On Fri, Sep 28, 2018 at 10:28 AM Ard Biesheuvel
[off-list ref] wrote:

Given that this patch applies to all architectures at once, it is
probably better to drop the unrelated reordering hunks to avoid
conflicts.

Ack. Will retain order for v7.

quoted

+static __must_check inline bool may_use_simd(void)
+{
+       return !in_interrupt();
+}
+

Remember this guy?

https://marc.info/?l=linux-arch&m=149631094625176&w=2

That was never merged, so let's get it right this time.

Wow, nice memory. I had forgotten all about that. Queued for v7.

quoted

+static inline void simd_relax(simd_context_t *ctx)
+{
+#ifdef CONFIG_PREEMPT
+       if ((*ctx & HAVE_SIMD_IN_USE) && need_resched()) {
+               simd_put(ctx);
+               simd_get(ctx);
+       }
+#endif

Could we return a bool here indicating whether we rescheduled or not?
In some cases, we could pass that into the asm code as a 'reload'
param, allowing repeated loads of key schedules, round constant tables
or S-boxes to be elided.

Sure, sounds easy enough.