exception handling in kernel code

[Stanislav Sedov]

On Tue, 22 Aug 2006 12:36:40 +0200
"Attilio Rao" <attilio at freebsd.org> mentioned:
> 
> Mmm, I think that a better approach would be refering to different
> MSRs tables for pentium, p6 and Pentium 4 (if I remind correctly they
> are which show differences). It is more extensible, portable and
> possibly cleaner (I.E: you could port automatically to openbsd/netbsd,
> adding new table and make minimum modifies, etc.)

I don't agree. We have a bunch of i386-compatible cpu vendors (Winbond,
Cyrix, Intel, AMD, etc) and several models for each of them. Each
have specific MSR set available. Thus, in that case we should add
a table per each cpu model into the code, that seems to me bogus,
since it will grow codesize dramatically and will not save from
#GP faults in case of 'degenerate' cpu models. That is, it requires
fault handlers anyway.

Current implementation works well providing MSR access to
userland and it garantee no kernel faults at all. It reports
MSR reading errors to userland too. Furthermore, porting
to other BSD isn't a goal.

-- 
Stanislav Sedov         MBSD labs, Inc.         <ssedov at mbsd.msk.ru>
Россия, Москва         http://mbsd.msk.ru

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