genode/repos/base-foc/include/signal_source/client.h

96 lines
2.5 KiB
C++

/*
* \brief Fiasco.OC-specific signal-source client interface
* \author Norman Feske
* \author Stefan Kalkowski
* \date 2010-02-03
*
* On Fiasco.OC, the signal source server does not provide a blocking
* 'wait_for_signal' function because this kernel does not support out-of-order
* IPC replies. Instead, we use an IRQ kernel-object to let the client block
* until a signal is present at the server.
*
* We request the IRQ object capability and attach to the IRQ on construction
* of the 'Signal_source_client' object.
*/
/*
* Copyright (C) 2010-2013 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#ifndef _INCLUDE__SIGNAL_SOURCE__CLIENT_H_
#define _INCLUDE__SIGNAL_SOURCE__CLIENT_H_
#include <base/rpc_client.h>
#include <base/thread.h>
#include <signal_source/foc_signal_source.h>
namespace Fiasco {
#include <l4/sys/irq.h>
}
namespace Genode {
class Signal_source_client : public Rpc_client<Foc_signal_source>
{
private:
/**
* Capability with 'dst' referring to a Fiasco.OC IRQ object
*/
Native_capability _sem;
/**
* Request Fiasco.OC IRQ object from signal-source server
*/
void _init_sem()
{
using namespace Fiasco;
/* request mapping of semaphore capability selector */
_sem = call<Rpc_request_semaphore>();
l4_msgtag_t tag = l4_irq_attach(_sem.dst(), 0,
Thread_base::myself()->tid().kcap);
if (l4_error(tag))
PERR("l4_irq_attach failed with %ld!", l4_error(tag));
}
public:
/**
* Constructor
*/
Signal_source_client(Capability<Signal_source> cap)
: Rpc_client<Foc_signal_source>(static_cap_cast<Foc_signal_source>(cap))
{ _init_sem(); }
/*****************************
** Signal source interface **
*****************************/
/* Build with frame pointer to make GDB backtraces work. See issue #1061. */
__attribute__((optimize("-fno-omit-frame-pointer")))
__attribute__((noinline))
Signal wait_for_signal()
{
using namespace Fiasco;
/* block on semaphore, will be unblocked if signal is available */
l4_irq_receive(_sem.dst(), L4_IPC_NEVER);
/*
* Now that the server has unblocked the semaphore, we are sure
* that there is a signal pending. The following 'wait_for_signal'
* request will be immediately answered.
*/
return call<Rpc_wait_for_signal>();
}
};
}
#endif /* _INCLUDE__SIGNAL_SOURCE__CLIENT_H_ */