Re: [PATCH 1/3] x86: drop unnecessary kernel_eflags variable from64 bit.

[H. Peter Anvin]

On 07/06/2011 04:17 PM, Andi Kleen wrote:
>> Well lets ask Linus and Andi?
> 
> The original idea was that if someone extends EFLAGS with new bits
> the BIOS could set them.  Strictly said the Intel Manual 
> specifies that ("reserved bits -- always set to values previously read")
>  
> But that never really worked out and I don't think anyone
> would dare extending it now.  So hardcoding is fine I guess.
> 

We already clear any undefined flags almost as soon as we enter the
kernel... and quite rightly so, because there are BIOSes which leave
random crap in the flags.

It is very different from what an *application* should do in this case,
however.

	-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/