kernel: memory: Add system_control code, which will be used for ASLR support.

src/core/CMakeLists.txt

@@ -159,6 +159,8 @@ add_library(core STATIC
     hle/kernel/memory/memory_block.h
     hle/kernel/memory/memory_types.h
     hle/kernel/memory/slab_heap.h
+    hle/kernel/memory/system_control.cpp
+    hle/kernel/memory/system_control.h
     hle/kernel/mutex.cpp
     hle/kernel/mutex.h
     hle/kernel/object.cpp

src/core/hle/kernel/memory/system_control.cpp

+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <random>
+
+#include "core/hle/kernel/memory/system_control.h"
+
+namespace Kernel::Memory::SystemControl {
+
+u64 GenerateRandomU64ForInit() {
+    std::random_device device;
+    std::mt19937 gen(device());
+    std::uniform_int_distribution<u64> distribution(1, std::numeric_limits<u64>::max());
+    return distribution(gen);
+}
+
+template <typename F>
+u64 GenerateUniformRange(u64 min, u64 max, F f) {
+    /* Handle the case where the difference is too large to represent. */
+    if (max == std::numeric_limits<u64>::max() && min == std::numeric_limits<u64>::min()) {
+        return f();
+    }
+
+    /* Iterate until we get a value in range. */
+    const u64 range_size = ((max + 1) - min);
+    const u64 effective_max = (std::numeric_limits<u64>::max() / range_size) * range_size;
+    while (true) {
+        if (const u64 rnd = f(); rnd < effective_max) {
+            return min + (rnd % range_size);
+        }
+    }
+}
+
+u64 GenerateRandomRange(u64 min, u64 max) {
+    return GenerateUniformRange(min, max, GenerateRandomU64ForInit);
+}
+
+} // namespace Kernel::Memory::SystemControl

src/core/hle/kernel/memory/system_control.h

+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_types.h"
+
+namespace Kernel::Memory::SystemControl {
+
+u64 GenerateRandomU64ForInit();
+
+template <typename F>
+u64 GenerateUniformRange(u64 min, u64 max, F f);
+
+u64 GenerateRandomRange(u64 min, u64 max);
+
+} // namespace Kernel::Memory::SystemControl