-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > > I've got some qeustion about ppc(ppc44x) paging: > > how can I manually map a virtual address to a physical address through a > specific pgd? How does ppc translate virt address to physical one? I think > besides from tlb, the CPU will search the page table entries via the pgd, can > I alter the pgd value to change the memory translation? under i386, it's very > simple, we can just rewrite %%cr3, it even could invalidate all tlb entries > automatically, how can I do this under ppc? I've tried rewrite > current->mm->pgd and current->thread.pgdir, but sounds like it still not > insufficiant, am I missing something vital? >
sur ! same thing flush the tlb or you will be totally inconsistant - actually the box should not have survived this treatment in a stable manner. You might want to look at kernel/ppc-stub.c as a good reference - its a similar problem gdb also writes into memory without the kernel knowing about it - that is comparable to what XM is doing - the solution flush the cache/tlb all over the place - now flushing the cache is evil - but I would do it for now and we can check alternatives and optimizations later - for now brute force is the way to go. for 4xx dont forget to isync after fidling with pgd/pte (see set_context in entry_4xx.S . As far as I understand 4xx all you would really need to do is clear the TLB entry and then you get an exception and that is handled via 0x1100/0x1200 D/I respectively (head_4xx.S) - admitedly Im not up to this task - need to give the manuals a lock my self to understand whats going on there ;) hofrat -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQFHHCmpnU7rXZKfY2oRAjLmAJ90QwCBHLaglOfJ5QAnJyCCIZDmGwCgh/fD E76Ki1FdfofUSuVBXL1tG0M= =/1C5 -----END PGP SIGNATURE----- _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
