Re: RELEASE BLOCKER: Linux doesn't follow x86/x86-64 ABI wrt direction flag

H. Peter Anvin
2008-03-06T15:55:18Z

H.J. Lu wrote:
> I agree with it. There is no right or wrong here Let's start from
> scratch and figure out
> what is the best way to handle this, assuming we are defining a new psABI.

No, I believe the right way to approach this is by applying the good
old-fashioned principle from Ask Mr. Protocol:

Be liberal in what you receive, conservative in what you send

In other words:

a. Fix the kernel. Already in progress.
b. Do *not* make gcc assume DF is clean for now. Adding a
switch would be a useful thing, since if nothing else it
would benefit embedded environments. We might assume
DF is clean on 64 bits, since it appears it is rarely used
anyway, and 64 bits is more important in the long run.
c. Once fixed kernels have been out long enough, we can
flip the default of the switch, one platform at a time if
need be (e.g. there may never be another SCO OpenServer.)

-hpa