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. |