Re: Sleeping in user_access section

[H. Peter Anvin]

On 11/23/18 3:57 AM, Julien Thierry wrote:
> 
> On x86, the EFLAGS.AC bit is also saved upon exception and I think it is
> cleared upon exception entry so there is implicit exit from the
> user_access mode when taking exception/interrupt.
> 

No, it is restored, not cleared.

In summary: on exceptions, user_access regions are suspended, and on
return the user_access status is resumed.

However, explicitly calling sleeping functions is not supported.

        -hpa