Re: [PATCH v2 0/3] Support rseq on arm64

[Mathieu Desnoyers <mathieu.desnoyers@efficios.com>]

----- On Jul 10, 2018, at 10:49 AM, Will Deacon will.deacon@arm.com wrote:

> On Mon, Jul 09, 2018 at 01:17:54PM -0400, Mathieu Desnoyers wrote:
>> ----- On Jul 9, 2018, at 12:53 PM, Will Deacon will.deacon@arm.com wrote:
>> 
>> > On Mon, Jul 09, 2018 at 12:06:22PM -0400, Mathieu Desnoyers wrote:
>> >> ----- On Jul 9, 2018, at 10:19 AM, Will Deacon will.deacon@arm.com wrote:
>> >> 
>> >> > Hello,
>> >> > 
>> >> > This is version two of the patches previously posted here:
>> >> > 
>> >> > http://lkml.kernel.org/r/1529949285-11013-1-git-send-email-will.deacon@arm.com
>> >> > 
>> >> > Changes since v1 include:
>> >> > 
>> >> >  * Move abort handler in-line to avoid possibility of it being
>> >> >    out-of-range for conditional branch instructions
>> >> > 
>> >> > I've tested both native and compat (little-endian only) with the selftests
>> >> > and they pass successfully on my Seattle box.
>> >> 
>> >> For the whole series:
>> >> 
>> >> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
>> > 
>> > Thanks, Mathieu! Are you ok with me taking this via the arm64 tree for
>> > 4.19 once I have an Ack for the asm-generic change, or would you rather
>> > this went via somewhere else?
>> 
>> Adding Thomas Gleixner in CC. He has been picking up the rseq bits for
>> 4.18. I've noticed it was rather easier to gather rseq stuff through a
>> single tree (less chances of confusion).
> 
> Whilst I can see that making some sense for the selftests (particularly
> if the ABI is liable to further changes before 4.18 is released), I'd
> prefer to take the arm64 bits via the arm64 tree, as they will conflict
> with some ongoing work to rewrite the syscall entry path in C which I
> plan to queue in the next week (pending final testing results).

Considering this, indeed going through the arm64 tree seems like the right
approach.

> 
>> Also, support for additional architectures (e.g. MIPS) was added to rseq
>> after rc1. Is it too late to merge arm64 support targeting 4.18 ?
> 
> Personally, I don't see the rush, but I won't stop anybody who wants to
> try steam-rollering them into mainline ;)

There is indeed no rush. 4.19 it is then.

Thanks!

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com