->lock);

  /* Remove the link on the `active resources' chain added by
     _hurd_setup_sighandler.  Its purpose was to make sure
     that we got called; now we have, it is done.  */
  _hurd_userlink_unlink (link);

  /* Restore the set of blocked signals, and the intr_port slot.  */
  ss->blocked = scp->sc_mask;
  ss->intr_port = scp->sc_intr_port;

  /* Check for pending signals that were blocked by the old set.  */
  if (ss->pending & ~ss->blocked)
    {
      /* There are pending signals that just became unblocked.  Wake up the
	 signal thread to deliver them.  But first, squirrel away SCP where
	 the signal thread will notice it if it runs another handler, and
	 arrange to have us called over again in the new reality.  */
      ss->context = scp;
      __spin_unlock (&ss->lock);
      __msg_sig_post (_hurd_msgport, 0, 0, __mach_task_self ());
      /* If a pending signal was handled, sig_post never returned.  */
      __spin_lock (&ss->lock);
      ss->context = NULL;
    }

  if (scp->sc_onstack)
    {
      ss->sigaltstack.ss_flags &= ~SA_ONSTACK; /* XXX threadvars */
      /* XXX cannot unlock until off sigstack */
      abort ();
    }
  else
    __spin_unlock (&ss->lock);

  /* Destroy the MiG reply port used by the signal handler, and restore the
     reply port in use by the thread when interrupted.  */
  reply_port =
    (mach_port_t *) __hurd_threadvar_location (_HURD_THREADVAR_MIG_REPLY);
  if (*reply_port)
    {
      mach_port_t port = *reply_port;

      /* Assigning MACH_PORT_DEAD here tells libc's mig_get_reply_port not to
	 get another reply port, but avoids mig_dealloc_reply_port trying to
	 deallocate it after the receive fails (which it will, because the
	 reply port will be bogus, whether we do this or not).  */
      *reply_port = MACH_PORT_DEAD;

      __mach_port_destroy (__mach_task_self (), port);
    }
  *reply_port = scp->sc_reply_port;

  if (scp->sc_coproc_used & SC_COPROC_USE_FPU)
    {
      /* Restore FPU state.  */
#define restore_fpr(n) \
  asm volatile ("l.d $f" #n ",%0" : : "m" (scp->sc_fpr[n]))

      /* Restore floating-point registers. */
#ifdef __mips64
      restore_fpr (0);
      restore_fpr (1);
      restore_fpr (2);
      restore_fpr (3);
      restore_fpr (4);
      restore_fpr (5);
      restore_fpr (6);
      restore_fpr (7);
      restore_fpr (8);
      restore_fpr (9);
      restore_fpr (10);
      restore_fpr (11);
      restore_fpr (12);
      restore_fpr (13);
      restore_fpr (14);
      restore_fpr (15);
      restore_fpr (16);
      restore_fpr (17);
      restore_fpr (18);
      restore_fpr (19);
      restore_fpr (20);
      restore_fpr (21);
      restore_fpr (22);
      restore_fpr (23);
      restore_fpr (24);
      restore_fpr (25);
      restore_fpr (26);
      restore_fpr (27);
      restore_fpr (28);
      restore_fpr (29);
      restore_fpr (30);
      restore_fpr (31);
#else
      restore_fpr (0);
      restore_fpr (2);
      restore_fpr (4);
      restore_fpr (6);
      restore_fpr (8);
      restore_fpr (10);
      restore_fpr (12);
      restore_fpr (14);
      restore_fpr (16);
      restore_fpr (18);
      restore_fpr (20);
      restore_fpr (22);
      restore_fpr (24);
      restore_fpr (26);
      restore_fpr (28);
      restore_fpr (30);
#endif

      /* Restore the floating-point control/status register ($f31).  */
      asm volatile ("ctc1 %0,$f31" : : "r" (scp->sc_fpcsr));
    }

  /* Load all the registers from the sigcontext.  */
#ifdef __mips64
#define restore_gpr(n) \
  asm volatile ("ld $" #n ",%0" : : "m" (scpreg->sc_gpr[n - 1]))
#else
#define restore_gpr(n) \
  asm volatile ("lw $" #n ",%0" : : "m" (scpreg->sc_gpr[n - 1]))
#endif

  {
    register const struct sigcontext *const scpreg asm ("$1") = scp;
    register int *at asm ("$1");

    /* First restore the multiplication result registers.  The compiler
       will use some temporary registers, so we do this before restoring
       the general registers.  */
    asm volatile ("mtlo %0" : : "r" (scpreg->sc_mdlo));
    asm volatile ("mthi %0" : : "r" (scpreg->sc_mdhi));

    /* In the word after the saved PC, store the saved $1 value.  */
    (&scpreg->sc_pc)[1] = scpreg->sc_gpr[0];

    asm volatile (".set noreorder; .set noat;");

    /* Restore the normal registers.  */
    restore_gpr (2);
    restore_gpr (3);
    restore_gpr (4);
    restore_gpr (5);
    restore_gpr (6);
    restore_gpr (7);
    restore_gpr (8);
    restore_gpr (9);
    restore_gpr (10);
    restore_gpr (11);
    restore_gpr (12);
    restore_gpr (13);
    restore_gpr (14);
    restore_gpr (15);
    restore_gpr (16);
    restore_gpr (17);
    restore_gpr (18);
    restore_gpr (19);
    restore_gpr (20);
    restore_gpr (21);
    restore_gpr (22);
    restore_gpr (23);
    restore_gpr (24);
    restore_gpr (25);
    /* Registers 26-27 are kernel-only.  */
    restore_gpr (28);
    restore_gpr (29);		/* Stack pointer.  */
    restore_gpr (30);		/* Frame pointer.  */
    restore_gpr (31);		/* Return address.  */

    at = &scpreg->sc_pc;
    /* This is an emulated instruction that will find at the address in $1
       two words: the PC value to restore, and the $1 value to restore.  */
    asm volatile (".word %0" : : "i" (op_sigreturn));
    asm volatile (".set reorder; .set at;");
    /* NOTREACHED */
    return at;		/* To prevent optimization.  */
  }

  /* NOTREACHED */
  return -1;
}

weak_alias (__sigreturn, sigreturn)