[RFC PATCH 00/29] arm64: Scalable Vector Extension core support
From: Szabolcs Nagy <hidden>
Date: 2016-11-30 12:22:32
Possibly related (same subject, not in this thread)
- 2016-11-30 · [RFC PATCH 00/29] arm64: Scalable Vector Extension core support · Dave.Martin@arm.com (Dave Martin)
- 2016-11-30 · [RFC PATCH 00/29] arm64: Scalable Vector Extension core support · Szabolcs Nagy <hidden>
- 2016-11-30 · [RFC PATCH 00/29] arm64: Scalable Vector Extension core support · Florian Weimer <hidden>
- 2016-11-30 · [RFC PATCH 00/29] arm64: Scalable Vector Extension core support · Yao Qi <hidden>
- 2016-11-25 · [RFC PATCH 00/29] arm64: Scalable Vector Extension core support · Dave.Martin@arm.com (Dave Martin)
On 30/11/16 12:06, Dave Martin wrote:
For setcontext/setjmp, we don't save/restore any SVE state due to the caller-save status of SVE, and I would not consider it necessary to save/restore VL itself because of the no-change-on-the-fly policy for this.
the problem is not changing VL within a thread, but that setcontext can resume a context of a different thread which had different VL and there might be SVE regs spilled on the stack according to that. (i consider this usage undefined, but at least the gccgo runtime does this)