Apple

On Jan 3, 2012, at 4:00 AM, Quinn The Eskimo! wrote:

>
> On 27 Dec 2011, at 21:49, José Cornado wrote:
>
>> In which ring level does a kext run?
>
> The Darwin kernel does not use the concept of rings. All kernel code runs in supervisor mode, and all user processes run in user mode. On x86 CPUs these map to rings 0 and 3, respectively, but to some extent that's an implementation detail. The kernel has and continues to run on a variety of different CPU architectures, most of which aren't based on rings.
>
>> Does GDT is memory protected? If so would a kext have access to it?
>
> What are you planning to do with the GDT? In most cases a KEXT can achieve its memory management goals without having to access the GDT directly, and accessing the GDT directly is likely to result in long-term binary compatibility problems.
>
> Share and Enjoy
> --
> Quinn "The Eskimo!" <http://www.apple.com/developer/>
> Apple Developer Relations, Developer Technical Support, Core OS/Hardware
>
>
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References:
	>Re: Kext ring level (From: "Quinn \"The Eskimo!\"" <email@hidden>)
	>Re: Kext ring level (From: Shantonu Sen <email@hidden>)