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
126ENTRY_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
131END(__sigtramp_siginfo_2)
132