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/*
* Mach Operating System
* Copyright (c) 1991,1990,1989 Carnegie Mellon University.
* Copyright (c) 1993,1994 The University of Utah and
* the Computer Systems Laboratory (CSL).
* All rights reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON, THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF
* THIS SOFTWARE IN ITS "AS IS" CONDITION, AND DISCLAIM ANY LIABILITY
* OF ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF
* THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
/*
* kern/ast.h: Definitions for Asynchronous System Traps.
*/
#ifndef _KERN_AST_H_
#define _KERN_AST_H_
/*
* A CPU takes an AST when it is about to return to user code.
* Instead of going back to user code, it calls ast_taken.
* Machine-dependent code is responsible for maintaining
* a set of reasons for an AST, and passing this set to ast_taken.
*/
#include "cpu_number.h"
#include <kern/macro_help.h>
#include <machine/ast.h>
/*
* Bits for reasons
*/
#define AST_ZILCH 0x0
#define AST_HALT 0x1
#define AST_TERMINATE 0x2
#define AST_BLOCK 0x4
#define AST_NETWORK 0x8
#define AST_NETIPC 0x10
#define AST_SCHEDULING (AST_HALT|AST_TERMINATE|AST_BLOCK)
/*
* Per-thread ASTs are reset at context-switch time.
* machine/ast.h can define MACHINE_AST_PER_THREAD.
*/
#ifndef MACHINE_AST_PER_THREAD
#define MACHINE_AST_PER_THREAD 0
#endif
#define AST_PER_THREAD (AST_HALT | AST_TERMINATE | MACHINE_AST_PER_THREAD)
typedef unsigned int ast_t;
extern volatile ast_t need_ast[NCPUS];
#ifdef MACHINE_AST
/*
* machine/ast.h is responsible for defining aston and astoff.
*/
#else /* MACHINE_AST */
#define aston(mycpu)
#define astoff(mycpu)
#endif /* MACHINE_AST */
extern void ast_taken(void);
/*
* ast_needed, ast_on, ast_off, ast_context, and ast_propagate
* assume splsched. mycpu is always cpu_number(). It is an
* argument in case cpu_number() is expensive.
*/
#define ast_needed(mycpu) need_ast[mycpu]
#define ast_on(mycpu, reasons) \
MACRO_BEGIN \
if ((need_ast[mycpu] |= (reasons)) != AST_ZILCH) \
{ aston(mycpu); } \
MACRO_END
#define ast_off(mycpu, reasons) \
MACRO_BEGIN \
if ((need_ast[mycpu] &= ~(reasons)) == AST_ZILCH) \
{ astoff(mycpu); } \
MACRO_END
#define ast_propagate(thread, mycpu) ast_on((mycpu), (thread)->ast)
#define ast_context(thread, mycpu) \
MACRO_BEGIN \
if ((need_ast[mycpu] = \
(need_ast[mycpu] &~ AST_PER_THREAD) | (thread)->ast) \
!= AST_ZILCH) \
{ aston(mycpu); } \
else \
{ astoff(mycpu); } \
MACRO_END
#define thread_ast_set(thread, reason) (thread)->ast |= (reason)
#define thread_ast_clear(thread, reason) (thread)->ast &= ~(reason)
#define thread_ast_clear_all(thread) (thread)->ast = AST_ZILCH
/*
* NOTE: if thread is the current thread, thread_ast_set should
* be followed by ast_propagate().
*/
#endif /* _KERN_AST_H_ */
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