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      1 /* $NetBSD: sig_machdep.c,v 1.9 2024/04/14 12:51:16 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 __KERNEL_RCSID(1, "$NetBSD: sig_machdep.c,v 1.9 2024/04/14 12:51:16 skrll Exp $");
     35 
     36 #include <sys/param.h>
     37 #include <sys/types.h>
     38 #include <sys/cpu.h>
     39 #include <sys/proc.h>
     40 #include <sys/signalvar.h>
     41 #include <sys/siginfo.h>
     42 
     43 #include <aarch64/frame.h>
     44 
     45 void
     46 sendsig_siginfo(const ksiginfo_t *ksi, const sigset_t *mask)
     47 {
     48 	struct lwp * const l = curlwp;
     49 	struct proc * const p = l->l_proc;
     50 	struct trapframe * const tf = lwp_trapframe(l);
     51 	stack_t * const ss = &l->l_sigstk;
     52 	const struct sigact_sigdesc * const sd =
     53 	    &p->p_sigacts->sa_sigdesc[ksi->ksi_signo];
     54 
     55 	const uintptr_t handler = (uintptr_t) sd->sd_sigact.sa_handler;
     56 	const bool onstack_p = (ss->ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0
     57 	    && (sd->sd_sigact.sa_flags & SA_ONSTACK) != 0;
     58 
     59 	vaddr_t sp;
     60 
     61 	/*
     62 	 * The user stack isn't guaranteed to be aligned to 16 bytes. Align
     63 	 * it before pushing anything onto it.
     64 	 */
     65 	sp = onstack_p ? ((vaddr_t)ss->ss_sp + ss->ss_size) : tf->tf_sp;
     66 	sp &= -16;
     67 
     68 	__CTASSERT(sizeof(ucontext_t) % 16 == 0);
     69 	sp -= sizeof(ucontext_t);
     70 	const vaddr_t ucp = sp;
     71 
     72 	sp -= roundup(sizeof(siginfo_t), 16);
     73 	const vaddr_t sip = sp;
     74 
     75 	ucontext_t uc;
     76 	memset(&uc, 0, sizeof(uc));
     77 	uc.uc_flags = _UC_SIGMASK;
     78 	uc.uc_sigmask = *mask;
     79 	uc.uc_link = l->l_ctxlink;
     80 	uc.uc_flags |= (l->l_sigstk.ss_flags & SS_ONSTACK)
     81 	    ? _UC_SETSTACK : _UC_CLRSTACK;
     82 	sendsig_reset(l, ksi->ksi_signo);
     83 	mutex_exit(p->p_lock);
     84 	cpu_getmcontext(l, &uc.uc_mcontext, &uc.uc_flags);
     85 
     86 	/*
     87 	 * Copy the siginfo and ucontext onto the user's stack.
     88 	 */
     89 	int error = copyout(&ksi->ksi_info, (void *)sip, sizeof(ksi->ksi_info));
     90 	if (error == 0) {
     91 		error = copyout(&uc, (void *)ucp, sizeof(uc));
     92 	}
     93 
     94 	mutex_enter(p->p_lock);
     95 
     96 	if (error || sd->sd_vers != __SIGTRAMP_SIGINFO_VERSION) {
     97 		/*
     98 		 * Thread has trashed its stack.  Blow it away.
     99 		 */
    100 		if (error == 0) {
    101 			printf("pid %d.%d(%s): %p(sig %d): bad version %d\n",
    102 			    p->p_pid, l->l_lid, p->p_comm, __func__,
    103 			    ksi->ksi_signo, sd->sd_vers);
    104 		}
    105 		sigexit(l, SIGILL);
    106 		/* NOTREACHED */
    107 	}
    108 
    109 	tf->tf_reg[0] = ksi->ksi_signo;
    110 	tf->tf_reg[1] = sip;
    111 	tf->tf_reg[2] = ucp;
    112 	tf->tf_reg[28] = ucp;	/* put in a callee saved register */
    113 
    114 	tf->tf_sp = sp;
    115 	tf->tf_lr = (uint64_t)sd->sd_tramp;
    116 	tf->tf_pc = handler;
    117 
    118 	/*
    119 	 * Remember if we're now on the signal stack.
    120 	 */
    121 	if (onstack_p)
    122 		ss->ss_flags |= SS_ONSTACK;
    123 }
    124