/* $OpenBSD: setjmp.S,v 1.15 2023/12/10 16:45:51 deraadt Exp $ */
/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "SYS.h"
#include <machine/setjmp.h>

        .section        .openbsd.randomdata,"aw",@progbits
        .balign 4
        .globl  __jmpxor
        .hidden __jmpxor
__jmpxor:
        .zero   4*3             # (eip, esp, ebp)
        END(__jmpxor)
        .type   __jmpxor,@object


/*
 * C library -- setjmp, longjmp
 *
 *      longjmp(a,v)
 * will generate a "return(v)" from the last call to
 *      setjmp(a)
 * by restoring registers from the stack.
 * The previous signal state is restored.
 */

ENTRY(setjmp)
        pushl   $0                      /* mask = empty */
        pushl   $1                      /* how = SIG_BLOCK */
        call    1f
1:      movl    $(SYS_sigprocmask),%eax
99:     int     $0x80                   /* leave oset in %eax */
        PINSYSCALL(SYS_sigprocmask, 99b)
        popl    %edx
        addl    $8,%esp
        addl    $__jmpxor-1b,%edx       # load cookie address

        movl    4(%esp),%ecx            # parameter, pointer to env
        movl    %eax,(_JB_SIGMASK * 4)(%ecx)
        movl    %ebx,(_JB_EBX * 4)(%ecx)
        movl    %esp,%eax
        xorl    0(%edx),%eax            # use esp cookie
        movl    %eax,(_JB_ESP * 4)(%ecx)
        movl    %ebp,%eax
        xorl    4(%edx),%eax            # use ebp cookie
        movl    %eax,(_JB_EBP * 4)(%ecx)
        movl    %esi,(_JB_ESI * 4)(%ecx)
        movl    %edi,(_JB_EDI * 4)(%ecx)
        movl    8(%edx),%edx            # load eip cookie over cookie address
        xorl    0(%esp),%edx            # caller address
        movl    %edx,(_JB_EIP * 4)(%ecx)
        fnstcw  (_JB_FCW * 4)(%ecx)
        xorl    %eax,%eax
        ret
END(setjmp)

ENTRY(longjmp)
        movl    4(%esp),%edx            # parameter, pointer to env
        pushl   (_JB_SIGMASK * 4)(%edx) /* mask from sc_mask */
        pushl   $3                      /* how = SIG_SETMASK */
        call    1f                      /* get our eip */
1:      movl    $(SYS_sigprocmask),%eax
98:     int     $0x80
        PINSYSCALL(SYS_sigprocmask, 98b)
        popl    %ecx
        addl    $8,%esp
        addl    $__jmpxor-1b,%ecx       # load cookie address

        movl    4(%esp),%edx            # parameter, pointer to env
        movl    8(%esp),%eax            # parameter, val
        fldcw   (_JB_FCW * 4)(%edx)
        movl    (_JB_EBX * 4)(%edx),%ebx
        movl    (_JB_ESP * 4)(%edx),%esi
        xorl    0(%ecx),%esi            # use esp cookie
        movl    %esi,%esp               # un-xor'ed esp is safe to use
        movl    (_JB_EBP * 4)(%edx),%ebp
        xorl    4(%ecx),%ebp            # use ebp cookie
        movl    (_JB_ESI * 4)(%edx),%esi
        movl    (_JB_EDI * 4)(%edx),%edi

        movl    8(%ecx),%ecx            # load eip cookie over cookie address
        xorl    (_JB_EIP * 4)(%edx),%ecx
        testl   %eax,%eax
        jnz     1f
        incl    %eax
1:      movl    %ecx,0(%esp)
        ret
END(longjmp)