On 04/11/2014 10:36 AM, tip-bot for H. Peter Anvin wrote: > Commit-ID: b3b42ac2cbae1f3cecbb6229964a4d48af31d382 > Gitweb: http://git.kernel.org/tip/b3b42ac2cbae1f3cecbb6229964a4d48af31d382 > Author: H. Peter Anvin <h...@linux.intel.com> > AuthorDate: Sun, 16 Mar 2014 15:31:54 -0700 > Committer: H. Peter Anvin <h...@linux.intel.com> > CommitDate: Fri, 11 Apr 2014 10:10:09 -0700 > > x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels > > The IRET instruction, when returning to a 16-bit segment, only > restores the bottom 16 bits of the user space stack pointer. We have > a software workaround for that ("espfix") for the 32-bit kernel, but > it relies on a nonzero stack segment base which is not available in > 32-bit mode. > > Since 16-bit support is somewhat crippled anyway on a 64-bit kernel > (no V86 mode), and most (if not quite all) 64-bit processors support > virtualization for the users who really need it, simply reject > attempts at creating a 16-bit segment when running on top of a 64-bit > kernel. > > Cc: Linus Torvalds <torva...@linux-foundation.org> > Signed-off-by: H. Peter Anvin <h...@linux.intel.com> > Link: http://lkml.kernel.org/n/tip-kicdm89kzw9lldryb1br9...@git.kernel.org > Cc: <sta...@vger.kernel.org>
If this is what I think it is (hi, Spender), then it is probably only useful for 3.14.y and not earlier kernels. --Andy -- 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/
