"matrix reloaded" <matrix_reloaded18@xxxxxxxxxxxxxx> writes: > Do you mean that kernel menory which would be 1 GB in this case is at a fixed > address physically and just by shifting the virtual address by PAGE_OFFSET we > can get Physical address ? Yes, in the low-memory-style x86 setup, the gigabyte of virtual pages starting at 0xC0000000 map to a gigabyte of physical addresses. It's not really a whole gigabyte, though, because the last part is used for some dynamic stuff. > As stated in the first mail that kernel has page table > base addresses from where it translates the addresses. Then what is that ? The CPU doesn't know that Linux has this gig-to-gig thing going on. That's the kernel's business. The CPU just knows that it has to translate all the virtual addresses. That's done in the MMU. The kernel sets up page tables for all the kernel virtual-to-physical translations when it starts up. I forget where it sets up those page tables, but this has been covered on kernelnewbies before, so some skillful googling should avail you. -- Ed L Cashin <ecashin@xxxxxxxxxx> -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
