On 20.02.2008 19:29, Corey Osgood wrote: > On Wed, Feb 20, 2008 at 1:09 PM, Carl-Daniel Hailfinger < > [EMAIL PROTECTED]> wrote: > > >> On 20.02.2008 18:52, Stefan Reinauer wrote: >> >>> Carl-Daniel Hailfinger wrote: >>> >>>> On 20.02.2008 17:19, Stefan Reinauer wrote: >>>> >>>> >>>>> * ron minnich <[EMAIL PROTECTED]> [071212 17:19]: >>>>> >>>>> >>>>>>> Question to you guys: why is the first wrmsr instruction there? >>>>>>> From my >>>>>>> understanding, by not properly initialising ECX, EAX and EDX this >>>>>>> will >>>>>>> overwrite whatever is in the MSR pointed to by ECX?! >>>>>>> >>>>>>> BTW I tried out your code on our target hardware (Intel Celeron M, >>>>>>> 600 MHz) >>>>>>> and with that first wrmsr line in place it hangs and without it, >>>>>>> it runs >>>>>>> just fine. >>>>>>> >>>>>>> >>>>>> Thanks Martin. That looks like quite a nice bug catch you've done :-) >>>>>> >>>>>> >>>>> Here's a patch that resolves the issue. >>>>> >>>>> Signed-off-by: Stefan Reinauer <[EMAIL PROTECTED]> >>>>> >>>>> Index: src/cpu/intel/microcode/microcode.c >>>>> =================================================================== >>>>> --- src/cpu/intel/microcode/microcode.c (revision 3111) >>>>> +++ src/cpu/intel/microcode/microcode.c (working copy) >>>>> @@ -33,7 +33,6 @@ >>>>> */ >>>>> msr_t msr; >>>>> __asm__ volatile ( >>>>> - "wrmsr\n\t" >>>>> >>>>> >>>> ACK. >>>> >>>> >>>> >>>>> "xorl %%eax, %%eax\n\t" >>>>> "xorl %%edx, %%edx\n\t" >>>>> "movl $0x8b, %%ecx\n\t" >>>>> @@ -60,7 +59,7 @@ >>>>> char *c; >>>>> msr_t msr; >>>>> >>>>> - /* cpuid sets msr 0x8B iff a microcode update has been loaded. */ >>>>> + /* cpuid sets msr 0x8B if a microcode update has been loaded. */ >>>>> >>>>> >>>> NACK. "IFF" is shorthand for "if and only if", see >>>> http://en.wikipedia.org/wiki/If_and_only_if >>>> >>>> >>> That's silly. This is not a mathematical expression nor a >>> philosophical disquisition but a sentence. I am not even convinced >>> that it was meant that way rather than being just a typo. If you have >>> reasons to assume it means "If and only if" then let's write it that >>> >> way. >> >> Merriam-Webster agrees with me that "iff" is a word: >> http://www.merriam-webster.com/dictionary/iff >> So this is a valid sentence and I see no reason to change it. Unless the >> bit can be set even of no microcode update has been uploaded, "iff" is >> the only correct word. >> >> Regards, >> Carl-Daniel >> >> > > Meriam-Webster and wikipedia might know, but not everyone does. Why can't we > just change it to "if and only if" instead of using an obscure word that > looks like a typo? >
OK, I was just used to the word from my Linux kernel and math background and thought everybody would understand it. "If and only if" is a longer phrase, but it seems to be understood by a wider audience, so I have dropped my objections against the change to that phrase. Regards, Carl-Daniel -- http://www.hailfinger.org/ -- coreboot mailing list [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
