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 …
Category: Linux
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 …