device_memory: Use smaller virtual reservation size for compatibility with 39-bit paging

src/core/device_memory.cpp

@@ -6,9 +6,15 @@
 
 namespace Core {
 
+#ifdef ANDROID
+constexpr size_t VirtualReserveSize = 1ULL << 38;
+#else
+constexpr size_t VirtualReserveSize = 1ULL << 39;
+#endif
+
 DeviceMemory::DeviceMemory()
     : buffer{Kernel::Board::Nintendo::Nx::KSystemControl::Init::GetIntendedMemorySize(),
-             1ULL << 39} {}
+             VirtualReserveSize} {}
 DeviceMemory::~DeviceMemory() = default;
 
 } // namespace Core

src/core/hle/kernel/k_address_space_info.cpp

@@ -25,7 +25,12 @@ constexpr std::array<KAddressSpaceInfo, 13> AddressSpaceInfos{{
    { .bit_width = 36, .address = 2_GiB       , .size = 64_GiB  - 2_GiB  , .type = KAddressSpaceInfo::Type::MapLarge, },
    { .bit_width = 36, .address = Size_Invalid, .size = 8_GiB            , .type = KAddressSpaceInfo::Type::Heap,     },
    { .bit_width = 36, .address = Size_Invalid, .size = 6_GiB            , .type = KAddressSpaceInfo::Type::Alias,    },
+#ifdef ANDROID
+   // With Android, we use a 38-bit address space due to memory limitations. This should (safely) truncate ASLR region.
+   { .bit_width = 39, .address = 128_MiB     , .size = 256_GiB - 128_MiB, .type = KAddressSpaceInfo::Type::Map39Bit, },
+#else
    { .bit_width = 39, .address = 128_MiB     , .size = 512_GiB - 128_MiB, .type = KAddressSpaceInfo::Type::Map39Bit, },
+#endif
    { .bit_width = 39, .address = Size_Invalid, .size = 64_GiB           , .type = KAddressSpaceInfo::Type::MapSmall  },
    { .bit_width = 39, .address = Size_Invalid, .size = 8_GiB            , .type = KAddressSpaceInfo::Type::Heap,     },
    { .bit_width = 39, .address = Size_Invalid, .size = 64_GiB           , .type = KAddressSpaceInfo::Type::Alias,    },