LinuxQuestions.org - linux/arch/arm/kernel/head.S

Hi,

just have a look into this file, it is well documented.

In short:

Code:

* Kernel startup code for all 32-bit CPUs

And in linux/arch/Doumentation/arm/README it is written:

Code:

Kernel entry (head.S)

--------------------------

  The initial entry into the kernel is via head.S, which uses machine

  independent code.  The machine is selected by the value of 'r1' on

  entry, which must be kept unique.



  Due to the large number of machines which the ARM port of Linux provides

  for, we have a method to manage this which ensures that we don't end up

  duplicating large amounts of code.



  We group machine (or platform) support code into machine classes.  A

  class typically based around one or more system on a chip devices, and

  acts as a natural container around the actual implementations.  These

  classes are given directories - arch/arm/mach-<class> and

  arch/arm/mach-<class> - which contain the source files to/include/mach

  support the machine class.  This directories also contain any machine

  specific supporting code.



  For example, the SA1100 class is based upon the SA1100 and SA1110 SoC

  devices, and contains the code to support the way the on-board and off-

  board devices are used, or the device is setup, and provides that

  machine specific "personality."



  This fine-grained machine specific selection is controlled by the machine

  type ID, which acts both as a run-time and a compile-time code selection

  method.



  You can register a new machine via the web site at:



    <http://www.arm.linux.org.uk/developer/machines/>