1 /* $NetBSD: compat_16_machdep.c,v 1.23 2021/10/27 04:15:00 thorpej 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 1.23 2021/10/27 04:15:00 thorpej 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
80 int sigdebug = 0;
81 int 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 */
90 void
sendsig_sigcontext(const ksiginfo_t * ksi,const sigset_t * returnmask)91 sendsig_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(l);
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 __SIGTRAMP_SIGCODE_VERSION: /* 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 __SIGTRAMP_SIGCONTEXT_VERSION:
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 */
232 int
compat_16_sys___sigreturn14(struct lwp * l,const struct compat_16_sys___sigreturn14_args * uap,register_t * retval)233 compat_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(ksc.sc_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(l);
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