[LinuxBIOS] SMM in LinuxBIOS

Stefan Reinauer stepan at coresystems.de
Tue Jan 9 15:37:50 CET 2007

* Arvind Seshadri <arvinds+ at cs.cmu.edu> [061230 05:13]:
> BTW, I was looking over the datasheet for the AMD8111 southbridge and
> found that several sources can generate an SMI. There are enable bits for
> the individual SMI sources as well as a global SMI enable/disable bit.
> Given that LinuxBIOS does not currently handle SMI, where is SMI disabled
> in the code? I did some grepping around in the code and could not find
> anything for the AMD K8. Is it the case that SMI is disabled after reset
> and has to explicitly enabled by the BIOS?
Global SMI Control Register (PM2C) is initialized with 00, thus
disabling all SMI activity in the system. If you want to change this,
you need to create an SMM handler, and set those bits you need, for
example in the Global SMI Enable Register (PM2A)

Unless you do, no SMIs will happen, and that situation is locked to
avoid malware messing with SMI.

One question: why are you going to need SMI? USB legacy emulation?


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