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__sigtramp2.S revision 1.6 
      1 /*	$NetBSD: __sigtramp2.S,v 1.6 2020/05/05 06:20:55 skrll Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1998-2001 Michael Shalayeff
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
     20  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     22  * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     24  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
     25  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     26  * THE POSSIBILITY OF SUCH DAMAGE.
     27  *
     28  * Portitions of this file are derived from other sources, see
     29  * the copyrights and acknowledgements below.
     30  */
     31 /*
     32  * Copyright (c) 1990,1991,1992,1994 The University of Utah and
     33  * the Computer Systems Laboratory (CSL).  All rights reserved.
     34  *
     35  * THE UNIVERSITY OF UTAH AND CSL PROVIDE THIS SOFTWARE IN ITS "AS IS"
     36  * CONDITION, AND DISCLAIM ANY LIABILITY OF ANY KIND FOR ANY DAMAGES
     37  * WHATSOEVER RESULTING FROM ITS USE.
     38  *
     39  * CSL requests users of this software to return to csl-dist (at) cs.utah.edu any
     40  * improvements that they make and grant CSL redistribution rights.
     41  *
     42  *	Utah $Hdr: locore.s 1.62 94/12/15$
     43  */
     44 /*
     45  *  (c) Copyright 1988 HEWLETT-PACKARD COMPANY
     46  *
     47  *  To anyone who acknowledges that this file is provided "AS IS"
     48  *  without any express or implied warranty:
     49  *      permission to use, copy, modify, and distribute this file
     50  *  for any purpose is hereby granted without fee, provided that
     51  *  the above copyright notice and this notice appears in all
     52  *  copies, and that the name of Hewlett-Packard Company not be
     53  *  used in advertising or publicity pertaining to distribution
     54  *  of the software without specific, written prior permission.
     55  *  Hewlett-Packard Company makes no representations about the
     56  *  suitability of this software for any purpose.
     57  */
     58 
     59 #include "SYS.h"
     60 
     61 /*
     62  * The hppa signal trampoline is required to call the handler
     63  * possibily via a PLABEL.
     64  *
     65  * On entry, stack looks like:
     66  *
     67  *	sp->					[x]
     68  * r3,arg2->	ucontext structure
     69  *    arg1->	siginfo structure		[0]
     70  *
     71  * where
     72  *	x = HPPA_FRAME_ROUND(sizeof(sigframe_siginfo))
     73  *
     74  * and
     75  * 	struct sigframe_siginfo {
     76  *		siginfo_t sf_si;
     77  *		ucontext_t sf_uc;
     78  *	};
     79  */
     80 
     81 ENTRY_NOPROFILE(__sigtramp_siginfo_2, 0)
     82 	.call
     83 
     84 	/*
     85 	 * Our sendsig() places the address of the signal handler in %arg3.
     86 	 * It may actually be a PLABEL.
     87 	 */
     88 	bb,>=,n	%arg3, 30, L$sigcode_bounce	; branch if not a PLABEL
     89 	depi	0, 31, 2, %arg3			; zero L bit in PLABEL pointer
     90 	ldw	4(%arg3), %r19			; load shared library linkage
     91 	ldw	0(%arg3), %arg3			; load real catcher address
     92 
     93 L$sigcode_bounce:
     94 
     95 	/*
     96 	 * This blr puts the address of the following nop in rp.
     97 	 * It also schedules the nop for execution, which is why
     98 	 * that instruction has to be a nop, or, rather, not any
     99 	 * instruction only meant to execute once the signal handler
    100 	 * returns.
    101 	 */
    102 	blr	%r0, %rp
    103 
    104 	/*
    105 	 * This bv schedules the instruction pointed to by arg3
    106 	 * for execution.  So, arg3 is the address of the signal
    107 	 * handler.
    108 	 */
    109 	bv,n	%r0(%arg3)
    110 	nop
    111 
    112 	/*
    113 	 * The signal handler has returned.  Since r3 is on the list
    114 	 * of callee-saved registers, it's whatever the sendsig
    115 	 * code wanted it set to.  Since we copy it into arg0,
    116 	 * it looks like sendsig leaves r3 holding the desired
    117 	 * single argument to sys_setcontext, i.e., the ucontext_t *.
    118 	 */
    119 
    120 	/* Make a SYS_setcontext system call. */
    121 	copy	%r3, %arg0
    122 	ldil	L%SYSCALLGATE, %r1
    123 	.call
    124 	ble	4(%sr2, %r1)
    125 	 ldi	SYS_setcontext, %t1
    126 
    127 	/* Make a SYS_exit system call. */
    128 	copy	%ret0, %arg0
    129 	ldil	L%SYSCALLGATE, %r1
    130 	.call
    131 	ble	4(%sr2, %r1)
    132 	 ldi	SYS_exit, %t1
    133 EXIT(__sigtramp_siginfo_2)
    134