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/*
* Copyright 2009 Novell. All Rights Reserved.
*
* Author:
* Gregory Haskins <ghaskins@novell.com>
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef _LINUX_SHM_SIGNAL_H
#define _LINUX_SHM_SIGNAL_H
#include <linux/types.h>
/*
*---------
* The following structures represent data that is shared across boundaries
* which may be quite disparate from one another (e.g. Windows vs Linux,
* 32 vs 64 bit, etc). Therefore, care has been taken to make sure they
* present data in a manner that is independent of the environment.
*-----------
*/
#define SHM_SIGNAL_MAGIC cpu_to_le32(0x58fa39df)
#define SHM_SIGNAL_VER cpu_to_le32(1)
struct shm_signal_irq {
__u8 enabled;
__u8 pending;
__u8 dirty;
};
enum shm_signal_locality {
shm_locality_north,
shm_locality_south,
};
struct shm_signal_desc {
__le32 magic;
__le32 ver;
struct shm_signal_irq irq[2];
};
/* --- END SHARED STRUCTURES --- */
#ifdef __KERNEL__
#include <linux/kref.h>
#include <linux/interrupt.h>
struct shm_signal_notifier {
void (*signal)(struct shm_signal_notifier *);
};
struct shm_signal;
struct shm_signal_ops {
int (*inject)(struct shm_signal *s);
void (*fault)(struct shm_signal *s, const char *fmt, ...);
void (*release)(struct shm_signal *s);
};
enum {
shm_signal_in_wakeup,
};
struct shm_signal {
struct kref kref;
spinlock_t lock;
enum shm_signal_locality locale;
unsigned long flags;
struct shm_signal_ops *ops;
struct shm_signal_desc *desc;
struct shm_signal_notifier *notifier;
struct tasklet_struct deferred_notify;
};
#define SHM_SIGNAL_FAULT(s, fmt, args...) \
((s)->ops->fault ? (s)->ops->fault((s), fmt, ## args) : panic(fmt, ## args))
/*
* These functions should only be used internally
*/
void _shm_signal_release(struct kref *kref);
void _shm_signal_wakeup(struct shm_signal *s);
/**
* shm_signal_init() - initialize an SHM_SIGNAL
* @s: SHM_SIGNAL context
*
* Initializes SHM_SIGNAL context before first use
*
**/
void shm_signal_init(struct shm_signal *s, enum shm_signal_locality locale,
struct shm_signal_ops *ops, struct shm_signal_desc *desc);
/**
* shm_signal_get() - acquire an SHM_SIGNAL context reference
* @s: SHM_SIGNAL context
*
**/
static inline struct shm_signal *shm_signal_get(struct shm_signal *s)
{
kref_get(&s->kref);
return s;
}
/**
* shm_signal_put() - release an SHM_SIGNAL context reference
* @s: SHM_SIGNAL context
*
**/
static inline void shm_signal_put(struct shm_signal *s)
{
kref_put(&s->kref, _shm_signal_release);
}
/**
* shm_signal_enable() - enables local notifications on an SHM_SIGNAL
* @s: SHM_SIGNAL context
* @flags: Reserved for future use, must be 0
*
* Enables/unmasks the registered notifier (if applicable) to receive wakeups
* whenever the remote side performs an shm_signal() operation. A notification
* will be dispatched immediately if any pending signals have already been
* issued prior to invoking this call.
*
* This is synonymous with unmasking an interrupt.
*
* Returns: success = 0, <0 = ERRNO
*
**/
int shm_signal_enable(struct shm_signal *s, int flags);
/**
* shm_signal_disable() - disable local notifications on an SHM_SIGNAL
* @s: SHM_SIGNAL context
* @flags: Reserved for future use, must be 0
*
* Disables/masks the registered shm_signal_notifier (if applicable) from
* receiving any further notifications. Any subsequent calls to shm_signal()
* by the remote side will update the shm as dirty, but will not traverse the
* locale boundary and will not invoke the notifier callback. Signals
* delivered while masked will be deferred until shm_signal_enable() is
* invoked.
*
* This is synonymous with masking an interrupt
*
* Returns: success = 0, <0 = ERRNO
*
**/
int shm_signal_disable(struct shm_signal *s, int flags);
/**
* shm_signal_inject() - notify the remote side about shm changes
* @s: SHM_SIGNAL context
* @flags: Reserved for future use, must be 0
*
* Marks the shm state as "dirty" and, if enabled, will traverse
* a locale boundary to inject a remote notification. The remote
* side controls whether the notification should be delivered via
* the shm_signal_enable/disable() interface.
*
* The specifics of how to traverse a locale boundary are abstracted
* by the shm_signal_ops->signal() interface and provided by a particular
* implementation. However, typically going north to south would be
* something like a syscall/hypercall, and going south to north would be
* something like a posix-signal/guest-interrupt.
*
* Returns: success = 0, <0 = ERRNO
*
**/
int shm_signal_inject(struct shm_signal *s, int flags);
#endif /* __KERNEL__ */
#endif /* _LINUX_SHM_SIGNAL_H */
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