forked from len0rd/rockbox
418 lines
16 KiB
C
418 lines
16 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2002 by Ulf Ralberg
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#ifndef THREAD_H
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#define THREAD_H
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#include "config.h"
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#include <inttypes.h>
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#include <stddef.h>
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#include <stdbool.h>
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#include "gcc_extensions.h"
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/* Priority scheduling (when enabled with HAVE_PRIORITY_SCHEDULING) works
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* by giving high priority threads more CPU time than lower priority threads
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* when they need it. Priority is differential such that the priority
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* difference between a lower priority runnable thread and the highest priority
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* runnable thread determines the amount of aging necessary for the lower
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* priority thread to be scheduled in order to prevent starvation.
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*
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* If software playback codec pcm buffer is going down to critical, codec
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* can gradually raise its own priority to override user interface and
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* prevent playback skipping.
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*/
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#define PRIORITY_RESERVED_HIGH 0 /* Reserved */
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#define PRIORITY_RESERVED_LOW 32 /* Reserved */
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#define HIGHEST_PRIORITY 1 /* The highest possible thread priority */
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#define LOWEST_PRIORITY 31 /* The lowest possible thread priority */
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/* Realtime range reserved for threads that will not allow threads of lower
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* priority to age and run (future expansion) */
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#define PRIORITY_REALTIME_1 1
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#define PRIORITY_REALTIME_2 2
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#define PRIORITY_REALTIME_3 3
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#define PRIORITY_REALTIME_4 4
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#define PRIORITY_REALTIME 4 /* Lowest realtime range */
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#define PRIORITY_BUFFERING 15 /* Codec buffering thread */
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#define PRIORITY_USER_INTERFACE 16 /* The main thread */
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#define PRIORITY_RECORDING 16 /* Recording thread */
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#define PRIORITY_PLAYBACK 16 /* Variable between this and MAX */
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#define PRIORITY_PLAYBACK_MAX 5 /* Maximum allowable playback priority */
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#define PRIORITY_SYSTEM 18 /* All other firmware threads */
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#define PRIORITY_BACKGROUND 20 /* Normal application threads */
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#define NUM_PRIORITIES 32
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#define PRIORITY_IDLE 32 /* Priority representative of no tasks */
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#define IO_PRIORITY_IMMEDIATE 0
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#define IO_PRIORITY_BACKGROUND 32
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#if CONFIG_CODEC == SWCODEC
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#ifdef HAVE_RECORDING
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#ifdef HAVE_HARDWARE_CLICK
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#define BASETHREADS 18
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#else
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#define BASETHREADS 17
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#endif
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#else
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#ifdef HAVE_HARDWARE_CLICK
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#define BASETHREADS 17
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#else
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#define BASETHREADS 16
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#endif
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#endif
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#else
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#define BASETHREADS 11
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#endif /* CONFIG_CODE == * */
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#ifndef TARGET_EXTRA_THREADS
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#define TARGET_EXTRA_THREADS 0
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#endif
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#define MAXTHREADS (BASETHREADS+TARGET_EXTRA_THREADS)
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/*
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* We need more stack when we run under a host
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* maybe more expensive C lib functions?
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*
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* simulator (possibly) doesn't simulate stack usage anyway but well ... */
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#if defined(HAVE_SDL_THREADS) || defined(__PCTOOL__)
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struct regs
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{
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void *t; /* OS thread */
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void *told; /* Last thread in slot (explained in thead-sdl.c) */
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void *s; /* Semaphore for blocking and wakeup */
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void (*start)(void); /* Start function */
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};
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#define DEFAULT_STACK_SIZE 0x100 /* tiny, ignored anyway */
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#else
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#include "asm/thread.h"
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#endif /* HAVE_SDL_THREADS */
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#ifdef CPU_PP
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#ifdef HAVE_CORELOCK_OBJECT
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/* No reliable atomic instruction available - use Peterson's algorithm */
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struct corelock
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{
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volatile unsigned char myl[NUM_CORES];
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volatile unsigned char turn;
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} __attribute__((packed));
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/* Too big to inline everywhere */
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void corelock_init(struct corelock *cl);
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void corelock_lock(struct corelock *cl);
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int corelock_try_lock(struct corelock *cl);
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void corelock_unlock(struct corelock *cl);
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#endif /* HAVE_CORELOCK_OBJECT */
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#endif /* CPU_PP */
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/* NOTE: The use of the word "queue" may also refer to a linked list of
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threads being maintained that are normally dealt with in FIFO order
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and not necessarily kernel event_queue */
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enum
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{
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/* States without a timeout must be first */
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STATE_KILLED = 0, /* Thread is killed (default) */
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STATE_RUNNING, /* Thread is currently running */
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STATE_BLOCKED, /* Thread is indefinitely blocked on a queue */
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/* These states involve adding the thread to the tmo list */
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STATE_SLEEPING, /* Thread is sleeping with a timeout */
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STATE_BLOCKED_W_TMO, /* Thread is blocked on a queue with a timeout */
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/* Miscellaneous states */
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STATE_FROZEN, /* Thread is suspended and will not run until
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thread_thaw is called with its ID */
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THREAD_NUM_STATES,
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TIMEOUT_STATE_FIRST = STATE_SLEEPING,
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};
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#if NUM_CORES > 1
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/* Pointer value for name field to indicate thread is being killed. Using
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* an alternate STATE_* won't work since that would interfere with operation
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* while the thread is still running. */
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#define THREAD_DESTRUCT ((const char *)~(intptr_t)0)
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#endif
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/* Link information for lists thread is in */
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struct thread_entry; /* forward */
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struct thread_list
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{
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struct thread_entry *prev; /* Previous thread in a list */
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struct thread_entry *next; /* Next thread in a list */
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};
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#ifndef HAVE_CORELOCK_OBJECT
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/* No atomic corelock op needed or just none defined */
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#define corelock_init(cl)
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#define corelock_lock(cl)
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#define corelock_try_lock(cl)
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#define corelock_unlock(cl)
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#endif /* HAVE_CORELOCK_OBJECT */
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#ifdef HAVE_PRIORITY_SCHEDULING
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struct blocker
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{
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struct thread_entry * volatile thread; /* thread blocking other threads
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(aka. object owner) */
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int priority; /* highest priority waiter */
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struct thread_entry * (*wakeup_protocol)(struct thread_entry *thread);
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};
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/* Choices of wakeup protocol */
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/* For transfer of object ownership by one thread to another thread by
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* the owning thread itself (mutexes) */
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struct thread_entry *
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wakeup_priority_protocol_transfer(struct thread_entry *thread);
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/* For release by owner where ownership doesn't change - other threads,
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* interrupts, timeouts, etc. (mutex timeout, queues) */
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struct thread_entry *
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wakeup_priority_protocol_release(struct thread_entry *thread);
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struct priority_distribution
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{
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uint8_t hist[NUM_PRIORITIES]; /* Histogram: Frequency for each priority */
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uint32_t mask; /* Bitmask of hist entries that are not zero */
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};
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#endif /* HAVE_PRIORITY_SCHEDULING */
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/* Information kept in each thread slot
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* members are arranged according to size - largest first - in order
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* to ensure both alignment and packing at the same time.
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*/
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struct thread_entry
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{
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struct regs context; /* Register context at switch -
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_must_ be first member */
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uintptr_t *stack; /* Pointer to top of stack */
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const char *name; /* Thread name */
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long tmo_tick; /* Tick when thread should be woken from
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timeout -
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states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
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struct thread_list l; /* Links for blocked/waking/running -
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circular linkage in both directions */
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struct thread_list tmo; /* Links for timeout list -
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Circular in reverse direction, NULL-terminated in
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forward direction -
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states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
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struct thread_entry **bqp; /* Pointer to list variable in kernel
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object where thread is blocked - used
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for implicit unblock and explicit wake
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states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
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#ifdef HAVE_CORELOCK_OBJECT
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struct corelock *obj_cl; /* Object corelock where thead is blocked -
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states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
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struct corelock waiter_cl; /* Corelock for thread_wait */
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struct corelock slot_cl; /* Corelock to lock thread slot */
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unsigned char core; /* The core to which thread belongs */
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#endif
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struct thread_entry *queue; /* List of threads waiting for thread to be
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removed */
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#ifdef HAVE_WAKEUP_EXT_CB
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void (*wakeup_ext_cb)(struct thread_entry *thread); /* Callback that
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performs special steps needed when being
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forced off of an object's wait queue that
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go beyond the standard wait queue removal
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and priority disinheritance */
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/* Only enabled when using queue_send for now */
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#endif
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#if defined(HAVE_SEMAPHORE_OBJECTS) || \
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defined(HAVE_EXTENDED_MESSAGING_AND_NAME) || \
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NUM_CORES > 1
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volatile intptr_t retval; /* Return value from a blocked operation/
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misc. use */
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#endif
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#ifdef HAVE_PRIORITY_SCHEDULING
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/* Priority summary of owned objects that support inheritance */
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struct blocker *blocker; /* Pointer to blocker when this thread is blocked
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on an object that supports PIP -
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states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
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struct priority_distribution pdist; /* Priority summary of owned objects
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that have blocked threads and thread's own
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base priority */
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int skip_count; /* Number of times skipped if higher priority
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thread was running */
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unsigned char base_priority; /* Base priority (set explicitly during
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creation or thread_set_priority) */
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unsigned char priority; /* Scheduled priority (higher of base or
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all threads blocked by this one) */
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#endif
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uint16_t id; /* Current slot id */
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unsigned short stack_size; /* Size of stack in bytes */
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unsigned char state; /* Thread slot state (STATE_*) */
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#ifdef HAVE_SCHEDULER_BOOSTCTRL
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unsigned char cpu_boost; /* CPU frequency boost flag */
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#endif
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#ifdef HAVE_IO_PRIORITY
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unsigned char io_priority;
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#endif
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};
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/*** Macros for internal use ***/
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/* Thread ID, 16 bits = |VVVVVVVV|SSSSSSSS| */
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#define THREAD_ID_VERSION_SHIFT 8
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#define THREAD_ID_VERSION_MASK 0xff00
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#define THREAD_ID_SLOT_MASK 0x00ff
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#define THREAD_ID_INIT(n) ((1u << THREAD_ID_VERSION_SHIFT) | (n))
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#ifdef HAVE_CORELOCK_OBJECT
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/* Operations to be performed just before stopping a thread and starting
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a new one if specified before calling switch_thread */
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enum
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{
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TBOP_CLEAR = 0, /* No operation to do */
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TBOP_UNLOCK_CORELOCK, /* Unlock a corelock variable */
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TBOP_SWITCH_CORE, /* Call the core switch preparation routine */
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};
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struct thread_blk_ops
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{
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struct corelock *cl_p; /* pointer to corelock */
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unsigned char flags; /* TBOP_* flags */
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};
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#endif /* NUM_CORES > 1 */
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/* Information kept for each core
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* Members are arranged for the same reason as in thread_entry
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*/
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struct core_entry
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{
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/* "Active" lists - core is constantly active on these and are never
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locked and interrupts do not access them */
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struct thread_entry *running; /* threads that are running (RTR) */
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struct thread_entry *timeout; /* threads that are on a timeout before
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running again */
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struct thread_entry *block_task; /* Task going off running list */
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#ifdef HAVE_PRIORITY_SCHEDULING
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struct priority_distribution rtr; /* Summary of running and ready-to-run
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threads */
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#endif
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long next_tmo_check; /* soonest time to check tmo threads */
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#ifdef HAVE_CORELOCK_OBJECT
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struct thread_blk_ops blk_ops; /* operations to perform when
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blocking a thread */
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struct corelock rtr_cl; /* Lock for rtr list */
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#endif /* NUM_CORES */
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};
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#ifdef HAVE_PRIORITY_SCHEDULING
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#define IF_PRIO(...) __VA_ARGS__
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#define IFN_PRIO(...)
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#else
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#define IF_PRIO(...)
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#define IFN_PRIO(...) __VA_ARGS__
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#endif
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void core_idle(void);
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void core_wake(IF_COP_VOID(unsigned int core));
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/* Initialize the scheduler */
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void init_threads(void) INIT_ATTR;
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/* Allocate a thread in the scheduler */
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#define CREATE_THREAD_FROZEN 0x00000001 /* Thread is frozen at create time */
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unsigned int create_thread(void (*function)(void),
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void* stack, size_t stack_size,
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unsigned flags, const char *name
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IF_PRIO(, int priority)
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IF_COP(, unsigned int core));
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/* Set and clear the CPU frequency boost flag for the calling thread */
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#ifdef HAVE_SCHEDULER_BOOSTCTRL
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void trigger_cpu_boost(void);
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void cancel_cpu_boost(void);
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#else
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#define trigger_cpu_boost() do { } while(0)
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#define cancel_cpu_boost() do { } while(0)
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#endif
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/* Return thread entry from id */
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struct thread_entry *thread_id_entry(unsigned int thread_id);
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/* Make a frozed thread runnable (when started with CREATE_THREAD_FROZEN).
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* Has no effect on a thread not frozen. */
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void thread_thaw(unsigned int thread_id);
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/* Wait for a thread to exit */
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void thread_wait(unsigned int thread_id);
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/* Exit the current thread */
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void thread_exit(void) NORETURN_ATTR;
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#if defined(DEBUG) || defined(ROCKBOX_HAS_LOGF)
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#define ALLOW_REMOVE_THREAD
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/* Remove a thread from the scheduler */
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void remove_thread(unsigned int thread_id);
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#endif
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/* Switch to next runnable thread */
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void switch_thread(void);
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/* Blocks a thread for at least the specified number of ticks (0 = wait until
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* next tick) */
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void sleep_thread(int ticks);
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/* Indefinitely blocks the current thread on a thread queue */
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void block_thread(struct thread_entry *current);
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/* Blocks the current thread on a thread queue until explicitely woken or
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* the timeout is reached */
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void block_thread_w_tmo(struct thread_entry *current, int timeout);
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/* Return bit flags for thread wakeup */
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#define THREAD_NONE 0x0 /* No thread woken up (exclusive) */
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#define THREAD_OK 0x1 /* A thread was woken up */
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#define THREAD_SWITCH 0x2 /* Task switch recommended (one or more of
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higher priority than current were woken) */
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/* A convenience function for waking an entire queue of threads. */
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unsigned int thread_queue_wake(struct thread_entry **list);
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/* Wakeup a thread at the head of a list */
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unsigned int wakeup_thread(struct thread_entry **list);
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#ifdef HAVE_PRIORITY_SCHEDULING
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int thread_set_priority(unsigned int thread_id, int priority);
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int thread_get_priority(unsigned int thread_id);
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#endif /* HAVE_PRIORITY_SCHEDULING */
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#ifdef HAVE_IO_PRIORITY
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void thread_set_io_priority(unsigned int thread_id, int io_priority);
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int thread_get_io_priority(unsigned int thread_id);
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#endif /* HAVE_IO_PRIORITY */
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#if NUM_CORES > 1
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unsigned int switch_core(unsigned int new_core);
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#endif
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/* Return the id of the calling thread. */
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unsigned int thread_self(void);
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/* Return the thread_entry for the calling thread.
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* INTERNAL: Intended for use by kernel and not for programs. */
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struct thread_entry* thread_self_entry(void);
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/* Debugging info - only! */
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int thread_stack_usage(const struct thread_entry *thread);
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#if NUM_CORES > 1
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int idle_stack_usage(unsigned int core);
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#endif
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void thread_get_name(char *buffer, int size,
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struct thread_entry *thread);
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#ifdef RB_PROFILE
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void profile_thread(void);
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#endif
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#endif /* THREAD_H */
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