Messages in this thread | | | Date | Tue, 12 Jun 2012 14:05:40 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [question] x86/x86_64 boot process |
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On 06/12/2012 01:49 PM, Brandon Falk wrote: > Greetings. Please CC me on any responses as I do not subscribe to the list. > > I'm currently working on a very very small boot loader. Currently it > uses BIOS int 0x13 to load up the 'setup' segments to 0x9000:0x0000. I > jump to this location, set up the kernel options, and then jump to > 0x9020:0x0000. Everything goes great. However, I get the message 'No > setup signature found...'. I'm assuming this is due to not loading up > the protected-mode code. I'm slightly confused as to how the protected > mode code is to be loaded. As my 'bzImage' is 2.6MB, I would need to > raise the A20 line to possibly load this up. Does the kernel assist in > this process at all? Should I set up a code32_start routine for my > code to load up the kernel? Once I'm in protected mode, how will I > even access the medium that the kernel is loaded from without creating > a driver? > > Currently the medium is a floppy image loaded in VMWare. It's a 64-bit > system. I'm just looking to be pointed in the right direction for the > next step (and if my current steps are valid for Protocol 2.10). > > Here's the current code (the code is manually overwritten onto the > bzImage, however only the code... the headers are left intact on the > bzImage): >
Please read Documentation/x86/boot.txt.
-hpa
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