On Tue, Aug 25, 2020 at 04:34:27PM -0700, Yu, Yu-cheng wrote:

On 8/25/2020 4:20 PM, Dave Hansen wrote:

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On 8/25/20 2:04 PM, Yu, Yu-cheng wrote:

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I think this is more arch-specific.  Even if it becomes a new syscall,
we still need to pass the same parameters.

Right, but without the copying in and out of memory.

Linux-api is already on the Cc list.  Do we need to add more people to
get some agreements for the syscall?

What kind of agreement are you looking for?  I'd suggest just coding it
up and posting the patches.  Adding syscalls really is really pretty
straightforward and isn't much code at all.

Sure, I will do that.

Alternatively, would a regular prctl() work here?

arch_prctl() feels like a historical weirdness for x86 -- other arches
all seem to be using regular prctl(), which allows for 4 args.  I don't
know the history behind the difference here.

(Since prctl() and arch_prctl() use non-clashing command numbers, I had
wondered whether it would be worth just merging the x86 calls in with
the rest and making the two calls aliases.  That's one for later,
though...)

Cheers
---Dave