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(¤t->kt_spin); 137 138 switch (current->state) { 139 case TASK_INTERRUPTIBLE: 140 time_before = ticks; 141 ssleep(current, ¤t->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, ¤t->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, ¤t->kt_spin, 0, "lst1", 1); 161 break; 162 } 163 164 spin_unlock(¤t->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_ */ 315