Re: [PATCH 2/2] xen64: disable 32-bit syscall/sysenter if notsupported.

From: Ingo Molnar
Date: Fri Jul 11 2008 - 09:47:32 EST



* Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:

> Old versions of Xen (3.1 and before) don't support sysenter or syscall
> from 32-bit compat userspaces. If we can't set the appropriate
> syscall callback, then disable the corresponding feature bit, which
> will cause the vdso32 setup to fall back appropriately.
>
> Linux assumes that syscall is always available to 32-bit userspace,
> and installs it by default if sysenter isn't available. In that case,
> we just disable vdso altogether, forcing userspace libc to fall back
> to int $0x80.

merged the latest version of tip/x86/core to tip/xen-64bit and then
added this patch to tip/xen-64bit - thanks Jeremy.

Ingo
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