xref: /illumos-gate/usr/src/lib/libc/amd64/gen/_stack_grow.S (revision 55fea89dcaa64928bed4327112404dcb3e07b79f)
1*5d9d9091SRichard Lowe/*
2*5d9d9091SRichard Lowe * CDDL HEADER START
3*5d9d9091SRichard Lowe *
4*5d9d9091SRichard Lowe * The contents of this file are subject to the terms of the
5*5d9d9091SRichard Lowe * Common Development and Distribution License (the "License").
6*5d9d9091SRichard Lowe * You may not use this file except in compliance with the License.
7*5d9d9091SRichard Lowe *
8*5d9d9091SRichard Lowe * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*5d9d9091SRichard Lowe * or http://www.opensolaris.org/os/licensing.
10*5d9d9091SRichard Lowe * See the License for the specific language governing permissions
11*5d9d9091SRichard Lowe * and limitations under the License.
12*5d9d9091SRichard Lowe *
13*5d9d9091SRichard Lowe * When distributing Covered Code, include this CDDL HEADER in each
14*5d9d9091SRichard Lowe * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15*5d9d9091SRichard Lowe * If applicable, add the following below this CDDL HEADER, with the
16*5d9d9091SRichard Lowe * fields enclosed by brackets "[]" replaced with your own identifying
17*5d9d9091SRichard Lowe * information: Portions Copyright [yyyy] [name of copyright owner]
18*5d9d9091SRichard Lowe *
19*5d9d9091SRichard Lowe * CDDL HEADER END
20*5d9d9091SRichard Lowe */
21*5d9d9091SRichard Lowe/*
22*5d9d9091SRichard Lowe * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
23*5d9d9091SRichard Lowe * Use is subject to license terms.
24*5d9d9091SRichard Lowe */
25*5d9d9091SRichard Lowe
26*5d9d9091SRichard Lowe	.file	"_stack_grow.s"
27*5d9d9091SRichard Lowe
28*5d9d9091SRichard Lowe/*
29*5d9d9091SRichard Lowe * void *
30*5d9d9091SRichard Lowe * _stack_grow(void *addr)
31*5d9d9091SRichard Lowe * {
32*5d9d9091SRichard Lowe *	uintptr_t base = (uintptr_t)curthread->ul_ustack.ss_sp;
33*5d9d9091SRichard Lowe *	size_t size = curthread->ul_ustack.ss_size;
34*5d9d9091SRichard Lowe *
35*5d9d9091SRichard Lowe *	if (size > (uintptr_t)addr - base)
36*5d9d9091SRichard Lowe *		return (addr);
37*5d9d9091SRichard Lowe *
38*5d9d9091SRichard Lowe *	if (size == 0)
39*5d9d9091SRichard Lowe *		return (addr);
40*5d9d9091SRichard Lowe *
41*5d9d9091SRichard Lowe *	if (size > %sp - base)
42*5d9d9091SRichard Lowe *		%sp = base - STACK_ALIGN;
43*5d9d9091SRichard Lowe *
44*5d9d9091SRichard Lowe *	*((char *)(base - 1));
45*5d9d9091SRichard Lowe *
46*5d9d9091SRichard Lowe *	_lwp_kill(_lwp_self(), SIGSEGV);
47*5d9d9091SRichard Lowe * }
48*5d9d9091SRichard Lowe */
49*5d9d9091SRichard Lowe
50*5d9d9091SRichard Lowe#include "SYS.h"
51*5d9d9091SRichard Lowe#include <../assym.h>
52*5d9d9091SRichard Lowe
53*5d9d9091SRichard Lowe	ENTRY(_stack_grow)
54*5d9d9091SRichard Lowe	movq	%rdi, %rax
55*5d9d9091SRichard Lowe	movq	%fs:UL_USTACK+SS_SP, %rcx
56*5d9d9091SRichard Lowe	movq	%fs:UL_USTACK+SS_SIZE, %rdx
57*5d9d9091SRichard Lowe	movq	%rax, %rbx
58*5d9d9091SRichard Lowe	subq	%rcx, %rbx
59*5d9d9091SRichard Lowe	cmpq	%rdx, %rbx
60*5d9d9091SRichard Lowe	jae	1f
61*5d9d9091SRichard Lowe	ret
62*5d9d9091SRichard Lowe1:
63*5d9d9091SRichard Lowe	/
64*5d9d9091SRichard Lowe	/ If the stack size is 0, stack checking is disabled.
65*5d9d9091SRichard Lowe	/
66*5d9d9091SRichard Lowe	cmpq	$0, %rdx
67*5d9d9091SRichard Lowe	jne	2f
68*5d9d9091SRichard Lowe	ret
69*5d9d9091SRichard Lowe2:
70*5d9d9091SRichard Lowe	/
71*5d9d9091SRichard Lowe	/ Move the stack pointer outside the stack bounds if it isn't already.
72*5d9d9091SRichard Lowe	/
73*5d9d9091SRichard Lowe	movq	%rsp, %rbx
74*5d9d9091SRichard Lowe	subq	%rcx, %rbx
75*5d9d9091SRichard Lowe	cmpq	%rdx, %rbx
76*5d9d9091SRichard Lowe	jae	3f
77*5d9d9091SRichard Lowe	pushq	%rbp
78*5d9d9091SRichard Lowe	movq	%rsp, %rbp
79*5d9d9091SRichard Lowe	movq	%rcx, %rsp
80*5d9d9091SRichard Lowe	subq	$STACK_ALIGN, %rsp
81*5d9d9091SRichard Lowe3:
82*5d9d9091SRichard Lowe	/
83*5d9d9091SRichard Lowe	/ Dereference an address in the guard page.
84*5d9d9091SRichard Lowe	/
85*5d9d9091SRichard Lowe	movb	-1(%rcx), %bl
86*5d9d9091SRichard Lowe
87*5d9d9091SRichard Lowe	/
88*5d9d9091SRichard Lowe	/ If the above load doesn't raise a SIGSEGV then do it ourselves.
89*5d9d9091SRichard Lowe	/
90*5d9d9091SRichard Lowe	SYSTRAP_RVAL1(lwp_self)
91*5d9d9091SRichard Lowe	movl	$SIGSEGV, %esi
92*5d9d9091SRichard Lowe	movl	%eax, %edi
93*5d9d9091SRichard Lowe	SYSTRAP_RVAL1(lwp_kill)
94*5d9d9091SRichard Lowe
95*5d9d9091SRichard Lowe	/
96*5d9d9091SRichard Lowe	/ Try one last time to take out the process.
97*5d9d9091SRichard Lowe	/
98*5d9d9091SRichard Lowe	movq	0x0, %rax
99*5d9d9091SRichard Lowe	SET_SIZE(_stack_grow)
100