OSDev.org

The Place to Start for Operating System Developers
It is currently Thu Mar 28, 2024 2:41 pm

All times are UTC - 6 hours




Post new topic Reply to topic  [ 3 posts ] 
Author Message
 Post subject: Strange value in PCI ABAR
PostPosted: Sat Jun 11, 2022 9:19 am 
Offline

Joined: Sat Jun 11, 2022 8:59 am
Posts: 2
Hello every body. I need help. I use Intel(R) Core(TM)2 Duo CPU P8600 @ 2.40GHz with BIOS v2 mother board. When I start PC (Laptop), BIOS is OK, then my personal loaders loads 40 sectors in memory starting at 0x7000 and I switch to protected mode and my personal software starts and runs correctly. There is only 3 GiB of memory installed and when I read ABAR (5) of the PCI SATA device, the answer is 0xFFCFF000. This Base Address is outside of the memory so of cause I can not use this PCI SATA Device. If I switch to long mode and give 1Gib available for the last GiByte (Top) I can write to 0xFFCFF000 +( Reg num) but nothings appends.
Q: Why BIOS provides ABAR5 outside of memory installed on its mother board.


Top
 Profile  
 
 Post subject: Re: Strange value in PCI ABAR
PostPosted: Tue Jun 14, 2022 10:49 am 
Offline
Member
Member

Joined: Mon Mar 25, 2013 7:01 pm
Posts: 5100
MMIO is not memory. The ABAR contains the physical address of AHCI MMIO.


Top
 Profile  
 
 Post subject: Re: Strange value in PCI ABAR
PostPosted: Wed Jun 15, 2022 8:37 am 
Offline

Joined: Sat Jun 11, 2022 8:59 am
Posts: 2
Thank you Octocontrabass. Yes of course ! I had forgot this :oops: I had modify my PML4E to access to that physical address and now all it is OK. Thank's a lot again. Best regards


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC - 6 hours


Who is online

Users browsing this forum: iansjack and 81 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group