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@ -1,5 +1,5 @@
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/*
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* \brief End point of inter-process communication
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* \brief Backend for end points of synchronous interprocess communication
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* \author Martin Stein
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* \date 2012-11-30
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*/
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@ -23,51 +23,7 @@
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namespace Kernel
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{
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/**
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* Sends requests to other IPC nodes, accumulates request announcments,
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* provides serial access to them and replies to them if expected.
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* Synchronizes communication.
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*
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* IPC node states:
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*
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* +----------+ +---------------+ +---------------+
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* --new-->| inactive |---send-request-await-reply--->| await reply | +--send-note--| prepare reply |
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* | |<--receive-reply---------------| | | | |
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* | |<--cancel-waiting--------------| | | | |
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* | | +---------------+ +------------>| |
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* | |<--request-is-a-note-------+---request-is-not-a-note------------------------>| |
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* | |<--------------------------(---not-await-request---+ | |
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* | | | +---------------+ | | |
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* | |---await-request-----------+-->| await request |<--+--send-reply-------------| |
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* | |<--cancel-waiting--------------| |------announce-request--+--->| |
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* | |---send-reply---------+----+-->| | | | |
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* | |---send-note--+ | | +---------------+ | | |
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* | | | | | | | |
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* | |<-------------+ | request available | | |
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* | |<--not-await-request--+ | | | |
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* | |<--request-is-a-note-------+-------------------request-is-not-a-note----(--->| |
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* | |<--request-is-a-note----------------------------------------------------+ | |
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* +----------+ +-------------------------+ | |
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* | prepare and await reply |<--send-request-and-await-reply--| |
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* | |---receive-reply---------------->| |
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* | |---cancel-waiting--------------->| |
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* +-------------------------+ +---------------+
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*
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* State model propagated to deriving classes:
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*
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* +--------------+ +----------------+
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* --new-->| has received |--send-request-await-reply-------------------->| awaits receipt |
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* | |--await-request----------------------------+-->| |
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* | | | | |
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* | |<--request-available-----------------------+ | |
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* | |--send-reply-------------------------------+-->| |
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* | |--send-note--+ | | |
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* | | | | | |
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* | |<------------+ | | |
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* | |<--request-available-or-not-await-request--+ | |
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* | |<--announce-request----------------------------| |
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* | |<--receive-reply-------------------------------| |
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* | |<--cancel-waiting------------------------------| |
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* +--------------+ +----------------+
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* Backend for end points of synchronous interprocess communication
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*/
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class Ipc_node;
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}
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@ -76,11 +32,10 @@ class Kernel::Ipc_node
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{
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private:
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template <typename T> class Fifo : public Genode::Fifo<T> { };
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class Message_buf;
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typedef Genode::Fifo<Message_buf> Message_fifo;
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/**
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* IPC node states as depicted initially
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*/
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enum State
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{
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INACTIVE = 1,
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@ -93,18 +48,19 @@ class Kernel::Ipc_node
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/**
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* Describes the buffer for incoming or outgoing messages
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*/
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struct Message_buf : public Fifo<Message_buf>::Element
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class Message_buf : public Message_fifo::Element
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{
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void * base;
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size_t size;
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Ipc_node * origin;
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public:
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void * base;
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size_t size;
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Ipc_node * origin;
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};
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Fifo<Message_buf> _request_queue; /* requests that waits to be
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* received by us */
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Message_buf _inbuf; /* buffers message we have received lastly */
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Message_buf _outbuf; /* buffers the message we aim to send */
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State _state; /* current node state */
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Message_fifo _request_queue;
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Message_buf _inbuf;
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Message_buf _outbuf;
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State _state;
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/**
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* Buffer next request from request queue in 'r' to handle it
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@ -122,8 +78,7 @@ class Kernel::Ipc_node
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_inbuf.origin = r->origin;
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/* update state */
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_state = r->origin->_awaits_reply() ? PREPARE_REPLY :
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INACTIVE;
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_state = PREPARE_REPLY;
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}
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/**
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@ -135,7 +90,7 @@ class Kernel::Ipc_node
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void _receive_reply(void * const base, size_t const size)
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{
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/* FIXME: when discard awaited replies userland must get a hint */
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if (!_awaits_reply() || size > _inbuf.size) {
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if (size > _inbuf.size) {
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PDBG("discard invalid IPC reply");
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return;
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}
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@ -164,15 +119,6 @@ class Kernel::Ipc_node
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_request_queue.enqueue(r);
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}
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/**
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* Wether we expect to receive a reply message
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*/
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bool _awaits_reply()
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{
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return _state == AWAIT_REPLY ||
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_state == PREPARE_AND_AWAIT_REPLY;
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}
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/**
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* IPC node waits for a message to receive to its inbuffer
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*/
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@ -280,30 +226,6 @@ class Kernel::Ipc_node
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}
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}
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/**
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* Send a notification and stay inactive
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*
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* \param dest targeted IPC node
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* \param note_base base of the note payload
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* \param note_size size of the note payload
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*
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* The caller must ensure that the note payload remains
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* until it is buffered by the targeted node.
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*/
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void send_note(Ipc_node * const dest,
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void * const note_base,
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size_t const note_size)
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{
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/* assert preconditions */
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assert(_state == INACTIVE || _state == PREPARE_REPLY);
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/* announce request message, our state says: No reply needed */
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_outbuf.base = note_base;
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_outbuf.size = note_size;
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_outbuf.origin = this;
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dest->_announce_request(&_outbuf);
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}
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/**
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* Stop waiting for a receipt if in a waiting state
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*/
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