compat_16_machdep.c revision 1.19 
1/*	$NetBSD: compat_16_machdep.c,v 1.19 2011/04/29 22:11:15 matt Exp $	*/
2
3/*-
4 * Copyright (c) 1998, 2001 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9 * NASA Ames Research Center and by Chris Demetriou.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33/*
34 * Copyright 1996 The Board of Trustees of The Leland Stanford
35 * Junior University. All Rights Reserved.
36 *
37 * Permission to use, copy, modify, and distribute this
38 * software and its documentation for any purpose and without
39 * fee is hereby granted, provided that the above copyright
40 * notice appear in all copies.  Stanford University
41 * makes no representations about the suitability of this
42 * software for any purpose.  It is provided "as is" without
43 * express or implied warranty.
44 */
45
46#include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
47
48__KERNEL_RCSID(0, "$NetBSD: compat_16_machdep.c,v 1.19 2011/04/29 22:11:15 matt Exp $");
49
50#ifdef _KERNEL_OPT
51#include "opt_cputype.h"
52#include "opt_compat_netbsd.h"
53#include "opt_compat_ultrix.h"
54#endif
55
56#include <sys/param.h>
57#include <sys/systm.h>
58#include <sys/kernel.h>
59#include <sys/proc.h>
60#include <sys/cpu.h>
61#include <sys/signal.h>
62#include <sys/signalvar.h>
63#include <sys/mount.h>
64#include <sys/syscallargs.h>
65
66#include <compat/sys/signal.h>
67#include <compat/sys/signalvar.h>
68
69#include <mips/regnum.h>
70#include <mips/frame.h>
71#include <mips/locore.h>
72#include <mips/pcb.h>
73#include <mips/reg.h>
74
75#if !defined(__mips_o32)
76#define	fpreg		fpreg_oabi
77#endif
78
79#ifdef DEBUG
80int sigdebug = 0;
81int sigpid = 0;
82#define SDB_FOLLOW	0x01
83#define SDB_KSTACK	0x02
84#define SDB_FPSTATE	0x04
85#endif
86
87/*
88 * Send a signal to process.
89 */
90void
91sendsig_sigcontext(const ksiginfo_t *ksi, const sigset_t *returnmask)
92{
93	int sig = ksi->ksi_signo;
94	struct lwp * const l = curlwp;
95	struct proc * const p = l->l_proc;
96	struct sigacts * const ps = p->p_sigacts;
97	struct pcb * const pcb = lwp_getpcb(l);
98	int onstack, error;
99	struct sigcontext *scp = getframe(l, sig, &onstack);
100	struct sigcontext ksc;
101	struct trapframe * const tf = l->l_md.md_utf;
102	sig_t catcher = SIGACTION(p, sig).sa_handler;
103
104#if !defined(__mips_o32)
105	if (p->p_md.md_abi != _MIPS_BSD_API_O32)
106		sigexit(l, SIGILL);
107#endif
108
109	scp--;
110
111#ifdef DEBUG
112	if ((sigdebug & SDB_FOLLOW) ||
113	    ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid))
114		printf("sendsig(%d): sig %d ssp %p scp %p\n",
115		       p->p_pid, sig, &onstack, scp);
116#endif
117
118	/* Build stack frame for signal trampoline. */
119	ksc.sc_pc = tf->tf_regs[_R_PC];
120	ksc.mullo = tf->tf_regs[_R_MULLO];
121	ksc.mulhi = tf->tf_regs[_R_MULHI];
122
123	/* Save register context. */
124	ksc.sc_regs[_R_ZERO] = 0xACEDBADE;		/* magic number */
125#if defined(__mips_o32)
126	memcpy(&ksc.sc_regs[1], &tf->tf_regs[1],
127	    sizeof(ksc.sc_regs) - sizeof(ksc.sc_regs[0]));
128#else
129	for (size_t i = 1; i < 32; i++)
130		ksc.sc_regs[i] = tf->tf_regs[i];
131#endif
132
133	/* Save the FP state, if necessary, then copy it. */
134	ksc.sc_fpused = fpu_used_p(l);
135#if !defined(NOFPU)
136	if (ksc.sc_fpused) {
137		/* if FPU has current state, save it first */
138		fpu_save();
139	}
140#endif
141	*(struct fpreg *)ksc.sc_fpregs = *(struct fpreg *)&pcb->pcb_fpregs;
142
143	/* Save signal stack. */
144	ksc.sc_onstack = l->l_sigstk.ss_flags & SS_ONSTACK;
145
146	/* Save signal mask. */
147	ksc.sc_mask = *returnmask;
148
149#if defined(COMPAT_13) || defined(COMPAT_ULTRIX)
150	/*
151	 * XXX We always have to save an old style signal mask because
152	 * XXX we might be delivering a signal to a process which will
153	 * XXX escape from the signal in a non-standard way and invoke
154	 * XXX sigreturn() directly.
155	 */
156	native_sigset_to_sigset13(returnmask, &ksc.__sc_mask13);
157#endif
158
159	sendsig_reset(l, sig);
160
161	mutex_exit(p->p_lock);
162	error = copyout(&ksc, (void *)scp, sizeof(ksc));
163	mutex_enter(p->p_lock);
164
165	if (error != 0) {
166		/*
167		 * Process has trashed its stack; give it an illegal
168		 * instruction to halt it in its tracks.
169		 */
170#ifdef DEBUG
171		if ((sigdebug & SDB_FOLLOW) ||
172		    ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid))
173			printf("sendsig(%d): copyout failed on sig %d\n",
174			    p->p_pid, sig);
175#endif
176		sigexit(l, SIGILL);
177		/* NOTREACHED */
178	}
179
180	/*
181	 * Set up the registers to directly invoke the signal
182	 * handler.  The return address will be set up to point
183	 * to the signal trampoline to bounce us back.
184	 */
185	tf->tf_regs[_R_A0] = sig;
186	tf->tf_regs[_R_A1] = ksi->ksi_trap;
187	tf->tf_regs[_R_A2] = (intptr_t)scp;
188	tf->tf_regs[_R_A3] = (intptr_t)catcher;		/* XXX ??? */
189
190	tf->tf_regs[_R_PC] = (intptr_t)catcher;
191	tf->tf_regs[_R_T9] = (intptr_t)catcher;
192	tf->tf_regs[_R_SP] = (intptr_t)scp;
193
194	switch (ps->sa_sigdesc[sig].sd_vers) {
195	case 0:		/* legacy on-stack sigtramp */
196		tf->tf_regs[_R_RA] = (intptr_t)p->p_sigctx.ps_sigcode;
197		break;
198#ifdef COMPAT_16
199	case 1:
200		tf->tf_regs[_R_RA] = (intptr_t)ps->sa_sigdesc[sig].sd_tramp;
201		break;
202#endif
203	default:
204		/* Don't know what trampoline version; kill it. */
205		sigexit(l, SIGILL);
206	}
207
208	/* Remember that we're now on the signal stack. */
209	if (onstack)
210		l->l_sigstk.ss_flags |= SS_ONSTACK;
211
212#ifdef DEBUG
213	if ((sigdebug & SDB_FOLLOW) ||
214	    ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid))
215		printf("sendsig(%d): sig %d returns\n",
216		       p->p_pid, sig);
217#endif
218}
219
220#ifdef COMPAT_16 /* not needed if COMPAT_ULTRIX only */
221/*
222 * System call to cleanup state after a signal
223 * has been taken.  Reset signal mask and
224 * stack state from context left by sendsig (above).
225 * Return to previous pc and psl as specified by
226 * context left by sendsig. Check carefully to
227 * make sure that the user has not modified the
228 * psl to gain improper privileges or to cause
229 * a machine fault.
230 */
231/* ARGSUSED */
232int
233compat_16_sys___sigreturn14(struct lwp *l, const struct compat_16_sys___sigreturn14_args *uap, register_t *retval)
234{
235	/* {
236		syscallarg(struct sigcontext *) sigcntxp;
237	} */
238	struct sigcontext *scp, ksc;
239	struct trapframe * const tf = l->l_md.md_utf;
240	struct proc * const p = l->l_proc;
241	struct pcb * const pcb = lwp_getpcb(l);
242	int error;
243
244#if !defined(__mips_o32)
245	if (p->p_md.md_abi != _MIPS_BSD_API_O32)
246		return ENOSYS;
247#endif
248
249	/*
250	 * The trampoline code hands us the context.
251	 * It is unsafe to keep track of it ourselves, in the event that a
252	 * program jumps out of a signal handler.
253	 */
254	scp = SCARG(uap, sigcntxp);
255#ifdef DEBUG
256	if (sigdebug & SDB_FOLLOW)
257		printf("sigreturn: pid %d, scp %p\n", l->l_proc->p_pid, scp);
258#endif
259	if ((error = copyin(scp, &ksc, sizeof(ksc))) != 0)
260		return (error);
261
262	if ((u_int) ksc.sc_regs[_R_ZERO] != 0xacedbadeU)/* magic number */
263		return (EINVAL);
264
265	/* Restore the register context. */
266	tf->tf_regs[_R_PC] = ksc.sc_pc;
267	tf->tf_regs[_R_MULLO] = ksc.mullo;
268	tf->tf_regs[_R_MULHI] = ksc.mulhi;
269#if defined(__mips_o32)
270	memcpy(&tf->tf_regs[1], &scp->sc_regs[1],
271	    sizeof(scp->sc_regs) - sizeof(scp->sc_regs[0]));
272#else
273	for (size_t i = 1; i < __arraycount(tf->tf_regs); i++)
274		tf->tf_regs[i] = ksc.sc_regs[i];
275#endif
276#if !defined(NOFPU)
277	if (scp->sc_fpused) {
278		fpu_discard();
279	}
280#endif
281	*(struct fpreg *)&pcb->pcb_fpregs = *(struct fpreg *)scp->sc_fpregs;
282
283	mutex_enter(p->p_lock);
284	/* Restore signal stack. */
285	if (ksc.sc_onstack & SS_ONSTACK)
286		l->l_sigstk.ss_flags |= SS_ONSTACK;
287	else
288		l->l_sigstk.ss_flags &= ~SS_ONSTACK;
289	/* Restore signal mask. */
290	(void) sigprocmask1(l, SIG_SETMASK, &ksc.sc_mask, 0);
291	mutex_exit(p->p_lock);
292
293	return (EJUSTRETURN);
294}
295#endif /* COMPAT_16 */
296