1/* $NetBSD: swapcontext.S,v 1.1 2014/09/03 19:34:25 matt 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 1.1 2014/09/03 19:34:25 matt Exp $") 36 37#define CALLFRAME_LR (-1*4) 38#define CALLFRAME_UCP (-2*4) 39#define CALLFRAME_OUCP (-3*4) 40#define CALLFRAME_GP (-4*4) 41#define CALLFRAME_SP (-5*4) 42#define CALLFRAME_LEN (-CALLFRAME_SP) 43 44ENTRY(swapcontext) 45 l.sw CALLFRAME_LR(r1),lr # save link register 46 l.sw CALLFRAME_OUCP(r1),r3 # save oucp 47 l.sw CALLFRAME_UCP(r1),r4 # save ucp 48 l.sw CALLFRAME_SP(r1),r1 # set up stack chain 49#ifdef __PIC__ 50 l.sw CALLFRAME_GP(r1),r16 # save r16 51 PIC_GOTSETUP(r16) # setup got pointer 52#endif 53 l.addi r1,r1,-CALLFRAME_LEN # adjust stack 54 l.jal PLT(_C_LABEL(_getcontext)) # getcontext(oucp) 55 l.nop # -- delay slot -- 56 l.sfeqi r11,0 # error? 57 l.bnf 1f # yes, cleanup 58 l.nop # -- delay slot -- 59 l.addi r5,r1,CALLFRAME_LEN # adjust stack 60 l.lwz r4,CALLFRAME_OUCP(r5) # load oucp for adjustment 61 l.sw UC_GREGS_PC(r4),lr # pc <- lr 62 l.sw UC_GREGS_SP(r4),r1 # adjust sp 63 l.lwz r3,CALLFRAME_UCP(r5) # load ucp 64 # can't do a tail call due to needing r16 for PLT 65 l.jal PLT(_C_LABEL(setcontext)) # setcontext(ucp) 66 l.nop # -- delay slot -- 671: 68 l.addi r1,r1,CALLFRAME_LEN # restore stack 69#ifdef __PIC__ 70 l.lwz r16,CALLFRAME_GP(r1) # restore r16 71#endif 72 l.lwz lr,CALLFRAME_LR(r1) # refetch lr 73 l.jr lr # simply return 74 l.nop # -- delay slot -- 75END(swapcontext) 76