gnumach4linux-libre/vm/vm_object.h

/*
 * Mach Operating System
 * Copyright (c) 1993-1987 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 *	File:	vm_object.h
 *	Author:	Avadis Tevanian, Jr., Michael Wayne Young
 *	Date:	1985
 *
 *	Virtual memory object module definitions.
 */

#ifndef	_VM_VM_OBJECT_H_
#define _VM_VM_OBJECT_H_

#include <sys/types.h>
#include <mach/kern_return.h>
#include <mach/boolean.h>
#include <mach/memory_object.h>
#include <mach/port.h>
#include <mach/vm_prot.h>
#include <mach/machine/vm_types.h>
#include <kern/queue.h>
#include <kern/lock.h>
#include <kern/assert.h>
#include <kern/debug.h>
#include <kern/macros.h>
#include <vm/pmap.h>
#include <ipc/ipc_types.h>

#if	MACH_PAGEMAP
#include <vm/vm_external.h>
#endif	/* MACH_PAGEMAP */

typedef struct ipc_port *	pager_request_t;
#define	PAGER_REQUEST_NULL	((pager_request_t) 0)

/*
 *	We use "struct ipc_port *" instead of "ipc_port_t"
 *	to avoid include file circularities.
 */

struct vm_object {
	queue_head_t		memq;		/* Resident memory */
	decl_simple_lock_data(,	Lock)		/* Synchronization */
#if	VM_OBJECT_DEBUG
	thread_t		LockHolder;	/* Thread holding Lock */
#endif	/* VM_OBJECT_DEBUG */
	vm_size_t		size;		/* Object size (only valid
						 * if internal)
						 */

	int			ref_count;	/* Number of references */
	unsigned long		resident_page_count;
						/* number of resident pages */

	struct vm_object	*copy;		/* Object that should receive
						 * a copy of my changed pages
						 */
	struct vm_object	*shadow;	/* My shadow */
	vm_offset_t		shadow_offset;	/* Offset into shadow */

	struct ipc_port		*pager;		/* Where to get data */
	vm_offset_t		paging_offset;	/* Offset into memory object */
	pager_request_t		pager_request;	/* Where data comes back */
	struct ipc_port		*pager_name;	/* How to identify region */

	memory_object_copy_strategy_t
				copy_strategy;	/* How to handle data copy */

	unsigned int
				absent_count;	/* The number of pages that
						 * have been requested but
						 * not filled.  That is, the
						 * number of pages for which
						 * the "absent" attribute is
						 * asserted.
						 */

	unsigned int /* boolean_t array */
				all_wanted;	/* Bit array of "want to be
						 * awakened" notations.  See
						 * VM_OBJECT_EVENT_* items
						 * below
						 */

	unsigned int
				paging_in_progress:16,
						/* The memory object ports are
						 * being used (e.g., for pagein
						 * or pageout) -- don't change any
						 * of these fields (i.e., don't
						 * collapse, destroy or terminate)
						 */
	/* boolean_t */		used_for_pageout:1,/* The object carries data sent to
						 * a memory manager, which signals
						 * it's done by releasing memory.
						 * This flag prevents coalescing so
						 * that unmapping memory immediately
						 * results in object termination.
						 */
	/* boolean_t */		pager_created:1,/* Has pager ever been created? */
	/* boolean_t */		pager_initialized:1,/* Are fields ready to use? */
	/* boolean_t */		pager_ready:1,	/* Will manager take requests? */

	/* boolean_t */		can_persist:1,	/* The kernel may keep the data
						 * for this object (and rights to
						 * the memory object) after all
						 * address map references are
						 * deallocated?
						 */
	/* boolean_t */		internal:1,	/* Created by the kernel (and
						 * therefore, managed by the
						 * default memory manger)
						 */
	/* boolean_t */		temporary:1,	/* Permanent objects may be changed
						 * externally by the memory manager,
						 * and changes made in memory must
						 * be reflected back to the memory
						 * manager.  Temporary objects lack
						 * both of these characteristics.
						 */
	/* boolean_t */		alive:1,	/* Not yet terminated (debug) */
	/* boolean_t */		lock_in_progress : 1,
						/* Is a multi-page lock
						 * request in progress?
						 */
	/* boolean_t */		lock_restart : 1,
						/* Should lock request in
						 * progress restart search?
						 */
	/* boolean_t */		use_shared_copy : 1,/* Use shared (i.e.,
						 * delayed) copy on write */
	/* boolean_t */		shadowed: 1,	/* Shadow may exist */

	/* boolean_t */		cached: 1;	/* Object is cached */
	queue_chain_t		cached_list;	/* Attachment point for the list
						 * of objects cached as a result
						 * of their can_persist value
						 */
	vm_offset_t		last_alloc;	/* last allocation offset */
#if	MACH_PAGEMAP
	vm_external_t		existence_info;
#endif	/* MACH_PAGEMAP */
};

extern
vm_object_t	kernel_object;		/* the single kernel object */

/*
 *	Declare procedures that operate on VM objects.
 */

extern void		vm_object_bootstrap(void);
extern void		vm_object_init(void);
extern void		vm_object_collect(vm_object_t);
extern void		vm_object_terminate(vm_object_t);
extern vm_object_t	vm_object_allocate(vm_size_t);
extern void		vm_object_reference(vm_object_t);
extern void		vm_object_deallocate(vm_object_t);
extern void		vm_object_pmap_protect(
	vm_object_t	object,
	vm_offset_t	offset,
	vm_size_t	size,
	pmap_t		pmap,
	vm_offset_t	pmap_start,
	vm_prot_t	prot);
extern void		vm_object_pmap_remove(
	vm_object_t	object,
	vm_offset_t	start,
	vm_offset_t	end);
extern void		vm_object_page_remove(
	vm_object_t	object,
	vm_offset_t	start,
	vm_offset_t	end);
extern void		vm_object_shadow(
	vm_object_t	*object,	/* in/out */
	vm_offset_t	*offset,	/* in/out */
	vm_size_t	length);
extern void		vm_object_collapse(vm_object_t);
extern vm_object_t	vm_object_lookup(struct ipc_port *);
extern vm_object_t	vm_object_lookup_name(struct ipc_port *);
extern struct ipc_port	*vm_object_name(vm_object_t);
extern void		vm_object_remove(vm_object_t);

extern boolean_t	vm_object_copy_temporary(
	vm_object_t	*_object,		/* in/out */
	vm_offset_t	*_offset,		/* in/out */
	boolean_t	*_src_needs_copy,	/* out */
	boolean_t	*_dst_needs_copy);	/* out */
extern kern_return_t	vm_object_copy_strategically(
	vm_object_t	src_object,
	vm_offset_t	src_offset,
	vm_size_t	size,
	vm_object_t	*dst_object,		/* out */
	vm_offset_t	*dst_offset,		/* out */
	boolean_t	*dst_needs_copy);	/* out */
extern kern_return_t	vm_object_copy_slowly(
	vm_object_t	src_object,
	vm_offset_t	src_offset,
	vm_size_t	size,
	boolean_t	interruptible,
	vm_object_t	*_result_object);	/* out */

extern vm_object_t	vm_object_enter(
	struct ipc_port	*pager,
	vm_size_t	size,
	boolean_t	internal);
extern void		vm_object_pager_create(
	vm_object_t	object);
extern void		vm_object_destroy(
	struct ipc_port	*pager);

extern void vm_object_page_map(
	vm_object_t,
        vm_offset_t,
        vm_size_t,
	vm_offset_t	(*)(void *, vm_offset_t),
	void *);

extern vm_object_t	vm_object_request_object(struct ipc_port *);

extern boolean_t vm_object_coalesce(
   vm_object_t prev_object,
   vm_object_t next_object,
   vm_offset_t prev_offset,
   vm_offset_t next_offset,
   vm_size_t   prev_size,
   vm_size_t   next_size);

extern void vm_object_pager_wakeup(ipc_port_t  pager);

void memory_object_release(
	ipc_port_t	pager,
	pager_request_t	pager_request,
	ipc_port_t	pager_name);

void vm_object_deactivate_pages(vm_object_t);

vm_object_t vm_object_copy_delayed(
	vm_object_t	src_object);

/*
 *	Event waiting handling
 */

#define	VM_OBJECT_EVENT_INITIALIZED		0
#define	VM_OBJECT_EVENT_PAGER_READY		1
#define	VM_OBJECT_EVENT_PAGING_IN_PROGRESS	2
#define	VM_OBJECT_EVENT_ABSENT_COUNT		3
#define	VM_OBJECT_EVENT_LOCK_IN_PROGRESS	4

#define	vm_object_wait(object, event, interruptible)			\
	MACRO_BEGIN							\
	(object)->all_wanted |= 1 << (event);				\
	vm_object_sleep(((vm_offset_t) object) + (event),		\
			(object),					\
			(interruptible));				\
	MACRO_END

#define	vm_object_assert_wait(object, event, interruptible)		\
	MACRO_BEGIN							\
	(object)->all_wanted |= 1 << (event);				\
	assert_wait((event_t)(((vm_offset_t) object) + (event)), (interruptible));	\
	MACRO_END

#define	vm_object_wakeup(object, event)					\
	MACRO_BEGIN							\
	if ((object)->all_wanted & (1 << (event)))			\
		thread_wakeup((event_t)(((vm_offset_t) object) + (event)));	\
	(object)->all_wanted &= ~(1 << (event));			\
	MACRO_END

/*
 *	Routines implemented as macros
 */

#define vm_object_collectable(object)					\
	(((object)->ref_count == 0)					\
	&& ((object)->resident_page_count == 0))

#define	vm_object_paging_begin(object) 					\
	((object)->paging_in_progress++)

#define	vm_object_paging_end(object) 					\
	MACRO_BEGIN							\
	assert((object)->paging_in_progress != 0);			\
	if (--(object)->paging_in_progress == 0) {			\
		vm_object_wakeup(object,				\
			VM_OBJECT_EVENT_PAGING_IN_PROGRESS);		\
	}								\
	MACRO_END

#define	vm_object_paging_wait(object, interruptible)			\
	MACRO_BEGIN							\
	while ((object)->paging_in_progress != 0) {			\
		vm_object_wait(	(object),				\
				VM_OBJECT_EVENT_PAGING_IN_PROGRESS,	\
				(interruptible));			\
		vm_object_lock(object);					\
									\
	  /*XXX if ((interruptible) &&	*/				\
	    /*XXX (current_thread()->wait_result != THREAD_AWAKENED))*/ \
		  /*XXX break; */					\
	}								\
	MACRO_END

#define	vm_object_absent_assert_wait(object, interruptible)		\
	MACRO_BEGIN							\
	vm_object_assert_wait(	(object),				\
			VM_OBJECT_EVENT_ABSENT_COUNT,			\
			(interruptible));				\
	MACRO_END


#define	vm_object_absent_release(object)				\
	MACRO_BEGIN							\
	(object)->absent_count--;					\
	vm_object_wakeup((object),					\
			 VM_OBJECT_EVENT_ABSENT_COUNT);			\
	MACRO_END

/*
 *	Object locking macros (with and without debugging)
 */

#if	VM_OBJECT_DEBUG
#define vm_object_lock_init(object) \
MACRO_BEGIN \
	simple_lock_init(&(object)->Lock); \
	(object)->LockHolder = 0; \
MACRO_END
#define vm_object_lock(object) \
MACRO_BEGIN \
	simple_lock(&(object)->Lock); \
	(object)->LockHolder = current_thread(); \
MACRO_END
#define vm_object_unlock(object) \
MACRO_BEGIN \
	if ((object)->LockHolder != current_thread()) \
	    panic("vm_object_unlock 0x%x", (object)); \
	(object)->LockHolder = 0; \
	simple_unlock(&(object)->Lock); \
MACRO_END
#define vm_object_lock_try(object) \
	(simple_lock_try(&(object)->Lock) \
	    ? ( ((object)->LockHolder = current_thread()) , TRUE) \
	    : FALSE)
#define vm_object_sleep(event, object, interruptible) \
MACRO_BEGIN \
	if ((object)->LockHolder != current_thread()) \
	    panic("vm_object_sleep %#x", (object)); \
	(object)->LockHolder = 0; \
	thread_sleep((event_t)(event), simple_lock_addr((object)->Lock), \
		(interruptible)); \
MACRO_END
#define	vm_object_lock_taken(object)	\
		((object)->LockHolder == current_thread())
#else	/* VM_OBJECT_DEBUG */
#define vm_object_lock_init(object)	simple_lock_init(&(object)->Lock)
#define vm_object_lock(object)		simple_lock(&(object)->Lock)
#define vm_object_unlock(object)	simple_unlock(&(object)->Lock)
#define vm_object_lock_try(object)	simple_lock_try(&(object)->Lock)
#define vm_object_sleep(event, object, interruptible)			\
		thread_sleep((event_t)(event), simple_lock_addr((object)->Lock), \
			     (interruptible))
#define	vm_object_lock_taken(object)	simple_lock_taken(&(object)->Lock)
#endif	/* VM_OBJECT_DEBUG */

/*
 *	Page cache accounting.
 *
 *	The page queues must be locked when changing these counters.
 */
extern int	vm_object_external_count;
extern int	vm_object_external_pages;

/* Add a reference to a locked VM object. */
static inline int
vm_object_reference_locked (vm_object_t obj)
{
  return (++obj->ref_count);
}

/* Remove a reference from a locked VM object. */
static inline int
vm_object_unreference_locked (vm_object_t obj)
{
  return (--obj->ref_count);
}

#endif	/* _VM_VM_OBJECT_H_ */