[coreboot] [RFC] use of SMM with SSE/MMX...

Rudolf Marek r.marek at assembler.cz
Sat Jul 2 17:29:04 CEST 2011


Hi all,

The MMX/SSE/x87 is not handled in save state map. GCC might produce such 
instructions if it wants.

Problem is what to do with that. Either we can compile all SMM code with 
-no-sse/mmx/fpu switches (I think those exists) or we could use the 
FXSAVE/FRSTORE instructions to backup the state. problem is that it needs 512 
bytes / CPU. Either could put that on stack which is 0x400 bytes total and make 
it 2 times smaller or for AMD we have 0x200 bytes still free in the save state 
map, but not on Intel.

Ideas?

Thanks
Rudolf




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