This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: RFC: Should x86-64 support arbitrary calling conventions?


On Mon, Mar 27, 2017 at 9:03 AM, Florian Weimer <fw@deneb.enyo.de> wrote:
> * H. J. Lu:
>
>> On Sun, Mar 26, 2017 at 10:36 PM, Richard Henderson <rth@twiddle.net> wrote:
>>> Not quite true, at least as written.  The STATE_SAVE_MASK define selects
>>> which components get saved.  This would have to be changed for additional
>>> cpu bits that could be modified.
>>>
>>> One *could* set EAX:EDX = -1 and store everything, and then, yes, we'd be
>>> done with changes to glibc for all cpu changes.
>>>
>>
>> For relevant CPU features, they probably need kernel support.  It should
>> be trivial to update STATE_SAVE_MASK when adding kernel support.
>
> Then we should add a mechanism to get the value from the kernel.
>
> I can assure you that it is *not* trivial to update the value once
> glibc releases have shipped.

By "trivial", I meant turning on some bits in STATE_SAVE_MASK, instead of
chaning a lot of codes.  I don't want to turn on bits in STATE_SAVE_MASK which
aren't needed or unknown at this time.

-- 
H.J.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]