[OpenBIOS] l440gx+ nvram writing ...
Ronald G. Minnich
rminnich at lanl.gov
Tue Feb 8 08:46:02 CET 2000
On Mon, 7 Feb 2000, David Christensen wrote:
> In case you're not aware, the SMI is the System Management Interrupt. When
> an SMI is asserted, the CPU will enter SMM, System Management Mode.
Yes, I've finally begun to realize this.
> It is a
> special mode of the CPU that was originally designed to make it easier for
> the BIOS to perform power management functions. The SMI is completely
> transparent to the OS and cannot be masked. The code that is executed in
> SMM is stored in a special memory area called SMRAM (generally mapped at
> A0000h-BFFFFh) and cannot be accessed unless operating in SMM (there is
> usually a lock bit in Intel chipsets that is set and cannot be cleared
> without resetting the system, this is to protect the SMI handler from being
> modified). The only way to modify the code in the SMI handler is to write
> your own BIOS.
openbios to the rescue, I suppose.
geez, this is awful stuff. I'll let you know where I get today.
ron
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