1/*	$NetBSD: sig_machdep.c,v 1.5 2023/05/07 12:41:49 skrll Exp $	*/
2
3/*-
4 * Copyright (c) 2014 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Matt Thomas of 3am Software Foundry.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33
34#ifndef COMPATNAME1
35__RCSID("$NetBSD: sig_machdep.c,v 1.5 2023/05/07 12:41:49 skrll Exp $");
36#endif
37
38#include <sys/param.h>
39#include <sys/cpu.h>
40#include <sys/mount.h>
41#include <sys/kernel.h>
42#include <sys/proc.h>
43#include <sys/signal.h>
44#include <sys/signalvar.h>
45
46#include <riscv/locore.h>
47#include <riscv/frame.h>
48
49#ifndef COMPATNAME1
50#define COMPATNAME1(x)		x
51#define COMPATNAME2(x)		x
52#define COMPATTYPE(x)		__CONCAT(x,_t)
53#define UCLINK_SET(uc,c)	((uc)->uc_link = (c))
54#define	COPY_SIGINFO(d,s)	((d)->sf_si._info = (s)->ksi_info)
55
56void *
57cpu_sendsig_getframe(struct lwp *l, int signo, bool *onstack)
58{
59	struct trapframe * const tf = l->l_md.md_utf;
60	struct proc * const p = l->l_proc;
61
62	/* Do we need to jump onto the signal stack? */
63	*onstack = (l->l_sigstk.ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0
64	    && (SIGACTION(p, signo).sa_flags & SA_ONSTACK) != 0;
65	if (*onstack)
66		return (char *)stack_align((intptr_t)l->l_sigstk.ss_sp + l->l_sigstk.ss_size);
67	return (void *)(intptr_t)stack_align(tf->tf_sp);
68}
69#endif
70
71#ifdef COMPATINC
72#include COMPATINC
73#endif
74
75struct COMPATNAME2(sigframe_siginfo) {
76	COMPATTYPE(siginfo) sf_si __aligned(__BIGGEST_ALIGNMENT__);
77	COMPATTYPE(ucontext) sf_uc;
78};
79
80/*
81 * Send a signal to process.
82 */
83void
84sendsig_siginfo(const ksiginfo_t *ksi, const sigset_t *mask)
85{
86	struct lwp * const l = curlwp;
87	struct proc * const p = l->l_proc;
88	struct sigacts * const sa = p->p_sigacts;
89	struct trapframe * const tf = l->l_md.md_utf;
90	const int signo = ksi->ksi_signo;
91	const sig_t catcher = SIGACTION(p, signo).sa_handler;
92	bool onstack;
93	struct COMPATNAME2(sigframe_siginfo) *sf =
94	    cpu_sendsig_getframe(l, signo, &onstack);
95	struct COMPATNAME2(sigframe_siginfo) ksf;
96
97	sf--;		// allocate sigframe
98
99	memset(&ksf, 0, sizeof(ksf));
100	COPY_SIGINFO(&ksf, ksi);
101	ksf.sf_uc.uc_flags = _UC_SIGMASK
102	    | (l->l_sigstk.ss_flags & SS_ONSTACK ? _UC_SETSTACK : _UC_CLRSTACK);
103	ksf.sf_uc.uc_sigmask = *mask;
104	UCLINK_SET(&ksf.sf_uc, l->l_ctxlink);
105	memset(&ksf.sf_uc.uc_stack, 0, sizeof(ksf.sf_uc.uc_stack));
106	sendsig_reset(l, signo);
107
108	mutex_exit(p->p_lock);
109	COMPATNAME2(cpu_getmcontext)(l, &ksf.sf_uc.uc_mcontext,
110	     &ksf.sf_uc.uc_flags);
111	int error = copyout(&ksf, sf, sizeof(ksf));
112	mutex_enter(p->p_lock);
113
114	if (error != 0) {
115		/*
116		 * Process has trashed its stack; give it an illegal
117		 * instruction to halt it in its tracks.
118		 */
119		sigexit(l, SIGILL);
120		/* NOTREACHED */
121	}
122
123	/*
124	 * Set up the registers to directly invoke the signal
125	 * handler.  The return address will be set up to point
126	 * to the signal trampoline to bounce us back.
127	 */
128	tf->tf_a0 = signo;
129	tf->tf_a1 = (intptr_t)&sf->sf_si;
130	tf->tf_a2 = (intptr_t)&sf->sf_uc;
131
132	tf->tf_pc = (intptr_t)catcher;
133	tf->tf_sp = (intptr_t)sf;
134	tf->tf_ra = (intptr_t)sa->sa_sigdesc[signo].sd_tramp;
135
136	/* Remember that we're now on the signal stack. */
137	if (onstack)
138		l->l_sigstk.ss_flags |= SS_ONSTACK;
139}
140