| 1 | /*
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| 2 | * Copyright (c) 2006 Ondrej Palkovsky
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | #ifndef _LIBC_PRIVATE_FIBRIL_H_
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| 30 | #define _LIBC_PRIVATE_FIBRIL_H_
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| 31 |
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| 32 | #include <adt/list.h>
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| 33 | #include <context.h>
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| 34 | #include <tls.h>
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| 35 | #include <fibril.h>
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| 36 | #include <ipc/common.h>
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| 37 |
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| 38 | #include "./futex.h"
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| 39 |
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| 40 | typedef struct {
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| 41 | fibril_t *fibril;
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| 42 | } fibril_event_t;
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| 43 |
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| 44 | #define FIBRIL_EVENT_INIT ((fibril_event_t) {0})
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| 45 |
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| 46 | struct fibril {
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| 47 | // XXX: The first two fields must not move (for taskdump).
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| 48 | link_t all_link;
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| 49 | context_t ctx;
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| 50 |
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| 51 | link_t link;
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| 52 | void *stack;
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| 53 | size_t stack_size;
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| 54 | void *arg;
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| 55 | errno_t (*func)(void *);
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| 56 | tcb_t *tcb;
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| 57 |
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| 58 | fibril_t *clean_after_me;
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| 59 | errno_t retval;
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| 60 |
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| 61 | fibril_t *thread_ctx;
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| 62 |
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| 63 | bool is_running : 1;
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| 64 | bool is_writer : 1;
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| 65 | /* In some places, we use fibril structs that can't be freed. */
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| 66 | bool is_freeable : 1;
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| 67 |
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| 68 | /* Debugging stuff. */
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| 69 | int rmutex_locks;
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| 70 | fibril_owner_info_t *waits_for;
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| 71 | fibril_event_t *sleep_event;
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| 72 | };
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| 73 |
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| 74 | extern fibril_t *fibril_alloc(void);
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| 75 | extern void fibril_setup(fibril_t *);
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| 76 | extern void fibril_teardown(fibril_t *f);
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| 77 | extern fibril_t *fibril_self(void);
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| 78 |
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| 79 | extern void __fibrils_init(void);
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| 80 | extern void __fibrils_fini(void);
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| 81 |
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| 82 | extern void fibril_wait_for(fibril_event_t *);
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| 83 | extern errno_t fibril_wait_timeout(fibril_event_t *, const struct timespec *);
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| 84 | extern void fibril_notify(fibril_event_t *);
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| 85 |
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| 86 | extern errno_t fibril_ipc_wait(ipc_call_t *, const struct timespec *);
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| 87 | extern void fibril_ipc_poke(void);
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| 88 |
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| 89 | /**
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| 90 | * "Restricted" fibril mutex.
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| 91 | *
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| 92 | * Similar to `fibril_mutex_t`, but has a set of restrictions placed on its
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| 93 | * use. Within a rmutex critical section, you
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| 94 | * - may not use any other synchronization primitive,
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| 95 | * save for another `fibril_rmutex_t`. This includes nonblocking
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| 96 | * operations like cvar signal and mutex unlock, unless otherwise
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| 97 | * specified.
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| 98 | * - may not read IPC messages
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| 99 | * - may not start a new thread/fibril
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| 100 | * (creating fibril without starting is fine)
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| 101 | *
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| 102 | * Additionally, locking with a timeout is not possible on this mutex,
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| 103 | * and there is no associated condition variable type.
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| 104 | * This is a design constraint, not a lack of implementation effort.
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| 105 | */
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| 106 | typedef struct {
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| 107 | // TODO: At this point, this is just silly handwaving to hide current
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| 108 | // futex use behind a fibril based abstraction. Later, the imple-
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| 109 | // mentation will change, but the restrictions placed on this type
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| 110 | // will allow it to be simpler and faster than a regular mutex.
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| 111 | // There might also be optional debug checking of the assumptions.
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| 112 | //
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| 113 | // Note that a consequence of the restrictions is that if we are
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| 114 | // running on a single thread, no other fibril can ever get to run
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| 115 | // while a fibril has a rmutex locked. That means that for
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| 116 | // single-threaded programs, we can reduce all rmutex locks and
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| 117 | // unlocks to simple branches on a global bool variable.
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| 118 |
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| 119 | futex_t futex;
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| 120 | } fibril_rmutex_t;
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| 121 |
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| 122 | extern errno_t fibril_rmutex_initialize(fibril_rmutex_t *);
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| 123 | extern void fibril_rmutex_destroy(fibril_rmutex_t *);
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| 124 | extern void fibril_rmutex_lock(fibril_rmutex_t *);
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| 125 | extern bool fibril_rmutex_trylock(fibril_rmutex_t *);
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| 126 | extern void fibril_rmutex_unlock(fibril_rmutex_t *);
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| 127 |
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| 128 | #endif
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