| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 |           Information about the Linux/PPC kernel images | 
 | 2 | ===================================================================== | 
 | 3 |  | 
 | 4 | Please mail me (Cort Dougan, cort@fsmlabs.com) if you have questions, | 
 | 5 | comments or corrections. | 
 | 6 |  | 
 | 7 | This document is meant to answer several questions I've had about how | 
 | 8 | the PReP system boots and how Linux/PPC interacts with that mechanism. | 
 | 9 | It would be nice if we could have information on how other architectures | 
 | 10 | boot here as well.  If you have anything to contribute, please | 
 | 11 | let me know. | 
 | 12 |  | 
 | 13 |  | 
 | 14 | 1. PReP boot file | 
 | 15 |  | 
 | 16 |   This is the file necessary to boot PReP systems from floppy or | 
 | 17 |   hard drive.  The firmware reads the PReP partition table entry | 
 | 18 |   and will load the image accordingly. | 
 | 19 |  | 
 | 20 |   To boot the zImage, copy it onto a floppy with dd if=zImage of=/dev/fd0h1440 | 
 | 21 |   or onto a PReP hard drive partition with dd if=zImage of=/dev/sda4 | 
 | 22 |   assuming you've created a PReP partition (type 0x41) with fdisk on | 
 | 23 |   /dev/sda4. | 
 | 24 |  | 
 | 25 |   The layout of the image format is: | 
 | 26 |  | 
 | 27 |   0x0     +------------+ | 
 | 28 |           |            | PReP partition table entry | 
 | 29 |           |            | | 
 | 30 |   0x400   +------------+ | 
 | 31 |           |            | Bootstrap program code + data | 
 | 32 |           |            | | 
 | 33 |           |            | | 
 | 34 |           +------------+ | 
 | 35 |           |            | compressed kernel, elf header removed | 
 | 36 |           +------------+ | 
 | 37 |           |            | initrd (if loaded) | 
 | 38 |           +------------+ | 
 | 39 |           |            | Elf section table for bootstrap program | 
 | 40 |           +------------+ | 
 | 41 |  | 
 | 42 |  | 
 | 43 | 2. MBX boot file | 
 | 44 |  | 
 | 45 |   The MBX boards can load an elf image, and relocate it to the | 
 | 46 |   proper location in memory - it copies the image to the location it was | 
 | 47 |   linked at. |