Thank you for your email. But what is the solution to that? I have seen this in a thesis:
"when using the OCM buses to connect memory, we can only use virtual memory as long as the virtual address is the same as the physical address, which is conceptually the same as using a system without MMU. Therefore porting Linux to a system based on an OCM memory system is not possible" http://ce.et.tudelft.nl/publicationfiles/1367_700_thesis.pdf Is that right? What do you suggest? -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Sergey Temerkhanov Sent: Monday, May 19, 2008 8:53 PM To: linuxppc-embedded@ozlabs.org Subject: Re: Instruction OCM mojtaba wrote: > > Dear all, > > I cannot run Linux when I have an instruction OCM in my design but, > without instruction OCM everything is fine. I tried to do some > debugging. It seems that the Linux memory management unit has a > problem with that. After entering the MMU initialization phase, it > suddenly jumps to address 0x00000700 it get stuck there. Is there > anybody who have tried a design with instruction OCM? Do I need to do > special configuration for the Linux kernel? > > Regards, > > Mojtaba > > ------------------------------------------------------------------------ > > _______________________________________________ > Linuxppc-embedded mailing list > Linuxppc-embedded@ozlabs.org > https://ozlabs.org/mailman/listinfo/linuxppc-embedded Address 0x700 means invalid opcode exception. If instruction OCM is same as data OCM (I think it's so) then any MMU mapping is not applicable to this region at all as OCM controller decodes virtual addresses bypassing any MMU mappings. In your situation MMU maps virtual address of OCM to physical address containing some random data and CPU tries to execute it. So you get invalid opcode exception. _______________________________________________ Linuxppc-embedded mailing list Linuxppc-embedded@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-embedded _______________________________________________ Linuxppc-embedded mailing list Linuxppc-embedded@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-embedded
