Re: mmap from 0xFFFF0000 -> 0xFFFFFFFF does not work, why?!
Richard B. Johnson (root@chaos.analogic.com)
Fri, 7 May 1999 10:41:19 -0400 (EDT)
On Fri, 7 May 1999, Matti Aarnio wrote:
[SNIPPED]
> >
> > Because the pentium processors have caches it is required to disable them
> > before access the flash memory (you know, time critical access). So i include
> > some assembler code that use the %cr0 pentium processor register but i get
> > segfaults while executing this source line :( How can i disable the cpu cache
> > withou using the assembler code within the user application ?! Of
> > course, only root can do that.
>
> "root" isn't powerfull enough, those must be executed
> in the supervisor mode -- within the kernel, that is.
> Another reason to go via device driver kernel module.
>
Will iopl(3) work for this?
Certainly a device-driver is the final solution, but he
may be able to test most things this way.
Cheers,
Dick Johnson
***** FILE SYSTEM WAS MODIFIED *****
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