amd64/163710: setjump in userboot.so causes stack corruption

[Peter Wemm]

The following reply was made to PR amd64/163710; it has been noted by GNATS.

From: Peter Wemm <peter at wemm.org>
To: Russell Cattelan <cattelan at thebarn.com>
Cc: freebsd-gnats-submit at freebsd.org
Subject: Re: amd64/163710: setjump in userboot.so causes stack corruption
Date: Fri, 30 Dec 2011 19:16:10 -0800

 On Fri, Dec 30, 2011 at 12:24 PM, Russell Cattelan <cattelan at thebarn.com> w=
 rote:
 > On 12/30/11 1:33 AM, Peter Wemm wrote:
 >> On Thu, Dec 29, 2011 at 7:16 PM, Russell Cattelan
 >> <cattelan at digitalelves.com> wrote:
 >>
 >>>> Description:
 >>> For some reason the forth interpreter is built and linked as 32bit even
 >>> on amd64.
 >> That's the catch. We use the same 32 bit loader on i386 and amd64.
 >> The common loader understands both kernel formats. =A0This unfortunately
 >> has meant that the libstand and sys/boot environment has had to be 32
 >> bit.
 >>
 > Yes this is bit of an odd situation.
 > the loader is linked 32bit but userboot.so / libstand is built 64bit
 > but pulls in the 32bit ficl lib.
 > The 64bit libstand provides the setjmp call that needs 96 bytes
 > of space but since ficl is built with the 32bit jump_buf (48 byte )
 > structure
 > things go sideways.
 
 We link the loader with the 32 bit libstand though.  It cannot work
 any other way.  BTX is 32 bit only.
 
 --=20
 Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com; KI6FJV
 "All of this is for nothing if we don't go to the stars" - JMS/B5
 "If Java had true garbage collection, most programs would delete
 themselves upon execution." -- Robert Sewell