Merge pull request #9918 from liamwhite/fwrapv

kernel: avoid signed overflow UB on MSVC
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Morph 2023-03-07 22:42:32 -05:00 committed by GitHub
commit a3ffea6a64
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3 changed files with 25 additions and 1 deletions

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@ -91,6 +91,7 @@ add_library(common STATIC
multi_level_page_table.h multi_level_page_table.h
nvidia_flags.cpp nvidia_flags.cpp
nvidia_flags.h nvidia_flags.h
overflow.h
page_table.cpp page_table.cpp
page_table.h page_table.h
param_package.cpp param_package.cpp

22
src/common/overflow.h Normal file
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@ -0,0 +1,22 @@
// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <type_traits>
#include "bit_cast.h"
namespace Common {
template <typename T>
requires(std::is_integral_v<T> && std::is_signed_v<T>)
inline T WrappingAdd(T lhs, T rhs) {
using U = std::make_unsigned_t<T>;
U lhs_u = BitCast<U>(lhs);
U rhs_u = BitCast<U>(rhs);
return BitCast<T>(lhs_u + rhs_u);
}
} // namespace Common

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@ -2,6 +2,7 @@
// SPDX-License-Identifier: GPL-2.0-or-later // SPDX-License-Identifier: GPL-2.0-or-later
#include "common/assert.h" #include "common/assert.h"
#include "common/overflow.h"
#include "core/core.h" #include "core/core.h"
#include "core/core_timing.h" #include "core/core_timing.h"
#include "core/hle/kernel/k_resource_limit.h" #include "core/hle/kernel/k_resource_limit.h"
@ -104,7 +105,7 @@ bool KResourceLimit::Reserve(LimitableResource which, s64 value, s64 timeout) {
ASSERT(current_hints[index] <= current_values[index]); ASSERT(current_hints[index] <= current_values[index]);
// If we would overflow, don't allow to succeed. // If we would overflow, don't allow to succeed.
if (current_values[index] + value <= current_values[index]) { if (Common::WrappingAdd(current_values[index], value) <= current_values[index]) {
break; break;
} }