xref: /illumos-gate/usr/src/lib/libc/sparc/gen/_stack_grow.S (revision 8119dad84d6416f13557b0ba8e2aaf9064cbcfd3)
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27	.file	"_stack_grow.s"
28
29#include "SYS.h"
30#include <../assym.h>
31
32/*
33 * void *
34 * _stack_grow(void *addr)
35 * {
36 *	uintptr_t base = (uintptr_t)curthread->ul_ustack.ss_sp;
37 *	size_t size = curthread->ul_ustack.ss_size;
38 *
39 *	if (size > (uintptr_t)addr - (base - STACK_BIAS))
40 *		return (addr);
41 *
42 *	if (size == 0)
43 *		return (addr);
44 *
45 *	if (size > %sp - (base - STACK_BIAS))
46 *		%sp = base - STACK_BIAS - STACK_ALIGN;
47 *
48 *	*((char *)(base - 1));
49 *
50 *	_lwp_kill(_lwp_self(), SIGSEGV);
51 * }
52 */
53
54#if defined(__sparcv9)
55#define	PN	,pn %xcc,
56#else
57#define	PN
58#endif
59
60	/*
61	 * o0: address to which the stack will be grown (biased)
62	 */
63	ENTRY(_stack_grow)
64	ldn	[%g7 + UL_USTACK + SS_SP], %o1
65	ldn	[%g7 + UL_USTACK + SS_SIZE], %o2
66	sub	%o1, STACK_BIAS, %o3
67
68	sub	%o0, %o3, %o4
69	cmp	%o2, %o4
70	bleu PN	1f
71	tst	%o2
72
73	retl
74	nop
751:
76	/*
77	 * If the stack size is 0, stack checking is disabled.
78	 */
79	bnz PN	2f
80	nop
81	retl
82	nop
832:
84	/*
85	 * Move the stack pointer outside the stack bounds if it isn't already.
86	 */
87	sub	%sp, %o3, %o4
88	cmp	%o2, %o4
89	bleu PN	3f
90	nop
91	sub	%o3, STACK_ALIGN, %sp
923:
93	/*
94	 * Dereference an address in the guard page.
95	 */
96	ldub	[%o1 - 1], %g0
97
98	/*
99	 * If the above load doesn't raise a SIGSEGV then do it ourselves.
100	 */
101	SYSTRAP_RVAL1(lwp_self)
102	mov	SIGSEGV, %o1
103	SYSTRAP_RVAL1(lwp_kill)
104
105	/*
106	 * We should never get here; explode if we do.
107	 */
108	illtrap
109	SET_SIZE(_stack_grow)
110