From: Andy Lutomirski <luto@amacapital.net>
Date: Wed, 23 Jul 2014 15:34:11 +0000 (-0700)
Subject: x86_64/entry/xen: Do not invoke espfix64 on Xen
X-Git-Tag: omap-for-v3.17/fixes-against-rc2~201^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7209a75d2009dbf7745e2fd354abf25c3deb3ca3;p=pandora-kernel.git

x86_64/entry/xen: Do not invoke espfix64 on Xen

This moves the espfix64 logic into native_iret.  To make this work,
it gets rid of the native patch for INTERRUPT_RETURN:
INTERRUPT_RETURN on native kernels is now 'jmp native_iret'.

This changes the 16-bit SS behavior on Xen from OOPSing to leaking
some bits of the Xen hypervisor's RSP (I think).

[ hpa: this is a nonzero cost on native, but probably not enough to
  measure. Xen needs to fix this in their own code, probably doing
  something equivalent to espfix64. ]

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/7b8f1d8ef6597cb16ae004a43c56980a7de3cf94.1406129132.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>
---

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