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      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  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     24  */
     25 
     26 	.file	"_stack_grow.s"
     27 
     28 /*
     29  * void *
     30  * _stack_grow(void *addr)
     31  * {
     32  *	uintptr_t base = (uintptr_t)curthread->ul_ustack.ss_sp;
     33  *	size_t size = curthread->ul_ustack.ss_size;
     34  *
     35  *	if (size > (uintptr_t)addr - base)
     36  *		return (addr);
     37  *
     38  *	if (size == 0)
     39  *		return (addr);
     40  *
     41  *	if (size > %sp - base)
     42  *		%sp = base - STACK_ALIGN;
     43  *
     44  *	*((char *)(base - 1));
     45  *
     46  *	_lwp_kill(_lwp_self(), SIGSEGV);
     47  * }
     48  */
     49 
     50 #include "SYS.h"
     51 #include <../assym.h>
     52 
     53 	ENTRY(_stack_grow)
     54 	movq	%rdi, %rax
     55 	movq	%fs:UL_USTACK+SS_SP, %rcx
     56 	movq	%fs:UL_USTACK+SS_SIZE, %rdx
     57 	movq	%rax, %rbx
     58 	subq	%rcx, %rbx
     59 	cmpq	%rdx, %rbx
     60 	jae	1f
     61 	ret
     62 1:
     63 	/
     64 	/ If the stack size is 0, stack checking is disabled.
     65 	/
     66 	cmpq	$0, %rdx
     67 	jne	2f
     68 	ret
     69 2:
     70 	/
     71 	/ Move the stack pointer outside the stack bounds if it isn't already.
     72 	/
     73 	movq	%rsp, %rbx
     74 	subq	%rcx, %rbx
     75 	cmpq	%rdx, %rbx
     76 	jae	3f
     77 	pushq	%rbp
     78 	movq	%rsp, %rbp
     79 	movq	%rcx, %rsp
     80 	subq	$STACK_ALIGN, %rsp
     81 3:
     82 	/
     83 	/ Dereference an address in the guard page.
     84 	/
     85 	movb	-1(%rcx), %bl
     86 
     87 	/
     88 	/ If the above load doesn't raise a SIGSEGV then do it ourselves.
     89 	/
     90 	SYSTRAP_RVAL1(lwp_self)
     91 	movl	$SIGSEGV, %esi
     92 	movl	%eax, %edi
     93 	SYSTRAP_RVAL1(lwp_kill)
     94 
     95 	/
     96 	/ Try one last time to take out the process.
     97 	/
     98 	movq	0x0, %rax
     99 	SET_SIZE(_stack_grow)
    100