1 /* $NetBSD: compat_16_machdep.c,v 1.24 2025/04/25 00:26:59 riastradh 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 1.24 2025/04/25 00:26:59 riastradh 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 sizeof(*scp), _Alignof(*scp));
101 struct sigcontext ksc;
102 struct trapframe * const tf = l->l_md.md_utf;
103 sig_t catcher = SIGACTION(p, sig).sa_handler;
104
105 #if !defined(__mips_o32)
106 if (p->p_md.md_abi != _MIPS_BSD_API_O32)
107 sigexit(l, SIGILL);
108 #endif
109
110 #ifdef DEBUG
111 if ((sigdebug & SDB_FOLLOW) ||
112 ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid))
113 printf("sendsig(%d): sig %d ssp %p scp %p\n",
114 p->p_pid, sig, &onstack, scp);
115 #endif
116
117 /* Build stack frame for signal trampoline. */
118 ksc.sc_pc = tf->tf_regs[_R_PC];
119 ksc.mullo = tf->tf_regs[_R_MULLO];
120 ksc.mulhi = tf->tf_regs[_R_MULHI];
121
122 /* Save register context. */
123 ksc.sc_regs[_R_ZERO] = 0xACEDBADE; /* magic number */
124 #if defined(__mips_o32)
125 memcpy(&ksc.sc_regs[1], &tf->tf_regs[1],
126 sizeof(ksc.sc_regs) - sizeof(ksc.sc_regs[0]));
127 #else
128 for (size_t i = 1; i < 32; i++)
129 ksc.sc_regs[i] = tf->tf_regs[i];
130 #endif
131
132 /* Save the FP state, if necessary, then copy it. */
133 ksc.sc_fpused = fpu_used_p(l);
134 #if !defined(NOFPU)
135 if (ksc.sc_fpused) {
136 /* if FPU has current state, save it first */
137 fpu_save(l);
138 }
139 #endif
140 *(struct fpreg *)ksc.sc_fpregs = *(struct fpreg *)&pcb->pcb_fpregs;
141
142 /* Save signal stack. */
143 ksc.sc_onstack = l->l_sigstk.ss_flags & SS_ONSTACK;
144
145 /* Save signal mask. */
146 ksc.sc_mask = *returnmask;
147
148 #if defined(COMPAT_13) || defined(COMPAT_ULTRIX)
149 /*
150 * XXX We always have to save an old style signal mask because
151 * XXX we might be delivering a signal to a process which will
152 * XXX escape from the signal in a non-standard way and invoke
153 * XXX sigreturn() directly.
154 */
155 native_sigset_to_sigset13(returnmask, &ksc.__sc_mask13);
156 #endif
157
158 sendsig_reset(l, sig);
159
160 mutex_exit(p->p_lock);
161 error = copyout(&ksc, (void *)scp, sizeof(ksc));
162 mutex_enter(p->p_lock);
163
164 if (error != 0) {
165 /*
166 * Process has trashed its stack; give it an illegal
167 * instruction to halt it in its tracks.
168 */
169 #ifdef DEBUG
170 if ((sigdebug & SDB_FOLLOW) ||
171 ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid))
172 printf("sendsig(%d): copyout failed on sig %d\n",
173 p->p_pid, sig);
174 #endif
175 sigexit(l, SIGILL);
176 /* NOTREACHED */
177 }
178
179 /*
180 * Set up the registers to directly invoke the signal
181 * handler. The return address will be set up to point
182 * to the signal trampoline to bounce us back.
183 */
184 tf->tf_regs[_R_A0] = sig;
185 tf->tf_regs[_R_A1] = ksi->ksi_trap;
186 tf->tf_regs[_R_A2] = (intptr_t)scp;
187 tf->tf_regs[_R_A3] = (intptr_t)catcher; /* XXX ??? */
188
189 tf->tf_regs[_R_PC] = (intptr_t)catcher;
190 tf->tf_regs[_R_T9] = (intptr_t)catcher;
191 tf->tf_regs[_R_SP] = (intptr_t)scp;
192
193 switch (ps->sa_sigdesc[sig].sd_vers) {
194 case __SIGTRAMP_SIGCODE_VERSION: /* legacy on-stack sigtramp */
195 tf->tf_regs[_R_RA] = (intptr_t)p->p_sigctx.ps_sigcode;
196 break;
197 #ifdef COMPAT_16
198 case __SIGTRAMP_SIGCONTEXT_VERSION:
199 tf->tf_regs[_R_RA] = (intptr_t)ps->sa_sigdesc[sig].sd_tramp;
200 break;
201 #endif
202 default:
203 /* Don't know what trampoline version; kill it. */
204 sigexit(l, SIGILL);
205 }
206
207 /* Remember that we're now on the signal stack. */
208 if (onstack)
209 l->l_sigstk.ss_flags |= SS_ONSTACK;
210
211 #ifdef DEBUG
212 if ((sigdebug & SDB_FOLLOW) ||
213 ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid))
214 printf("sendsig(%d): sig %d returns\n",
215 p->p_pid, sig);
216 #endif
217 }
218
219 #ifdef COMPAT_16 /* not needed if COMPAT_ULTRIX only */
220 /*
221 * System call to cleanup state after a signal
222 * has been taken. Reset signal mask and
223 * stack state from context left by sendsig (above).
224 * Return to previous pc and psl as specified by
225 * context left by sendsig. Check carefully to
226 * make sure that the user has not modified the
227 * psl to gain improper privileges or to cause
228 * a machine fault.
229 */
230 /* ARGSUSED */
231 int
compat_16_sys___sigreturn14(struct lwp * l,const struct compat_16_sys___sigreturn14_args * uap,register_t * retval)232 compat_16_sys___sigreturn14(struct lwp *l, const struct compat_16_sys___sigreturn14_args *uap, register_t *retval)
233 {
234 /* {
235 syscallarg(struct sigcontext *) sigcntxp;
236 } */
237 struct sigcontext *scp, ksc;
238 struct trapframe * const tf = l->l_md.md_utf;
239 struct proc * const p = l->l_proc;
240 struct pcb * const pcb = lwp_getpcb(l);
241 int error;
242
243 #if !defined(__mips_o32)
244 if (p->p_md.md_abi != _MIPS_BSD_API_O32)
245 return ENOSYS;
246 #endif
247
248 /*
249 * The trampoline code hands us the context.
250 * It is unsafe to keep track of it ourselves, in the event that a
251 * program jumps out of a signal handler.
252 */
253 scp = SCARG(uap, sigcntxp);
254 #ifdef DEBUG
255 if (sigdebug & SDB_FOLLOW)
256 printf("sigreturn: pid %d, scp %p\n", l->l_proc->p_pid, scp);
257 #endif
258 if ((error = copyin(scp, &ksc, sizeof(ksc))) != 0)
259 return (error);
260
261 if ((u_int) ksc.sc_regs[_R_ZERO] != 0xacedbadeU)/* magic number */
262 return (EINVAL);
263
264 /* Restore the register context. */
265 tf->tf_regs[_R_PC] = ksc.sc_pc;
266 tf->tf_regs[_R_MULLO] = ksc.mullo;
267 tf->tf_regs[_R_MULHI] = ksc.mulhi;
268 #if defined(__mips_o32)
269 memcpy(&tf->tf_regs[1], &scp->sc_regs[1],
270 sizeof(scp->sc_regs) - sizeof(scp->sc_regs[0]));
271 #else
272 for (size_t i = 1; i < __arraycount(ksc.sc_regs); i++)
273 tf->tf_regs[i] = ksc.sc_regs[i];
274 #endif
275 #if !defined(NOFPU)
276 if (scp->sc_fpused) {
277 fpu_discard(l);
278 }
279 #endif
280 *(struct fpreg *)&pcb->pcb_fpregs = *(struct fpreg *)scp->sc_fpregs;
281
282 mutex_enter(p->p_lock);
283 /* Restore signal stack. */
284 if (ksc.sc_onstack & SS_ONSTACK)
285 l->l_sigstk.ss_flags |= SS_ONSTACK;
286 else
287 l->l_sigstk.ss_flags &= ~SS_ONSTACK;
288 /* Restore signal mask. */
289 (void) sigprocmask1(l, SIG_SETMASK, &ksc.sc_mask, 0);
290 mutex_exit(p->p_lock);
291
292 return (EJUSTRETURN);
293 }
294 #endif /* COMPAT_16 */
295