A question about privilege levels

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neville

Joined: 13 Jul 2008
Posts: 507
Location: New Zealand

neville 19 Nov 2008, 22:43

If you set up a GDT with its mandatory null entry followed by a 64-bit code descriptor, and then do for example a

jmp 8:longmode_code

am I right in thinking the selector 8 above defines PL=0 i.e. Ring 0, but if you did

jmp 0Bh:longmode_code

the same code would be executed but this time with PL=3 i.e. in Ring 3 ???

Is that how privilege level control is done ???

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19 Nov 2008, 22:43

baldr

Joined: 19 Mar 2008
Posts: 1651

baldr 20 Nov 2008, 18:16

neville,

Read CPU manuals (CPL, RPL, DPL & conforming code segments). It's not that simple.

20 Nov 2008, 18:16

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