> > > Are there any kernel pointers in memory at fixed known locations > > which are not mapped to any process PTEs? > > They have to be mapped in order to be accessible. There must > be a PTE because Linux uses paging as the fundamental basis > for its virtual memory implementation - although on other > architectures, such as those "substantially conforming to the > PowerPC Architectural Specification" > (blah blah blah blah) there are mapping registers which are > called BATs or whatever is the name for a particular > processor family. These allow single large mappings to take > place mapping 896MB or whatever of physical RAM at the > PAGE_OFFSET in kernel virtual memory. Some architectures with > variable sized PTEs use just one or two large mappings for > the kernel. This covers Intel (doesn't it? any Intel weenie > want to talk about that? ;-) ) and certain embedded > processors such as the IBM 40x series. > My understanding is that the Linux uses 4MB pages on intel ( not 4K ) when mapping physical memory above PAGE_OFFSET. But vmalloc() uses 4K pages. > > Jon. > > -- > Kernelnewbies: Help each other learn about the Linux kernel. > Archive: http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
