Re: SYSENTER based syscalls patch, 2.1.105, RFC

Frank Heldt (Frank.Heldt@t-online.de)
Sun, 14 Jun 1998 13:29:04 +0200


Wow mingo,

this is hot stuff !
*******************

Well, you wanted a few comments/suggestions, so here they are:

First, it doesn´t patch clean against 2.1.105. :-(

Second (and more important to me, as a K6 owner):

1. The K6 has no SYSENTER/SYSEXIT opcodes, it has what AMD calls
SYSCALL/SYSRET (opcodes 0F05h and 0F07h), which are IIRC basicly
the same instructions. There is a very good pdf-file on the K6
website (i think it was on http://www.amd.com/K6/k6docs/)
about SYSCALL/SYSRET.

2. The K6 doesn't accept these instructions per default, they
have to be enabled per "wrmsr".

3. What hurt's me most :-( The older K6 have a bug with these
instructions (see the release notes on the above site).

Well, it would be great, if this stuff could be integrated in
your patch.

I don't know about the Cyrix Family, do these support SYSENTER/
SYSEXIT too? This cries for a X86_FEATURE_* define...

Anyhow, thank's a lot, mingo. This and your MMX patch will give
Linux on the x86 another kick B-)

Bye
Frank

---
Frank Heldt *** Join the Army,
mailto:Frank.Heldt@t-online.de *** meet interesting people,
mailto:Frank.Heldt@mahr.de *** kill them.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu