Maybe a Stupid Question

[distantvoices]

you should use the virtual address.

Where in virtual address space have you mapped your kernel? from 0xc0000000 or somewhere different? Identity mapped?

[ich_will]

identy mapped

it is loaded at 0x10000 by bochs (I think bochs doesn't enable paging)

[Pype.Clicker]

f.e. if the page with the virtual_address 0x617000 is set (page-index 1559):

from_addr + i*4096 is 0xC30000
0x617000 + 1559*4096 --> 0xC30000 (you shouldn't use this address for invlpg, i think)

I may have misunderstood your use of 'i' ...

Let's say you want to clear pages from 0x617000 to 0x619000, you need to call (among other things) the following sequence.

Code: Select all

   _invlpg(0x617000);
   _invlpg(0x618000);
   _invlpg(0x619000);

CLR_12_BITS(...) == 0x617000 *only* because you have 1:1 mapping for that region, but it won't work any longer after this ...

(checking my own code for a hopefully correct nasm-like "invlpg" ...)

[ich_will]

thx, i'll try

[ich_will]

AAAAAAARRRRGGGGGH, I found the mistake, all the paging things seems to work fine, but I've never tried to write to one page (I've played to much with the loop code):

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for(i = 0; i > 4096; i++)
    { *((char*)(0x617000 + i)) = '1'; }

do this i > 4096, i will never be bigger than 4096 if it starts by zero.

Thanks alot, first the mistake was the not existing invlpg call.

Now all works. F***.
It's better if you can read.