On Fri, Oct 27, 2017 at 06:52:50PM +0100, Alex Bennée wrote: > > Dave Martin <Dave.Martin@xxxxxxx> writes: > > > This patch adds two arm64-specific prctls, to permit userspace to > > control its vector length: > > > > * PR_SVE_SET_VL: set the thread's SVE vector length and vector > > length inheritance mode. > > > > * PR_SVE_GET_VL: get the same information. > > > > Although these prctls resemble instruction set features in the SVE > > architecture, they provide additional control: the vector length > > inheritance mode is Linux-specific and nothing to do with the > > architecture, and the architecture does not permit EL0 to set its > > own vector length directly. Both can be used in portable tools > > without requiring the use of SVE instructions. > > > > Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx> > > Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx> > > Cc: Alex Bennée <alex.bennee@xxxxxxxxxx> > > FYI there is a minor conflict applying this on current master. There are some trivial conflicts with one or two patches that already went into arm64/for-next/core, so I based on that for this posting, not torvalds/master. There's a note in the cover letter giving the precise commit I based on, though the branch doesn't seem to have moved yet since I posted. Otherwise, I don't see any conflict -- can you give details? Cheers ---Dave
