xref: /openbsd-src/lib/libc/arch/arm/gen/_setjmp.S (revision a8d2d9e857f3e0e5e619a6a7a1a692b947560973)
1/*	$OpenBSD: _setjmp.S,v 1.8 2022/05/25 17:32:36 guenther Exp $	*/
2/*	$NetBSD: _setjmp.S,v 1.5 2003/04/05 23:08:51 bjh21 Exp $	*/
3
4/*
5 * Copyright (c) 1997 Mark Brinicombe
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by Mark Brinicombe
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include "DEFS.h"
37#include <machine/setjmp.h>
38
39	.section	.openbsd.randomdata,"aw",%progbits
40	.balign	4
41	.globl	__jmpxor
42__jmpxor:
43	.zero 4*2		/* (sp, lr) */
44	END(__jmpxor)
45	.type	__jmpxor,%object
46
47
48/*
49 * C library -- _setjmp, _longjmp
50 *
51 *	_longjmp(a,v)
52 * will generate a "return(v)" from the last call to
53 *	_setjmp(a)
54 * by restoring registers from the stack.
55 * The previous signal state is NOT restored.
56 *
57 * Note: r0 is the return value
58 *       r1-r3 are scratch registers in functions
59 */
60
61ENTRY(_setjmp)
62	ldr	r1, .L_setjmp_magic
63	str	r1, [r0], #4
64	ldr	r2, .L_jmpxor_setjmp
651:	add	r2, pc, r2			/* r2 = &__jmpxor */
66	ldr	r3, [r2], #4			/* r3 = __jmpxor[1] */
67	ldr	r2, [r2] 			/* r2 = __jmpxor[0] */
68	eor	r2, r13, r2			/* r2 = sp ^ __jmpxor[0] */
69	eor	r3, lr, r3			/* r3 = lr ^ __jmpxor[1] */
70
71#ifdef SOFTFLOAT
72	add	r0, r0, #68
73#else
74	/* Store fpcsr */
75	vmrs	r1, fpscr
76	str	r1, [r0], #4
77	/* Store fp registers */
78	vstmia	r0!, {d8-d15}
79#endif	/* SOFTFLOAT */
80	/* Store integer registers */
81	stmia	r0, {r2-r11}
82
83	mov	r0, #0x00000000
84	mov	r2, r0				/* overwrite __jmpxor copies */
85	mov	r3, r0
86	mov	pc, lr
87
88.L_setjmp_magic:
89	.word	_JB_MAGIC__SETJMP
90
91.L_jmpxor_setjmp:
92	.word	__jmpxor - 1b
93END_STRONG(_setjmp)
94
95ENTRY(_longjmp)
96	ldr	r2, .L_setjmp_magic
97	ldr	r3, [r0], #4
98	teq	r2, r3
99	bne	.Lbotch
100
101#ifdef SOFTFLOAT
102	add	r0, r0, #68
103#else
104	/* Restore fpcsr */
105	ldr	r4, [r0], #4
106	vmsr	fpscr, r4
107	/* Restore fp registers */
108	vldmia	r0!, {d8-d15}
109#endif	/* SOFTFLOAT */
110	/* Restore integer registers */
111	ldmia	r0, {r2-r11}
112
113	ldr	r0, .L_jmpxor_longjmp
1141:	add	r0, pc, r0			/* r0 = &__jmpxor */
115	ldr	lr, [r0], #4			/* lr = __jmpxor[1] */
116	eor	lr, r3, lr			/* lr ^= jmpbuf[LR] */
117	ldr	r0, [r0] 			/* r0 = __jmpxor[0] */
118	eor	r13, r0, r2		/* sp = __jmpxor[0] ^ jmpbuf[SP] */
119	mov	r2, r1				/* overwrite __jmpxor copies */
120	mov	r3, r1
121
122	/* Validate sp and lr */
123	teq	sp, #0
124	teqne	lr, #0
125	beq	.Lbotch
126
127	/* Set return value */
128	mov	r0, r1
129	teq	r0, #0x00000000
130	moveq	r0, #0x00000001
131	mov	pc, lr
132
133.L_jmpxor_longjmp:
134	.word	__jmpxor - 1b
135
136	/* validation failed, die die die. */
137.Lbotch:
138	bl	_HIDDEN(abort)
139	b	. - 8		/* Cannot get here */
140END_STRONG(_longjmp)
141