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longjmp.c revision 1.3 
      1 /*	$NetBSD: longjmp.c,v 1.3 2011/04/30 23:41:12 martin Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2003 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christian Limpach.
      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 "namespace.h"
     33 #include <sys/types.h>
     34 #include <ucontext.h>
     35 #include <signal.h>
     36 #include <stdlib.h>
     37 #include <string.h>
     38 #include <stddef.h>
     39 
     40 #define __LIBC12_SOURCE__
     41 #include <setjmp.h>
     42 #include <compat/include/setjmp.h>
     43 
     44 struct __jmp_buf_regs_t {
     45 	__greg_t	g4;
     46 	__greg_t	g7;
     47 	__greg_t	save_mask;
     48 };
     49 
     50 /*
     51  * setjmp.S uses hard coded offsets into the jump_buf,
     52  * make sure any changes cause a compile failure here
     53  */
     54 __CTASSERT(56 == offsetof(struct __jmp_buf_regs_t,save_mask) +
     55 	sizeof(struct sigcontext));
     56 __CTASSERT(sizeof(sigjmp_buf) >= sizeof(struct __jmp_buf_regs_t) +
     57 	sizeof(struct sigcontext));
     58 
     59 /*
     60  * Use setcontext to reload the stack pointer, program counter <pc,npc>, and
     61  * set the return value in %o0.  The %i and %l registers will be reloaded
     62  * from the place to which %sp points.
     63  */
     64 void
     65 __longjmp14(jmp_buf env, int val)
     66 {
     67 	struct sigcontext *sc = (void *)env;
     68 	struct __jmp_buf_regs_t *r = (void*)&sc[1];
     69 	ucontext_t uc;
     70 
     71 	/* Ensure non-zero SP */
     72 	if (sc->sc_sp == 0)
     73 		goto err;
     74 
     75 	/* Initialise the context */
     76 	memset(&uc, 0, sizeof(uc));
     77 
     78 	/*
     79 	 * Set _UC_{SET,CLR}STACK according to SS_ONSTACK.
     80 	 *
     81 	 * Restore the signal mask with sigprocmask() instead of _UC_SIGMASK,
     82 	 * since libpthread may want to interpose on signal handling.
     83 	 */
     84 	uc.uc_flags = _UC_CPU | (sc->sc_onstack ? _UC_SETSTACK : _UC_CLRSTACK);
     85 
     86 	sigprocmask(SIG_SETMASK, &sc->sc_mask, NULL);
     87 
     88 	/* Extract PSR, PC, NPC and SP from jmp_buf */
     89 	uc.uc_mcontext.__gregs[_REG_PSR] = sc->sc_psr;
     90 	uc.uc_mcontext.__gregs[_REG_PC] = sc->sc_pc;
     91 	uc.uc_mcontext.__gregs[_REG_nPC] = sc->sc_pc+4;
     92 	uc.uc_mcontext.__gregs[_REG_O6] = sc->sc_sp;
     93 	uc.uc_mcontext.__gregs[_REG_G2] = sc->sc_g1;
     94 	uc.uc_mcontext.__gregs[_REG_G3] = sc->sc_npc;
     95 	uc.uc_mcontext.__gregs[_REG_G4] = r->g4;
     96 	uc.uc_mcontext.__gregs[_REG_G7] = r->g7;
     97 
     98 	/* Set the return value; make sure it's non-zero */
     99 	uc.uc_mcontext.__gregs[_REG_O0] = (val != 0 ? val : 1);
    100 
    101 	setcontext(&uc);
    102 
    103 err:
    104 	longjmperror();
    105 	abort();
    106 	/* NOTREACHED */
    107 }
    108