Is it possible to relocate a kernel page in physical memory?

[arvid.brodin@enea.com (Arvid Brodin)]

I want to do memory checks (? la memtest86) on a running system. I know using
ECC memory would be a better approach, but unfortunately that is not an option
in this case. Also, this seems like an excellent opportunity to learn more
about the memory system in Linux.

This is on a AVR32 embedded system, BTW.

One approach is to use the AVR32's built-in SRAM pages to store and run kernel
code that periodically takes a spinlock and checks a small part of the physical
memory, before writing back its original value. This has numerous problems,
among others that the SRAM pages are also used by the power management code on
these processors. And of course, it's not exactly portable...

Another approach is to run the test as a part of the normal kernel. For memory
allocated by user processes, this should be pretty straight-forward (I think):
just copy the page data to another physical page and modify the page tables
(right?). When in comes to the kernel, I might be able to skip testing of the
(read-only) text segment by doing md5summing over it instead (would this have
any drawbacks)? But how would one test writable pages allocated by the kernel?

Is there a way to "relocate" a kernel page in physical memory?

-- 
Arvid Brodin
Enea Services Stockholm AB