On Fri, Jan 28, 2011 at 1:03 AM, Mathias Krause <[email protected]>wrote:
> Hi, > > flashrom currently tries to unlock the chip before each read/write/erase > command. To prevent further modifications of the chip content, e.g. for > security reasons, it would be helpful if flashrom would also be capable > of the opposite operation. I talked with Carl-Daniel a little about it > and he mentioned problems like having to implement features like partial > locks, chips that cannot be unlocked after being locked, etc. To support > those features and handle the problematic chips something more than this > little patch can do must be implemented. But for now it would be nice to > have *something*. See it as a starting point to solve the much bigger > problem. > Yep, it certainly gets hairy. On Fri, Jan 28, 2011 at 1:03 AM, Mathias Krause <[email protected]> wrote: > This patch adds a function pointer to struct flashchip and a command > line option to trigger this function to enable full flash chip write > protection. It's currently only implemented for the Atmel AT26DF081A > since this is the chip I'm currently working with and which I can test > easily. > For what it's worth, we've been doing something similar in the Chromium OS branch (http://git.chromium.org/gitweb/?p=flashrom.git;a=tree). Apologies if it seems a bit sloppy at the moment, we've had to wedge in a lot stuff to solve immediate concerns. We also added a member to the flashchip structure (.wp), but in our case it is a pointer to a "writeprotect" structure which contains a bunch of function pointers. We felt this was necessary since write protection varies greatly between chips and we want fine-grained control. In our model, the user specifies the byte range (offset and length) and enables write protection in two steps. For example: "flashrom --wp-range 0x200000 0x200000 --wp-enable". Most of the ugly stuff in our code is contained within writeprotect.c. So if you want to give it a try it should integrate into your tree pretty easily. -- David Hendricks (dhendrix) Systems Software Engineer, Google Inc.
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