Re: [2.6 patch] i386: always use 4k stacks

Paulo Marques
2005-11-15T15:12:48Z

Giridhar Pemmasani wrote:
> Alan Cox wrote:
>
>>reasons. The ndis wrapper people have known it is coming for a long
>>time, and if it has a lot of users I'm sure someone in that community
>>will take the time to make patches.
>
>[...]
> Any suggestions on how ndiswrapper can live with this patch would be greatly
> appreciated.

One idea that has not yet been suggested, is to use a x86 emulator to
run the driver code.

I did some development a while ago, to reduce the size a x86 emulator to
run VGA BIOS functions. If an emulator like this would make it to the
kernel it could also be used to change video modes even using the VESA
driver, suspend/resume the VGA using the VGA own code, etc.

The final size of the emulator was a little over 30k, but there was
still room for even more reductions.

The advantages:

- the driver runs in a complete sandbox

- support for running NDIS drivers in multiple architectures (not just
x86)

- the emulator could be shared amongst more kernel subsystems in need
of an emulator (VESA, for instance)

Disadvantages:

- increase in kernel code size (about 30k)

- decrease in driver code execution speed

I'm not really advocating for this, just wanted to make sure people
would be aware of all the solutions available before committing to any
approach.

--
Paulo Marques - www.grupopie.com

The rule is perfect: in all matters of opinion our
adversaries are insane.
Mark Twain