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() is written in assembler since it has to capture the correct 41 * machine state of the calle. 42 * 43 * As swapcontext() is actually equivalent to getcontext() + setcontext(), 44 * swapcontext() shares the most code with getcontext(). 45 */ 46 47#define GETCONTEXT_IMPL(offset) \ 48 pushq %rdi; /* preserve the ucontext_t pointer */ \ 49 call __getcontext; \ 50 /* call getcontext: syscall */ \ 51 popq %rdx; \ 52 andl %eax, %eax; /* if (error_return_from_syscall) */ \ 53 je 1f; \ 54 addq $offset, %rsp; \ 55 ret; /* then just return */ \ 561: \ 57 /* \ 58 * fix up %rsp and %rip \ 59 */ \ 60 addq $UC_MCONTEXT_GREGS, %rdx; \ 61 /* &ucp->uc_mcontext.gregs */ \ 62 movq offset+0(%rsp), %rax; \ 63 /* read return PC from stack */ \ 64 movq %rax, RIP_OFF (%rdx); \ 65 /* store ret PC in EIP of env var */ \ 66 leaq offset+8(%rsp), %rax; \ 67 /* get caller's sp at time of call */ \ 68 movq %rax, RSP_OFF (%rdx); \ 69 /* store the sp into UESP of env var */ \ 70 xorq %rax, %rax; /* return 0 */ \ 71 movq %rax, RAX_OFF (%rdx); \ 72 /* getcontext returns 0 after setcontext */ 73 74/* 75 * getcontext(ucontext_t *ucp) 76 */ 77 78 ENTRY(getcontext) 79 GETCONTEXT_IMPL(0) 80 ret 81 SET_SIZE(getcontext) 82 83/* 84 * swapcontext(ucontext_t *oucp, const ucontext_t *ucp) 85 */ 86 87 ENTRY(swapcontext) 88 pushq %rsi /* preserve the 2nd argument */ 89 90 GETCONTEXT_IMPL(8) 91 92 /* call setcontext */ 93 popq %rdi 94 call setcontext 95 ret 96 SET_SIZE(swapcontext) 97