1/* $OpenBSD: brk.S,v 1.6 2023/12/10 16:45:52 deraadt Exp $ */ 2 3/* 4 * Copyright (c) 1996 Dale Rahn 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28#include "SYS.h" 29 30 .extern __curbrk 31 .extern _end 32 33 .weak brk 34 35SYSENTRY(brk) 36 RETGUARD_SETUP(brk, %r11) 37 38 /* check >= _end, if not make the call for _end */ 39 addis %r5, %r2, .LC0@toc@ha 40 ld %r5, .LC0@toc@l(%r5) /* # %r5 = &_end */ 41 42 cmpld %r3, %r5 43 bge+ .L_brk_call 44 mr %r3, %r5 45 46.L_brk_call: 47 mr %r7, %r3 48 /* call break(size) */ 49 addis %r6, %r2, __curbrk@toc@ha 50 addi %r6, %r6, __curbrk@toc@l /* # %r6 = &__curbrk */ 51 52 li %r0, SYS_break 5399: sc 54 PINSYSCALL(SYS_break, 99b) 55 56 /* check for error */ 57 cmpwi %r0, 0 58 beq+ .L_brk_ok /* OK so this is stupid but I haven't read b */ 59 stw %r0, R13_OFFSET_ERRNO(%r13) 60 li %r3, -1 61 b .L_done 62 nop 63 64 /* update, __curbrk and return */ 65.L_brk_ok: 66 std %r7, 0(%r6) /* # remember, %r6=&__curbrk, %r3=new value */ 67 mr %r3, 0 /* # return 0 */ 68.L_done: 69 RETGUARD_CHECK(brk, %r11); 70 blr 71END(brk) 72 73 .section .toc,"aw",@progbits 74.LC0: 75 .tc _end[TC],_end 76