Re: AMD Geode NOPL emulation for kernel 2.6.36-rc2

[H. Peter Anvin]

On 08/27/2010 02:32 PM, Matteo Croce wrote:
> can I ignore the return value when I expect val to be non zero?
> the doc says: "On error, the variable @x is set to zero."

No.  You need to deliver a page fault to the application in this case.

The *real* test for this kind of crap is correct page fault behavior,
and so forth.

Also, at the very least you need to check for:

- CS == USER_CS
- IP in the proper range for user space

Your patch in its current form is one big security hole.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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