kernel/include/kernel_structs.h

/*
 * Copyright (c) 2016 Wind River Systems, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#ifndef _kernel_structs__h_
#define _kernel_structs__h_

#include <kernel.h>

#if !defined(_ASMLANGUAGE)
#include <atomic.h>
#include <misc/dlist.h>
#include <string.h>
#endif

/*
 * Bitmask definitions for the struct k_thread.thread_state field.
 *
 * Must be before kerneL_arch_data.h because it might need them to be already
 * defined.
 */


/* states: common uses low bits, arch-specific use high bits */

/* Not a real thread */
#define _THREAD_DUMMY (1 << 0)

/* Thread is waiting on an object */
#define _THREAD_PENDING (1 << 1)

/* Thread has not yet started */
#define _THREAD_PRESTART (1 << 2)

/* Thread has terminated */
#define _THREAD_DEAD (1 << 3)

/* Thread is suspended */
#define _THREAD_SUSPENDED (1 << 4)

/* Thread is actively looking at events to see if they are ready */
#define _THREAD_POLLING (1 << 5)

/* end - states */

#ifdef CONFIG_STACK_SENTINEL
/* Magic value in lowest bytes of the stack */
#define STACK_SENTINEL 0xF0F0F0F0
#endif

/* lowest value of _thread_base.preempt at which a thread is non-preemptible */
#define _NON_PREEMPT_THRESHOLD 0x0080

/* highest value of _thread_base.preempt at which a thread is preemptible */
#define _PREEMPT_THRESHOLD (_NON_PREEMPT_THRESHOLD - 1)

#include <kernel_arch_data.h>

#if !defined(_ASMLANGUAGE)

struct _ready_q {

	/* always contains next thread to run: cannot be NULL */
	struct k_thread *cache;

	/* bitmap of priorities that contain at least one ready thread */
	u32_t prio_bmap[K_NUM_PRIO_BITMAPS];

	/* ready queues, one per priority */
	sys_dlist_t q[K_NUM_PRIORITIES];
};

typedef struct _ready_q _ready_q_t;

struct _kernel {

	/* nested interrupt count */
	u32_t nested;

	/* interrupt stack pointer base */
	char *irq_stack;

	/* currently scheduled thread */
	struct k_thread *current;

#ifdef CONFIG_SYS_CLOCK_EXISTS
	/* queue of timeouts */
	sys_dlist_t timeout_q;
#endif

#ifdef CONFIG_SYS_POWER_MANAGEMENT
	s32_t idle; /* Number of ticks for kernel idling */
#endif

	/*
	 * ready queue: can be big, keep after small fields, since some
	 * assembly (e.g. ARC) are limited in the encoding of the offset
	 */
	struct _ready_q ready_q;

#ifdef CONFIG_FP_SHARING
	/*
	 * A 'current_sse' field does not exist in addition to the 'current_fp'
	 * field since it's not possible to divide the IA-32 non-integer
	 * registers into 2 distinct blocks owned by differing threads.  In
	 * other words, given that the 'fxnsave/fxrstor' instructions
	 * save/restore both the X87 FPU and XMM registers, it's not possible
	 * for a thread to only "own" the XMM registers.
	 */

	/* thread (fiber or task) that owns the FP regs */
	struct k_thread *current_fp;
#endif

#if defined(CONFIG_THREAD_MONITOR)
	struct k_thread *threads; /* singly linked list of ALL fiber+tasks */
#endif

	/* arch-specific part of _kernel */
	struct _kernel_arch arch;
};

typedef struct _kernel _kernel_t;

extern struct _kernel _kernel;

#define _current _kernel.current
#define _ready_q _kernel.ready_q
#define _timeout_q _kernel.timeout_q
#define _threads _kernel.threads

#include <kernel_arch_func.h>

static ALWAYS_INLINE void
_set_thread_return_value_with_data(struct k_thread *thread,
				   unsigned int value,
				   void *data)
{
	_set_thread_return_value(thread, value);
	thread->base.swap_data = data;
}

extern void _init_thread_base(struct _thread_base *thread_base,
			      int priority, u32_t initial_state,
			      unsigned int options);

static ALWAYS_INLINE void _new_thread_init(struct k_thread *thread,
					    char *pStack, size_t stackSize,
					    int prio, unsigned int options)
{
#if !defined(CONFIG_INIT_STACKS) && !defined(CONFIG_THREAD_STACK_INFO)
	ARG_UNUSED(pStack);
	ARG_UNUSED(stackSize);
#endif

#ifdef CONFIG_INIT_STACKS
	memset(pStack, 0xaa, stackSize);
#endif
#ifdef CONFIG_STACK_SENTINEL
	/* Put the stack sentinel at the lowest 4 bytes of the stack area.
	 * We periodically check that it's still present and kill the thread
	 * if it isn't.
	 */
	*((u32_t *)pStack) = STACK_SENTINEL;
#endif /* CONFIG_STACK_SENTINEL */
	/* Initialize various struct k_thread members */
	_init_thread_base(&thread->base, prio, _THREAD_PRESTART, options);

	/* static threads overwrite it afterwards with real value */
	thread->init_data = NULL;
	thread->fn_abort = NULL;

#ifdef CONFIG_THREAD_CUSTOM_DATA
	/* Initialize custom data field (value is opaque to kernel) */
	thread->custom_data = NULL;
#endif

#if defined(CONFIG_THREAD_STACK_INFO)
	thread->stack_info.start = (u32_t)pStack;
	thread->stack_info.size = (u32_t)stackSize;
#endif /* CONFIG_THREAD_STACK_INFO */
}

#if defined(CONFIG_THREAD_MONITOR)
/*
 * Add a thread to the kernel's list of active threads.
 */
static ALWAYS_INLINE void thread_monitor_init(struct k_thread *thread)
{
	unsigned int key;

	key = irq_lock();
	thread->next_thread = _kernel.threads;
	_kernel.threads = thread;
	irq_unlock(key);
}
#else
#define thread_monitor_init(thread)		\
	do {/* do nothing */			\
	} while ((0))
#endif /* CONFIG_THREAD_MONITOR */

#endif /* _ASMLANGUAGE */

#endif /* _kernel_structs__h_ */