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<damo22>youpi: "Rather use another kernel_page_dir, otherwise this is messing with the original kernel_page_dir of the BSP." i dont understand this part of the code, i just copied it because i thought it was needed. do we need it at all for APs?

<damo22>if there is a mapping in the page directory, why cant it be seen by the AP?

<youpi>the mapping is only temporary

<youpi>I don't know if you need it in the case of bsp, i'd have to thinki about it

<damo22>i think its only there for linux drivers to work

<damo22>because they access low memory

<youpi>no

<youpi>they use kvtolin etc. for that

<youpi> /*

<youpi> * We'll have to temporarily install a direct mapping

<youpi> * between physical memory and low linear memory,

<youpi> * until we start using our new kernel segment descriptors.

<youpi> */

<youpi>see that comment

<youpi>it's there only until segmentation works

<damo22>ohh

<damo22>we should get rid of it altogther and just make sure segmentation works when its needed?

<youpi>except you can't

<youpi>since you can set up at the same time paging and segmentation

<youpi>s/can/can't

<damo22>oh

<damo22>once the gdt is loaded, you dont need the mapping?

<youpi>yes

<youpi>because segmentation makes kvtolin then work

<youpi>(err, lintokv)

<damo22>oh i thought it was a local variable, but its extern

<damo22>the kernel_page_dir

<damo22>thats why i was confused

IRC channel logs

2022-10-28.log