process.h

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#ifndef _GPXE_PROCESS_H
#define _GPXE_PROCESS_H

/** @file
 *
 * Processes
 *
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <gpxe/list.h>
#include <gpxe/refcnt.h>
#include <gpxe/tables.h>

/** A process */
struct process {
        /** List of processes */
        struct list_head list;
        /**
         * Single-step the process
         *
         * This method should execute a single step of the process.
         * Returning from this method is isomorphic to yielding the
         * CPU to another process.
         */
        void ( * step ) ( struct process *process );
        /** Reference counter
         *
         * If this interface is not part of a reference-counted
         * object, this field may be NULL.
         */
        struct refcnt *refcnt;
};

extern void process_add ( struct process *process );
extern void process_del ( struct process *process );
extern void step ( void );

/**
 * Initialise process without adding to process list
 *
 * @v process           Process
 * @v step              Process' step() method
 */
static inline __attribute__ (( always_inline )) void
process_init_stopped ( struct process *process,
                       void ( * step ) ( struct process *process ),
                       struct refcnt *refcnt ) {
        INIT_LIST_HEAD ( &process->list );
        process->step = step;
        process->refcnt = refcnt;
}

/**
 * Initialise process and add to process list
 *
 * @v process           Process
 * @v step              Process' step() method
 */
static inline __attribute__ (( always_inline )) void
process_init ( struct process *process,
               void ( * step ) ( struct process *process ),
               struct refcnt *refcnt ) {
        process_init_stopped ( process, step, refcnt );
        process_add ( process );
}

/** Permanent process table */
#define PERMANENT_PROCESSES __table ( struct process, "processes" )

/**
 * Declare a permanent process
 *
 * Permanent processes will be automatically added to the process list
 * at initialisation time.
 */
#define __permanent_process __table_entry ( PERMANENT_PROCESSES, 01 )

#endif /* _GPXE_PROCESS_H */