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      1 /*	$NetBSD: SYS.h,v 1.5 2023/05/19 06:41:41 skrll Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2014,2022 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, and Nick Hudson.
      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/syscall.h>
     33 #include <machine/asm.h>
     34 
     35 #define SYSTRAP(x)							\
     36 	li	t6, SYS_ ## x;						\
     37 	ecall
     38 
     39 #define	JUMP_TO_CERROR()						\
     40 	.option push							;\
     41 	.option norelax							;\
     42 	tail	_C_LABEL(__cerror)					;\
     43 	.option pop
     44 
     45 #define	SYSTRAP_NOERROR(x)						\
     46 	SYSTRAP(x)							;\
     47 	nop; nop		/* size of ... 			*/	;\
     48 	nop; nop		/*     JUMP_TO_CERROR		*/	;\
     49 
     50 /*
     51  * Do a syscall that cannot fail (sync, get{p,u,g,eu,eg)id)
     52  */
     53 #define RSYSCALL_NOERROR(x)						\
     54 	PSEUDO_NOERROR(x,x)
     55 
     56 /*
     57  * Do a normal syscall.
     58  */
     59 #define RSYSCALL(x)							\
     60 	PSEUDO(x,x)
     61 
     62 /*
     63  * Do a syscall that has an internal name and a weak external alias.
     64  */
     65 #define	WSYSCALL(weak,strong)						\
     66 	WEAK_ALIAS(weak,strong)						;\
     67 	PSEUDO(strong,weak)
     68 
     69 /*
     70  * Do a renamed or pseudo syscall (e.g., _exit()), where the entrypoint
     71  * and syscall name are not the same.
     72  */
     73 #define PSEUDO_NOERROR(x,y)						\
     74 ENTRY(x)								;\
     75 	SYSTRAP_NOERROR(y)						;\
     76 	ret			/* success */				;\
     77 END(x)
     78 
     79 #define PSEUDO(x,y)							\
     80 ENTRY(x)								;\
     81 	SYSTRAP(y)							;\
     82 	JUMP_TO_CERROR()	/* error */				;\
     83 	ret			/* success */				;\
     84 END(x)
     85