On Wed, 11 May 2011 14:43:35 +0200, Luca Tettamanti wrote: > lahf is present in the assembly block inside the driver in i8k_smm; lahf > moves the lowest byte of eflags into ah. > Wikipedia[1] tells me that: > > Early AMD64 and Intel 64 CPUs lacked LAHF and SAHF instructions. AMD > introduced the instructions with their Athlon 64, Opteron and Turion 64 > revision D processors in March 2005 while Intel introduced > the instructions with the Pentium 4 G1 stepping in December 2005. > > Jeff's CPU does indeed lack lahf (see cpuinfo), so the driver should not > unconditionally use the intruction. > The driver should check X86_FEATURE_LAHF_LM or use use a different > method to read EFLAFS (pushf?). Thanks for the investigation, BTW... Brilliant! > drivers/char/toshiba.c (tosh_smm) also suffers from the same issue. That one currently depends on X86_32, which I seem to understand is unaffected by the bug. But if this driver is ever extended to work on 64-bit machines, then yes, care will be needed. -- Jean Delvare _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
