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#include "kernel/test_support/simulated_memory.hpp"
#include "kapi/memory.hpp"
#include <kstd/units>
#include <cerrno>
#include <cstddef>
#include <cstring>
#include <format>
#include <stdexcept>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>
namespace kernel::tests
{
simulated_memory::simulated_memory(kstd::units::bytes physical_size, kstd::units::bytes virtual_size)
: m_descriptor{memfd_create("teachos_simulated_memory", 0)}
, m_physical_size{physical_size}
, m_virtual_size{virtual_size}
{
if (m_descriptor < 0)
{
auto error = std::format("Failed to allocate backing memory: {}", strerror(errno));
throw std::runtime_error(error);
}
if (ftruncate(m_descriptor, static_cast<off_t>(m_physical_size.value)) < 0)
{
auto error = std::format("Failed to reserve backing memory: {}", strerror(errno));
throw std::runtime_error(error);
}
auto physical_storage = mmap(nullptr, m_physical_size.value, PROT_READ | PROT_WRITE, MAP_SHARED, m_descriptor, 0);
if (physical_storage == MAP_FAILED)
{
auto error = std::format("Failed to map backing memory: {}", strerror(errno));
throw std::runtime_error(error);
}
auto virtual_pointer = mmap(nullptr, virtual_size.value, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (virtual_pointer == MAP_FAILED)
{
auto error = std::format("Failed to reserve virtual memory: {}", strerror(errno));
throw std::runtime_error(error);
}
m_physical_base = static_cast<std::byte *>(physical_storage);
m_virtual_base = static_cast<std::byte *>(virtual_pointer);
clear();
}
simulated_memory::~simulated_memory()
{
munmap(m_virtual_base, m_virtual_size.value);
munmap(m_physical_base, m_physical_size.value);
close(m_descriptor);
}
auto simulated_memory::clear() -> void
{
std::memset(m_physical_base, 0, m_physical_size.value);
}
auto simulated_memory::physical_base() noexcept -> std::byte *
{
return m_physical_base;
}
auto simulated_memory::physical_base() const noexcept -> std::byte const *
{
return m_physical_base;
}
auto simulated_memory::physical_size() const noexcept -> kstd::units::bytes
{
return m_physical_size;
}
auto simulated_memory::virtual_base() const noexcept -> kapi::memory::linear_address
{
return kapi::memory::linear_address{m_virtual_base};
}
auto simulated_memory::virtual_size() const noexcept -> kstd::units::bytes
{
return m_virtual_size;
}
auto simulated_memory::map(kstd::units::bytes size, std::byte * to, off_t offset) -> std::byte *
{
auto mapped_ptr = mmap(to, size.value, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, m_descriptor, offset);
if (mapped_ptr == MAP_FAILED)
{
auto error = std::format("Failed to map page: {}", strerror(errno));
throw std::runtime_error(error);
}
return static_cast<std::byte *>(mapped_ptr);
}
} // namespace kernel::tests
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