1 /* 2 * Copyright (c) 2015-2020 François Tigeot <ftigeot@wolfpond.org> 3 * Copyright (c) 2019 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 struct task_struct { 81 struct thread *dfly_td; 82 volatile long state; 83 struct mm_struct *mm; /* mirror copy in p->p_linux_mm */ 84 int prio; 85 86 /* kthread-specific data */ 87 unsigned long kt_flags; 88 struct completion kt_exited; 89 int (*kt_fn)(void *data); 90 void *kt_fndata; 91 int kt_exitvalue; 92 }; 93 94 #define __set_current_state(state_value) current->state = (state_value); 95 96 #define set_current_state(state_value) \ 97 do { \ 98 __set_current_state(state_value); \ 99 mb(); \ 100 } while (0) 101 102 /* 103 * schedule_timeout: puts the current thread to sleep until timeout 104 * if its state allows it to. 105 */ 106 static inline long 107 schedule_timeout(signed long timeout) 108 { 109 unsigned long time_before, time_after; 110 long slept, ret = 0; 111 int timo; 112 113 if (timeout < 0) { 114 kprintf("schedule_timeout(): timeout cannot be negative\n"); 115 goto done; 116 } 117 118 /* 119 * Indefinite wait if timeout is MAX_SCHEDULE_TIMEOUT, but we are 120 * also translating to an integer. The first conditional will 121 * cover both but to code defensively test both. 122 */ 123 if (timeout >= INT_MAX || timeout == MAX_SCHEDULE_TIMEOUT) 124 timo = 0; 125 else 126 timo = timeout; 127 128 switch (current->state) { 129 case TASK_INTERRUPTIBLE: 130 time_before = ticks; 131 tsleep(current, PCATCH, "lstim", timo); 132 time_after = ticks; 133 slept = time_after - time_before; 134 ret = timeout - slept; 135 if (ret < 0) 136 ret = 0; 137 break; 138 case TASK_UNINTERRUPTIBLE: 139 tsleep(current, 0, "lstim", timo); 140 break; 141 default: 142 /* We are supposed to return immediately here */ 143 tsleep(current, 0, "lstim", 1); 144 break; 145 } 146 147 done: 148 if (timeout == MAX_SCHEDULE_TIMEOUT) 149 ret = MAX_SCHEDULE_TIMEOUT; 150 151 current->state = TASK_RUNNING; 152 return ret; 153 } 154 155 static inline void 156 schedule(void) 157 { 158 (void)schedule_timeout(MAX_SCHEDULE_TIMEOUT); 159 } 160 161 static inline signed long 162 schedule_timeout_uninterruptible(signed long timeout) 163 { 164 __set_current_state(TASK_UNINTERRUPTIBLE); 165 return schedule_timeout(timeout); 166 } 167 168 static inline long 169 io_schedule_timeout(signed long timeout) 170 { 171 return schedule_timeout(timeout); 172 } 173 174 #define TASK_COMM_LEN MAXCOMLEN 175 176 /* 177 * local_clock: fast time source, monotonic on the same cpu 178 */ 179 static inline uint64_t 180 local_clock(void) 181 { 182 struct timespec ts; 183 184 getnanouptime(&ts); 185 return (ts.tv_sec * NSEC_PER_SEC) + ts.tv_nsec; 186 } 187 188 static inline void 189 yield(void) 190 { 191 lwkt_yield(); 192 } 193 194 static inline int 195 wake_up_process(struct task_struct *tsk) 196 { 197 /* Among other things, this function is supposed to act as 198 * a barrier */ 199 smp_wmb(); 200 wakeup(tsk); 201 202 return 1; /* Always indicate the process was woken up */ 203 } 204 205 static inline int 206 signal_pending(struct task_struct *p) 207 { 208 struct thread *t = p->dfly_td; 209 210 /* Some kernel threads do not have lwp, t->td_lwp can be NULL */ 211 if (t->td_lwp == NULL) 212 return 0; 213 214 return CURSIG(t->td_lwp); 215 } 216 217 static inline int 218 fatal_signal_pending(struct task_struct *p) 219 { 220 struct thread *t = p->dfly_td; 221 sigset_t pending_set; 222 223 /* Some kernel threads do not have lwp, t->td_lwp can be NULL */ 224 if (t->td_lwp == NULL) 225 return 0; 226 227 pending_set = lwp_sigpend(t->td_lwp); 228 return SIGISMEMBER(pending_set, SIGKILL); 229 } 230 231 static inline int 232 signal_pending_state(long state, struct task_struct *p) 233 { 234 if (state & TASK_INTERRUPTIBLE) 235 return (signal_pending(p)); 236 else 237 return (fatal_signal_pending(p)); 238 } 239 240 /* Explicit rescheduling in order to reduce latency */ 241 static inline int 242 cond_resched(void) 243 { 244 lwkt_yield(); 245 return 0; 246 } 247 248 static inline int 249 send_sig(int sig, struct proc *p, int priv) 250 { 251 ksignal(p, sig); 252 return 0; 253 } 254 255 static inline void 256 set_need_resched(void) 257 { 258 /* do nothing for now */ 259 /* used on ttm_bo_reserve failures */ 260 } 261 262 static inline bool 263 need_resched(void) 264 { 265 return any_resched_wanted(); 266 } 267 268 static inline int 269 sched_setscheduler_nocheck(struct task_struct *ts, 270 int policy, const struct sched_param *param) 271 { 272 /* We do not allow different thread scheduling policies */ 273 return 0; 274 } 275 276 static inline int 277 pagefault_disabled(void) 278 { 279 return (curthread->td_flags & TDF_NOFAULT); 280 } 281 282 #endif /* _LINUX_SCHED_H_ */ 283