Re: [patch] use __asm__ and __volatile__ in asm-x86_64/msr.h

From: Christoph Hellwig
Date: Mon Jun 18 2007 - 14:37:16 EST


On Mon, Jun 18, 2007 at 10:02:21AM -0400, Mike Frysinger wrote:
> > This is wrong for two reasons:
> >
> > - MSRs are not accessible in user space.
> > - .section .fixup is not applicable to user space.
> >
> > Anything MSR-related should be protected by __KERNEL__ instead.
> >
> > This NAK doesn't apply to rdtsc* and rdpmc* changes, however, as those
> > instructions are legitimate in userspace.
>
> then someone needs to audit msr.h for this because currently it lacks
> __KERNEL__ of any kind yet is exported completely to userspace ... i dont
> know anything about this instructions so that someone != me
>
> this is similar to what i heard last time i tried to fixup msr.h for
> userspace, but the file still hasnt been updated ...

asm-i386/msr.h should not be exported to userspace at all, it contains
nothing but kernel-internal helpers.
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