+++ /dev/null
-/******************************************************************************
- * ctrl_if.c
- *
- * Management functions for special interface to the domain controller.
- *
- * Copyright (c) 2004, K A Fraser
- *
- * This file may be distributed separately from the Linux kernel, or
- * incorporated into other software packages, subject to the following license:
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this source file (the "Software"), to deal in the Software without
- * restriction, including without limitation the rights to use, copy, modify,
- * merge, publish, distribute, sublicense, and/or sell copies of the Software,
- * and to permit persons to whom the Software is furnished to do so, subject to
- * the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
- * IN THE SOFTWARE.
- */
-
-#include <linux/config.h>
-#include <linux/kernel.h>
-#include <linux/sched.h>
-#include <linux/slab.h>
-#include <linux/string.h>
-#include <linux/errno.h>
-#include <linux/irq.h>
-#include <linux/interrupt.h>
-#include <linux/module.h>
-#include <asm-xen/ctrl_if.h>
-#include <asm-xen/evtchn.h>
-
-#if 0
-#define DPRINTK(_f, _a...) printk(KERN_ALERT "(file=%s, line=%d) " _f, \
- __FILE__ , __LINE__ , ## _a )
-#else
-#define DPRINTK(_f, _a...) ((void)0)
-#endif
-
-/*
- * Extra ring macros to sync a consumer index up to the public producer index.
- * Generally UNSAFE, but we use it for recovery and shutdown in some cases.
- */
-#define RING_DROP_PENDING_REQUESTS(_r) \
- do { \
- (_r)->req_cons = (_r)->sring->req_prod; \
- } while (0)
-#define RING_DROP_PENDING_RESPONSES(_r) \
- do { \
- (_r)->rsp_cons = (_r)->sring->rsp_prod; \
- } while (0)
-
-/*
- * Only used by initial domain which must create its own control-interface
- * event channel. This value is picked up by the user-space domain controller
- * via an ioctl.
- */
-int initdom_ctrlif_domcontroller_port = -1;
-
-static int ctrl_if_evtchn;
-static int ctrl_if_irq;
-static spinlock_t ctrl_if_lock;
-
-static struct irqaction ctrl_if_irq_action;
-
-static ctrl_front_ring_t ctrl_if_tx_ring;
-static ctrl_back_ring_t ctrl_if_rx_ring;
-
-/* Incoming message requests. */
- /* Primary message type -> message handler. */
-static ctrl_msg_handler_t ctrl_if_rxmsg_handler[256];
- /* Primary message type -> callback in process context? */
-static unsigned long ctrl_if_rxmsg_blocking_context[256/sizeof(unsigned long)];
- /* Is it late enough during bootstrap to use schedule_task()? */
-static int safe_to_schedule_task;
- /* Queue up messages to be handled in process context. */
-static ctrl_msg_t ctrl_if_rxmsg_deferred[CONTROL_RING_SIZE];
-static CONTROL_RING_IDX ctrl_if_rxmsg_deferred_prod;
-static CONTROL_RING_IDX ctrl_if_rxmsg_deferred_cons;
-
-/* Incoming message responses: message identifier -> message handler/id. */
-static struct {
- ctrl_msg_handler_t fn;
- unsigned long id;
-} ctrl_if_txmsg_id_mapping[CONTROL_RING_SIZE];
-
-/* For received messages that must be deferred to process context. */
-static void __ctrl_if_rxmsg_deferred(void *unused);
-static DECLARE_WORK(ctrl_if_rxmsg_deferred_work,
- __ctrl_if_rxmsg_deferred,
- NULL);
-
-/* Deferred callbacks for people waiting for space in the transmit ring. */
-static DECLARE_TASK_QUEUE(ctrl_if_tx_tq);
-
-static DECLARE_WAIT_QUEUE_HEAD(ctrl_if_tx_wait);
-static void __ctrl_if_tx_tasklet(unsigned long data);
-static DECLARE_TASKLET(ctrl_if_tx_tasklet, __ctrl_if_tx_tasklet, 0);
-
-static void __ctrl_if_rx_tasklet(unsigned long data);
-static DECLARE_TASKLET(ctrl_if_rx_tasklet, __ctrl_if_rx_tasklet, 0);
-
-#define get_ctrl_if() ((control_if_t *)((char *)HYPERVISOR_shared_info + 2048))
-
-static void ctrl_if_notify_controller(void)
-{
- notify_via_evtchn(ctrl_if_evtchn);
-}
-
-static void ctrl_if_rxmsg_default_handler(ctrl_msg_t *msg, unsigned long id)
-{
- msg->length = 0;
- ctrl_if_send_response(msg);
-}
-
-static void __ctrl_if_tx_tasklet(unsigned long data)
-{
- ctrl_msg_t *msg;
- int was_full = RING_FULL(&ctrl_if_tx_ring);
- RING_IDX i, rp;
-
- i = ctrl_if_tx_ring.rsp_cons;
- rp = ctrl_if_tx_ring.sring->rsp_prod;
- rmb(); /* Ensure we see all requests up to 'rp'. */
-
- for ( ; i != rp; i++ )
- {
- msg = RING_GET_RESPONSE(&ctrl_if_tx_ring, i);
-
- DPRINTK("Rx-Rsp %u/%u :: %d/%d\n", i-1,
- ctrl_if_tx_ring.sring->rsp_prod,
- msg->type, msg->subtype);
-
- /* Execute the callback handler, if one was specified. */
- if ( msg->id != 0xFF )
- {
- (*ctrl_if_txmsg_id_mapping[msg->id].fn)(
- msg, ctrl_if_txmsg_id_mapping[msg->id].id);
- smp_mb(); /* Execute, /then/ free. */
- ctrl_if_txmsg_id_mapping[msg->id].fn = NULL;
- }
- }
-
- /*
- * Step over messages in the ring /after/ finishing reading them. As soon
- * as the index is updated then the message may get blown away.
- */
- smp_mb();
- ctrl_if_tx_ring.rsp_cons = i;
-
- if ( was_full && !RING_FULL(&ctrl_if_tx_ring) )
- {
- wake_up(&ctrl_if_tx_wait);
- run_task_queue(&ctrl_if_tx_tq);
- }
-}
-
-static void __ctrl_if_rxmsg_deferred(void *unused)
-{
- ctrl_msg_t *msg;
- CONTROL_RING_IDX dp;
-
- dp = ctrl_if_rxmsg_deferred_prod;
- rmb(); /* Ensure we see all deferred requests up to 'dp'. */
-
- while ( ctrl_if_rxmsg_deferred_cons != dp )
- {
- msg = &ctrl_if_rxmsg_deferred[MASK_CONTROL_IDX(
- ctrl_if_rxmsg_deferred_cons++)];
- (*ctrl_if_rxmsg_handler[msg->type])(msg, 0);
- }
-}
-
-static void __ctrl_if_rx_tasklet(unsigned long data)
-{
- ctrl_msg_t msg, *pmsg;
- CONTROL_RING_IDX dp;
- RING_IDX rp, i;
-
- i = ctrl_if_rx_ring.req_cons;
- rp = ctrl_if_rx_ring.sring->req_prod;
- dp = ctrl_if_rxmsg_deferred_prod;
- rmb(); /* Ensure we see all requests up to 'rp'. */
-
- for ( ; i != rp; i++)
- {
- pmsg = RING_GET_REQUEST(&ctrl_if_rx_ring, i);
- memcpy(&msg, pmsg, offsetof(ctrl_msg_t, msg));
-
- DPRINTK("Rx-Req %u/%u :: %d/%d\n", i-1,
- ctrl_if_rx_ring.sring->req_prod,
- msg.type, msg.subtype);
-
- if ( msg.length > sizeof(msg.msg) )
- msg.length = sizeof(msg.msg);
-
- if ( msg.length != 0 )
- memcpy(msg.msg, pmsg->msg, msg.length);
-
- if ( test_bit(msg.type,
- (unsigned long *)&ctrl_if_rxmsg_blocking_context) )
- memcpy(&ctrl_if_rxmsg_deferred[MASK_CONTROL_IDX(dp++)],
- &msg, offsetof(ctrl_msg_t, msg) + msg.length);
- else
- (*ctrl_if_rxmsg_handler[msg.type])(&msg, 0);
- }
-
- ctrl_if_rx_ring.req_cons = i;
-
- if ( dp != ctrl_if_rxmsg_deferred_prod )
- {
- wmb();
- ctrl_if_rxmsg_deferred_prod = dp;
- schedule_work(&ctrl_if_rxmsg_deferred_work);
- }
-}
-
-static irqreturn_t ctrl_if_interrupt(int irq, void *dev_id,
- struct pt_regs *regs)
-{
- if ( RING_HAS_UNCONSUMED_RESPONSES(&ctrl_if_tx_ring) )
- tasklet_schedule(&ctrl_if_tx_tasklet);
-
- if ( RING_HAS_UNCONSUMED_REQUESTS(&ctrl_if_rx_ring) )
- tasklet_schedule(&ctrl_if_rx_tasklet);
-
- return IRQ_HANDLED;
-}
-
-int
-ctrl_if_send_message_noblock(
- ctrl_msg_t *msg,
- ctrl_msg_handler_t hnd,
- unsigned long id)
-{
- unsigned long flags;
- ctrl_msg_t *dmsg;
- int i;
-
- spin_lock_irqsave(&ctrl_if_lock, flags);
-
- if ( RING_FULL(&ctrl_if_tx_ring) )
- {
- spin_unlock_irqrestore(&ctrl_if_lock, flags);
- return -EAGAIN;
- }
-
- msg->id = 0xFF;
- if ( hnd != NULL )
- {
- for ( i = 0; ctrl_if_txmsg_id_mapping[i].fn != NULL; i++ )
- continue;
- ctrl_if_txmsg_id_mapping[i].fn = hnd;
- ctrl_if_txmsg_id_mapping[i].id = id;
- msg->id = i;
- }
-
- DPRINTK("Tx-Req %u/%u :: %d/%d\n",
- ctrl_if_tx_ring.req_prod_pvt,
- ctrl_if_tx_ring.rsp_cons,
- msg->type, msg->subtype);
-
- dmsg = RING_GET_REQUEST(&ctrl_if_tx_ring,
- ctrl_if_tx_ring.req_prod_pvt);
- memcpy(dmsg, msg, sizeof(*msg));
- ctrl_if_tx_ring.req_prod_pvt++;
- RING_PUSH_REQUESTS(&ctrl_if_tx_ring);
-
- spin_unlock_irqrestore(&ctrl_if_lock, flags);
-
- ctrl_if_notify_controller();
-
- return 0;
-}
-
-int
-ctrl_if_send_message_block(
- ctrl_msg_t *msg,
- ctrl_msg_handler_t hnd,
- unsigned long id,
- long wait_state)
-{
- DECLARE_WAITQUEUE(wait, current);
- int rc;
-
- /* Fast path. */
- if ( (rc = ctrl_if_send_message_noblock(msg, hnd, id)) != -EAGAIN )
- return rc;
-
- add_wait_queue(&ctrl_if_tx_wait, &wait);
-
- for ( ; ; )
- {
- set_current_state(wait_state);
-
- if ( (rc = ctrl_if_send_message_noblock(msg, hnd, id)) != -EAGAIN )
- break;
-
- rc = -ERESTARTSYS;
- if ( signal_pending(current) && (wait_state == TASK_INTERRUPTIBLE) )
- break;
-
- schedule();
- }
-
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&ctrl_if_tx_wait, &wait);
-
- return rc;
-}
-
-/* Allow a reponse-callback handler to find context of a blocked requester. */
-struct rsp_wait {
- ctrl_msg_t *msg; /* Buffer for the response message. */
- struct task_struct *task; /* The task that is blocked on the response. */
- int done; /* Indicate to 'task' that response is rcv'ed. */
-};
-
-static void __ctrl_if_get_response(ctrl_msg_t *msg, unsigned long id)
-{
- struct rsp_wait *wait = (struct rsp_wait *)id;
- struct task_struct *task = wait->task;
-
- memcpy(wait->msg, msg, sizeof(*msg));
- wmb();
- wait->done = 1;
-
- wake_up_process(task);
-}
-
-int
-ctrl_if_send_message_and_get_response(
- ctrl_msg_t *msg,
- ctrl_msg_t *rmsg,
- long wait_state)
-{
- struct rsp_wait wait;
- int rc;
-
- wait.msg = rmsg;
- wait.done = 0;
- wait.task = current;
-
- if ( (rc = ctrl_if_send_message_block(msg, __ctrl_if_get_response,
- (unsigned long)&wait,
- wait_state)) != 0 )
- return rc;
-
- for ( ; ; )
- {
- /* NB. Can't easily support TASK_INTERRUPTIBLE here. */
- set_current_state(TASK_UNINTERRUPTIBLE);
- if ( wait.done )
- break;
- schedule();
- }
-
- set_current_state(TASK_RUNNING);
- return 0;
-}
-
-int
-ctrl_if_enqueue_space_callback(
- struct tq_struct *task)
-{
- /* Fast path. */
- if ( !RING_FULL(&ctrl_if_tx_ring) )
- return 0;
-
- (void)queue_task(task, &ctrl_if_tx_tq);
-
- /*
- * We may race execution of the task queue, so return re-checked status. If
- * the task is not executed despite the ring being non-full then we will
- * certainly return 'not full'.
- */
- smp_mb();
- return RING_FULL(&ctrl_if_tx_ring);
-}
-
-void
-ctrl_if_send_response(
- ctrl_msg_t *msg)
-{
- unsigned long flags;
- ctrl_msg_t *dmsg;
-
- /*
- * NB. The response may the original request message, modified in-place.
- * In this situation we may have src==dst, so no copying is required.
- */
- spin_lock_irqsave(&ctrl_if_lock, flags);
-
- DPRINTK("Tx-Rsp %u :: %d/%d\n",
- ctrl_if_rx_ring.rsp_prod_pvt,
- msg->type, msg->subtype);
-
- dmsg = RING_GET_RESPONSE(&ctrl_if_rx_ring,
- ctrl_if_rx_ring.rsp_prod_pvt);
- if ( dmsg != msg )
- memcpy(dmsg, msg, sizeof(*msg));
-
- ctrl_if_rx_ring.rsp_prod_pvt++;
- RING_PUSH_RESPONSES(&ctrl_if_rx_ring);
-
- spin_unlock_irqrestore(&ctrl_if_lock, flags);
-
- ctrl_if_notify_controller();
-}
-
-int
-ctrl_if_register_receiver(
- u8 type,
- ctrl_msg_handler_t hnd,
- unsigned int flags)
-{
- unsigned long _flags;
- int inuse;
-
- spin_lock_irqsave(&ctrl_if_lock, _flags);
-
- inuse = (ctrl_if_rxmsg_handler[type] != ctrl_if_rxmsg_default_handler);
-
- if ( inuse )
- {
- printk(KERN_INFO "Receiver %p already established for control "
- "messages of type %d.\n", ctrl_if_rxmsg_handler[type], type);
- }
- else
- {
- ctrl_if_rxmsg_handler[type] = hnd;
- clear_bit(type, (unsigned long *)&ctrl_if_rxmsg_blocking_context);
- if ( flags == CALLBACK_IN_BLOCKING_CONTEXT )
- {
- set_bit(type, (unsigned long *)&ctrl_if_rxmsg_blocking_context);
- if ( !safe_to_schedule_task )
- BUG();
- }
- }
-
- spin_unlock_irqrestore(&ctrl_if_lock, _flags);
-
- return !inuse;
-}
-
-void
-ctrl_if_unregister_receiver(
- u8 type,
- ctrl_msg_handler_t hnd)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&ctrl_if_lock, flags);
-
- if ( ctrl_if_rxmsg_handler[type] != hnd )
- printk(KERN_INFO "Receiver %p is not registered for control "
- "messages of type %d.\n", hnd, type);
- else
- ctrl_if_rxmsg_handler[type] = ctrl_if_rxmsg_default_handler;
-
- spin_unlock_irqrestore(&ctrl_if_lock, flags);
-
- /* Ensure that @hnd will not be executed after this function returns. */
- tasklet_unlock_wait(&ctrl_if_rx_tasklet);
-}
-
-void ctrl_if_suspend(void)
-{
- teardown_irq(ctrl_if_irq, &ctrl_if_irq_action);
- unbind_evtchn_from_irq(ctrl_if_evtchn);
-}
-
-void ctrl_if_resume(void)
-{
- control_if_t *ctrl_if = get_ctrl_if();
-
- if ( xen_start_info->flags & SIF_INITDOMAIN )
- {
- /*
- * The initial domain must create its own domain-controller link.
- * The controller is probably not running at this point, but will
- * pick up its end of the event channel from
- */
- evtchn_op_t op;
- extern void bind_evtchn_to_cpu(unsigned port, unsigned cpu);
-
- op.cmd = EVTCHNOP_bind_interdomain;
- op.u.bind_interdomain.dom1 = DOMID_SELF;
- op.u.bind_interdomain.dom2 = DOMID_SELF;
- op.u.bind_interdomain.port1 = 0;
- op.u.bind_interdomain.port2 = 0;
- if ( HYPERVISOR_event_channel_op(&op) != 0 )
- BUG();
- xen_start_info->domain_controller_evtchn = op.u.bind_interdomain.port1;
- initdom_ctrlif_domcontroller_port = op.u.bind_interdomain.port2;
- bind_evtchn_to_cpu(op.u.bind_interdomain.port1, 0);
- }
-
- /* Sync up with shared indexes. */
- FRONT_RING_ATTACH(&ctrl_if_tx_ring, &ctrl_if->tx_ring, CONTROL_RING_MEM);
- BACK_RING_ATTACH(&ctrl_if_rx_ring, &ctrl_if->rx_ring, CONTROL_RING_MEM);
-
- ctrl_if_evtchn = xen_start_info->domain_controller_evtchn;
- ctrl_if_irq = bind_evtchn_to_irq(ctrl_if_evtchn);
-
- memset(&ctrl_if_irq_action, 0, sizeof(ctrl_if_irq_action));
- ctrl_if_irq_action.handler = ctrl_if_interrupt;
- ctrl_if_irq_action.name = "ctrl-if";
- (void)setup_irq(ctrl_if_irq, &ctrl_if_irq_action);
-}
-
-void __init ctrl_if_init(void)
-{
- control_if_t *ctrl_if = get_ctrl_if();
- int i;
-
- for ( i = 0; i < 256; i++ )
- ctrl_if_rxmsg_handler[i] = ctrl_if_rxmsg_default_handler;
-
- FRONT_RING_ATTACH(&ctrl_if_tx_ring, &ctrl_if->tx_ring, CONTROL_RING_MEM);
- BACK_RING_ATTACH(&ctrl_if_rx_ring, &ctrl_if->rx_ring, CONTROL_RING_MEM);
-
- spin_lock_init(&ctrl_if_lock);
-
- ctrl_if_resume();
-}
-
-
-/* This is called after it is safe to call schedule_task(). */
-static int __init ctrl_if_late_setup(void)
-{
- safe_to_schedule_task = 1;
- return 0;
-}
-__initcall(ctrl_if_late_setup);
-
-
-/*
- * !! The following are DANGEROUS FUNCTIONS !!
- * Use with care [for example, see xencons_force_flush()].
- */
-
-int ctrl_if_transmitter_empty(void)
-{
- return (ctrl_if_tx_ring.sring->req_prod == ctrl_if_tx_ring.rsp_cons);
-
-}
-
-void ctrl_if_discard_responses(void)
-{
- RING_DROP_PENDING_RESPONSES(&ctrl_if_tx_ring);
-}
-
-EXPORT_SYMBOL(ctrl_if_send_message_noblock);
-EXPORT_SYMBOL(ctrl_if_send_message_block);
-EXPORT_SYMBOL(ctrl_if_send_message_and_get_response);
-EXPORT_SYMBOL(ctrl_if_enqueue_space_callback);
-EXPORT_SYMBOL(ctrl_if_send_response);
-EXPORT_SYMBOL(ctrl_if_register_receiver);
-EXPORT_SYMBOL(ctrl_if_unregister_receiver);
+++ /dev/null
-/******************************************************************************
- * ctrl_if.h
- *
- * Management functions for special interface to the domain controller.
- *
- * Copyright (c) 2004, K A Fraser
- *
- * This file may be distributed separately from the Linux kernel, or
- * incorporated into other software packages, subject to the following license:
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this source file (the "Software"), to deal in the Software without
- * restriction, including without limitation the rights to use, copy, modify,
- * merge, publish, distribute, sublicense, and/or sell copies of the Software,
- * and to permit persons to whom the Software is furnished to do so, subject to
- * the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
- * IN THE SOFTWARE.
- */
-
-#ifndef __ASM_XEN__CTRL_IF_H__
-#define __ASM_XEN__CTRL_IF_H__
-
-#include <asm-xen/hypervisor.h>
-#include <asm-xen/queues.h>
-
-typedef control_msg_t ctrl_msg_t;
-
-/*
- * Callback function type. Called for asynchronous processing of received
- * request messages, and responses to previously-transmitted request messages.
- * The parameters are (@msg, @id).
- * @msg: Original request/response message (not a copy). The message can be
- * modified in-place by the handler (e.g., a response callback can
- * turn a request message into a response message in place). The message
- * is no longer accessible after the callback handler returns -- if the
- * message is required to persist for longer then it must be copied.
- * @id: (Response callbacks only) The 'id' that was specified when the
- * original request message was queued for transmission.
- */
-typedef void (*ctrl_msg_handler_t)(ctrl_msg_t *, unsigned long);
-
-/*
- * Send @msg to the domain controller. Execute @hnd when a response is
- * received, passing the response message and the specified @id. This
- * operation will not block: it will return -EAGAIN if there is no space.
- * Notes:
- * 1. The @msg is copied if it is transmitted and so can be freed after this
- * function returns.
- * 2. If @hnd is NULL then no callback is executed.
- */
-int
-ctrl_if_send_message_noblock(
- ctrl_msg_t *msg,
- ctrl_msg_handler_t hnd,
- unsigned long id);
-
-/*
- * Send @msg to the domain controller. Execute @hnd when a response is
- * received, passing the response message and the specified @id. This
- * operation will block until the message is sent, or a signal is received
- * for the calling process (unless @wait_state is TASK_UNINTERRUPTIBLE).
- * Notes:
- * 1. The @msg is copied if it is transmitted and so can be freed after this
- * function returns.
- * 2. If @hnd is NULL then no callback is executed.
- */
-int
-ctrl_if_send_message_block(
- ctrl_msg_t *msg,
- ctrl_msg_handler_t hnd,
- unsigned long id,
- long wait_state);
-
-/*
- * Send @msg to the domain controller. Block until the response is received,
- * and then copy it into the provided buffer, @rmsg.
- */
-int
-ctrl_if_send_message_and_get_response(
- ctrl_msg_t *msg,
- ctrl_msg_t *rmsg,
- long wait_state);
-
-/*
- * Request a callback when there is /possibly/ space to immediately send a
- * message to the domain controller. This function returns 0 if there is
- * already space to trasnmit a message --- in this case the callback task /may/
- * still be executed. If this function returns 1 then the callback /will/ be
- * executed when space becomes available.
- */
-int
-ctrl_if_enqueue_space_callback(
- struct tq_struct *task);
-
-/*
- * Send a response (@msg) to a message from the domain controller. This will
- * never block.
- * Notes:
- * 1. The @msg is copied and so can be freed after this function returns.
- * 2. The @msg may be the original request message, modified in-place.
- */
-void
-ctrl_if_send_response(
- ctrl_msg_t *msg);
-
-/*
- * Register a receiver for typed messages from the domain controller. The
- * handler (@hnd) is called for every received message of specified @type.
- * Returns TRUE (non-zero) if the handler was successfully registered.
- * If CALLBACK_IN_BLOCKING CONTEXT is specified in @flags then callbacks will
- * occur in a context in which it is safe to yield (i.e., process context).
- */
-#define CALLBACK_IN_BLOCKING_CONTEXT 1
-int ctrl_if_register_receiver(
- u8 type,
- ctrl_msg_handler_t hnd,
- unsigned int flags);
-
-/*
- * Unregister a receiver for typed messages from the domain controller. The
- * handler (@hnd) will not be executed after this function returns.
- */
-void
-ctrl_if_unregister_receiver(
- u8 type, ctrl_msg_handler_t hnd);
-
-/* Suspend/resume notifications. */
-void ctrl_if_suspend(void);
-void ctrl_if_resume(void);
-
-/* Start-of-day setup. */
-void ctrl_if_init(void);
-
-/*
- * Returns TRUE if there are no outstanding message requests at the domain
- * controller. This can be used to ensure that messages have really flushed
- * through when it is not possible to use the response-callback interface.
- * WARNING: If other subsystems are using the control interface then this
- * function might never return TRUE!
- */
-int ctrl_if_transmitter_empty(void); /* !! DANGEROUS FUNCTION !! */
-
-/*
- * Manually discard response messages from the domain controller.
- * WARNING: This is usually done automatically -- this function should only
- * be called when normal interrupt mechanisms are disabled!
- */
-void ctrl_if_discard_responses(void); /* !! DANGEROUS FUNCTION !! */
-
-#endif /* __ASM_XEN__CONTROL_IF_H__ */
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