service.cpp

// This file is a part of the IncludeOS unikernel - www.includeos.org
//
// Copyright 2015 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 <expects>
#include <kernel/context.hpp>
#include <cmath>

extern "C" uintptr_t get_cpu_esp();

constexpr auto STACK_SIZE = 0x20000;
static const double float1 = 0.987;
static const double float2 = 0.654;
static const double float3 = 0.321;

static double much_float(double d) {
  return sqrt(2) * d;
}

void Service::start(const std::string&)
{
  INFO("Context", "Testing stack switches");

  auto esp0 = get_cpu_esp();

  auto res1 = much_float(float1);
  auto res2 = much_float(float2);
  auto res3 = much_float(float3);

  Context::create(STACK_SIZE,
  [res1, res2] ()
  {
    const auto esp1 = get_cpu_esp();
    printf("Context 1, stack at %p\n", (void*) esp1);
    Expects(esp1 >= OS::heap_begin() and esp1 <= OS::heap_end());

    const volatile double my_float = much_float(float1);

    Context::create(STACK_SIZE,
    [esp1, res2] ()
    {
      const auto esp2 = get_cpu_esp();

      Expects(esp2 >= OS::heap_begin() and esp2 <= OS::heap_end());
      Expects(std::abs(long(esp2 - esp1)) >= STACK_SIZE);

      auto my_float = much_float(float2);
      Expects(my_float == res2);

      printf("Context 2, stack at %p\n", (void*) esp2);
    });

    Expects(my_float == res1);
  });

  // Stack should be back to where it was.
  auto esp3 = get_cpu_esp();
  Expects(esp0 == esp3);

  auto my_float = much_float(float3);
  Expects(my_float == res3);

  INFO("Context","SUCCESS");
}