yuzu/src/video_core/rasterizer_accelerated.h

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// SPDX-FileCopyrightText: Copyright 2019 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <array>
#include <atomic>
#include "common/common_types.h"
#include "video_core/rasterizer_interface.h"
namespace Core::Memory {
class Memory;
}
namespace VideoCore {
/// Implements the shared part in GPU accelerated rasterizers in RasterizerInterface.
class RasterizerAccelerated : public RasterizerInterface {
public:
explicit RasterizerAccelerated(Core::Memory::Memory& cpu_memory_);
~RasterizerAccelerated() override;
void UpdatePagesCachedCount(VAddr addr, u64 size, int delta) override;
private:
class CacheEntry final {
public:
CacheEntry() = default;
std::atomic_uint16_t& Count(std::size_t page) {
return values[page & 3];
}
const std::atomic_uint16_t& Count(std::size_t page) const {
return values[page & 3];
}
private:
std::array<std::atomic_uint16_t, 4> values{};
};
static_assert(sizeof(CacheEntry) == 8, "CacheEntry should be 8 bytes!");
Fixes and workarounds to make UBSan happier on macOS There are still some other issues not addressed here, but it's a start. Workarounds for false-positive reports: - `RasterizerAccelerated`: Put a gigantic array behind a `unique_ptr`, because UBSan has a [hardcoded limit](https://stackoverflow.com/questions/64531383/c-runtime-error-using-fsanitize-undefined-object-has-a-possibly-invalid-vp) of how big it thinks objects can be, specifically when dealing with offset-to-top values used with multiple inheritance. Hopefully this doesn't have a performance impact. - `QueryCacheBase::QueryCacheBase`: Avoid an operation that UBSan thinks is UB even though it at least arguably isn't. See the link in the comment for more information. Fixes for correct reports: - `PageTable`, `Memory`: Use `uintptr_t` values instead of pointers to avoid UB from pointer overflow (when pointer arithmetic wraps around the address space). - `KScheduler::Reload`: `thread->GetOwnerProcess()` can be `nullptr`; avoid calling methods on it in this case. (The existing code returns a garbage reference to a field, which is then passed into `LoadWatchpointArray`, and apparently it's never used, so it's harmless in practice but still triggers UBSan.) - `KAutoObject::Close`: This function calls `this->Destroy()`, which overwrites the beginning of the object with junk (specifically a free list pointer). Then it calls `this->UnregisterWithKernel()`. UBSan complains about a type mismatch because the vtable has been overwritten, and I believe this is indeed UB. `UnregisterWithKernel` also loads `m_kernel` from the 'freed' object, which seems to be technically safe (the overwriting doesn't extend as far as that field), but seems dubious. Switch to a `static` method and load `m_kernel` in advance.
2023-07-01 23:00:39 +01:00
using CachedPages = std::array<CacheEntry, 0x2000000>;
std::unique_ptr<CachedPages> cached_pages;
Core::Memory::Memory& cpu_memory;
};
} // namespace VideoCore