Sparse warns that the percpu variables aren't declared before they are
defined.  Rather than hacking around it, move espfix definitions into
a proper header file.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

The IRET instruction, when returning to a 16-bit segment, only
restores the bottom 16 bits of the user space stack pointer.  This
causes some 16-bit software to break, but it also leaks kernel state
to user space.  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 64-bit mode.

In checkin:

    b3b42ac2cbae x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels

we "solved" this by forbidding 16-bit segments on 64-bit kernels, with
the logic that 16-bit support is crippled on 64-bit kernels anyway (no
V86 support), but it turns out that people are doing stuff like
running old Win16 binaries under Wine and expect it to work.

This works around this by creating percpu "ministacks", each of which
is mapped 2^16 times 64K apart.  When we detect that the return SS is
on the LDT, we copy the IRET frame to the ministack and use the
relevant alias to return to userspace.  The ministacks are mapped
readonly, so if IRET faults we promote #GP to #DF which is an IST
vector and thus has its own stack; we then do the fixup in the #DF
handler.

(Making #GP an IST exception would make the msr_safe functions unsafe
in NMI/MC context, and quite possibly have other effects.)

Special thanks to:

- Andy Lutomirski, for the suggestion of using very small stack slots
  and copy (as opposed to map) the IRET frame there, and for the
  suggestion to mark them readonly and let the fault promote to #DF.
- Konrad Wilk for paravirt fixup and testing.
- Borislav Petkov for testing help and useful comments.

Reported-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrew Lutomriski <amluto@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dirk Hohndel <dirk@hohndel.org>
Cc: Arjan van de Ven <arjan.van.de.ven@intel.com>
Cc: comex <comexk@gmail.com>
Cc: Alexander van Heukelum <heukelum@fastmail.fm>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: <stable@vger.kernel.org> # consider after upstream merge

The SGI Visual Workstation seems to be dead; remove support so we
don't have to continue maintaining it.

Cc: Andrey Panin <pazke@donpac.ru>
Cc: Michael Reed <mdr@sgi.com>
Link: http://lkml.kernel.org/r/530CFD6C.7040705@zytor.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

The ramdisk can possibly get relocated if the whole image is not mapped.
And since we're going over it in the microcode loader and fishing out
the relevant microcode patches, we want access it at its new location.
Thus, export it.

Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>

mrst is used as common name to represent all intel_mid type
soc's. But moorsetwon is just one of the intel_mid soc. So
renamed them to use intel_mid.

This patch mainly renames the variables and related
functions that uses *mrst* prefix with *intel_mid*.

To ensure that there are no functional changes, I have compared
the objdump of related files before and after rename and found
the only difference is symbol and name changes.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: http://lkml.kernel.org/r/1382049336-21316-6-git-send-email-david.a.cohen@linux.intel.com
Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Obviously these functions have to be visible, otherwise
the whole kernel could be optimized away.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1375740170-7446-5-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>

This sets all up the other bits that need to be INTEL_MID
specific rather than Moorestown specific.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Link: http://lkml.kernel.org/r/20111217174318.7207.91543.stgit@bob.linux.org.uk
Signed-off-by: Ingo Molnar <mingo@elte.hu>

* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Introduce pci_map_biosrom()
  x86, olpc: Use device tree for platform identification

The section called .discard.text has tracing attached to it and is
currently ignored by ftrace. But it does include a call to the mcount
stub. Adding a notrace to the code keeps gcc from adding the useless
mcount caller to it.

Link: http://lkml.kernel.org/r/20110421023739.243651696@goodmis.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>