amd64/111955: [install] Install CD boot panic due to missing BIOS smap on 5.5 through to 7.0-Current Snapshot 200704

John Baldwin jhb at FreeBSD.org
Mon Feb 11 12:50:03 PST 2008


The following reply was made to PR amd64/111955; it has been noted by GNATS.

From: John Baldwin <jhb at freebsd.org>
To: bug-followup at freebsd.org, Roque at itg.uni-muenchen.de
Cc:  
Subject: Re: amd64/111955: [install] Install CD boot panic due to missing BIOS smap on 5.5 through to 7.0-Current Snapshot 200704
Date: Mon, 11 Feb 2008 15:46:04 -0500

 So the SMAP problem is that in the one BIOS I looked at, the SMAP BIOS call 
 only works from real mode.  Even if invoked from virtual 86 mode, the BIOS 
 call fails.  FreeBSD only calls the BIOS SMAP call from virtual 86 mode both 
 in the loader and in the i386 kernel.  The fix is quite complicated and 
 involves rewriting the boot code to invoke BIOS calls from real mode rather 
 than virtual 86 mode.
 
 -- 
 John Baldwin


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