mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-22 11:17:19 +00:00
1634f50b1b
when we create contexts. The meaning of the flags are documented in <machine/ucontext.h>. I only list them here to help browsing the commit logs: _MC_FLAGS_ASYNC_CONTEXT _MC_FLAGS_HIGHFP_VALID _MC_FLAGS_KSE_SET_MBOX _MC_FLAGS_RETURN_VALID _MC_FLAGS_SCRATCH_VALID Yes, _MC_FLAGS_KSE_SET_MBOX is a hack and I'm proud of it :-)
100 lines
4.4 KiB
C
100 lines
4.4 KiB
C
/*-
|
|
* Copyright (c) 1999 Marcel Moolenaar
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer
|
|
* in this position and unchanged.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. The name of the author may not be used to endorse or promote products
|
|
* derived from this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
#ifndef _MACHINE_UCONTEXT_H_
|
|
#define _MACHINE_UCONTEXT_H_
|
|
|
|
#include <machine/_regset.h>
|
|
|
|
/*
|
|
* The mc_flags field provides the necessary clues when dealing with the gory
|
|
* details of ia64 specific contexts. A comprehensive explanation is added for
|
|
* everybody's sanity, including the author's.
|
|
*
|
|
* The first and foremost variation in the context is synchronous contexts
|
|
* (= synctx) versus asynchronous contexts (= asynctx). A synctx is created
|
|
* synchronously WRT program execution and has the advantage that none of the
|
|
* scratch registers have to be saved. They are assumed to be clobbered by the
|
|
* call to the function that creates the context. An asynctx needs to have the
|
|
* scratch registers preserved because it can describe any point in a thread's
|
|
* (or process') execution.
|
|
*
|
|
* Below a description of the flags and their meaning:
|
|
*
|
|
* _MC_FLAGS_ASYNC_CONTEXT
|
|
* If set, indicates that mc_scratch and mc_scratch_fp are both
|
|
* valid. IFF not set, _MC_FLAGS_RETURN_VALID indicates if the
|
|
* return registers are valid or not.
|
|
* _MC_FLAGS_HIGHFP_VALID
|
|
* If set, indicates that the high FP registers (f32-f127) are
|
|
* valid. This flag is very likely not going to be set for any
|
|
* sensible synctx, but is not explicitly disallowed. Any synctx
|
|
* that has this flag may or may not have the high FP registers
|
|
* restored. In short: don't do it.
|
|
* _MC_FLAGS_KSE_SET_MBOX
|
|
* This flag is special to setcontext(2) and swapcontext(2). It
|
|
* instructs the kernel to write the value in mc_special.isr to
|
|
* the memory address pointed to by mc_special.ifa. This allows
|
|
* the kernel to switch to a new context in a KSE based threaded
|
|
* program. Note that this is a non-srandard extension to the
|
|
* otherwise standard system calls and use of this flag should be
|
|
* limited to KSE.
|
|
* _MC_FLAGS_RETURN_VALID
|
|
* If set and _MC_FLAGS_ASYNC_CONTEXT is not set indicates that
|
|
* the ABI defined return registers are valid. Both getcontext(2)
|
|
* and swapcontext(2) need to save the system call return values.
|
|
* Any synctx that does not have this flag may still have the
|
|
* return registers restored from the context.
|
|
* _MC_FLAGS_SCRATCH_VALID
|
|
* If set and _MC_FLAGS_ASYNC_CONTEXT is not set indicates that
|
|
* the scratch registers, but not the FP registers are valid.
|
|
* This flag is set in contexts passed to signal handlers. This
|
|
* flag is a superset of _MC_FLAGS_RETURN_VALID. If both flags
|
|
* are set, this flag takes precedence.
|
|
*/
|
|
|
|
typedef struct __mcontext {
|
|
unsigned long mc_flags;
|
|
#define _MC_FLAGS_ASYNC_CONTEXT 0x0001
|
|
#define _MC_FLAGS_HIGHFP_VALID 0x0002
|
|
#define _MC_FLAGS_KSE_SET_MBOX 0x0004
|
|
#define _MC_FLAGS_RETURN_VALID 0x0008
|
|
#define _MC_FLAGS_SCRATCH_VALID 0x0010
|
|
unsigned long _reserved_;
|
|
struct _special mc_special;
|
|
struct _callee_saved mc_preserved;
|
|
struct _callee_saved_fp mc_preserved_fp;
|
|
struct _caller_saved mc_scratch;
|
|
struct _caller_saved_fp mc_scratch_fp;
|
|
struct _high_fp mc_high_fp;
|
|
} mcontext_t;
|
|
|
|
#endif /* !_MACHINE_UCONTEXT_H_ */
|