Messages in this thread | | | Date | Fri, 15 Jun 2007 09:51:15 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 04/10] i386: clean up bzImage generation |
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Jeremy Fitzhardinge wrote: > H. Peter Anvin wrote: >> Jeremy Fitzhardinge wrote: >> >>> -setup_move_size: .word 0x8000 # size to move, when setup is not >>> +setup_move_size: .word _setup_size # size to move, when setup is not >>> # loaded at 0x90000. We will move setup >>> # to 0x90000 then just before jumping >>> # into the kernel. However, only the >>> >> This is WRONG and will break 2.00 protocol bootloaders, if any still >> exist, and quite possibly some 2.01 protocol bootloaders. There are >> definitiely bootloaders in the field that rely on this implicit value. > > Ah, I see. I didn't see any documentation saying that this must be > 0x8000. Or does _setup_size just have to be <= 0x8000? >
The default for unaware bootloaders has been 0x8000 since the boot protocol was created, and bootloaders are known to (improperly) rely on it. _setup_size does have to be <= 0x8000, but that's another issue.
>>> @@ -246,7 +246,6 @@ setup2: >>> jnz 1f >>> movw $0xfffc, %sp # Make sure we're not zero >>> 1: movzwl %sp, %esp # Clear upper half of %esp >>> - sti >>> >> Motivation, please? >> > > We talked about this, and you said it was a mistake. It needn't be in > this patch; it could be separate, or just dropped as far as I'm concerned. >
I said it probably wouldn't hurt to drop it. I don't believe you ever actually explained why you wanted it dropped.
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