Yes... That is one reason I think it is a real problem. Dave Hansen <dave at sr71.net> wrote: >On 04/12/2013 07:56 AM, H. Peter Anvin wrote: >> On 04/12/2013 07:31 AM, Vivek Goyal wrote: >>>> I also have to admit that I don't see the difference between >/dev/mem >>>> and /dev/oldmem, as the former allows access to memory ranges >outside >>>> the ones used by the current kernel, which is what the oldmem >device >>>> seems to be intended to od. > >It varies from arch to arch of course. > >But, /dev/mem has restrictions on it, like CONFIG_STRICT_DEVMEM or the >ARCH_HAS_VALID_PHYS_ADDR_RANGE. There's a lot of stuff that depends on >it, *and* folks have tried to fix it up so that it's not _as_ blatant >of >a way to completely screw your system. > >/dev/mem also tries to be nice to arches that have restrictions like: > >> /* >> * On ia64 if a page has been mapped >somewhere as >> * uncached, then it must also be accessed >uncached >> * by the kernel or data corruption may occur >> */ > >I think /dev/oldmem isn't so nice and could actually cause some real >problems if used on ia64 where the cached/uncached accesses are mixed. -- Sent from my mobile phone. Please excuse brevity and lack of formatting.
