Date: Wed, 31 Jan 1996 14:33:36 -0800
From: brianh@lexus.West.Sun.COM (Brian Horn)
Subject: Item #312: PPC: Add load-base to .note section

P1275 Open Firmware Working Group Proposal -- Proposal #312 Ver 1.0

Title:		Add load-base to .note section

Author:		Brian.Horn@west.sun.com

Date:		Jan 31, 1996

Ed/Tech:	Technical

Synopsis:	Add a address field in the .note section to set "load-base"

Doc & Version:	PowerPC Processor Binding Draft revision 1.6

Problem:	Some systems won't boot without manual user intervention

Proposal:	

	Add after line 35 on page 19:

	/L	field	ns.load-base

	and add text to the effect:

	If the ns.load-base value is not -1 then that value is compared
	against the current value of the configuration variable "load-base".
	If they are equal no further action is taken.  If they are
	not equal then the configuration variable "load-base" is set to
	the value of ns.load-base and the system is rebooted.

	The reason this is necessary is best shown by example.

	Assume that the default value for load-base is 4M (0x00400000).
	Further assume that the Open Firmware client ELF image header requires
	that it be mapped at 4M + 4K (0x00401000) (and of course the memory
	image of the client is greater than 4Kbytes).  This causes a conflict
	where the client program may not run as on page 20 line 28 says
	"The implementation need not take precautions to ensure that the
	process of copying and zeroing program sections does not overwrite
	portions of the load image...".  In this case the client image
	would never execute correctly unless a) the implementation goes
	beyond the specification and does take precautions when copying and
	zeroing or b) the configuration variable "load-base" is altered
	manually by the user.

	Forcing manual intervention by the user should be avoided if at all
	possible.

[ P1275 Item #312 -- Received: Wed Jan 31 14:30:58 PST 1996 ]