I wasn't clear on this. My OS is going to use some part of the memory
below 511Kb in the sense that I am going to link some part (the SMP
boot code) in a location which is below 511Kb (with p_vaddr ==
p_paddr). Which means that I will not be able to check at OS runtime
which areas the OS is alowed to use. I will need this area at load
time since the bootloader will have to load this segment at the right
physical location.
I would like to have an area that is known not to be used by GRUB so
that I can link some code to be in this area. For the moment you write
it is [0x78000 to 0x80000], but it would really be great to have it
specified in the Multiboot sepcs.
Thanks
Nicolas
______________________________ Reply Separator _________________________________
> when I implement SMP. Would it be possible to specify an area in the
> first 511Kb that the OS would be free to use as part of the MultiBoot
> spec?! I am sure that you can leave a few Kb!
If you can permit to depend on the GRUB internal, you can use
[0x78000,0x80000] freely in your OS. But this assumption is
deprecated, because we may change the memory layout in the
future. Perhaps the right thing to be done is to detect which memory
range is used based on the Multiboot information dynamically. I don't
know how difficult this is. Maybe it would be easier to move the
necessary parts of the information to somewhere so that your OS could
use the low memory region without any risk. I think the OSKit
Multiboot support does the latter, but I'm not sure.
Okuji
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