Re: KSYMS_CLOSEST

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

On Sun, Dec 25, 2022 at 15:42:47 +0100, Anders Magnusson wrote:

> Den 2022-12-25 kl. 13:43, skrev Valery Ushakov:
> > On Sun, Dec 25, 2022 at 09:20:49 +0100, Anders Magnusson wrote:
> > 
> > > IIRC it was to match the ddb "sift" command.
> > I'm not sure I get how it might be used for sifting - a kind of "next"
> > for external iteration?  Since we never got around to do that do we
> > still want to keep it, or shall we deprecate/delete it?
>
> Ah! I had to look at the code - no, it has nothing to do with sift.
> I think it is implicit when asking for a name these days; it is used
> to get nearest lower address address in debug output. (like
> tstile+0x18 )

Right, right, but I wonder what could it possibly mean then, when the
flag is not specified - as opposed to the example above.  I.e. if
KSYMS_CLOSEST is foo+0x10, what KSYMS_EXTERN (i.e. no specific flags)
could be, other than foo+0x10, for the same address?  I mean,
technically, netbsd + 0xcaffe42 would also be a correct reply in that
case :)

Also, checking the very first versions of ksyms code I don't see
KSYMS_CLOSEST ever actually handled (it's defined and specified in the
ddb strategy defines, but never tested in ksyms).  May be I missed
some later short-lived incarnation.

The existing call sites that supply the flag look like cargo-cult^W^W
common sense ("looks like you might need to specify that flag to get
foo+0x10, well, *shrug*, won't hurt").

-uwe