What's left in a segment register after a failed segment selector load?

chrstrbrts

Senior member
Aug 12, 2014
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Hello guys,

If I attempt to load a segment selector into a segment register and fail a privilege check, what does the processor leave in the register that I attempted to load?

Does it just leave whatever was in there unchanged?

Also, these errors usually end in a process abort, yes?
 

Schmide

Diamond Member
Mar 7, 2002
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If you failed privilege nothing changes. Segment registers are generally not used anymore and just point to the default base segment

See protected mode here.
 

chrstrbrts

Senior member
Aug 12, 2014
522
3
81
I knew that in 64-bit mode segmentation was largely disabled and that the only segments that really mean anything anymore are CS and SS.

But I thought that in 32-bit protected mode full segmentation was still employed.

Reading your link, though, I guess I was wrong.

Segment registers are generally not used anymore and just point to the default base segment

Yes, but they have to be used to some extent to implement privilege level security, yes?