Annotation of OSKit-Mach/kern/ast.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Mach Operating System
        !             3:  * Copyright (c) 1991,1990,1989 Carnegie Mellon University.
        !             4:  * Copyright (c) 1993,1994 The University of Utah and
        !             5:  * the Computer Systems Laboratory (CSL).
        !             6:  * All rights reserved.
        !             7:  *
        !             8:  * Permission to use, copy, modify and distribute this software and its
        !             9:  * documentation is hereby granted, provided that both the copyright
        !            10:  * notice and this permission notice appear in all copies of the
        !            11:  * software, derivative works or modified versions, and any portions
        !            12:  * thereof, and that both notices appear in supporting documentation.
        !            13:  *
        !            14:  * CARNEGIE MELLON, THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF
        !            15:  * THIS SOFTWARE IN ITS "AS IS" CONDITION, AND DISCLAIM ANY LIABILITY
        !            16:  * OF ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF
        !            17:  * THIS SOFTWARE.
        !            18:  *
        !            19:  * Carnegie Mellon requests users of this software to return to
        !            20:  *
        !            21:  *  Software Distribution Coordinator  or  [email protected]
        !            22:  *  School of Computer Science
        !            23:  *  Carnegie Mellon University
        !            24:  *  Pittsburgh PA 15213-3890
        !            25:  *
        !            26:  * any improvements or extensions that they make and grant Carnegie Mellon
        !            27:  * the rights to redistribute these changes.
        !            28:  */
        !            29: /*
        !            30:  *     kern/ast.h: Definitions for Asynchronous System Traps.
        !            31:  */
        !            32: 
        !            33: #ifndef        _KERN_AST_H_
        !            34: #define _KERN_AST_H_
        !            35: 
        !            36: /*
        !            37:  *     A CPU takes an AST when it is about to return to user code.
        !            38:  *     Instead of going back to user code, it calls ast_taken.
        !            39:  *     Machine-dependent code is responsible for maintaining
        !            40:  *     a set of reasons for an AST, and passing this set to ast_taken.
        !            41:  */
        !            42: 
        !            43: #include <cpus.h>
        !            44: 
        !            45: #include "cpu_number.h"
        !            46: #include <kern/macro_help.h>
        !            47: #include <machine/ast.h>
        !            48: 
        !            49: /*
        !            50:  *     Bits for reasons
        !            51:  */
        !            52: 
        !            53: #define        AST_ZILCH       0x0
        !            54: #define AST_HALT       0x1
        !            55: #define AST_TERMINATE  0x2
        !            56: #define AST_BLOCK      0x4
        !            57: #define AST_NETWORK    0x8
        !            58: #define AST_NETIPC     0x10
        !            59: 
        !            60: #define        AST_SCHEDULING  (AST_HALT|AST_TERMINATE|AST_BLOCK)
        !            61: 
        !            62: /*
        !            63:  * Per-thread ASTs are reset at context-switch time.
        !            64:  * machine/ast.h can define MACHINE_AST_PER_THREAD.
        !            65:  */
        !            66: 
        !            67: #ifndef        MACHINE_AST_PER_THREAD
        !            68: #define        MACHINE_AST_PER_THREAD  0
        !            69: #endif
        !            70: 
        !            71: #define AST_PER_THREAD  (AST_HALT | AST_TERMINATE | MACHINE_AST_PER_THREAD)
        !            72: 
        !            73: typedef unsigned int ast_t;
        !            74: 
        !            75: extern volatile ast_t need_ast[NCPUS];
        !            76: 
        !            77: #ifdef MACHINE_AST
        !            78: /*
        !            79:  *     machine/ast.h is responsible for defining aston and astoff.
        !            80:  */
        !            81: #else  /* MACHINE_AST */
        !            82: 
        !            83: #define aston(mycpu)
        !            84: #define astoff(mycpu)
        !            85: 
        !            86: #endif /* MACHINE_AST */
        !            87: 
        !            88: extern void ast_taken();
        !            89: 
        !            90: /*
        !            91:  *     ast_needed, ast_on, ast_off, ast_context, and ast_propagate
        !            92:  *     assume splsched.  mycpu is always cpu_number().  It is an
        !            93:  *     argument in case cpu_number() is expensive.
        !            94:  */
        !            95: 
        !            96: #define ast_needed(mycpu)              need_ast[mycpu]
        !            97: 
        !            98: #define ast_on(mycpu, reasons)                                         \
        !            99: MACRO_BEGIN                                                            \
        !           100:        if ((need_ast[mycpu] |= (reasons)) != AST_ZILCH)                \
        !           101:                { aston(mycpu); }                                       \
        !           102: MACRO_END
        !           103: 
        !           104: #define ast_off(mycpu, reasons)                                                \
        !           105: MACRO_BEGIN                                                            \
        !           106:        if ((need_ast[mycpu] &= ~(reasons)) == AST_ZILCH)               \
        !           107:                { astoff(mycpu); }                                      \
        !           108: MACRO_END
        !           109: 
        !           110: #define ast_propagate(thread, mycpu)   ast_on((mycpu), (thread)->ast)
        !           111: 
        !           112: #define ast_context(thread, mycpu)                                     \
        !           113: MACRO_BEGIN                                                            \
        !           114:        if ((need_ast[mycpu] =                                          \
        !           115:             (need_ast[mycpu] &~ AST_PER_THREAD) | (thread)->ast)       \
        !           116:                                        != AST_ZILCH)                   \
        !           117:                { aston(mycpu); }                                       \
        !           118:        else                                                            \
        !           119:                { astoff(mycpu); }                                      \
        !           120: MACRO_END
        !           121: 
        !           122: 
        !           123: #define        thread_ast_set(thread, reason)          (thread)->ast |= (reason)
        !           124: #define thread_ast_clear(thread, reason)       (thread)->ast &= ~(reason)
        !           125: #define thread_ast_clear_all(thread)           (thread)->ast = AST_ZILCH
        !           126: 
        !           127: /*
        !           128:  *     NOTE: if thread is the current thread, thread_ast_set should
        !           129:  *     be followed by ast_propagate().
        !           130:  */
        !           131: 
        !           132: #endif /* _KERN_AST_H_ */

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