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/* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27#pragma ident "%Z%%M% %I% %E% SMI" 28 29 .file "%M%" 30 31#include <sys/asm_linkage.h> 32 33 ANSI_PRAGMA_WEAK(getcontext,function) 34 ANSI_PRAGMA_WEAK(swapcontext,function) 35 36#include "SYS.h" 37#include <assym.h> 38 39/* 40 * getcontext() and swapcontext() are written in assembler since it has to 41 * capture the correct machine state of the caller, including 42 * the registers: %edi, %esi and %ebx. 43 * 44 * As swapcontext() is actually equivalent to getcontext() + setcontext(), 45 * swapcontext() shares the most code with getcontext(). 46 */ 47 48 49#define GETCONTEXT_IMPL \ 50 movl 4(%esp), %eax; /* %eax <-- first arg: ucp */ \ 51 pushl %eax; /* push ucp for system call */ \ 52 call __getcontext; /* call getcontext: syscall */ \ 53 addl $4, %esp; /* pop arg */ \ 54 andl %eax, %eax; /* if (err_ret_from_syscall) */ \ 55 je 1f; \ 56 ret; /* then return */ \ 571: \ 58 movl 4(%esp), %eax; /* recompute first arg */ \ 59 /* \ 60 * fix up %esp and %eip \ 61 */ \ 62 leal UC_MCONTEXT_GREGS (%eax), %edx; \ 63 /* %edx <-- &ucp->uc_mcontext.gregs */ \ 64 movl 0(%esp), %eax; /* read return PC from stack */ \ 65 movl %eax, EIP_OFF (%edx); \ 66 /* store ret PC in EIP of env var */ \ 67 leal 4(%esp), %eax; /* get caller's sp at time of call */ \ 68 movl %eax, UESP_OFF (%edx); \ 69 /* store the sp into UESP of env var */ \ 70 xorl %eax, %eax; /* return 0 */ \ 71 movl %eax, EAX_OFF (%edx); \ 72 /* getcontext returns 0 after a setcontext */ 73 74/* 75 * getcontext(ucontext_t *ucp) 76 */ 77 ENTRY(getcontext) 78 GETCONTEXT_IMPL 79 ret 80 SET_SIZE(getcontext) 81 82 83/* 84 * swapcontext(ucontext_t *oucp, const ucontext_t *ucp) 85 */ 86 ENTRY(swapcontext) 87 GETCONTEXT_IMPL 88 / call setcontext 89 movl 8(%esp), %eax /* %eax <-- second arg: ucp */ 90 pushl %eax /* push ucp for setcontext */ 91 call setcontext 92 addl $4, %esp /* pop arg: just in case */ 93 ret 94 SET_SIZE(swapcontext) 95