ucontext.h revision 118590
1/*- 2 * Copyright (c) 1999 Marcel Moolenaar 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD: head/sys/ia64/include/ucontext.h 118590 2003-08-07 07:52:39Z marcel $ 29 */ 30 31#ifndef _MACHINE_UCONTEXT_H_ 32#define _MACHINE_UCONTEXT_H_ 33 34#include <machine/_regset.h> 35 36/* 37 * The mc_flags field provides the necessary clues when dealing with the gory 38 * details of ia64 specific contexts. A comprehensive explanation is added for 39 * everybody's sanity, including the author's. 40 * 41 * The first and foremost variation in the context is synchronous contexts 42 * (= synctx) versus asynchronous contexts (= asynctx). A synctx is created 43 * synchronously WRT program execution and has the advantage that none of the 44 * scratch registers have to be saved. They are assumed to be clobbered by the 45 * call to the function that creates the context. An asynctx needs to have the 46 * scratch registers preserved because it can describe any point in a thread's 47 * (or process') execution. 48 * 49 * Below a description of the flags and their meaning: 50 * 51 * _MC_FLAGS_ASYNC_CONTEXT 52 * If set, indicates that mc_scratch and mc_scratch_fp are both 53 * valid. IFF not set, _MC_FLAGS_RETURN_VALID indicates if the 54 * return registers are valid or not. 55 * _MC_FLAGS_HIGHFP_VALID 56 * If set, indicates that the high FP registers (f32-f127) are 57 * valid. This flag is very likely not going to be set for any 58 * sensible synctx, but is not explicitly disallowed. Any synctx 59 * that has this flag may or may not have the high FP registers 60 * restored. In short: don't do it. 61 * _MC_FLAGS_KSE_SET_MBOX 62 * This flag is special to setcontext(2) and swapcontext(2). It 63 * instructs the kernel to write the value in mc_special.isr to 64 * the memory address pointed to by mc_special.ifa. This allows 65 * the kernel to switch to a new context in a KSE based threaded 66 * program. Note that this is a non-srandard extension to the 67 * otherwise standard system calls and use of this flag should be 68 * limited to KSE. 69 * _MC_FLAGS_RETURN_VALID 70 * If set and _MC_FLAGS_ASYNC_CONTEXT is not set indicates that 71 * the ABI defined return registers are valid. Both getcontext(2) 72 * and swapcontext(2) need to save the system call return values. 73 * Any synctx that does not have this flag may still have the 74 * return registers restored from the context. 75 * _MC_FLAGS_SCRATCH_VALID 76 * If set and _MC_FLAGS_ASYNC_CONTEXT is not set indicates that 77 * the scratch registers, but not the FP registers are valid. 78 * This flag is set in contexts passed to signal handlers. This 79 * flag is a superset of _MC_FLAGS_RETURN_VALID. If both flags 80 * are set, this flag takes precedence. 81 */ 82 83typedef struct __mcontext { 84 unsigned long mc_flags; 85#define _MC_FLAGS_ASYNC_CONTEXT 0x0001 86#define _MC_FLAGS_HIGHFP_VALID 0x0002 87#define _MC_FLAGS_KSE_SET_MBOX 0x0004 88#define _MC_FLAGS_RETURN_VALID 0x0008 89#define _MC_FLAGS_SCRATCH_VALID 0x0010 90 unsigned long _reserved_; 91 struct _special mc_special; 92 struct _callee_saved mc_preserved; 93 struct _callee_saved_fp mc_preserved_fp; 94 struct _caller_saved mc_scratch; 95 struct _caller_saved_fp mc_scratch_fp; 96 struct _high_fp mc_high_fp; 97} mcontext_t; 98 99#endif /* !_MACHINE_UCONTEXT_H_ */ 100