Fixing interpose

[Blue Swirl]

Fixing the handling of interposed devices would allow booting a lot more OSes.

If I understand correctly the interpose solution discussed earlier,
the ihandle>phandle in line 28 in:
http://www.openbios.org/viewvc/openbios-devel/forth/device/package.fs?view=a...
should become more like something in OBP line 72:
http://openbios.org/viewvc/obp/os/bootprom/instance.fth?view=annotate&ro...

Is this right? Or could someone more knowledgeable in Forth propose a fix?

[Segher Boessenkool]

> Fixing the handling of interposed devices would allow booting a lot  
> more OSes.
>
> If I understand correctly the interpose solution discussed earlier,
> the ihandle>phandle in line 28 in:
> http://www.openbios.org/viewvc/openbios-devel/forth/device/package.fs? 
> view=annotate&root=OpenBIOS
> should become more like something in OBP line 72:
> http://openbios.org/viewvc/obp/os/bootprom/instance.fth? 
> view=annotate&root=OpenBOOT
>
> Is this right? Or could someone more knowledgeable in Forth propose a  
> fix?

You cannot simply reuse that code, since the internal
structure of OpenBIOS is different from OBP here; but
yes, the algorithm should skip the interposed nodes.
Not sure if ihandle>phandle is the right place though,
that one is probably used in places where you _do_ want
to look at the interposed nodes as well; I don't
remember what the interposition doc says, but I guess
it should be done in instance-to-package in the client
interface only?

Segher

[Stefan Reinauer]

* Blue Swirl  [070423 18:28]:
> Fixing the handling of interposed devices would allow booting a lot more OSes.
>
> If I understand correctly the interpose solution discussed earlier,
> the ihandle>phandle in line 28 in:
> http://www.openbios.org/viewvc/openbios-devel/forth/device/package.fs?view=a...
> should become more like something in OBP line 72:
> http://openbios.org/viewvc/obp/os/bootprom/instance.fth?view=annotate&ro...
>
> Is this right? Or could someone more knowledgeable in Forth propose a fix?

get-instance-path from forth/admin/device.fs does a similar thing.

This is a quick hack, and it is untested and may be completely wrong:

Index: forth/device/package.fs
===================================================================
--- forth/device/package.fs     (revision 126)
+++ forth/device/package.fs     (working copy)
@@ -26,6 +26,9 @@
 ;

: ihandle>phandle ( ihandle -- phandle )
+  dup >in.interposed @ if
+    >in.my-parent @
+  then
> in.device-node @

;

[Blue Swirl]

> This is a quick hack, and it is untested and may be completely wrong:

Sorry, but it doesn't boot anything.