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      1 /*	$NetBSD: sched.h,v 1.23 2021/12/27 13:28:41 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _LINUX_SCHED_H_
     33 #define _LINUX_SCHED_H_
     34 
     35 #include <sys/param.h>
     36 
     37 #include <sys/cdefs.h>
     38 #include <sys/kernel.h>
     39 #include <sys/lwp.h>
     40 #include <sys/proc.h>
     41 #include <sys/sched.h>
     42 
     43 #include <asm/barrier.h>
     44 #include <asm/param.h>
     45 #include <asm/processor.h>
     46 
     47 #include <linux/device.h>
     48 #include <linux/errno.h>
     49 
     50 struct seq_file;
     51 
     52 #define	TASK_COMM_LEN	MAXCOMLEN
     53 
     54 #define	MAX_SCHEDULE_TIMEOUT	(INT_MAX/2)	/* paranoia */
     55 
     56 #define	TASK_UNINTERRUPTIBLE	__BIT(0)
     57 #define	TASK_INTERRUPTIBLE	__BIT(1)
     58 
     59 #define	current	curproc
     60 
     61 static inline pid_t
     62 task_pid_nr(struct proc *p)
     63 {
     64 	return p->p_pid;
     65 }
     66 
     67 static inline long
     68 schedule_timeout_uninterruptible(long timeout)
     69 {
     70 	unsigned start, end;
     71 
     72 	KASSERT(timeout >= 0);
     73 	KASSERT(timeout < MAX_SCHEDULE_TIMEOUT);
     74 
     75 	if (cold) {
     76 		unsigned us;
     77 		if (hz <= 1000) {
     78 			unsigned ms = hztoms(MIN((unsigned long)timeout,
     79 			    mstohz(INT_MAX/2)));
     80 			us = MIN(ms, INT_MAX/1000)*1000;
     81 		} else if (hz <= 1000000) {
     82 			us = MIN(timeout, (INT_MAX/1000000)/hz)*hz*1000000;
     83 		} else {
     84 			us = timeout/(1000000/hz);
     85 		}
     86 		DELAY(us);
     87 		return 0;
     88 	}
     89 
     90 	start = getticks();
     91 	/* Caller is expected to loop anyway, so no harm in truncating.  */
     92 	(void)kpause("loonix", /*intr*/false, MIN(timeout, INT_MAX/2), NULL);
     93 	end = getticks();
     94 
     95 	return timeout - MIN(timeout, (end - start));
     96 }
     97 
     98 static inline bool
     99 need_resched(void)
    100 {
    101 
    102 	return preempt_needed();
    103 }
    104 
    105 static inline void
    106 cond_resched(void)
    107 {
    108 
    109 	preempt_point();
    110 }
    111 
    112 static inline bool
    113 signal_pending_state(int state, struct proc *p)
    114 {
    115 
    116 	KASSERT(p == current);
    117 	KASSERT(state & (TASK_INTERRUPTIBLE|TASK_UNINTERRUPTIBLE));
    118 	if (state & TASK_UNINTERRUPTIBLE)
    119 		return false;
    120 	return sigispending(curlwp, 0);
    121 }
    122 
    123 static inline void
    124 sched_setscheduler(struct proc *p, int class, struct sched_param *param)
    125 {
    126 
    127 	KASSERT(p == curproc);
    128 	KASSERT(class == SCHED_FIFO);
    129 	KASSERT(param->sched_priority == 1);
    130 
    131 	lwp_lock(curlwp);
    132 	curlwp->l_class = class;
    133 	lwp_changepri(curlwp, PRI_KERNEL_RT);
    134 	lwp_unlock(curlwp);
    135 }
    136 
    137 #endif  /* _LINUX_SCHED_H_ */
    138