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      1 /*	$NetBSD: __sigtramp2.S,v 1.5 2021/11/27 10:00:01 skrll Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe.
      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.h"
     33 #include "assym.h"
     34 
     35 #if defined(LIBC_SCCS) && !defined(lint)
     36 __RCSID("$NetBSD: __sigtramp2.S,v 1.5 2021/11/27 10:00:01 skrll Exp $")
     37 #endif /* LIBC_SCCS && !lint */
     38 
     39 /*
     40  * On entry to user space, stack and registers look like:
     41  *
     42  *	r3	signal number
     43  *	r4	pointer to siginfo structure
     44  *	r5	pointer to ucontext structure
     45  *	r30	pointer to ucontext structure
     46  *	srr0	address of handler
     47  *	lr	address of this trampoline
     48  *
     49  * We use r30 as the CFA base register since it's been conveniently set up
     50  * for us that way.  The DWARF register numbers used in the .eh_frame are:
     51  *
     52  *   0 - 31	GPRs
     53  *  32 - 63	FPRs
     54  *  65		LR
     55  *  66		CTR
     56  *  68-75	CRs
     57  *  76		XER
     58  *  77 - 108	AltiVec regs
     59  *  99		signal trampoline return address
     60  * 109		VRSAVE
     61  * 110		VCSR
     62  *
     63  * N.B. Only one CR slot is used (CR2) in the SVR4 ABI.
     64  */
     65 
     66 #define	DWARF_LR_REG			65
     67 #define	DWARF_CTR_REG			66
     68 #define	DWARF_CR2_REG			70
     69 #define	DWARF_XER_REG			76
     70 #define	DWARF_SIGRETURN_REG		99
     71 
     72 #define	CFI_OFFSET_DWARF_REG(d, r)	.cfi_offset d, r * 4
     73 #define	CFI_OFFSET(r)			CFI_OFFSET_DWARF_REG(r, r)
     74 
     75 	.text
     76 	.cfi_startproc simple
     77 	.cfi_signal_frame
     78 	.cfi_def_cfa _REG_R30, UC_GREGS
     79 	CFI_OFFSET(_REG_R0)
     80 	CFI_OFFSET(_REG_R1)
     81 	CFI_OFFSET(_REG_R2)
     82 	CFI_OFFSET(_REG_R3)
     83 	CFI_OFFSET(_REG_R4)
     84 	CFI_OFFSET(_REG_R5)
     85 	CFI_OFFSET(_REG_R6)
     86 	CFI_OFFSET(_REG_R7)
     87 	CFI_OFFSET(_REG_R8)
     88 	CFI_OFFSET(_REG_R9)
     89 	CFI_OFFSET(_REG_R10)
     90 	CFI_OFFSET(_REG_R11)
     91 	CFI_OFFSET(_REG_R12)
     92 	CFI_OFFSET(_REG_R13)
     93 	CFI_OFFSET(_REG_R14)
     94 	CFI_OFFSET(_REG_R15)
     95 	CFI_OFFSET(_REG_R16)
     96 	CFI_OFFSET(_REG_R17)
     97 	CFI_OFFSET(_REG_R18)
     98 	CFI_OFFSET(_REG_R19)
     99 	CFI_OFFSET(_REG_R20)
    100 	CFI_OFFSET(_REG_R21)
    101 	CFI_OFFSET(_REG_R22)
    102 	CFI_OFFSET(_REG_R23)
    103 	CFI_OFFSET(_REG_R24)
    104 	CFI_OFFSET(_REG_R25)
    105 	CFI_OFFSET(_REG_R26)
    106 	CFI_OFFSET(_REG_R27)
    107 	CFI_OFFSET(_REG_R28)
    108 	CFI_OFFSET(_REG_R29)
    109 	CFI_OFFSET(_REG_R30)
    110 	CFI_OFFSET(_REG_R31)
    111 	CFI_OFFSET_DWARF_REG(DWARF_CR2_REG, _REG_CR)
    112 	CFI_OFFSET_DWARF_REG(DWARF_LR_REG, _REG_LR)
    113 	CFI_OFFSET_DWARF_REG(DWARF_CTR_REG, _REG_CTR)
    114 	CFI_OFFSET_DWARF_REG(DWARF_XER_REG, _REG_XER)
    115 	.cfi_return_column DWARF_SIGRETURN_REG
    116 	CFI_OFFSET_DWARF_REG(DWARF_SIGRETURN_REG, _REG_PC)
    117 
    118 /*
    119  * The unwind entry includes one instruction slot prior to the trampoline
    120  * because the unwinder will look up to (return PC - 1 insn) while unwinding.
    121  * Normally this would be the jump / branch, but since there isn't one in
    122  * this case, we place an explicit nop there instead.
    123  */
    124 	nop
    125 
    126 ENTRY_NOPROFILE(__sigtramp_siginfo_2)
    127 	mr	%r3,%r30		/* restore ucontext pointer */
    128 	_DOSYSCALL(setcontext)		/* restore machine state */
    129 	_DOSYSCALL(exit)		/* or exit with errno if failed */
    130 	.cfi_endproc
    131 END(__sigtramp_siginfo_2)
    132