Re: [PATCH] Use more conservative fences on RISC-V

2017-03-20 Thread Palmer Dabbelt
On Fri, 17 Mar 2017 15:52:54 PDT (-0700), Palmer Dabbelt wrote: > The RISC-V memory model is still in the process of being formally > specified, so for now we're going to be safe and add the I/O bits to > userspace fences because there's no way to know if userspace is touching > memory-mapped I/O r

[PATCH] Use more conservative fences on RISC-V

2017-03-17 Thread Palmer Dabbelt
The RISC-V memory model is still in the process of being formally specified, so for now we're going to be safe and add the I/O bits to userspace fences because there's no way to know if userspace is touching memory-mapped I/O regions at compile time. This will have no impact on existing microarchi