mirror of
https://github.com/RGBCube/serenity
synced 2025-05-23 19:55:08 +00:00
75564b4a5f
This expands the reach of error propagation greatly throughout the kernel. Sadly, it also exposes the fact that we're allocating (and doing other fallible things) in constructors all over the place. This patch doesn't attempt to address that of course. That's work for our future selves.
78 lines
2.2 KiB
C++
78 lines
2.2 KiB
C++
/*
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* Copyright (c) 2021, the SerenityOS developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/Bus/VirtIO/RNG.h>
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#include <Kernel/Sections.h>
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namespace Kernel::VirtIO {
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UNMAP_AFTER_INIT NonnullRefPtr<RNG> RNG::must_create(PCI::Address address)
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{
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return adopt_ref_if_nonnull(new RNG(address)).release_nonnull();
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}
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UNMAP_AFTER_INIT void RNG::initialize()
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{
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Device::initialize();
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bool success = negotiate_features([&](auto) {
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return 0;
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});
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if (success) {
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success = setup_queues(1);
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}
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if (success) {
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finish_init();
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m_entropy_buffer = MM.allocate_contiguous_kernel_region(PAGE_SIZE, "VirtIO::RNG", Memory::Region::Access::ReadWrite).release_value();
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if (m_entropy_buffer) {
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memset(m_entropy_buffer->vaddr().as_ptr(), 0, m_entropy_buffer->size());
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request_entropy_from_host();
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}
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}
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}
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UNMAP_AFTER_INIT RNG::RNG(PCI::Address address)
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: VirtIO::Device(address)
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{
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}
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bool RNG::handle_device_config_change()
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{
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return false; // Device has no config
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}
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void RNG::handle_queue_update(u16 queue_index)
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{
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VERIFY(queue_index == REQUESTQ);
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size_t available_entropy = 0, used;
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auto& queue = get_queue(REQUESTQ);
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{
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SpinlockLocker lock(queue.lock());
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auto chain = queue.pop_used_buffer_chain(used);
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if (chain.is_empty())
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return;
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VERIFY(chain.length() == 1);
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chain.for_each([&available_entropy](PhysicalAddress, size_t length) {
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available_entropy = length;
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});
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chain.release_buffer_slots_to_queue();
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}
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dbgln_if(VIRTIO_DEBUG, "VirtIO::RNG: received {} bytes of entropy!", available_entropy);
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for (auto i = 0u; i < available_entropy; i++) {
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m_entropy_source.add_random_event(m_entropy_buffer->vaddr().as_ptr()[i]);
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}
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// TODO: When should we get some more entropy?
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}
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void RNG::request_entropy_from_host()
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{
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auto& queue = get_queue(REQUESTQ);
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SpinlockLocker lock(queue.lock());
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QueueChain chain(queue);
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chain.add_buffer_to_chain(m_entropy_buffer->physical_page(0)->paddr(), PAGE_SIZE, BufferType::DeviceWritable);
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supply_chain_and_notify(REQUESTQ, chain);
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}
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}
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