xref: /netbsd/lib/libc/arch/alpha/sys/__sigtramp2.S (revision 7ea5251b)
1/*	$NetBSD: __sigtramp2.S,v 1.8 2021/11/20 19:26:20 thorpej Exp $	*/
2
3/*
4 * Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
5 * All rights reserved.
6 *
7 * Author: Chris G. Demetriou
8 *
9 * Permission to use, copy, modify and distribute this software and
10 * its documentation is hereby granted, provided that both the copyright
11 * notice and this permission notice appear in all copies of the
12 * software, derivative works or modified versions, and any portions
13 * thereof, and that both notices appear in supporting documentation.
14 *
15 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
16 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
17 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
18 *
19 * Carnegie Mellon requests users of this software to return to
20 *
21 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
22 *  School of Computer Science
23 *  Carnegie Mellon University
24 *  Pittsburgh PA 15213-3890
25 *
26 * any improvements or extensions that they make and grant Carnegie the
27 * rights to redistribute these changes.
28 */
29
30#include "SYS.h"
31#include "assym.h"
32
33/*
34 * The Alpha signal trampoline is invoked only to return from
35 * the signal; the kernel calls the signal handler directly.
36 *
37 * On entry, the stack looks like:
38 *
39 *		ucontext structure	[128] == sp + sizeof(siginfo_t)]
40 *	sp->	siginfo structure	[0]
41 *
42 * The DWARF register numbers for the general purpose registers are the
43 * same as the architected register numbers.  For Alpha, there is a DWARF
44 * pseudo-register for signal handler return addresses.
45 */
46
47#if defined(__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__)
48#define	DWARF_SIGRETURN_REG		__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__
49#else
50#define	DWARF_SIGRETURN_REG		64
51#endif
52
53#define	CFI_OFFSET_DWARF_REG(d, r)	.cfi_offset d, r*8
54#define	CFI_OFFSET(r)			CFI_OFFSET_DWARF_REG(r, r)
55
56	.cfi_startproc simple
57	.cfi_signal_frame
58	.cfi_def_cfa _REG_SP, SIZEOF_SIGINFO + UC_GREGS
59	CFI_OFFSET(_REG_V0)
60	CFI_OFFSET(_REG_T0)
61	CFI_OFFSET(_REG_T1)
62	CFI_OFFSET(_REG_T2)
63	CFI_OFFSET(_REG_T3)
64	CFI_OFFSET(_REG_T4)
65	CFI_OFFSET(_REG_T5)
66	CFI_OFFSET(_REG_T6)
67	CFI_OFFSET(_REG_T7)
68	CFI_OFFSET(_REG_S0)
69	CFI_OFFSET(_REG_S1)
70	CFI_OFFSET(_REG_S2)
71	CFI_OFFSET(_REG_S3)
72	CFI_OFFSET(_REG_S4)
73	CFI_OFFSET(_REG_S5)
74	CFI_OFFSET(_REG_S6)
75	CFI_OFFSET(_REG_A0)
76	CFI_OFFSET(_REG_A1)
77	CFI_OFFSET(_REG_A2)
78	CFI_OFFSET(_REG_A3)
79	CFI_OFFSET(_REG_A4)
80	CFI_OFFSET(_REG_A5)
81	CFI_OFFSET(_REG_T8)
82	CFI_OFFSET(_REG_T9)
83	CFI_OFFSET(_REG_T10)
84	CFI_OFFSET(_REG_T11)
85	CFI_OFFSET(_REG_RA)
86	CFI_OFFSET(_REG_T12)	/* a.k.a. _REG_PV */
87	CFI_OFFSET(_REG_AT)
88	CFI_OFFSET(_REG_GP)
89	CFI_OFFSET(_REG_SP)
90	.cfi_return_column DWARF_SIGRETURN_REG
91	CFI_OFFSET_DWARF_REG(DWARF_SIGRETURN_REG, _REG_PC)
92
93/*
94 * The unwind entry includes one instruction slot prior to the trampoline
95 * because the unwinder will look up to (return PC - 1 insn) while unwinding.
96 * Normally this would be the jump / branch, but since there isn't one in
97 * this case, we place an explicit nop there instead.
98 */
99	nop
100
101NESTED_NOPROFILE(__sigtramp_siginfo_2,0,0,ra,0,0)
102	ldgp	gp,0(ra)
103	lda	a0,(SIZEOF_SIGINFO)(sp)	/* get pointer to ucontext */
104	CALLSYS_NOERROR(setcontext)	/* and call setcontext() with it */
105	ldiq	a0,-1			/* if that failed, set an exit code */
106	CALLSYS_NOERROR(exit)		/* and call exit() */
107	.cfi_endproc
108END(__sigtramp_siginfo_2)
109