The ubiquitous i.MX6 Ultra Lite is high performance processor that offers a wide range of hardware security features such as ARM TrustZone, High Assurance Boot (HAB) and a Cryptographic Acceleration and Assurance Module (CAAM). The exact features and details depend on the specific part and are documented in detail in the Security Reference Manual (locked …
Author: Andrew Murray
Discovering CPU features from userspace with ELF_HWCAP
As hardware architectures evolve they introduce new features – many of these features are abstracted away by the kernel yet result in some benefit to the user such as improved security or performance. However some features, like the introduction of a new CPU instruction can only benefit user-space if user-space is able to determine that …
Booting ARM without an ARM
It’s possible (and easy) to develop software for ARM based platforms without having physical ARM based hardware on your desk – there are many ways to do this such as using the QEMU emulator. However by using something known as a Fixed Virtual Platform (FVP) it’s possible to run software on a simulation of some …
The indirection of outb, iowrite and friends
The {in,out}{b,w,l} functions of the kernel provide the mechanism for reading from and writing to what we may describe as port I/O (PIO). The API is not architecture specific and thus present in most architectures and used by a wide variety of device drivers. However the mechanism to support PIO varies widely between architectures and …