rockbox/firmware/kernel/thread-internal.h
Michael Sevakis 4d4b0c5a07 In queue_wait_w_tmo, guarantee wait duration
It is possible to have a thread awoken and subsequently the message
that was placed in the queue has been removed by the time the thread
is able to check the queue. Ensure theads that failed to find a
message do not return prematurely.

It was at worst imprecise when a timeout is specified. It's entirely
incorrect if the function ever returns with SYS_TIMEOUT when using
TIMEOUT_BLOCK.

Change-Id: Ibd41eae8c787adf7a320a24603cf64ff8a6da66a
2017-02-02 23:51:55 -05:00

427 lines
14 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Ulf Ralberg
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef THREAD_INTERNAL_H
#define THREAD_INTERNAL_H
#include "thread.h"
#include <stdio.h>
#include "panic.h"
#include "debug.h"
/*
* We need more stack when we run under a host
* maybe more expensive C lib functions?
*
* simulator (possibly) doesn't simulate stack usage anyway but well ... */
#if defined(HAVE_SDL_THREADS) || defined(__PCTOOL__)
struct regs
{
void *t; /* OS thread */
void *told; /* Last thread in slot (explained in thead-sdl.c) */
void *s; /* Semaphore for blocking and wakeup */
void (*start)(void); /* Start function */
};
#define DEFAULT_STACK_SIZE 0x100 /* tiny, ignored anyway */
#else
#include "asm/thread.h"
#endif /* HAVE_SDL_THREADS */
/* NOTE: The use of the word "queue" may also refer to a linked list of
threads being maintained that are normally dealt with in FIFO order
and not necessarily kernel event_queue */
enum
{
/* States without a timeout must be first */
STATE_KILLED = 0, /* Thread is killed (default) */
STATE_RUNNING, /* Thread is currently running */
STATE_BLOCKED, /* Thread is indefinitely blocked on a queue */
/* These states involve adding the thread to the tmo list */
STATE_SLEEPING, /* Thread is sleeping with a timeout */
STATE_BLOCKED_W_TMO, /* Thread is blocked on a queue with a timeout */
/* Miscellaneous states */
STATE_FROZEN, /* Thread is suspended and will not run until
thread_thaw is called with its ID */
THREAD_NUM_STATES,
TIMEOUT_STATE_FIRST = STATE_SLEEPING,
};
#ifdef HAVE_PRIORITY_SCHEDULING
/* Quick-disinherit of priority elevation. Must be a running thread. */
void priority_disinherit(struct thread_entry *thread, struct blocker *bl);
struct priority_distribution
{
uint8_t hist[NUM_PRIORITIES]; /* Histogram: Frequency for each priority */
priobit_t mask; /* Bitmask of hist entries that are not zero */
};
#endif /* HAVE_PRIORITY_SCHEDULING */
#define __rtr_queue lldc_head
#define __rtr_queue_node lldc_node
#define __tmo_queue ll_head
#define __tmo_queue_node ll_node
/* Information kept in each thread slot
* members are arranged according to size - largest first - in order
* to ensure both alignment and packing at the same time.
*/
struct thread_entry
{
struct regs context; /* Register context at switch -
_must_ be first member */
#ifndef HAVE_SDL_THREADS
uintptr_t *stack; /* Pointer to top of stack */
#endif
const char *name; /* Thread name */
long tmo_tick; /* Tick when thread should be woken */
struct __rtr_queue_node rtr; /* Node for run queue */
struct __tmo_queue_node tmo; /* Links for timeout list */
struct __wait_queue_node wq; /* Node for wait queue */
struct __wait_queue *volatile wqp; /* Pointer to registered wait queue */
#if NUM_CORES > 1
struct corelock waiter_cl; /* Corelock for thread_wait */
struct corelock slot_cl; /* Corelock to lock thread slot */
unsigned char core; /* The core to which thread belongs */
#endif
struct __wait_queue queue; /* List of threads waiting for thread to be
removed */
volatile intptr_t retval; /* Return value from a blocked operation/
misc. use */
uint32_t id; /* Current slot id */
int __errno; /* Thread error number (errno tls) */
#ifdef HAVE_PRIORITY_SCHEDULING
/* Priority summary of owned objects that support inheritance */
struct blocker *blocker; /* Pointer to blocker when this thread is blocked
on an object that supports PIP -
states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
struct priority_distribution pdist; /* Priority summary of owned objects
that have blocked threads and thread's own
base priority */
int skip_count; /* Number of times skipped if higher priority
thread was running */
unsigned char base_priority; /* Base priority (set explicitly during
creation or thread_set_priority) */
unsigned char priority; /* Scheduled priority (higher of base or
all threads blocked by this one) */
#endif
#ifndef HAVE_SDL_THREADS
unsigned short stack_size; /* Size of stack in bytes */
#endif
unsigned char state; /* Thread slot state (STATE_*) */
#ifdef HAVE_SCHEDULER_BOOSTCTRL
unsigned char cpu_boost; /* CPU frequency boost flag */
#endif
};
/* Thread ID, 32 bits = |VVVVVVVV|VVVVVVVV|VVVVVVVV|SSSSSSSS| */
#define THREAD_ID_VERSION_SHIFT 8
#define THREAD_ID_VERSION_MASK 0xffffff00
#define THREAD_ID_SLOT_MASK 0x000000ff
#define THREAD_ID_INIT(n) ((1u << THREAD_ID_VERSION_SHIFT) | (n))
#define THREAD_ID_SLOT(id) ((id) & THREAD_ID_SLOT_MASK)
#define DEADBEEF ((uintptr_t)0xdeadbeefdeadbeefull)
/* Information kept for each core
* Members are arranged for the same reason as in thread_entry
*/
struct core_entry
{
/* "Active" lists - core is constantly active on these and are never
locked and interrupts do not access them */
struct __rtr_queue rtr; /* Threads that are runnable */
struct __tmo_queue tmo; /* Threads on a bounded wait */
struct thread_entry *running; /* Currently running thread */
#ifdef HAVE_PRIORITY_SCHEDULING
struct priority_distribution rtr_dist; /* Summary of runnables */
#endif
long next_tmo_check; /* Next due timeout check */
#if NUM_CORES > 1
struct corelock rtr_cl; /* Lock for rtr list */
#endif /* NUM_CORES */
};
/* Hide a few scheduler details from itself to make allocation more flexible */
#define __main_thread_name \
({ extern const char __main_thread_name_str[]; \
__main_thread_name_str; })
static FORCE_INLINE
void * __get_main_stack(size_t *stacksize)
{
#if (CONFIG_PLATFORM & PLATFORM_NATIVE)
extern uintptr_t stackbegin[];
extern uintptr_t stackend[];
#else
extern uintptr_t *stackbegin;
extern uintptr_t *stackend;
#endif
*stacksize = (uintptr_t)stackend - (uintptr_t)stackbegin;
return stackbegin;
}
void format_thread_name(char *buf, size_t bufsize,
const struct thread_entry *thread);
static FORCE_INLINE
struct core_entry * __core_id_entry(unsigned int core)
{
#if NUM_CORES > 1
extern struct core_entry * __cores[NUM_CORES];
return __cores[core];
#else
extern struct core_entry __cores[NUM_CORES];
return &__cores[core];
#endif
}
#define __running_self_entry() \
__core_id_entry(CURRENT_CORE)->running
static FORCE_INLINE
struct thread_entry * __thread_slot_entry(unsigned int slotnum)
{
extern struct thread_entry * __threads[MAXTHREADS];
return __threads[slotnum];
}
#define __thread_id_entry(id) \
__thread_slot_entry(THREAD_ID_SLOT(id))
#define THREAD_FROM(p, member) \
container_of(p, struct thread_entry, member)
#define RTR_EMPTY(rtrp) \
({ (rtrp)->head == NULL; })
#define RTR_THREAD_FIRST(rtrp) \
({ THREAD_FROM((rtrp)->head, rtr); })
#define RTR_THREAD_NEXT(thread) \
({ THREAD_FROM((thread)->rtr.next, rtr); })
#define TMO_THREAD_FIRST(tmop) \
({ struct __tmo_queue *__tmop = (tmop); \
__tmop->head ? THREAD_FROM(__tmop->head, tmo) : NULL; })
#define TMO_THREAD_NEXT(thread) \
({ struct __tmo_queue_node *__next = (thread)->tmo.next; \
__next ? THREAD_FROM(__next, tmo) : NULL; })
#define WQ_THREAD_FIRST(wqp) \
({ struct __wait_queue *__wqp = (wqp); \
__wqp->head ? THREAD_FROM(__wqp->head, wq) : NULL; })
#define WQ_THREAD_NEXT(thread) \
({ struct __wait_queue_node *__next = (thread)->wq.next; \
__next ? THREAD_FROM(__next, wq) : NULL; })
void thread_alloc_init(void) INIT_ATTR;
struct thread_entry * thread_alloc(void);
void thread_free(struct thread_entry *thread);
void new_thread_id(struct thread_entry *thread);
/* Switch to next runnable thread */
void switch_thread(void);
/* Blocks a thread for at least the specified number of ticks (0 = wait until
* next tick) */
void sleep_thread(int ticks);
/* Blocks the current thread on a thread queue (< 0 == infinite) */
void block_thread_(struct thread_entry *current, int timeout);
#ifdef HAVE_PRIORITY_SCHEDULING
#define block_thread(thread, timeout, __wqp, bl) \
({ struct thread_entry *__t = (thread); \
__t->wqp = (__wqp); \
if (!__builtin_constant_p(bl) || (bl)) \
__t->blocker = (bl); \
block_thread_(__t, (timeout)); })
#else
#define block_thread(thread, timeout, __wqp, bl...) \
({ struct thread_entry *__t = (thread); \
__t->wqp = (__wqp); \
block_thread_(__t, (timeout)); })
#endif
/* Return bit flags for thread wakeup */
#define THREAD_NONE 0x0 /* No thread woken up (exclusive) */
#define THREAD_OK 0x1 /* A thread was woken up */
#define THREAD_SWITCH 0x2 /* Task switch recommended (one or more of
higher priority than current were woken) */
/* A convenience function for waking an entire queue of threads. */
unsigned int wait_queue_wake(struct __wait_queue *wqp);
/* Wakeup a thread at the head of a list */
enum wakeup_thread_protocol
{
WAKEUP_DEFAULT,
WAKEUP_TRANSFER,
WAKEUP_RELEASE,
WAKEUP_TRANSFER_MULTI,
};
unsigned int wakeup_thread_(struct thread_entry *thread
IF_PRIO(, enum wakeup_thread_protocol proto));
#ifdef HAVE_PRIORITY_SCHEDULING
#define wakeup_thread(thread, proto) \
wakeup_thread_((thread), (proto))
#else
#define wakeup_thread(thread, proto...) \
wakeup_thread_((thread));
#endif
#ifdef RB_PROFILE
void profile_thread(void);
#endif
static inline void rtr_queue_init(struct __rtr_queue *rtrp)
{
lldc_init(rtrp);
}
static inline void rtr_queue_make_first(struct __rtr_queue *rtrp,
struct thread_entry *thread)
{
rtrp->head = &thread->rtr;
}
static inline void rtr_queue_add(struct __rtr_queue *rtrp,
struct thread_entry *thread)
{
lldc_insert_last(rtrp, &thread->rtr);
}
static inline void rtr_queue_remove(struct __rtr_queue *rtrp,
struct thread_entry *thread)
{
lldc_remove(rtrp, &thread->rtr);
}
#define TMO_NOT_QUEUED (NULL + 1)
static inline bool tmo_is_queued(struct thread_entry *thread)
{
return thread->tmo.next != TMO_NOT_QUEUED;
}
static inline void tmo_set_dequeued(struct thread_entry *thread)
{
thread->tmo.next = TMO_NOT_QUEUED;
}
static inline void tmo_queue_init(struct __tmo_queue *tmop)
{
ll_init(tmop);
}
static inline void tmo_queue_expire(struct __tmo_queue *tmop,
struct thread_entry *prev,
struct thread_entry *thread)
{
ll_remove_next(tmop, prev ? &prev->tmo : NULL);
tmo_set_dequeued(thread);
}
static inline void tmo_queue_remove(struct __tmo_queue *tmop,
struct thread_entry *thread)
{
if (tmo_is_queued(thread))
{
ll_remove(tmop, &thread->tmo);
tmo_set_dequeued(thread);
}
}
static inline void tmo_queue_register(struct __tmo_queue *tmop,
struct thread_entry *thread)
{
if (!tmo_is_queued(thread))
ll_insert_last(tmop, &thread->tmo);
}
static inline void wait_queue_init(struct __wait_queue *wqp)
{
lld_init(wqp);
}
static inline void wait_queue_register(struct thread_entry *thread)
{
lld_insert_last(thread->wqp, &thread->wq);
}
static inline struct __wait_queue *
wait_queue_ptr(struct thread_entry *thread)
{
return thread->wqp;
}
static inline struct __wait_queue *
wait_queue_remove(struct thread_entry *thread)
{
struct __wait_queue *wqp = thread->wqp;
thread->wqp = NULL;
lld_remove(wqp, &thread->wq);
return wqp;
}
static inline struct __wait_queue *
wait_queue_try_remove(struct thread_entry *thread)
{
struct __wait_queue *wqp = thread->wqp;
if (wqp)
{
thread->wqp = NULL;
lld_remove(wqp, &thread->wq);
}
return wqp;
}
static inline void blocker_init(struct blocker *bl)
{
bl->thread = NULL;
#ifdef HAVE_PRIORITY_SCHEDULING
bl->priority = PRIORITY_IDLE;
#endif
}
static inline void blocker_splay_init(struct blocker_splay *blsplay)
{
blocker_init(&blsplay->blocker);
#ifdef HAVE_PRIORITY_SCHEDULING
threadbit_clear(&blsplay->mask);
#endif
corelock_init(&blsplay->cl);
}
static inline long get_tmo_tick(struct thread_entry *thread)
{
return thread->tmo_tick;
}
#endif /* THREAD_INTERNAL_H */