/*      $NetBSD: __sigtramp3.S,v 1.3 2021/11/24 15:05:16 thorpej Exp $  */

/*
 * Copyright (c) 2003 Matt Thomas <matt@3am-software.com>
 * All rights reserved.
 *
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 "assym.h"

#ifdef SYSLIBC_SCCS
RCSID("$NetBSD: __sigtramp3.S,v 1.3 2021/11/24 15:05:16 thorpej Exp $")
#endif

/*
 * Signal trampoline; registers when called:
 *      pc, psl - obvious
 *      sp, ap - points to a CALLG argument list
 *      fp - address of signal handler
 *
 * Stack is set up like so:
 *              ucontext structure
 *              siginfo structure
 *              vvvv CALLG argument list vvvv
 *              12(ap) -- pointer to ucontext
 *               8(ap) -- pointer to siginfo
 *               4(ap) -- signal number
 *      sp ->    0(ap) -- argument count
 *              ^^^^ CALLG argument list ^^^^
 *
 * N.B. all of the DWARF register numbers match our _REG_* constants.
 * Also notice that while the %ap is adjusted inside the trampoline,
 * the %sp is not adjusted, and so the CFA base does not change.
 */

#define CFI_OFFSET(r)                   .cfi_offset r, r * 4

        .text
#if 0
        .cfi_startproc simple
        .cfi_signal_frame
        .cfi_def_cfa _REG_SP, 16 + SIZEOF_SIGINFO + UC_GREGS
        CFI_OFFSET(_REG_R0)
        CFI_OFFSET(_REG_R1)
        CFI_OFFSET(_REG_R2)
        CFI_OFFSET(_REG_R3)
        CFI_OFFSET(_REG_R4)
        CFI_OFFSET(_REG_R5)
        CFI_OFFSET(_REG_R6)
        CFI_OFFSET(_REG_R7)
        CFI_OFFSET(_REG_R8)
        CFI_OFFSET(_REG_R9)
        CFI_OFFSET(_REG_R10)
        CFI_OFFSET(_REG_R11)
        CFI_OFFSET(_REG_AP)
        CFI_OFFSET(_REG_FP)
        CFI_OFFSET(_REG_SP)
        CFI_OFFSET(_REG_PC)
        CFI_OFFSET(_REG_PSL)
#endif

/*
 * The unwind entry includes one instruction slot prior to the trampoline
 * because the unwinder will look up to (return PC - 1) while unwinding.
 * Normally this would be the jump / branch, but since there isn't one in
 * this case, we place an explicit nop there instead.
 */

#if 0
        nop
#endif
        _ALIGN_TEXT

        .globl  _C_LABEL(__sigtramp_siginfo_3)
_C_LABEL(__sigtramp_siginfo_3):
        nop; nop
        callg (%ap),(%fp)               # use global arg list
        addl2 $8,%ap                    # arg is pointer to ucontext
        SYSTRAP(setcontext)             # exit from here
        halt                            # illegal insn
#if 0
        .cfi_endproc
#endif