1 1.9 riastrad /* $NetBSD: resumecontext.S,v 1.9 2025/05/03 19:55:32 riastradh Exp $ */ 2 1.2 thorpej 3 1.2 thorpej /*- 4 1.2 thorpej * Copyright (c) 1999 The NetBSD Foundation, Inc. 5 1.2 thorpej * All rights reserved. 6 1.2 thorpej * 7 1.2 thorpej * This code is derived from software contributed to The NetBSD Foundation 8 1.2 thorpej * by Klaus Klein. 9 1.2 thorpej * 10 1.2 thorpej * Redistribution and use in source and binary forms, with or without 11 1.2 thorpej * modification, are permitted provided that the following conditions 12 1.2 thorpej * are met: 13 1.2 thorpej * 1. Redistributions of source code must retain the above copyright 14 1.2 thorpej * notice, this list of conditions and the following disclaimer. 15 1.2 thorpej * 2. Redistributions in binary form must reproduce the above copyright 16 1.2 thorpej * notice, this list of conditions and the following disclaimer in the 17 1.2 thorpej * documentation and/or other materials provided with the distribution. 18 1.2 thorpej * 19 1.2 thorpej * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 1.2 thorpej * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 1.2 thorpej * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 1.2 thorpej * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 1.2 thorpej * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 1.2 thorpej * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 1.2 thorpej * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 1.2 thorpej * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 1.2 thorpej * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 1.2 thorpej * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 1.2 thorpej * POSSIBILITY OF SUCH DAMAGE. 30 1.2 thorpej */ 31 1.2 thorpej 32 1.2 thorpej #include <machine/asm.h> 33 1.5 drochner #include "SYS.h" 34 1.2 thorpej 35 1.2 thorpej #if defined(LIBC_SCCS) && !defined(lint) 36 1.9 riastrad RCSID("$NetBSD: resumecontext.S,v 1.9 2025/05/03 19:55:32 riastradh Exp $") 37 1.2 thorpej #endif /* LIBC_SCCS && !lint */ 38 1.2 thorpej 39 1.2 thorpej /* 40 1.2 thorpej * This assembly-language implementation differs from the (obvious) 41 1.2 thorpej * C-language implementation only in not clobbering the previous 42 1.2 thorpej * function's return address (us), which is the point of the exercise. 43 1.2 thorpej */ 44 1.2 thorpej 45 1.2 thorpej NENTRY(_resumecontext) /* profiling prologue would clobber TOS */ 46 1.4 kleink leal -(4 + 776)(%esp),%ecx /* retaddr + sizeof (ucontext_t) */ 47 1.4 kleink andl $~(0xf),%ecx /* align on _UC_UCONTEXT_ALIGN */ 48 1.4 kleink movl %ecx,%esp 49 1.2 thorpej PIC_PROLOGUE 50 1.2 thorpej pushl %ecx 51 1.2 thorpej call PIC_PLT(_C_LABEL(_getcontext)) 52 1.2 thorpej addl $4,%esp 53 1.2 thorpej PIC_EPILOGUE 54 1.4 kleink movl 4(%esp),%ecx /* uc_link */ 55 1.2 thorpej PIC_PROLOGUE 56 1.5 drochner pushl %ecx /* argument for exit() or setcontext() */ 57 1.5 drochner testl %ecx,%ecx /* link end? */ 58 1.5 drochner jnz 9f /* watch out for local label use in PIC_* */ 59 1.5 drochner 60 1.5 drochner /* normal exit */ 61 1.5 drochner call PIC_PLT(_C_LABEL(exit)) 62 1.5 drochner /* NOTREACHED */ 63 1.5 drochner 64 1.5 drochner 9: 65 1.2 thorpej call PIC_PLT(_C_LABEL(setcontext)) 66 1.2 thorpej /* NOTREACHED */ 67 1.5 drochner 68 1.5 drochner /* something is wrong, pull the brake */ 69 1.5 drochner pushl $-1 70 1.5 drochner pushl %eax /* unused return address */ 71 1.5 drochner SYSTRAP(exit) 72 1.8 uebayasi END(_resumecontext) 73
Indexes created Tue Sep 23 14:10:03 GMT 2025