master
1/* $NetBSD: lwp.h,v 1.217 2022/07/23 19:15:29 mrg Exp $ */
2
3/*
4 * Copyright (c) 2001, 2006, 2007, 2008, 2009, 2010, 2019, 2020
5 * The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Nathan J. Williams and Andrew Doran.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33#ifndef _SYS_LWP_H_
34#define _SYS_LWP_H_
35
36#if defined(_KERNEL) || defined(_KMEMUSER)
37
38#include <sys/param.h>
39#include <sys/time.h>
40#include <sys/queue.h>
41#include <sys/callout.h>
42#include <sys/kcpuset.h>
43#include <sys/mutex.h>
44#include <sys/condvar.h>
45#include <sys/signalvar.h>
46#include <sys/sched.h>
47#include <sys/specificdata.h>
48#include <sys/syncobj.h>
49#include <sys/resource.h>
50
51#if defined(_KERNEL)
52struct lwp;
53/* forward declare this for <machine/cpu.h> so it can get l_cpu. */
54static __inline struct cpu_info *lwp_getcpu(struct lwp *);
55#include <machine/cpu.h> /* curcpu() and cpu_info */
56#include <sys/atomic.h>
57#ifdef _KERNEL_OPT
58#include "opt_kcov.h"
59#include "opt_kmsan.h"
60#include "opt_maxlwp.h"
61#endif
62#endif
63
64#include <machine/proc.h> /* Machine-dependent proc substruct. */
65
66/*
67 * Lightweight process. Field markings and the corresponding locks:
68 *
69 * a: proc_lock
70 * c: condition variable interlock, passed to cv_wait()
71 * l: *l_mutex
72 * p: l_proc->p_lock
73 * s: spc_mutex, which may or may not be referenced by l_mutex
74 * S: l_selcluster->sc_lock
75 * (: unlocked, stable
76 * !: unlocked, may only be reliably accessed by the LWP itself
77 *
78 * Fields are clustered together by usage (to increase the likelihood
79 * of cache hits) and by size (to reduce dead space in the structure).
80 */
81
82#include <sys/pcu.h>
83
84struct lockdebug;
85struct sysent;
86
87struct lwp {
88 /* Must not be zeroed on free. */
89 struct cpu_info *volatile l_cpu;/* s: CPU we're on if LSONPROC */
90 kmutex_t * volatile l_mutex; /* l: ptr to mutex on sched state */
91 struct turnstile *l_ts; /* l: current turnstile */
92 int l_stat; /* l: overall LWP status */
93 int l__reserved; /* : padding - reuse as needed */
94
95 /* Scheduling and overall state. */
96#define l_startzero l_runq
97 TAILQ_ENTRY(lwp) l_runq; /* s: run queue */
98 union {
99 void * info; /* s: scheduler-specific structure */
100 u_int timeslice; /* l: time-quantum for SCHED_M2 */
101 } l_sched;
102 void *l_addr; /* l: PCB address; use lwp_getpcb() */
103 struct mdlwp l_md; /* l: machine-dependent fields. */
104 struct bintime l_rtime; /* l: real time */
105 struct bintime l_stime; /* l: start time (while ONPROC) */
106 int l_flag; /* l: misc flag values */
107 u_int l_swtime; /* l: time swapped in or out */
108 u_int l_rticks; /* l: Saved start time of run */
109 u_int l_rticksum; /* l: Sum of ticks spent running */
110 u_int l_slpticks; /* l: Saved start time of sleep */
111 u_int l_slpticksum; /* l: Sum of ticks spent sleeping */
112 int l_biglocks; /* l: biglock count before sleep */
113 int l_class; /* l: scheduling class */
114 int l_kpriority; /* !: has kernel priority boost */
115 pri_t l_kpribase; /* !: kernel priority base level */
116 pri_t l_priority; /* l: scheduler priority */
117 pri_t l_inheritedprio;/* l: inherited priority */
118 pri_t l_protectprio; /* l: for PTHREAD_PRIO_PROTECT */
119 pri_t l_auxprio; /* l: max(inherit,protect) priority */
120 int l_protectdepth; /* l: for PTHREAD_PRIO_PROTECT */
121 u_int l_cpticks; /* (: Ticks of CPU time */
122 psetid_t l_psid; /* l: assigned processor-set ID */
123 fixpt_t l_pctcpu; /* p: %cpu during l_swtime */
124 fixpt_t l_estcpu; /* l: cpu time for SCHED_4BSD */
125 volatile uint64_t l_ncsw; /* l: total context switches */
126 volatile uint64_t l_nivcsw; /* l: involuntary context switches */
127 SLIST_HEAD(, turnstile) l_pi_lenders; /* l: ts lending us priority */
128 struct cpu_info *l_target_cpu; /* l: target CPU to migrate */
129 struct lwpctl *l_lwpctl; /* p: lwpctl block kernel address */
130 struct lcpage *l_lcpage; /* p: lwpctl containing page */
131 kcpuset_t *l_affinity; /* l: CPU set for affinity */
132
133 /* Synchronisation. */
134 struct syncobj *l_syncobj; /* l: sync object operations set */
135 LIST_ENTRY(lwp) l_sleepchain; /* l: sleep queue */
136 wchan_t l_wchan; /* l: sleep address */
137 const char *l_wmesg; /* l: reason for sleep */
138 struct sleepq *l_sleepq; /* l: current sleep queue */
139 callout_t l_timeout_ch; /* !: callout for tsleep */
140 kcondvar_t l_waitcv; /* a: vfork() wait */
141 u_int l_slptime; /* l: time since last blocked */
142 bool l_vforkwaiting; /* a: vfork() waiting */
143
144 /* User-space synchronization. */
145 uintptr_t l_robust_head; /* !: list of robust futexes */
146 uint32_t l___rsvd1; /* reserved for future use */
147
148#if PCU_UNIT_COUNT > 0
149 struct cpu_info * volatile l_pcu_cpu[PCU_UNIT_COUNT];
150 uint32_t l_pcu_valid;
151#endif
152
153 /* Process level and global state, misc. */
154 lwpid_t l_lid; /* (: LWP identifier; local to proc */
155 LIST_ENTRY(lwp) l_list; /* a: entry on list of all LWPs */
156 void *l_ctxlink; /* p: uc_link {get,set}context */
157 struct proc *l_proc; /* p: parent process */
158 LIST_ENTRY(lwp) l_sibling; /* p: entry on proc's list of LWPs */
159 char *l_name; /* (: name, optional */
160 lwpid_t l_waiter; /* p: first LWP waiting on us */
161 lwpid_t l_waitingfor; /* p: specific LWP we are waiting on */
162 int l_prflag; /* p: process level flags */
163 u_int l_refcnt; /* p: reference count on this LWP */
164
165 /* State of select() or poll(). */
166 int l_selflag; /* S: polling state flags */
167 int l_selret; /* S: return value of select/poll */
168 SLIST_HEAD(,selinfo) l_selwait; /* S: descriptors waited on */
169 uintptr_t l_selrec; /* !: argument for selrecord() */
170 struct selcluster *l_selcluster;/* !: associated cluster data */
171 void * l_selbits; /* (: select() bit-field */
172 size_t l_selni; /* (: size of a single bit-field */
173
174 /* Signals. */
175 int l_sigrestore; /* p: need to restore old sig mask */
176 sigset_t l_sigwaitset; /* p: signals being waited for */
177 kcondvar_t l_sigcv; /* p: for sigsuspend() */
178 struct ksiginfo *l_sigwaited; /* p: delivered signals from set */
179 sigpend_t *l_sigpendset; /* p: XXX issignal()/postsig() baton */
180 LIST_ENTRY(lwp) l_sigwaiter; /* p: chain on list of waiting LWPs */
181 stack_t l_sigstk; /* p: sp & on stack state variable */
182 sigset_t l_sigmask; /* p: signal mask */
183 sigpend_t l_sigpend; /* p: signals to this LWP */
184 sigset_t l_sigoldmask; /* p: mask for sigpause */
185
186 /* Private data. */
187 specificdata_reference
188 l_specdataref; /* !: subsystem lwp-specific data */
189 struct timespec l_ktrcsw; /* !: for ktrace CSW trace XXX */
190 void *l_private; /* !: svr4-style lwp-private data */
191 struct lwp *l_switchto; /* !: mi_switch: switch to this LWP */
192 struct kauth_cred *l_cred; /* !: cached credentials */
193 struct filedesc *l_fd; /* !: cached copy of proc::p_fd */
194 void *l_emuldata; /* !: kernel lwp-private data */
195 struct fstrans_lwp_info *l_fstrans; /* (: fstrans private data */
196 u_short l_shlocks; /* !: lockdebug: shared locks held */
197 u_short l_exlocks; /* !: lockdebug: excl. locks held */
198 u_short l_psrefs; /* !: count of psref held */
199 u_short l_blcnt; /* !: count of kernel_lock held */
200 volatile int l_nopreempt; /* !: don't preempt me! */
201 volatile u_int l_dopreempt; /* s: kernel preemption pending */
202 int l_pflag; /* !: LWP private flags */
203 int l_dupfd; /* !: side return from cloning devs XXX */
204 const struct sysent * volatile l_sysent;/* !: currently active syscall */
205 struct rusage l_ru; /* !: accounting information */
206 uint64_t l_pfailtime; /* !: for kernel preemption */
207 uintptr_t l_pfailaddr; /* !: for kernel preemption */
208 uintptr_t l_pfaillock; /* !: for kernel preemption */
209 _TAILQ_HEAD(,struct lockdebug,volatile) l_ld_locks;/* !: locks held by LWP */
210 volatile void *l_ld_wanted; /* !: lock currently wanted by LWP */
211 uintptr_t l_rwcallsite; /* !: rwlock actual callsite */
212 int l_tcgen; /* !: for timecounter removal */
213
214 /* These are only used by 'options SYSCALL_TIMES'. */
215 uint32_t l_syscall_time; /* !: time epoch for current syscall */
216 uint64_t *l_syscall_counter; /* !: counter for current process */
217
218 struct kdtrace_thread *l_dtrace; /* (: DTrace-specific data. */
219
220#ifdef KMSAN
221 void *l_kmsan; /* !: KMSAN private data. */
222#endif
223#ifdef KCOV
224 void *l_kcov; /* !: KCOV private data. */
225#endif
226};
227
228/*
229 * UAREA_PCB_OFFSET: an offset of PCB structure in the uarea. MD code may
230 * define it in <machine/proc.h>, to indicate a different uarea layout.
231 */
232#ifndef UAREA_PCB_OFFSET
233#define UAREA_PCB_OFFSET 0
234#endif
235
236LIST_HEAD(lwplist, lwp); /* A list of LWPs. */
237
238#ifdef _KERNEL
239extern struct lwplist alllwp; /* List of all LWPs. */
240extern lwp_t lwp0; /* LWP for proc0. */
241extern int maxlwp __read_mostly; /* max number of lwps */
242#ifndef MAXLWP
243#define MAXLWP 4096 /* default max */
244#endif
245#ifndef MAXMAXLWP
246#define MAXMAXLWP 65535 /* absolute max */
247#endif
248#endif
249
250#endif /* _KERNEL || _KMEMUSER */
251
252/*
253 * These flags are kept in l_flag, and they are modified only with the LWP
254 * locked.
255 */
256#define LW_IDLE 0x00000001 /* Idle lwp. */
257#define LW_LWPCTL 0x00000002 /* Adjust lwpctl in userret */
258#define LW_STIMO 0x00000040 /* Sleep timed out */
259#define LW_SINTR 0x00000080 /* Sleep is interruptible. */
260#define LW_CATCHINTR 0x00000100 /* LW_SINTR intent; see sleepq_block(). */
261#define LW_SYSTEM 0x00000200 /* Kernel thread */
262#define LW_SYSTEM_FPU 0x00000400 /* Kernel thread with vector/FP enabled */
263#define LW_DBGSUSPEND 0x00010000 /* Suspend by debugger */
264#define LW_WSUSPEND 0x00020000 /* Suspend before return to user */
265#define LW_BATCH 0x00040000 /* LWP tends to hog CPU */
266#define LW_WCORE 0x00080000 /* Stop for core dump on return to user */
267#define LW_WEXIT 0x00100000 /* Exit before return to user */
268#define LW_PENDSIG 0x01000000 /* Pending signal for us */
269#define LW_CANCELLED 0x02000000 /* tsleep should not sleep */
270#define LW_WREBOOT 0x08000000 /* System is rebooting, please suspend */
271#define LW_UNPARKED 0x10000000 /* Unpark op pending */
272#define LW_RUMP_CLEAR 0x40000000 /* Clear curlwp in RUMP scheduler */
273#define LW_RUMP_QEXIT 0x80000000 /* LWP should exit ASAP */
274
275/*
276 * The second set of flags is kept in l_pflag, and they are modified only by
277 * the LWP itself, or modified when it's known the LWP cannot be running.
278 * LP_RUNNING is typically updated with the LWP locked, but not always in
279 * the case of soft interrupt handlers.
280 */
281#define LP_KTRACTIVE 0x00000001 /* Executing ktrace operation */
282#define LP_KTRCSW 0x00000002 /* ktrace context switch marker */
283#define LP_KTRCSWUSER 0x00000004 /* ktrace context switch marker */
284 /* 0x00000008 was LP_PIDLID */
285#define LP_OWEUPC 0x00000010 /* Owe user profiling tick */
286#define LP_MPSAFE 0x00000020 /* Starts life without kernel_lock */
287#define LP_INTR 0x00000040 /* Soft interrupt handler */
288#define LP_SYSCTLWRITE 0x00000080 /* sysctl write lock held */
289#define LP_MUSTJOIN 0x00000100 /* Must join kthread on exit */
290#define LP_SINGLESTEP 0x00000400 /* Single step thread in ptrace(2) */
291#define LP_TIMEINTR 0x00010000 /* Time this soft interrupt */
292#define LP_PREEMPTING 0x00020000 /* mi_switch called involuntarily */
293#define LP_RUNNING 0x20000000 /* Active on a CPU */
294#define LP_TELEPORT 0x40000000 /* Teleport to new CPU on preempt() */
295#define LP_BOUND 0x80000000 /* Bound to a CPU */
296
297/*
298 * The third set of flags is kept in l_prflag and they are modified only
299 * with p_lock held.
300 */
301#define LPR_DETACHED 0x00800000 /* Won't be waited for. */
302#define LPR_CRMOD 0x00000100 /* Credentials modified */
303#define LPR_DRAINING 0x80000000 /* Draining references before exiting */
304
305/*
306 * Mask indicating that there is "exceptional" work to be done on return to
307 * user.
308 */
309#define LW_USERRET \
310 (LW_WEXIT | LW_PENDSIG | LW_WREBOOT | LW_WSUSPEND | LW_WCORE | LW_LWPCTL)
311
312/*
313 * Status values.
314 *
315 * A note about LSRUN and LSONPROC: LSRUN indicates that a process is
316 * runnable but *not* yet running, i.e. is on a run queue. LSONPROC
317 * indicates that the process is actually executing on a CPU, i.e.
318 * it is no longer on a run queue.
319 *
320 * These values are set in stone and must not be reused with future changes.
321 */
322#define LSIDL 1 /* Process being created by fork. */
323#define LSRUN 2 /* Currently runnable. */
324#define LSSLEEP 3 /* Sleeping on an address. */
325#define LSSTOP 4 /* Process debugging or suspension. */
326#define LSZOMB 5 /* Awaiting collection by parent. */
327/* define LSDEAD 6 Process is almost a zombie. (removed in 5.0) */
328#define LSONPROC 7 /* Process is currently on a CPU. */
329#define LSSUSPENDED 8 /* Not running, not signalable. */
330
331#if defined(_KERNEL) || defined(_KMEMUSER)
332static __inline void *
333lwp_getpcb(struct lwp *l)
334{
335
336 return l->l_addr;
337}
338#endif /* _KERNEL || _KMEMUSER */
339
340#ifdef _KERNEL
341#define LWP_CACHE_CREDS(l, p) \
342do { \
343 (void)p; \
344 if (__predict_false((l)->l_prflag & LPR_CRMOD)) \
345 lwp_update_creds(l); \
346} while (/* CONSTCOND */ 0)
347
348void lwpinit(void);
349void lwp0_init(void);
350
351void lwp_startup(lwp_t *, lwp_t *);
352void startlwp(void *);
353
354int lwp_locked(lwp_t *, kmutex_t *);
355kmutex_t *lwp_setlock(lwp_t *, kmutex_t *);
356void lwp_unlock_to(lwp_t *, kmutex_t *);
357int lwp_trylock(lwp_t *);
358void lwp_addref(lwp_t *);
359void lwp_delref(lwp_t *);
360void lwp_delref2(lwp_t *);
361bool lwp_drainrefs(lwp_t *);
362bool lwp_alive(lwp_t *);
363lwp_t *lwp_find_first(proc_t *);
364
365int lwp_wait(lwp_t *, lwpid_t, lwpid_t *, bool);
366void lwp_continue(lwp_t *);
367void lwp_unsleep(lwp_t *, bool);
368void lwp_unstop(lwp_t *);
369void lwp_exit(lwp_t *);
370int lwp_suspend(lwp_t *, lwp_t *);
371int lwp_create1(lwp_t *, const void *, size_t, u_long, lwpid_t *);
372void lwp_start(lwp_t *, int);
373void lwp_update_creds(lwp_t *);
374void lwp_migrate(lwp_t *, struct cpu_info *);
375lwp_t * lwp_find2(pid_t, lwpid_t);
376lwp_t * lwp_find(proc_t *, int);
377void lwp_userret(lwp_t *);
378void lwp_need_userret(lwp_t *);
379void lwp_free(lwp_t *, bool, bool);
380uint64_t lwp_pctr(void);
381int lwp_setprivate(lwp_t *, void *);
382int do_lwp_create(lwp_t *, void *, u_long, lwp_t **, const sigset_t *,
383 const stack_t *);
384
385void lwp_thread_cleanup(lwp_t *);
386
387void lwpinit_specificdata(void);
388int lwp_specific_key_create(specificdata_key_t *, specificdata_dtor_t);
389void lwp_specific_key_delete(specificdata_key_t);
390void lwp_initspecific(lwp_t *);
391void lwp_finispecific(lwp_t *);
392void *lwp_getspecific(specificdata_key_t);
393#if defined(_LWP_API_PRIVATE)
394void *_lwp_getspecific_by_lwp(lwp_t *, specificdata_key_t);
395#endif
396void lwp_setspecific(specificdata_key_t, void *);
397void lwp_setspecific_by_lwp(lwp_t *, specificdata_key_t, void *);
398
399/* Syscalls. */
400int lwp_park(clockid_t, int, struct timespec *);
401int lwp_unpark(const lwpid_t *, const u_int);
402
403/* DDB. */
404void lwp_whatis(uintptr_t, void (*)(const char *, ...) __printflike(1, 2));
405
406/*
407 * Lock an LWP. XXX _MODULE
408 */
409static __inline void
410lwp_lock(lwp_t *l)
411{
412 kmutex_t *old = atomic_load_consume(&l->l_mutex);
413
414 /*
415 * Note: mutex_spin_enter() will have posted a read barrier.
416 * Re-test l->l_mutex. If it has changed, we need to try again.
417 */
418 mutex_spin_enter(old);
419 while (__predict_false(atomic_load_relaxed(&l->l_mutex) != old)) {
420 mutex_spin_exit(old);
421 old = atomic_load_consume(&l->l_mutex);
422 mutex_spin_enter(old);
423 }
424}
425
426/*
427 * Unlock an LWP. XXX _MODULE
428 */
429static __inline void
430lwp_unlock(lwp_t *l)
431{
432 mutex_spin_exit(l->l_mutex);
433}
434
435static __inline void
436lwp_changepri(lwp_t *l, pri_t pri)
437{
438 KASSERT(mutex_owned(l->l_mutex));
439
440 if (l->l_priority == pri)
441 return;
442
443 (*l->l_syncobj->sobj_changepri)(l, pri);
444 KASSERT(l->l_priority == pri);
445}
446
447static __inline void
448lwp_lendpri(lwp_t *l, pri_t pri)
449{
450 KASSERT(mutex_owned(l->l_mutex));
451
452 (*l->l_syncobj->sobj_lendpri)(l, pri);
453 KASSERT(l->l_inheritedprio == pri);
454}
455
456static __inline pri_t
457lwp_eprio(lwp_t *l)
458{
459 pri_t pri;
460
461 pri = l->l_priority;
462 if ((l->l_flag & LW_SYSTEM) == 0 && l->l_kpriority && pri < PRI_KERNEL)
463 pri = (pri >> 1) + l->l_kpribase;
464 return MAX(l->l_auxprio, pri);
465}
466
467int lwp_create(lwp_t *, struct proc *, vaddr_t, int, void *, size_t,
468 void (*)(void *), void *, lwp_t **, int, const sigset_t *, const stack_t *);
469
470/*
471 * XXX _MODULE
472 * We should provide real stubs for the below that modules can use.
473 */
474
475static __inline void
476spc_lock(struct cpu_info *ci)
477{
478 mutex_spin_enter(ci->ci_schedstate.spc_mutex);
479}
480
481static __inline void
482spc_unlock(struct cpu_info *ci)
483{
484 mutex_spin_exit(ci->ci_schedstate.spc_mutex);
485}
486
487static __inline void
488spc_dlock(struct cpu_info *ci1, struct cpu_info *ci2)
489{
490 struct schedstate_percpu *spc1 = &ci1->ci_schedstate;
491 struct schedstate_percpu *spc2 = &ci2->ci_schedstate;
492
493 KASSERT(ci1 != ci2);
494 if (ci1 < ci2) {
495 mutex_spin_enter(spc1->spc_mutex);
496 mutex_spin_enter(spc2->spc_mutex);
497 } else {
498 mutex_spin_enter(spc2->spc_mutex);
499 mutex_spin_enter(spc1->spc_mutex);
500 }
501}
502
503/*
504 * Allow machine-dependent code to override curlwp in <machine/cpu.h> for
505 * its own convenience. Otherwise, we declare it as appropriate.
506 */
507#if !defined(curlwp)
508#if defined(MULTIPROCESSOR)
509#define curlwp curcpu()->ci_curlwp /* Current running LWP */
510#else
511extern struct lwp *curlwp; /* Current running LWP */
512#endif /* MULTIPROCESSOR */
513#endif /* ! curlwp */
514#define curproc (curlwp->l_proc)
515
516/*
517 * This provides a way for <machine/cpu.h> to get l_cpu for curlwp before
518 * struct lwp is defined.
519 */
520static __inline struct cpu_info *
521lwp_getcpu(struct lwp *l)
522{
523 return l->l_cpu;
524}
525
526static __inline bool
527CURCPU_IDLE_P(void)
528{
529 struct cpu_info *ci = curcpu();
530 return ci->ci_onproc == ci->ci_data.cpu_idlelwp;
531}
532
533/*
534 * Disable and re-enable preemption. Only for low-level kernel
535 * use. Device drivers and anything that could potentially be
536 * compiled as a module should use kpreempt_disable() and
537 * kpreempt_enable().
538 */
539static __inline void
540KPREEMPT_DISABLE(lwp_t *l)
541{
542
543 KASSERT(l == curlwp);
544 l->l_nopreempt++;
545 __insn_barrier();
546}
547
548static __inline void
549KPREEMPT_ENABLE(lwp_t *l)
550{
551
552 KASSERT(l == curlwp);
553 KASSERT(l->l_nopreempt > 0);
554 __insn_barrier();
555 if (--l->l_nopreempt != 0)
556 return;
557 __insn_barrier();
558 if (__predict_false(l->l_dopreempt))
559 kpreempt(0);
560 __insn_barrier();
561}
562
563/* For lwp::l_dopreempt */
564#define DOPREEMPT_ACTIVE 0x01
565#define DOPREEMPT_COUNTED 0x02
566
567/*
568 * Prevent curlwp from migrating between CPUs between curlwp_bind and
569 * curlwp_bindx. One use case is psref(9) that has a contract that
570 * forbids migrations.
571 */
572static __inline int
573curlwp_bind(void)
574{
575 int bound;
576
577 bound = curlwp->l_pflag & LP_BOUND;
578 curlwp->l_pflag |= LP_BOUND;
579 __insn_barrier();
580
581 return bound;
582}
583
584static __inline void
585curlwp_bindx(int bound)
586{
587
588 KASSERT(curlwp->l_pflag & LP_BOUND);
589 __insn_barrier();
590 curlwp->l_pflag ^= bound ^ LP_BOUND;
591}
592
593#endif /* _KERNEL */
594
595/* Flags for _lwp_create(), as per Solaris. */
596#define LWP_DETACHED 0x00000040
597#define LWP_SUSPENDED 0x00000080
598
599/* Kernel-internal flags for LWP creation. */
600 /* 0x40000000 was LWP_PIDLID */
601#define LWP_VFORK 0x80000000
602
603#endif /* !_SYS_LWP_H_ */