Re: [PATCH v2 14/28] arm64/sve: Backend logic for setting the vector length

[Dave Martin <Dave.Martin@arm.com>]

On Wed, Sep 13, 2017 at 10:29:11AM -0700, Catalin Marinas wrote:
> On Thu, Aug 31, 2017 at 06:00:46PM +0100, Dave P Martin wrote:
> > This patch implements the core logic for changing a task's vector
> > length on request from userspace.  This will be used by the ptrace
> > and prctl frontends that are implemented in later patches.
> > 
> > The SVE architecture permits, but does not require, implementations
> > to support vector lengths that are not a power of two.  To handle
> > this, logic is added to check a requested vector length against a
> > possibly sparse bitmap of available vector lengths at runtime, so
> > that the best supported value can be chosen.
> > 
> > Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> > Cc: Alex Bennée <alex.bennee@linaro.org>
> 
> Can this be merged with patch 20? It seems to add the PR_ definitions
> which get actually used later when the prctl interface is added.

This patch is used both by patch 19 and by patch 20, which I preferred
not to merge with each other: ptrace and prctl are significantly
different things.

The prctl bit definitions are added here because they are the canonical
definitions used by both interfaces.  The ptrace #defines are based on
them.

Does it make sense if I merge patch 20 into this one and apply patch 19
on top?  This avoide the appearance of prctl #defines with no prctl
implementation.

Cheers
---Dave