Messages in this thread | | | Date | Tue, 12 Jun 2012 17:14:16 -0400 | Subject | Re: [question] x86/x86_64 boot process | From | Brandon Falk <> |
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All I really see related to the post-setup stage is:
'The 32-bit (non-real-mode) kernel starts at offset (setup_sects+1)*512 in the kernel file (again, if setup_sects == 0 the real value is 4.) It should be loaded at address 0x10000 for Image/zImage kernels and 0x100000 for bzImage kernels.'
I've read this document a few times, and it doesn't seem to mention if the kernel assists in loading. Do I have to load up the whole protected-mode kernel? Just the first few sectors? I guess that's what I'm trying to figure out, and I feel the boot.txt has not answered that for me.
On Tue, Jun 12, 2012 at 5:05 PM, H. Peter Anvin <hpa@zytor.com> wrote: > 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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