sys/dev/drm/include/linux/sched.h

   1 /*
   2  * Copyright (c) 2015-2020 François Tigeot <ftigeot@wolfpond.org>
   3  * Copyright (c) 2019-2020 Matthew Dillon <dillon@backplane.com>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice unmodified, this list of conditions, and the following
  11  *    disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #ifndef _LINUX_SCHED_H_
  29 #define _LINUX_SCHED_H_
  30
  31 #include <linux/capability.h>
  32 #include <linux/threads.h>
  33 #include <linux/kernel.h>
  34 #include <linux/types.h>
  35 #include <linux/jiffies.h>
  36 #include <linux/rbtree.h>
  37 #include <linux/thread_info.h>
  38 #include <linux/cpumask.h>
  39 #include <linux/errno.h>
  40 #include <linux/mm_types.h>
  41 #include <linux/preempt.h>
  42
  43 #include <asm/page.h>
  44
  45 #include <linux/smp.h>
  46 #include <linux/compiler.h>
  47 #include <linux/completion.h>
  48 #include <linux/pid.h>
  49 #include <linux/rcupdate.h>
  50 #include <linux/rculist.h>
  51
  52 #include <linux/time.h>
  53 #include <linux/timer.h>
  54 #include <linux/hrtimer.h>
  55 #include <linux/llist.h>
  56 #include <linux/gfp.h>
  57
  58 #include <asm/processor.h>
  59
  60 #include <linux/spinlock.h>
  61
  62 #include <sys/param.h>
  63 #include <sys/systm.h>
  64 #include <sys/proc.h>
  65 #include <sys/sched.h>
  66 #include <sys/signal2.h>
  67
  68 #include <machine/cpu.h>
  69
  70 struct seq_file;
  71
  72 #define TASK_RUNNING            0
  73 #define TASK_INTERRUPTIBLE      1
  74 #define TASK_UNINTERRUPTIBLE    2
  75
  76 #define TASK_NORMAL             (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
  77
  78 #define MAX_SCHEDULE_TIMEOUT    LONG_MAX
  79
  80 #define TASK_COMM_LEN   MAXCOMLEN
  81
  82 struct task_struct {
  83         struct thread *dfly_td;
  84         volatile long state;
  85         struct mm_struct *mm;   /* mirror copy in p->p_linux_mm */
  86         int prio;
  87
  88         /* kthread-specific data */
  89         unsigned long           kt_flags;
  90         int                     (*kt_fn)(void *data);
  91         void                    *kt_fndata;
  92         int                     kt_exitvalue;
  93
  94         /* executable name without path */
  95         char                    comm[TASK_COMM_LEN];
  96
  97         atomic_t usage_counter;
  98         pid_t pid;
  99         struct spinlock         kt_spin;
 100 };
 101
 102 #define __set_current_state(state_value)        current->state = (state_value);
 103
 104 #define set_current_state(state_value)          \
 105 do {                                            \
 106         __set_current_state(state_value);       \
 107         mb();                                   \
 108 } while (0)
 109
 110 /*
 111  * schedule_timeout: puts the current thread to sleep until timeout
 112  * if its state allows it to.
 113  */
 114 static inline long
 115 schedule_timeout(signed long timeout)
 116 {
 117         unsigned long time_before, time_after;
 118         long slept, ret = 0;
 119         int timo;
 120
 121         if (timeout < 0) {
 122                 kprintf("schedule_timeout(): timeout cannot be negative\n");
 123                 goto done;
 124         }
 125
 126         /*
 127          * Indefinite wait if timeout is MAX_SCHEDULE_TIMEOUT, but we are
 128          * also translating to an integer.  The first conditional will
 129          * cover both but to code defensively test both.
 130          */
 131         if (timeout >= INT_MAX || timeout == MAX_SCHEDULE_TIMEOUT)
 132                 timo = 0;
 133         else
 134                 timo = timeout;
 135
 136         spin_lock(&current->kt_spin);
 137
 138         switch (current->state) {
 139         case TASK_INTERRUPTIBLE:
 140                 time_before = ticks;
 141                 ssleep(current, &current->kt_spin, PCATCH, "lstim", timo);
 142                 time_after = ticks;
 143                 slept = time_after - time_before;
 144                 ret = timeout - slept;
 145                 if (ret < 0)
 146                         ret = 0;
 147                 break;
 148         case TASK_UNINTERRUPTIBLE:
 149                 ssleep(current, &current->kt_spin, 0, "lstim", timo);
 150                 break;
 151         default:
 152                 /*
 153                  * Task has been flagged running before we could
 154                  * enter the sleep.
 155                  *
 156                  * XXX should be able to remove this ssleep(), have it
 157                  * here to protect against live-locks in case we mess
 158                  * up the task->state.
 159                  */
 160                 ssleep(current, &current->kt_spin, 0, "lst1", 1);
 161                 break;
 162         }
 163
 164         spin_unlock(&current->kt_spin);
 165
 166 done:
 167         if (timeout == MAX_SCHEDULE_TIMEOUT)
 168                 ret = MAX_SCHEDULE_TIMEOUT;
 169
 170         current->state = TASK_RUNNING;
 171         return ret;
 172 }
 173
 174 static inline void
 175 schedule(void)
 176 {
 177         (void)schedule_timeout(MAX_SCHEDULE_TIMEOUT);
 178 }
 179
 180 static inline signed long
 181 schedule_timeout_uninterruptible(signed long timeout)
 182 {
 183         __set_current_state(TASK_UNINTERRUPTIBLE);
 184         return schedule_timeout(timeout);
 185 }
 186
 187 static inline long
 188 io_schedule_timeout(signed long timeout)
 189 {
 190         return schedule_timeout(timeout);
 191 }
 192
 193 /*
 194  * local_clock: fast time source, monotonic on the same cpu
 195  */
 196 static inline uint64_t
 197 local_clock(void)
 198 {
 199         struct timespec ts;
 200
 201         getnanouptime(&ts);
 202         return (ts.tv_sec * NSEC_PER_SEC) + ts.tv_nsec;
 203 }
 204
 205 static inline void
 206 yield(void)
 207 {
 208         lwkt_yield();
 209 }
 210
 211 static inline int
 212 wake_up_process(struct task_struct *tsk)
 213 {
 214         long ostate;
 215
 216         /*
 217          * Among other things, this function is supposed to act as
 218          * a barrier
 219          */
 220         smp_wmb();
 221         spin_lock(&tsk->kt_spin);
 222         ostate = tsk->state;
 223         tsk->state = TASK_RUNNING;
 224         spin_unlock(&tsk->kt_spin);
 225         /* if (ostate != TASK_RUNNING) */
 226         wakeup(tsk);
 227
 228         return 1;       /* Always indicate the process was woken up */
 229 }
 230
 231 static inline int
 232 signal_pending(struct task_struct *p)
 233 {
 234         struct thread *t = p->dfly_td;
 235
 236         /* Some kernel threads do not have lwp, t->td_lwp can be NULL */
 237         if (t->td_lwp == NULL)
 238                 return 0;
 239
 240         return CURSIG(t->td_lwp);
 241 }
 242
 243 static inline int
 244 fatal_signal_pending(struct task_struct *p)
 245 {
 246         struct thread *t = p->dfly_td;
 247         sigset_t pending_set;
 248
 249         /* Some kernel threads do not have lwp, t->td_lwp can be NULL */
 250         if (t->td_lwp == NULL)
 251                 return 0;
 252
 253         pending_set = lwp_sigpend(t->td_lwp);
 254         return SIGISMEMBER(pending_set, SIGKILL);
 255 }
 256
 257 static inline int
 258 signal_pending_state(long state, struct task_struct *p)
 259 {
 260         if (state & TASK_INTERRUPTIBLE)
 261                 return (signal_pending(p));
 262         else
 263                 return (fatal_signal_pending(p));
 264 }
 265
 266 /* Explicit rescheduling in order to reduce latency */
 267 static inline int
 268 cond_resched(void)
 269 {
 270         lwkt_yield();
 271         return 0;
 272 }
 273
 274 static inline int
 275 send_sig(int sig, struct proc *p, int priv)
 276 {
 277         ksignal(p, sig);
 278         return 0;
 279 }
 280
 281 static inline void
 282 set_need_resched(void)
 283 {
 284         /* do nothing for now */
 285         /* used on ttm_bo_reserve failures */
 286 }
 287
 288 static inline bool
 289 need_resched(void)
 290 {
 291         return any_resched_wanted();
 292 }
 293
 294 static inline int
 295 sched_setscheduler_nocheck(struct task_struct *ts,
 296                            int policy, const struct sched_param *param)
 297 {
 298         /* We do not allow different thread scheduling policies */
 299         return 0;
 300 }
 301
 302 static inline int
 303 pagefault_disabled(void)
 304 {
 305         return (curthread->td_flags & TDF_NOFAULT);
 306 }
 307
 308 static inline void
 309 mmgrab(struct mm_struct *mm)
 310 {
 311         atomic_inc(&mm->mm_count);
 312 }
 313
 314 #endif  /* _LINUX_SCHED_H_ */