On Sat, 17 Sep 2011 00:27:34 +0200 Carl-Daniel Hailfinger <c-d.hailfinger.devel.2...@gmx.net> wrote:
> Am 04.09.2011 00:21 schrieb Stefan Tauner: > > On Fri, 02 Sep 2011 20:27:37 +0200 > > Carl-Daniel Hailfinger <c-d.hailfinger.devel.2...@gmx.net> wrote: > > > >> Am 20.08.2011 12:39 schrieb Stefan Tauner: > >> > >> How do we handle chips where a part of the chip is not part of any > >> region? What does the hardware enforce in that situation? > > i am not entirely sure yet if my hypothesis is correct, but i think > > the hardware prohibits any accesses outside defined regions (i.e. > > flash cycle error and/or access error log) - most probably only if the > > flash descriptor is valid of course (and the flash descriptor > > security override pin is not pulled down)... > > > > for some more detail please see > > 201108170859.p7h8xgcb007...@mail2.student.tuwien.ac.at in the "report > > for Intel QM67 | Winbond W25Q64" thread. > > > > and due to this new information, i am not so sure anymore this patch is > > a good idea... either we should add a check for PR-based protections and > > that the regions cover the whole chip too (probably the right thing to > > do according to my guts), > > I think that would be a good idea. Maybe print a warning "please report > foo to flashrom@" in case the chip is not completely covered by regions > so we get a feeling for what's ok and what's not ok. dunno if there is much more insight to be gained by reports of probings only, but a more explicit warning and request for a report does not hurt that much. we still get the 0.9.2 nvidia mcp reports, but i think it is not *that* annoying to *not* make this "error" again :) > > or drop the patch. > > > > OTOH improved layout support would make it possible to > > read/write/verify unprotected parts without a problem. with this patch > > --force is needed to write them, correct? > > I'm not sure how --force would change anything here. in chip_safety_check we check for !programmer_may_write and do *not* bail out if --force is used. and afaics this is the only place where we read this variable, so --force would indeed override it... like i thought(?) > > would be ok with me... as long > > as it would not completely hinder the user from writing. > > If any part of the write has a chance of not working reliably, we should > completely block writing until we can exactly limit writes to writable > regions. well, i *think* that updating the bios/firmware region *only* may actually be enough to update a mobo. i guess no one has tried yet though so it is just a theory. if it is true disabling write access completely reduces flashrom's capabilities... well that's pretty academic nonsense, but that's how i work :P i'd like to keep the --force override like it is for now (so the write protection of a refined patch can still be overriden). so i suggest we drop this patch for now until i have a refined one and bring in the rest (of this patch set). i guess i will have a new patch before all my other patches are reviewed, so it is not a big deal anyway ;) -- Kind regards/Mit freundlichen Grüßen, Stefan Tauner _______________________________________________ flashrom mailing list flashrom@flashrom.org http://www.flashrom.org/mailman/listinfo/flashrom
