resumecontext.S revision 1.7
1 1.7 riastrad /* $NetBSD: resumecontext.S,v 1.7 2025/05/03 19:56:21 riastradh Exp $ */ 2 1.1 fvdl 3 1.1 fvdl /*- 4 1.1 fvdl * Copyright (c) 1999 The NetBSD Foundation, Inc. 5 1.1 fvdl * All rights reserved. 6 1.1 fvdl * 7 1.1 fvdl * This code is derived from software contributed to The NetBSD Foundation 8 1.1 fvdl * by Klaus Klein. 9 1.1 fvdl * 10 1.1 fvdl * Redistribution and use in source and binary forms, with or without 11 1.1 fvdl * modification, are permitted provided that the following conditions 12 1.1 fvdl * are met: 13 1.1 fvdl * 1. Redistributions of source code must retain the above copyright 14 1.1 fvdl * notice, this list of conditions and the following disclaimer. 15 1.1 fvdl * 2. Redistributions in binary form must reproduce the above copyright 16 1.1 fvdl * notice, this list of conditions and the following disclaimer in the 17 1.1 fvdl * documentation and/or other materials provided with the distribution. 18 1.1 fvdl * 19 1.1 fvdl * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 1.1 fvdl * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 1.1 fvdl * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 1.1 fvdl * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 1.1 fvdl * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 1.1 fvdl * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 1.1 fvdl * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 1.1 fvdl * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 1.1 fvdl * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 1.1 fvdl * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 1.1 fvdl * POSSIBILITY OF SUCH DAMAGE. 30 1.1 fvdl * 31 1.1 fvdl * Modified for x86-64 by fvdl (at) wasabisystems.com 32 1.1 fvdl */ 33 1.1 fvdl 34 1.1 fvdl #include <machine/asm.h> 35 1.3 drochner #include "SYS.h" 36 1.1 fvdl 37 1.1 fvdl #if defined(LIBC_SCCS) && !defined(lint) 38 1.7 riastrad RCSID("$NetBSD: resumecontext.S,v 1.7 2025/05/03 19:56:21 riastradh Exp $") 39 1.1 fvdl #endif /* LIBC_SCCS && !lint */ 40 1.1 fvdl 41 1.1 fvdl /* 42 1.1 fvdl * This assembly-language implementation differs from the (obvious) 43 1.1 fvdl * C-language implementation only in not clobbering the previous 44 1.1 fvdl * function's return address (us), which is the point of the exercise. 45 1.1 fvdl */ 46 1.1 fvdl 47 1.1 fvdl NENTRY(_resumecontext) /* profiling prologue would clobber TOS */ 48 1.1 fvdl leaq -(8 + 784)(%rsp),%rdi /* retaddr + sizeof (ucontext_t) */ 49 1.1 fvdl andq $~15,%rdi /* align on _UC_UCONTEXT_ALIGN */ 50 1.1 fvdl movq %rdi,%rsp 51 1.1 fvdl call PIC_PLT(_C_LABEL(_getcontext)) 52 1.3 drochner movq 8(%rsp),%rdi /* uc_link */ 53 1.3 drochner testq %rdi,%rdi /* link end? */ 54 1.3 drochner jnz 9f 55 1.3 drochner 56 1.3 drochner /* normal exit */ 57 1.3 drochner call PIC_PLT(_C_LABEL(exit)) 58 1.3 drochner 59 1.3 drochner 9: 60 1.1 fvdl call PIC_PLT(_C_LABEL(setcontext)) 61 1.1 fvdl /* NOTREACHED */ 62 1.3 drochner 63 1.3 drochner /* something is wrong, pull the brake */ 64 1.3 drochner movq $-1,%rdi 65 1.3 drochner movq $SYS_exit,%rax 66 1.3 drochner syscall 67 1.3 drochner /* NOTREACHED */ 68 1.6 uebayasi END(_resumecontext) 69
Indexes created Wed Oct 01 19:09:53 GMT 2025