On Wed, Dec 2, 2015 at 5:26 PM, Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote: > On Thu, Dec 3, 2015 at 2:22 AM, Andy Lutomirski <luto@xxxxxxxxxx> wrote: >> On Wed, Dec 2, 2015 at 5:13 PM, Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote: >>> Hi, >>> >>> On Thu, Dec 3, 2015 at 1:37 AM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: >>>> [resend as plain text] >>>> >>>> I want to bundle up an arbitrary ACPI_OBJECT into a copyable stream of >>>> bytes, is there some standard way to do this? >>>> >>>> I'm asking because I want to try to upstream something resembling the >>>> rusty old acpi_call module to allow users with debugfs access who are >>>> willing to taint their kernel to evaluate ACPI objects from userspace. >>>> Presumably there would be a user tool to get object info and to >>>> evaluate methods, and we could handle translation to/from strings in >>>> userspace, but I still need some way to shove the data back and forth. >>> >>> Please don't do that, this is broken as a concept. >>> >>> User space has no idea whatsoever about when and it what conditions a >>> given AML can be executed in the first place, so in addition to >>> tainting the kernel it may just outright break things. >>> >>> Not to mention the possibility of confusing the kernel's reference >>> counting and breaking assumptions made by it on the current state of >>> things based on what AML has been already executed. >> >> This is something that I want as a reader of decompiled DSDTs and a >> writer of drivers. I think we could do it in a way that it doesn't >> get used for evil. For example, make it a module, taint the kernel if >> it's loaded and enabled, only expose the interface if an actual *boot* >> parameter allow_user_acpi_calls=1 is set, encourage distros to >> seriously consider not building the module, disallow it entirely under >> secure boot, etc. >> >> I want to use it for things like "hey, it looks like \NEXP might have >> a funny value -- let's see what's there without manually figuring out >> how to peek at the relevant OpRegion". > > So please check the debugger thing. > > Lv, can you please help Andy with this? > Ooh, that's really cool! It looks like acpidbg -b "execute \WHATEVER" is *exactly* what I want. Is there a git tree or up-to-date patchset that works? It looks like 4.4-rc3 has some but not all of the pieces needed. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
