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/gfp.h> 56 57 #include <asm/processor.h> 58 59 #include <linux/spinlock.h> 60 61 #include <sys/param.h> 62 #include <sys/systm.h> 63 #include <sys/proc.h> 64 #include <sys/sched.h> 65 #include <sys/signal2.h> 66 67 #include <machine/cpu.h> 68 69 struct seq_file; 70 71 #define TASK_RUNNING 0 72 #define TASK_INTERRUPTIBLE 1 73 #define TASK_UNINTERRUPTIBLE 2 74 75 #define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE) 76 77 #define MAX_SCHEDULE_TIMEOUT LONG_MAX 78 79 struct task_struct { 80 struct thread *dfly_td; 81 volatile long state; 82 struct mm_struct *mm; /* mirror copy in p->p_linux_mm */ 83 int prio; 84 85 /* kthread-specific data */ 86 unsigned long kt_flags; 87 struct completion kt_exited; 88 int (*kt_fn)(void *data); 89 void *kt_fndata; 90 int kt_exitvalue; 91 }; 92 93 #define __set_current_state(state_value) current->state = (state_value); 94 95 #define set_current_state(state_value) \ 96 do { \ 97 __set_current_state(state_value); \ 98 mb(); \ 99 } while (0) 100 101 /* 102 * schedule_timeout: puts the current thread to sleep until timeout 103 * if its state allows it to. 104 */ 105 static inline long 106 schedule_timeout(signed long timeout) 107 { 108 unsigned long time_before, time_after; 109 long slept, ret = 0; 110 int timo; 111 112 if (timeout < 0) { 113 kprintf("schedule_timeout(): timeout cannot be negative\n"); 114 goto done; 115 } 116 117 /* 118 * Indefinite wait if timeout is MAX_SCHEDULE_TIMEOUT, but we are 119 * also translating to an integer. The first conditional will 120 * cover both but to code defensively test both. 121 */ 122 if (timeout >= INT_MAX || timeout == MAX_SCHEDULE_TIMEOUT) 123 timo = 0; 124 else 125 timo = timeout; 126 127 switch (current->state) { 128 case TASK_INTERRUPTIBLE: 129 time_before = ticks; 130 tsleep(current, PCATCH, "lstim", timo); 131 time_after = ticks; 132 slept = time_after - time_before; 133 ret = timeout - slept; 134 if (ret < 0) 135 ret = 0; 136 break; 137 case TASK_UNINTERRUPTIBLE: 138 tsleep(current, 0, "lstim", timo); 139 break; 140 default: 141 /* We are supposed to return immediately here */ 142 tsleep(current, 0, "lstim", 1); 143 break; 144 } 145 146 done: 147 if (timeout == MAX_SCHEDULE_TIMEOUT) 148 ret = MAX_SCHEDULE_TIMEOUT; 149 150 current->state = TASK_RUNNING; 151 return ret; 152 } 153 154 static inline void 155 schedule(void) 156 { 157 (void)schedule_timeout(MAX_SCHEDULE_TIMEOUT); 158 } 159 160 static inline signed long 161 schedule_timeout_uninterruptible(signed long timeout) 162 { 163 __set_current_state(TASK_UNINTERRUPTIBLE); 164 return schedule_timeout(timeout); 165 } 166 167 static inline long 168 io_schedule_timeout(signed long timeout) 169 { 170 return schedule_timeout(timeout); 171 } 172 173 #define TASK_COMM_LEN MAXCOMLEN 174 175 /* 176 * local_clock: fast time source, monotonic on the same cpu 177 */ 178 static inline uint64_t 179 local_clock(void) 180 { 181 struct timespec ts; 182 183 getnanouptime(&ts); 184 return (ts.tv_sec * NSEC_PER_SEC) + ts.tv_nsec; 185 } 186 187 static inline void 188 yield(void) 189 { 190 lwkt_yield(); 191 } 192 193 static inline int 194 wake_up_process(struct task_struct *tsk) 195 { 196 /* Among other things, this function is supposed to act as 197 * a barrier */ 198 smp_wmb(); 199 wakeup(tsk); 200 201 return 1; /* Always indicate the process was woken up */ 202 } 203 204 static inline int 205 signal_pending(struct task_struct *p) 206 { 207 struct thread *t = p->dfly_td; 208 209 /* Some kernel threads do not have lwp, t->td_lwp can be NULL */ 210 if (t->td_lwp == NULL) 211 return 0; 212 213 return CURSIG(t->td_lwp); 214 } 215 216 static inline int 217 fatal_signal_pending(struct task_struct *p) 218 { 219 struct thread *t = p->dfly_td; 220 sigset_t pending_set; 221 222 /* Some kernel threads do not have lwp, t->td_lwp can be NULL */ 223 if (t->td_lwp == NULL) 224 return 0; 225 226 pending_set = lwp_sigpend(t->td_lwp); 227 return SIGISMEMBER(pending_set, SIGKILL); 228 } 229 230 static inline int 231 signal_pending_state(long state, struct task_struct *p) 232 { 233 if (state & TASK_INTERRUPTIBLE) 234 return (signal_pending(p)); 235 else 236 return (fatal_signal_pending(p)); 237 } 238 239 /* Explicit rescheduling in order to reduce latency */ 240 static inline int 241 cond_resched(void) 242 { 243 lwkt_yield(); 244 return 0; 245 } 246 247 static inline int 248 send_sig(int sig, struct proc *p, int priv) 249 { 250 ksignal(p, sig); 251 return 0; 252 } 253 254 static inline void 255 set_need_resched(void) 256 { 257 /* do nothing for now */ 258 /* used on ttm_bo_reserve failures */ 259 } 260 261 static inline bool 262 need_resched(void) 263 { 264 return any_resched_wanted(); 265 } 266 267 static inline int 268 sched_setscheduler_nocheck(struct task_struct *ts, 269 int policy, const struct sched_param *param) 270 { 271 /* We do not allow different thread scheduling policies */ 272 return 0; 273 } 274 275 static inline int 276 pagefault_disabled(void) 277 { 278 return (curthread->td_flags & TDF_NOFAULT); 279 } 280 281 #endif /* _LINUX_SCHED_H_ */ 282