Re: [PATCH 0/3] Remove interrupt stack table usage from x86_64 kernel

[Andi Kleen]

On Sun, Dec 28, 2008 at 04:09:26PM +0200, Avi Kivity wrote:
> I don't see how syscall could work on i386, and indeed:

i386 has task gates which support unconditional stack switching. But there 
are no 64bit task gates, just ISTs.

BTW I think there are more similar problems in your patch too.

> 
> >vdso32.so-$(VDSO32-y)        += int80
> >vdso32.so-$(CONFIG_COMPAT)    += syscall
> >vdso32.so-$(VDSO32-y)        += sysenter
> 
> It's disabled.  Is that the reason?

No.  All interesting 32bit CPUs have SYSENTER; the only one who has SYSCALL 
but no SYSENTER is the K6, but it has a weird early variant of SYSCALL with
more problems which was never worth supporting.

-Andi
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