Messages in this thread | | | From | Albert Cahalan <> | Subject | Re: NexGen Processors and Linux kernel 2.0 | Date | Fri, 14 Jun 1996 13:35:23 -0400 (EDT) |
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> ----------------------------------------------------------------------- > FROM NEXGEN's WEBSITE's FAQ: > > Why is my Nx586 identified by my application or operating system > as an 80386, or some other microprocessor? > A small number of applications attempt to identify a PC's > microprocessor. Occasionally, the processor is identified > incorrectly. Most often, the incorrect CPU ID results > simply in a display of the wrong CPU type. In some cases, > an Nx586 processor may be misidentified as an 80386. The > NexGen CPU ID page provides more detailed discussion of CPU > ID issues and resolutions. > > The NexGen CPU ID page's URL is: > http://www.nexgen.com/support/pscpuid.htm > ------------------------------------------------------------------------
That is almost wrong...
> I run a Linux server, transient.net. Currently I use kernel 1.2.13, > though from time to time I've considered the 1.3.*'s. When 2.0.0 came out, > I finished updating my system (got gcc-2.7.2, the new libc everything).
> The compilation went fine. In the configuration, I specified [P]entium, > because I have a NexGen586/90, that can do everything that a Pentium can.
False. There are things that the NexGen can't do.
> I normally (when compiling things) use GCC's -m486, > and have no problems (and get faster programs). > > Things we not good though. I booted from the floppy... It uncompressed > the kernel... and then died saying that this is a 386, and the kernel has > been optimized for a 486 or faster. Giving up... > > Now, my older (1.2.13) kernel was also -m486 optimized, but It never had > a problem. I had been aware that sometimes the chip gave false readings, > but heard it was harmless. uname -a likes to indicate that I have an i386. > Which is not that big a deal.
You do have a 386. (Yes I know it is fast and they said it was a Pentium)
> I am mailing this to the linux-kernel mailing-list to make the kernel > developers (developer) aware of this problem, with the hopes that it may > be fixed, or patched, or what not (though I know you had hopes of not > having to go beyond 2.0.0 into 2.0.1, and I also don't know if this > justifies a full patch... however, I, and probably most NexGen owners > (there are a bunch) would rather not have to use a sub-optimized kernel > 2, when 1.2.13 lets you optimize...
It lets you optimize for a 486 or Pentium, which you do not have.
> I am mailing this to the GCC-bugs list to let them know of this problem, > because although it is not a specific error of GCC's, it could be useful > to implement a warning or change some of the code to route around this > problem. NexGen has some sample code for fixing this problem, at the > above url.
Nope, the problem is hand-coded assembly. Gcc will never create the problem code.
At the very least, your CPU is missing the page invalidate instruction. Maybe it also lacks 4 MB pages.
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