Re: Memory Rusting Effect [re: Linux hostile to poverty]

Richard B. Johnson (root@chaos.analogic.com)
Tue, 21 Jul 1998 14:12:22 -0400 (EDT)


On Tue, 21 Jul 1998, Stefan Traby wrote:

>
> > I'm not sure how you would handle FPU code if the module couldn't be loaded.
> > I guess you could alwas kill the process with a SIGILL or something, doesn't
> > seem like a very nice solution.
>
> BTW: my mom always said "Don't use floating-point code in kernel." ;-}
>
> Compile drivers/scsi/scsi_debug.c after defining "SCSI_DATARATE" and
> "SCSI_SETUP_LATENCY".
>
> This generates floating-point code in kernel, on intel something like:
>
> fldl .LC25
> fmulp %st,%st(1)
> fldl .LC26
> fdivr %st,%st(1)
>

Yes, generated by ../linux/drivers/scsi/ibmmca.c. Guess this one slipped
by. The state of the FP unit is undefined when the kernel executes.
Further, a FP fault can create a double fault when the FP fault occurs
within the kernel.

This needs to be fixed.

Cheers,
Dick Johnson
***** FILE SYSTEM MODIFIED *****
Penguin : Linux version 2.1.108 on an i586 machine (66.15 BogoMips).
Warning : It's hard to remain at the trailing edge of technology.

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