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      1 /*	$NetBSD: __sigtramp3.S,v 1.3 2021/11/24 15:05:16 thorpej Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2003 Matt Thomas <matt (at) 3am-software.com>
      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  * 3. The name of the author may not be used to endorse or promote products
     16  *    derived from this software without specific prior written permission
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     28  */
     29 
     30 #include "SYS.h"
     31 #include "assym.h"
     32 
     33 #ifdef SYSLIBC_SCCS
     34 RCSID("$NetBSD: __sigtramp3.S,v 1.3 2021/11/24 15:05:16 thorpej Exp $")
     35 #endif
     36 
     37 /*
     38  * Signal trampoline; registers when called:
     39  *	pc, psl - obvious
     40  *	sp, ap - points to a CALLG argument list
     41  *	fp - address of signal handler
     42  *
     43  * Stack is set up like so:
     44  *		ucontext structure
     45  *		siginfo structure
     46  *		vvvv CALLG argument list vvvv
     47  *		12(ap) -- pointer to ucontext
     48  *		 8(ap) -- pointer to siginfo
     49  *		 4(ap) -- signal number
     50  *	sp ->	 0(ap) -- argument count
     51  *		^^^^ CALLG argument list ^^^^
     52  *
     53  * N.B. all of the DWARF register numbers match our _REG_* constants.
     54  * Also notice that while the %ap is adjusted inside the trampoline,
     55  * the %sp is not adjusted, and so the CFA base does not change.
     56  */
     57 
     58 #define	CFI_OFFSET(r)			.cfi_offset r, r * 4
     59 
     60 	.text
     61 #if 0
     62 	.cfi_startproc simple
     63 	.cfi_signal_frame
     64 	.cfi_def_cfa _REG_SP, 16 + SIZEOF_SIGINFO + UC_GREGS
     65 	CFI_OFFSET(_REG_R0)
     66 	CFI_OFFSET(_REG_R1)
     67 	CFI_OFFSET(_REG_R2)
     68 	CFI_OFFSET(_REG_R3)
     69 	CFI_OFFSET(_REG_R4)
     70 	CFI_OFFSET(_REG_R5)
     71 	CFI_OFFSET(_REG_R6)
     72 	CFI_OFFSET(_REG_R7)
     73 	CFI_OFFSET(_REG_R8)
     74 	CFI_OFFSET(_REG_R9)
     75 	CFI_OFFSET(_REG_R10)
     76 	CFI_OFFSET(_REG_R11)
     77 	CFI_OFFSET(_REG_AP)
     78 	CFI_OFFSET(_REG_FP)
     79 	CFI_OFFSET(_REG_SP)
     80 	CFI_OFFSET(_REG_PC)
     81 	CFI_OFFSET(_REG_PSL)
     82 #endif
     83 
     84 /*
     85  * The unwind entry includes one instruction slot prior to the trampoline
     86  * because the unwinder will look up to (return PC - 1) while unwinding.
     87  * Normally this would be the jump / branch, but since there isn't one in
     88  * this case, we place an explicit nop there instead.
     89  */
     90 
     91 #if 0
     92 	nop
     93 #endif
     94 	_ALIGN_TEXT
     95 
     96 	.globl	_C_LABEL(__sigtramp_siginfo_3)
     97 _C_LABEL(__sigtramp_siginfo_3):
     98 	nop; nop
     99 	callg (%ap),(%fp)		# use global arg list
    100 	addl2 $8,%ap			# arg is pointer to ucontext
    101 	SYSTRAP(setcontext)		# exit from here
    102 	halt				# illegal insn
    103 #if 0
    104 	.cfi_endproc
    105 #endif
    106