1/* $NetBSD: swapcontext.S,v 1.8 2018/02/28 20:51:58 uwe Exp $ */ 2 3/*- 4 * Copyright (c) 2001 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Klaus Klein. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include "SYS.h" 33#include "assym.h" 34 35__RCSID("$NetBSD: swapcontext.S,v 1.8 2018/02/28 20:51:58 uwe Exp $") 36 37#define XCALLFRAMELEN (((2+3)*SZREG + CALLFRAMELEN - 1) & -CALLFRAMELEN) 38#define XCALLFRAME_R30 (XCALLFRAMELEN-1*SZREG) 39#define XCALLFRAME_UCP (XCALLFRAMELEN-2*SZREG) 40#define XCALLFRAME_OUCP (XCALLFRAMELEN-3*SZREG) 41 42ENTRY(swapcontext) 43 stwu %r1,-XCALLFRAMELEN(%r1) # set up new stack frame 44 mflr %r0 45 stw %r0,XCALLFRAMELEN+CALLFRAME_LR(%r1) # save link register 46 stw %r3,XCALLFRAME_OUCP(%r1) # must save oucp 47 stw %r4,XCALLFRAME_UCP(%r1) # must save ucp 48#ifdef __PIC__ 49 stw %r30,XCALLFRAME_R30(%r1) # must save r30 50 PIC_TOCSETUP(swapcontext,%r30) # setup toc pointer 51#endif 52 bl PIC_PLT(_C_LABEL(_getcontext)) # getcontext(oucp) 53 cmpwi %r3,0 54 bne 1f 55 lwz %r11,XCALLFRAME_OUCP(%r1) # load oucp for adjustment 56 lwz %r0,XCALLFRAMELEN+CALLFRAME_LR(%r1) 57 stw %r0,UC_GREGS_PC(%r11) # pc <- lr 58 addi %r0,%r1,XCALLFRAMELEN 59 stw %r0,UC_GREGS_R1(%r11) # adjust sp 60#ifdef __PIC__ 61 lwz %r0,XCALLFRAME_R30(%r1) 62 stw %r0,UC_GREGS_R30(%r11) # caller's r30 63#endif 64 lwz %r3,XCALLFRAME_UCP(%r1) # load ucp 65 bl PIC_PLT(_C_LABEL(setcontext)) # setcontext(ucp) 661: 67 lwz %r0,XCALLFRAMELEN+CALLFRAME_LR(%r1) 68#ifdef __PIC__ 69 lwz %r30,XCALLFRAME_R30(%r1) 70#endif 71 mtlr %r0 72 addi %r1,%r1,XCALLFRAMELEN 73 blr 74END(swapcontext) 75