248 lines
5.3 KiB
C++
248 lines
5.3 KiB
C++
/*
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* \brief Example block service
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* \author Norman Feske
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* \date 2018-12-06
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*/
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/*
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* Copyright (C) 2018 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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/* Genode includes */
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#include <block/request_stream.h>
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#include <base/component.h>
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#include <base/attached_ram_dataspace.h>
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#include <root/root.h>
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namespace Test {
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struct Block_session_component;
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template <unsigned> struct Jobs;
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struct Main;
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using namespace Genode;
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}
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struct Test::Block_session_component : Rpc_object<Block::Session>,
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private Block::Request_stream
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{
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Entrypoint &_ep;
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static constexpr size_t BLOCK_SIZE = 4096;
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static constexpr size_t NUM_BLOCKS = 16;
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using Block::Request_stream::with_requests;
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using Block::Request_stream::with_content;
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using Block::Request_stream::try_acknowledge;
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using Block::Request_stream::wakeup_client_if_needed;
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Block_session_component(Region_map &rm,
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Dataspace_capability ds,
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Entrypoint &ep,
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Signal_context_capability sigh)
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:
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Request_stream(rm, ds, ep, sigh,
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Info { .block_size = BLOCK_SIZE,
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.block_count = NUM_BLOCKS,
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.align_log2 = log2(BLOCK_SIZE),
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.writeable = true }),
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_ep(ep)
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{
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_ep.manage(*this);
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}
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~Block_session_component() { _ep.dissolve(*this); }
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Info info() const override { return Request_stream::info(); }
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Capability<Tx> tx_cap() override { return Request_stream::tx_cap(); }
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};
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template <unsigned N>
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struct Test::Jobs : Noncopyable
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{
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struct Entry
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{
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Block::Request request;
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enum State { UNUSED, IN_PROGRESS, COMPLETE } state;
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};
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Entry _entries[N] { };
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bool acceptable(Block::Request) const
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{
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for (unsigned i = 0; i < N; i++)
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if (_entries[i].state == Entry::UNUSED)
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return true;
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return false;
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}
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void submit(Block::Request request)
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{
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for (unsigned i = 0; i < N; i++) {
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if (_entries[i].state == Entry::UNUSED) {
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_entries[i] = Entry { .request = request,
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.state = Entry::IN_PROGRESS };
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return;
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}
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}
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error("failed to accept request");
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}
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bool execute()
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{
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bool progress = false;
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for (unsigned i = 0; i < N; i++) {
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if (_entries[i].state == Entry::IN_PROGRESS) {
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_entries[i].state = Entry::COMPLETE;
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_entries[i].request.success = true;
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progress = true;
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}
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}
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return progress;
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}
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void completed_job(Block::Request &out)
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{
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out = Block::Request { };
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for (unsigned i = 0; i < N; i++) {
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if (_entries[i].state == Entry::COMPLETE) {
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out = _entries[i].request;
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_entries[i].state = Entry::UNUSED;
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return;
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}
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}
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}
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/**
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* Apply 'fn' with completed job, reset job
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*/
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template <typename FN>
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void with_any_completed_job(FN const &fn)
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{
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Block::Request request { };
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completed_job(request);
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if (request.operation.valid())
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fn(request);
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}
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};
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struct Test::Main : Rpc_object<Typed_root<Block::Session> >
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{
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Env &_env;
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Constructible<Attached_ram_dataspace> _block_ds { };
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Constructible<Block_session_component> _block_session { };
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Signal_handler<Main> _request_handler { _env.ep(), *this, &Main::_handle_requests };
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Jobs<10> _jobs { };
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void _handle_requests()
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{
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if (!_block_session.constructed())
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return;
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Block_session_component &block_session = *_block_session;
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for (;;) {
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bool progress = false;
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/* import new requests */
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block_session.with_requests([&] (Block::Request request) {
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if (!_jobs.acceptable(request))
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return Block::Request_stream::Response::RETRY;
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/* access content of the request */
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block_session.with_content(request, [&] (void *ptr, size_t size) {
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(void)ptr;
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(void)size;
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});
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_jobs.submit(request);
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progress = true;
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return Block::Request_stream::Response::ACCEPTED;
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});
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/* process I/O */
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progress |= _jobs.execute();
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/* acknowledge finished jobs */
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block_session.try_acknowledge([&] (Block::Request_stream::Ack &ack) {
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_jobs.with_any_completed_job([&] (Block::Request request) {
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progress |= true;
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ack.submit(request);
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});
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});
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if (!progress)
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break;
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}
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block_session.wakeup_client_if_needed();
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}
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/*
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* Root interface
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*/
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Capability<Session> session(Root::Session_args const &args,
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Affinity const &) override
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{
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log("new block session: ", args.string());
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size_t const ds_size =
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Arg_string::find_arg(args.string(), "tx_buf_size").ulong_value(0);
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Ram_quota const ram_quota = ram_quota_from_args(args.string());
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if (ds_size >= ram_quota.value) {
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warning("communication buffer size exceeds session quota");
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throw Insufficient_ram_quota();
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}
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_block_ds.construct(_env.ram(), _env.rm(), ds_size);
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_block_session.construct(_env.rm(), _block_ds->cap(), _env.ep(),
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_request_handler);
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return _block_session->cap();
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}
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void upgrade(Capability<Session>, Root::Upgrade_args const &) override { }
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void close(Capability<Session>) override
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{
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_block_session.destruct();
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_block_ds.destruct();
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}
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Main(Env &env) : _env(env)
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{
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_env.parent().announce(_env.ep().manage(*this));
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}
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};
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void Component::construct(Genode::Env &env) { static Test::Main inst(env); }
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