Android Rowhammer attack vulnerability (Drammer)

                                                PoC代码请参考：    https://github.com/vusec/drammer

# Native installation
To build the native binary, you need an Android NDK toolchain. I used
android-ndk-r11c:
```
wget https://dl.google.com/android/repository/android-ndk-r11c-linux-x86_64.zip
unzip android-ndk-r11c-linux-x86_64.zip
cd android-ndk-r11c
./build/tools/make-standalone-toolschain.sh --ndk-dir=`pwd` --arch=arm --platform=android-24 --install-dir=./sysroot-arm/ --verbose
```
You should then update the `STANDALONE_TOOLCHAIN` variable and be able to compile the binary:
```
cd native
sed -i 's#^\(STANDALONE_TOOLCHAIN=\s*\).*$#\1/path/to/android-ndk-r11c/sysroot-arm/bin#' Makefile
make
```
This gives you a stripped ARMv7 binary that you can run on both ARMv7 (32-bit)
and ARMv8 (64-bit) devices. The Makefile provides an install feature that uses
the Android Debug Bridge (adb) to push the binary to your device's
/data/local/tmp/ directory. You can install adb by doing a `sudo apt-get install
android-tools-adb` (on Ubuntu) or by installing the Android SDK via
[android.com](https://developer.android.com/studio/index.html#downloads). Then
do a:
```
make install
make test
```
to install and start the Rowhammer test binary. Once installed, you may also
invoke it from the shell directly:
```
adb shell
cd /data/local/tmp
./rh-test
```