apps

Demo applications and utilities

Contents:

• Sample usages of the cpusysregs kernel module
• Demo applications
• Sample Arm features without using the kernel module

Sample usages of the cpusysregs kernel module

sysregs is a generic tool to read and write the system registers.

Demo applications

These applications attempt to read or write the PAC key registers and should be used on Linux only. On macOS, the PAC key registers are protected from kernel access and the demo can only run with the current PAC keys, without reading or modifying them.

• demo-pac demonstrates some usages of the pointer authentication features.
• pacga computes PAC values using specified keys and values.

Sample Arm features without using the kernel module

On Linux, linux-hwcaps.cpp demonstrates how to determine a subset of the Arm features using getauxval() from userland.

On macOS, mac-sysctl demonstrates how to determine a subset of the Arm features using sysctl() from userland.

The program demo-userfeatures demonstrates the usage of the C++ class UserFeatures which returns the most important Arm features in a portable way, independently of the rest of this project, without the help of a kernel module. The class can be reused in any project. It works well on macOS. On Linux, however, some less used features are incorrectly reported by the kernel (incomplete MRS emulation).