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// This file is a part of the IncludeOS unikernel - www.includeos.org
//
// Copyright 2016 Oslo and Akershus University College of Applied Sciences
// and Alfred Bratterud
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <os>
#include <statman>
#include <kernel/events.hpp>
// Keep track of blocking levels
static uint32_t* blocking_level = nullptr;
static uint32_t* highest_blocking_level = nullptr;
// Getters, mostly for testing
extern "C" uint32_t os_get_blocking_level() {
return *blocking_level;
}
extern "C" uint32_t os_get_highest_blocking_level() {
return *highest_blocking_level;
}
/**
* A quick and dirty implementation of blocking calls, which simply halts,
* then calls the event loop, then returns.
**/
void os::block() noexcept
{
// Initialize stats
if (not blocking_level) {
blocking_level = &Statman::get()
.create(Stat::UINT32, std::string("blocking.current_level")).get_uint32();
*blocking_level = 0;
}
if (not highest_blocking_level) {
highest_blocking_level = &Statman::get()
.create(Stat::UINT32, std::string("blocking.highest")).get_uint32();
*highest_blocking_level = 0;
}
// Increment level
*blocking_level += 1;
// Increment highest if applicable
if (*blocking_level > *highest_blocking_level)
*highest_blocking_level = *blocking_level;
// Process immediate events
Events::get().process_events();
// Await next interrupt
os::halt();
// Process events (again?)
Events::get().process_events();
// Decrement level
*blocking_level -= 1;
}