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      1 /*	$NetBSD: sig_machdep.c,v 1.6 2024/08/04 08:16:26 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 1.6 2024/08/04 08:16:26 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 
     56 void *
     57 cpu_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 
     75 struct 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  */
     83 void
     84 sendsig_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