On Fri, Apr 21, 2017 at 02:35:51PM -0600, Vishal Verma wrote:
> On 04/21, Luck, Tony wrote:
> > Needs extra parentheses to make it right. Vishal, sorry I led you astray.
> >
> > if (!((mce->status & 0xef80) == BIT(7)))
>
> Is this still right though? Anything AND'ed with 0xef80 will never equal
> BIT(7) which is simply 01000000 binary (the lowest byte of the left hand
> side is '0')
I think so ... here it is in binary
ef80 = 1110 1111 1000 0000
BIT7 = 0000 0000 1000 0000
so the "&" will zap bits {6:0} and bit {12} [and everything not part
of the MCACOD field].
If mce->status had some bit above BIT(7) set, it won't be zapped, so we
won't match the exact value BIT(7).
-Tony