question on inline assembly and long long values

Benjamin Herrenschmidt benh at
Thu Apr 7 09:49:23 EST 2005

On Wed, 2005-04-06 at 17:30 -0600, Chris Friesen wrote:
> Benjamin Herrenschmidt wrote:
> > On Wed, 2005-04-06 at 12:26 -0600, Chris Friesen wrote:
> > 
> >>I want to retrieve the msr (which is 64-bits) on a 970 when running in 
> >>32-bit mode.
> > Is this in kernel mode ? Why are you doing that ? 
> Yes it is.
> We wanted to manipulate the high word of the msr on the 970, from C 
> code, while running in 32-bit mode.  I'll be doing something similar to 
> get at the high word of HID1 (to enable the en_icbi bit).
> Is there some other way to do this?

But the kernel code always runs in 64 bits mode... or are you trying to
pass that down to userland ? In the later case, your optimisations are
pretty much nothing compared to the cost of a syscall


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