/* * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved. * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* * @OSF_COPYRIGHT@ */ /* * Mach Operating System * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University * 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 ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS 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. */ /* */ /* * * This file contains routines to check whether an ast is needed. * * ast_check() - check whether ast is needed for interrupt or context * switch. Usually called by clock interrupt handler. * */ #include <cputypes.h> #include <cpus.h> #include <platforms.h> #include <kern/ast.h> #include <kern/counters.h> #include <kern/cpu_number.h> #include <kern/misc_protos.h> #include <kern/queue.h> #include <kern/sched_prim.h> #include <kern/thread.h> #include <kern/thread_act.h> #include <kern/thread_swap.h> #include <kern/processor.h> #include <kern/spl.h> #include <mach/policy.h> volatile ast_t need_ast[NCPUS]; void ast_init(void) { #ifndef MACHINE_AST register int i; for (i=0; i<NCPUS; i++) { need_ast[i] = AST_NONE; } #endif /* MACHINE_AST */ } /* * Called at splsched. */ void ast_taken( ast_t reasons, boolean_t enable ) { register thread_t self = current_thread(); register int mycpu = cpu_number(); boolean_t preempt_trap = (reasons == AST_PREEMPTION); reasons &= need_ast[mycpu]; need_ast[mycpu] &= ~reasons; /* * Handle ASTs for all threads * except idle processor threads. */ if (!(self->state & TH_IDLE)) { /* * Check for urgent preemption. */ if ( (reasons & AST_URGENT) && wait_queue_assert_possible(self) ) { if (reasons & AST_PREEMPT) { counter(c_ast_taken_block++); thread_block_reason(THREAD_CONTINUE_NULL, AST_PREEMPT | AST_URGENT); } reasons &= ~AST_PREEMPTION; } /* * The kernel preempt traps * skip all other ASTs. */ if (!preempt_trap) { ml_set_interrupts_enabled(enable); #ifdef MACH_BSD /* * Handle BSD hook. */ if (reasons & AST_BSD) { extern void bsd_ast(thread_act_t act); thread_act_t act = self->top_act; thread_ast_clear(act, AST_BSD); bsd_ast(act); } #endif /* * Thread APC hook. */ if (reasons & AST_APC) act_execute_returnhandlers(); ml_set_interrupts_enabled(FALSE); /* * Check for preemption. */ if (reasons & AST_PREEMPT) { processor_t myprocessor = current_processor(); if (csw_needed(self, myprocessor)) reasons = AST_PREEMPT; else reasons = AST_NONE; } if ( (reasons & AST_PREEMPT) && wait_queue_assert_possible(self) ) { counter(c_ast_taken_block++); thread_block_reason(thread_exception_return, AST_PREEMPT); } } } ml_set_interrupts_enabled(enable); } /* * Called at splsched. */ void ast_check( processor_t processor) { register thread_t self = processor->active_thread; processor->current_pri = self->sched_pri; if (processor->state == PROCESSOR_RUNNING) { register ast_t preempt; processor_running: /* * Propagate thread ast to processor. */ ast_propagate(self->top_act->ast); /* * Context switch check. */ if ((preempt = csw_check(self, processor)) != AST_NONE) ast_on(preempt); } else if ( processor->state == PROCESSOR_DISPATCHING || processor->state == PROCESSOR_IDLE ) { return; } else if (processor->state == PROCESSOR_SHUTDOWN) goto processor_running; }