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gems-kernel/source/THIRDPARTY/xnu/bsd/sys/eventvar.h
Sam Sneed f5727805f2 add darwin/xnu functionality
2024-06-03 11:29:39 -05:00

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/*
* Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* Copyright (c) 1999,2000 Jonathan Lemon <jlemon@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: src/sys/sys/eventvar.h,v 1.1.2.2 2000/07/18 21:49:12 jlemon Exp $
*/
#ifndef _SYS_EVENTVAR_H_
#define _SYS_EVENTVAR_H_
#include <sys/event.h>
#include <sys/select.h>
#include <kern/kern_types.h>
#include <kern/waitq.h>
#if defined(XNU_KERNEL_PRIVATE)
typedef int (*kevent_callback_t)(struct kevent_qos_s *, struct kevent_ctx_s *);
#include <stdint.h>
#include <kern/locks.h>
#include <mach/thread_policy.h>
#include <pthread/workqueue_internal.h>
#include <os/refcnt.h>
/*
* Lock ordering:
*
* The kqueue locking order can follow a few different patterns:
*
* Standard file-based kqueues (from above):
* proc fd lock -> kq lock -> kq-waitq-set lock -> thread lock
*
* WorkQ/WorkLoop kqueues (from above):
* proc fd lock -> kq lock -> workq lock -> thread lock
*
* Whenever kqueues interact with source locks, it drops all of its own
* locks in exchange for a use-reference on the knote used to synchronize
* with the source code. When those sources post events from below, they
* have the following lock hierarchy.
*
* Standard file-based kqueues (from below):
* XXX lock -> kq lock -> kq-waitq-set lock -> thread lock
*
* WorkQ/WorkLoop kqueues (from below):
* XXX lock -> kq lock -> workq lock -> thread lock
*/
#define KQEXTENT 256 /* linear growth by this amount */
struct knote_lock_ctx {
struct knote *knlc_knote;
thread_t knlc_thread;
uintptr_t knlc_waiters;
LIST_ENTRY(knote_lock_ctx) knlc_link;
#if DEBUG || DEVELOPMENT
#define KNOTE_LOCK_CTX_UNLOCKED 0
#define KNOTE_LOCK_CTX_LOCKED 1
#define KNOTE_LOCK_CTX_WAITING 2
int knlc_state;
#endif
};
LIST_HEAD(knote_locks, knote_lock_ctx);
#if DEBUG || DEVELOPMENT
/*
* KNOTE_LOCK_CTX(name) is a convenience macro to define a knote lock context on
* the stack named `name`. In development kernels, it uses tricks to make sure
* not locks was still held when exiting the C-scope that contains this context.
*/
static inline void
knote_lock_ctx_chk(struct knote_lock_ctx *knlc)
{
/* evil hackery to make sure no one forgets to unlock */
assert(knlc->knlc_state == KNOTE_LOCK_CTX_UNLOCKED);
}
#define KNOTE_LOCK_CTX(n) \
struct knote_lock_ctx n __attribute__((cleanup(knote_lock_ctx_chk))); \
n.knlc_state = KNOTE_LOCK_CTX_UNLOCKED
#else
#define KNOTE_LOCK_CTX(n) \
struct knote_lock_ctx n
#endif
__options_decl(kq_state_t, uint16_t, {
KQ_SLEEP = 0x0002, /* thread is waiting for events */
KQ_PROCWAIT = 0x0004, /* thread waiting for processing */
KQ_KEV32 = 0x0008, /* kq is used with 32-bit events */
KQ_KEV64 = 0x0010, /* kq is used with 64-bit events */
KQ_KEV_QOS = 0x0020, /* kq events carry QoS info */
KQ_WORKQ = 0x0040, /* KQ is bound to process workq */
KQ_WORKLOOP = 0x0080, /* KQ is part of a workloop */
KQ_PROCESSING = 0x0100, /* KQ is being processed */
KQ_DRAIN = 0x0200, /* kq is draining */
KQ_DYNAMIC = 0x0800, /* kqueue is dynamically managed */
KQ_R2K_ARMED = 0x1000, /* ast notification armed */
KQ_HAS_TURNSTILE = 0x2000, /* this kqueue has a turnstile */
});
/*
* kqueue - common core definition of a kqueue
*
* No real structures are allocated of this type. They are
* either kqfile objects or kqworkq objects - each of which is
* derived from this definition.
*/
struct kqueue {
lck_spin_t kq_lock; /* kqueue lock */
kq_state_t kq_state; /* state of the kq */
uint16_t kq_level; /* nesting level of the kqfile */
uint32_t kq_count; /* number of queued events */
struct proc *kq_p; /* process containing kqueue */
struct knote_locks kq_knlocks; /* list of knote locks held */
};
/*
* kqfile - definition of a typical kqueue opened as a file descriptor
* via the kqueue() system call.
*
* Adds selinfo support to the base kqueue definition, as these
* fds can be fed into select().
*/
struct kqfile {
struct kqueue kqf_kqueue; /* common kqueue core */
struct kqtailq kqf_queue; /* queue of woken up knotes */
struct kqtailq kqf_suppressed; /* suppression queue */
struct selinfo kqf_sel; /* parent select/kqueue info */
#define kqf_lock kqf_kqueue.kq_lock
#define kqf_state kqf_kqueue.kq_state
#define kqf_level kqf_kqueue.kq_level
#define kqf_count kqf_kqueue.kq_count
#define kqf_p kqf_kqueue.kq_p
};
#define QOS_INDEX_KQFILE 0 /* number of qos levels in a file kq */
/*
* WorkQ kqueues need to request threads to service the triggered
* knotes in the queue. These threads are brought up on a
* effective-requested-QoS basis. Knotes are segregated based on
* that value - calculated by computing max(event-QoS, kevent-QoS).
* Only one servicing thread is requested at a time for all the
* knotes at a given effective-requested-QoS.
*/
#if !defined(KQWQ_QOS_MANAGER)
#define KQWQ_QOS_MANAGER (THREAD_QOS_LAST)
#endif
#if !defined(KQWQ_NBUCKETS)
#define KQWQ_NBUCKETS (KQWQ_QOS_MANAGER)
#endif
/*
* kqworkq - definition of a private kqueue used to coordinate event
* handling for pthread work queues.
*
* These have per-qos processing queues and state to coordinate with
* the pthread kext to ask for threads at corresponding pthread priority
* values.
*/
struct kqworkq {
struct kqueue kqwq_kqueue;
struct kqtailq kqwq_queue[KQWQ_NBUCKETS]; /* array of queues */
struct kqtailq kqwq_suppressed[KQWQ_NBUCKETS]; /* Per-QoS suppression queues */
workq_threadreq_s kqwq_request[KQWQ_NBUCKETS]; /* per-QoS request states */
};
#define kqwq_lock kqwq_kqueue.kq_lock
#define kqwq_state kqwq_kqueue.kq_state
#define kqwq_waitq_hook kqwq_kqueue.kq_waitq_hook
#define kqwq_count kqwq_kqueue.kq_count
#define kqwq_p kqwq_kqueue.kq_p
/*
* WorkLoop kqueues need to request a thread to service the triggered
* knotes in the queue. The thread is brought up on a
* effective-requested-QoS basis. Knotes are segregated based on
* that value. Once a request is made, it cannot be undone. If
* events with higher QoS arrive after, they are stored in their
* own queues and an override applied to the original request based
* on the delta between the two QoS values.
*/
#if !defined(KQWL_NBUCKETS)
#define KQWL_NBUCKETS (THREAD_QOS_LAST - 1)
#endif
/*
* kqworkloop - definition of a private kqueue used to coordinate event
* handling for pthread workloops.
*
* Workloops vary from workqs in that only a single thread is ever
* requested to service a workloop at a time. But unlike workqs,
* workloops may be "owned" by user-space threads that are
* synchronously draining an event off the workloop. In those cases,
* any overrides have to be applied to the owner until it relinqueshes
* ownership.
*
* NOTE: "lane" support is TBD.
*/
#if CONFIG_PREADOPT_TG_DEBUG
__options_decl(kqwl_preadopt_tg_op_t, uint8_t, {
KQWL_PREADOPT_OP_SERVICER_BIND = 0x01,
KQWL_PREADOPT_OP_SERVICER_REBIND = 0x02,
KQWL_PREADOPT_OP_SERVICER_UNBIND = 0x3,
KQWL_PREADOPT_OP_INCOMING_IPC = 0x4,
});
#endif
#if CONFIG_PREADOPT_TG
/*
* We have this typedef to distinguish when there is a thread_qos_t embedded
* in the last 3 bits inside the pointer
*/
typedef struct thread_group *thread_group_qos_t;
/* The possible states for kqwl_preadopt_tg:
*
* 1) Valid thread group with a QoS masked in the last 3 bits. This is used today
* by sync IPC thread group preadoption path with max QoS < THREAD_QOS_LAST.
* 2) A known constant value (enumerated below). For these known constant
* values, no QoS is merged into them.
* 3) Permanently associated with a thread group from a work interval that this
* kqwl is configured with. The QoS masked in last 3 bits will be THREAD_QOS_LAST
* to uniquely identify it from (1). See KQWL_HAS_PERMANENT_PREADOPTED_TG.
*
* @const KQWL_PREADOPTED_TG_NULL
* NULL implies that the kqwl is capable of preadopting a thread group and it
* hasn't got such a thread group to preadopt
* @const KQWL_PREADOPTED_TG_SENTINEL
* SENTINEL is set when the kqwl is no longer capable of preadopting a thread
* group because it has bound to a servicer - the reference of the thread group
* is passed to the servicer
* @const KQWL_PREADOPTED_TG_PROCESSED
* PROCESSED is set when the kqwl's servicer has processed and preadopted the
* thread group of the first EVFILT_MACHPORT knote that it is going to deliver
* to userspace.
* @const KQWL_PREADOPTED_TG_NEVER
* NEVER is set when the kqwl is not capable of preadopting a thread
* group because it is an app
*/
#define KQWL_PREADOPTED_TG_NULL ((struct thread_group *) 0)
#define KQWL_PREADOPTED_TG_SENTINEL ((struct thread_group *) -1)
#define KQWL_PREADOPTED_TG_PROCESSED ((struct thread_group *) -2)
#define KQWL_PREADOPTED_TG_NEVER ((struct thread_group *) -3)
#define KQWL_ENCODE_PREADOPTED_TG_QOS(tg, qos) \
(struct thread_group *) ((uintptr_t) tg | (uintptr_t) qos);
#define KQWL_PREADOPT_TG_MASK ~((uint64_t) THREAD_QOS_LAST)
#define KQWL_GET_PREADOPTED_TG(tg) \
(struct thread_group *)(((uintptr_t) tg) & KQWL_PREADOPT_TG_MASK)
#define KQWL_PREADOPT_TG_QOS_MASK ((uint64_t) THREAD_QOS_LAST)
#define KQWL_GET_PREADOPTED_TG_QOS(tg) \
(thread_qos_t) (((uintptr_t) tg) & KQWL_PREADOPT_TG_QOS_MASK)
#define KQWL_HAS_VALID_PREADOPTED_TG(tg) \
((tg != KQWL_PREADOPTED_TG_NULL) && \
(tg != KQWL_PREADOPTED_TG_SENTINEL) && \
(tg != KQWL_PREADOPTED_TG_NEVER) && \
(tg != KQWL_PREADOPTED_TG_PROCESSED) && \
(KQWL_GET_PREADOPTED_TG(tg) != NULL))
/*
* The preadopt thread group on a kqwl can be permanently configured when the kqwl
* is created so it does not change over the course of the kqwl's lifetime. Such
* kqwl does not participate in thread group preadoption for incoming sync IPCs.
* Today, this happens for kqwl configured with os workgroups.
*/
#define KQWL_ENCODE_PERMANENT_PREADOPTED_TG(tg) \
KQWL_ENCODE_PREADOPTED_TG_QOS(tg, THREAD_QOS_LAST)
#define KQWL_HAS_PERMANENT_PREADOPTED_TG(tg) \
(KQWL_HAS_VALID_PREADOPTED_TG(tg) && \
(KQWL_GET_PREADOPTED_TG_QOS(tg) == THREAD_QOS_LAST))
#define KQWL_CAN_ADOPT_PREADOPT_TG(tg) \
((tg != KQWL_PREADOPTED_TG_SENTINEL) && \
(tg != KQWL_PREADOPTED_TG_NEVER) && \
(tg != KQWL_PREADOPTED_TG_PROCESSED) && \
(!KQWL_HAS_PERMANENT_PREADOPTED_TG(tg)))
struct thread_group *
kqr_preadopt_thread_group(workq_threadreq_t req);
_Atomic(struct thread_group *) *
kqr_preadopt_thread_group_addr(workq_threadreq_t req);
#endif
struct kqworkloop {
struct kqueue kqwl_kqueue; /* queue of events */
struct kqtailq kqwl_queue[KQWL_NBUCKETS]; /* array of queues */
struct kqtailq kqwl_suppressed; /* Per-QoS suppression queues */
workq_threadreq_s kqwl_request; /* thread request state */
#if CONFIG_PREADOPT_TG
_Atomic thread_group_qos_t kqwl_preadopt_tg;
#endif
lck_spin_t kqwl_statelock; /* state/debounce lock */
thread_t kqwl_owner; /* current [sync] owner thread */
os_ref_atomic_t kqwl_retains; /* retain references */
thread_qos_t kqwl_wakeup_qos; /* QoS/override woke */
_Atomic uint8_t kqwl_iotier_override; /* iotier override */
#if CONFIG_PREADOPT_TG
/* The point of the kqwl_preadopt_tg_needs_redrive bit is to be able to
* coordinate which thread is going to push information about modifications
* to the kqwl_preadopt_thread group on the kqwl, to the workqueue
* subsystem. This coordination is needed because the preadoption thread
* group is set on the kqwl in the filter call without the kqlock.
*
* As such, if there is another thread holding the kqlock at this time and
* observes the write to the preadoption thread group and the need for a
* redrive request, that thread will take the responsibility of pushing that
* information down to the workqueue subsystem, thereby ack-ing the request.
*
* Otherwise, the original thread which modified the kqwl, will do so when
* it gets the kqlock.
*
* Note: Only a 1 single bit is required here but the 2 bytes here were
* wasted in packing so I've created a new atomic field for it. Only the
* bottom bit is being used, the remaining bits can be reused for other
* purposes.
*/
#define KQWL_PREADOPT_TG_NEEDS_REDRIVE (uint16_t) 0x1
#define KQWL_PREADOPT_TG_CLEAR_REDRIVE (uint16_t) 0x0
_Atomic uint16_t kqwl_preadopt_tg_needs_redrive;
#endif
#if CONFIG_PREADOPT_TG_DEBUG
/* Keep track of history of events that happened to the kqworkloop wrt to tg preadoption */
#define KQWL_PREADOPT_TG_HISTORY_COUNT 32
#define KQWL_PREADOPT_TG_HISTORY_WRITE_ENTRY(kqwl, ...) ({\
struct kqworkloop *__kqwl = (kqwl); \
unsigned int __index = os_atomic_inc_orig(&__kqwl->kqwl_preadopt_tg_history_index, relaxed); \
struct kqwl_preadopt_tg _preadopt_tg = { mach_approximate_time(), __VA_ARGS__}; \
__kqwl->kqwl_preadopt_tg_history[__index % KQWL_PREADOPT_TG_HISTORY_COUNT] = \
(struct kqwl_preadopt_tg) _preadopt_tg; \
})
struct kqwl_preadopt_tg {
uint64_t time;
kqwl_preadopt_tg_op_t op;
struct thread_group *old_preadopt_tg;
struct thread_group *new_preadopt_tg;
} kqwl_preadopt_tg_history[KQWL_PREADOPT_TG_HISTORY_COUNT];
unsigned int kqwl_preadopt_tg_history_index;
#else
#define KQWL_PREADOPT_TG_HISTORY_WRITE_ENTRY(kqwl, ...)
#endif /* CONFIG_PREADOPT_TG_DEBUG */
struct turnstile *kqwl_turnstile; /* turnstile for sync IPC/waiters */
kqueue_id_t kqwl_dynamicid; /* dynamic identity */
uint64_t kqwl_params; /* additional parameters */
LIST_ENTRY(kqworkloop) kqwl_hashlink; /* linkage for search list */
#if CONFIG_WORKLOOP_DEBUG
#define KQWL_HISTORY_COUNT 32
#define KQWL_HISTORY_WRITE_ENTRY(kqwl, ...) ({ \
struct kqworkloop *__kqwl = (kqwl); \
unsigned int __index = os_atomic_inc_orig(&__kqwl->kqwl_index, relaxed); \
__kqwl->kqwl_history[__index % KQWL_HISTORY_COUNT] = \
(struct kqwl_history)__VA_ARGS__; \
})
struct kqwl_history {
thread_t updater; /* Note: updates can be reordered */
thread_t servicer;
thread_t old_owner;
thread_t new_owner;
uint64_t kev_ident;
int16_t error;
uint16_t kev_flags;
uint32_t kev_fflags;
uint64_t kev_mask;
uint64_t kev_value;
uint64_t in_value;
} kqwl_history[KQWL_HISTORY_COUNT];
unsigned int kqwl_index;
#endif // CONFIG_WORKLOOP_DEBUG
};
LIST_HEAD(kqwllist, kqworkloop);
typedef union {
struct kqueue *kq;
struct kqworkq *kqwq;
struct kqfile *kqf;
struct kqworkloop *kqwl;
} __attribute__((transparent_union)) kqueue_t;
#define kqwl_lock kqwl_kqueue.kq_lock
#define kqwl_state kqwl_kqueue.kq_state
#define kqwl_waitq_hook kqwl_kqueue.kq_waitq_hook
#define kqwl_count kqwl_kqueue.kq_count
#define kqwl_p kqwl_kqueue.kq_p
#define KQ_WORKLOOP_RETAINS_MAX UINT32_MAX
extern void kqueue_threadreq_unbind(struct proc *p, workq_threadreq_t);
// called with the kq req held
#define KQUEUE_THREADERQ_BIND_NO_INHERITOR_UPDATE 0x1
extern void kqueue_threadreq_bind(struct proc *p, workq_threadreq_t req,
thread_t thread, unsigned int flags);
struct turnstile *kqueue_threadreq_get_turnstile(workq_threadreq_t kqr);
// called with the wq lock held
extern void
kqueue_threadreq_bind_prepost(struct proc *p, workq_threadreq_t req,
struct uthread *uth);
// called with no lock held
extern void kqueue_threadreq_bind_commit(struct proc *p, thread_t thread);
extern void kqueue_threadreq_cancel(struct proc *p, workq_threadreq_t req);
// lock not held as kqwl_params is immutable after creation
extern workq_threadreq_param_t kqueue_threadreq_workloop_param(workq_threadreq_t req);
extern struct kqueue *kqueue_alloc(struct proc *);
extern void kqueue_dealloc(struct kqueue *);
extern void kqworkq_dealloc(struct kqworkq *kqwq);
extern void knotes_dealloc(struct proc *);
extern void kqworkloops_dealloc(struct proc *);
extern int kevent_register(struct kqueue *, struct kevent_qos_s *,
struct knote **);
extern int kqueue_scan(struct kqueue *, int flags,
struct kevent_ctx_s *, kevent_callback_t);
extern int kqueue_stat(struct kqueue *, void *, int, proc_t);
extern void kevent_set_workq_quantum_expiry_user_tsd(proc_t p, thread_t t,
uint64_t flags);
#endif /* XNU_KERNEL_PRIVATE */
#endif /* !_SYS_EVENTVAR_H_ */
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