On Fri, Dec 12, 2014 at 12:27 PM, Dave Hansen <d...@sr71.net> wrote: > On 12/12/2014 12:22 PM, Andy Lutomirski wrote: >> On 12/12/2014 11:12 AM, Dave Hansen wrote: >>> This is 3.20 material. I'm hoping to get some comments early >>> in case folks have some issues with the way it's being done. >>> >>> The MPX hardware structures differ in layout in 32 and 64-bit >>> mode. A 32-bit binary running on a 64-bit kernel needs the >>> 32-bit structures, so we need code which switches between >>> the two modes. >> >> The OS community figured out years ago that you aren't supposed to do >> this. Did everyone forget to tell the hardware people? > > What is your concern with it, exactly? > > You want the same size structures with the same format for 32-bit and > 64-bit modes?
Yes. Especially because programs can switch between 32-bit and 64-bit mode entirely in userspace. I don't know whether any do in practice, but programs *can*. Or better yet: Intel could have skipped supporting it at all in 32-bit mode. Isn't mpx somewhat of an address space hog anyway? --Andy -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
