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Re: Question on asmlinkage

Hi///

On 2/4/08, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote:
> Just a few pointers for everyone to look further:
>
> a.   kernel space is (for Intel x86) Ring0, and userspace is Ring3,
> and so when u make transition between these two - u are subjected to
> HARDWARE control on how the stack space can be used.   So Intel manual
> (System Programming 3a specifically) is useful to read.

Thanks for the clue :)

> b.   The keyword is "stack switching" (there exists a difference
> between 32bit vs 64bit).   Look it up - chapter 5 (interrupt and
> exception handling).

yep, stack plays important role here.

> c.   Essentially, kernelspace should always be protected from
> userspace manipulation, and so the stack registers for userspace is
> NOT used in kernelspace.   And switch context occurred, the entire
> registers set is restored/saved into memory.

yep, agree.

regards,

Mulyadi.

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