commit 7d453eee36ae ("x86/efi: Wire up CONFIG_EFI_MIXED") introduced a
regression for the functionality to load kernels above 4G. The relevant
(incorrect) reasoning behind this change can be seen in the commit
message,

  "The xloadflags field in the bzImage header is also updated to reflect
  that the kernel supports both entry points by setting both of
  XLF_EFI_HANDOVER_32 and XLF_EFI_HANDOVER_64 when CONFIG_EFI_MIXED=y.
  XLF_CAN_BE_LOADED_ABOVE_4G is disabled so that the kernel text is
  guaranteed to be addressable with 32-bits."

This is obviously bogus since 32-bit EFI loaders will never place the
kernel above the 4G mark. So this restriction is entirely unnecessary.

But things are worse than that - since we want to encourage people to
always compile with CONFIG_EFI_MIXED=y so that their kernels work out of
the box for both 32-bit and 64-bit firmware, commit 7d453eee36ae
effectively disables XLF_CAN_BE_LOADED_ABOVE_4G completely.

Remove the overzealous and superfluous restriction and restore the
XLF_CAN_BE_LOADED_ABOVE_4G functionality.

Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1402140380-15377-1-git-send-email-matt@console-pimps.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

As requested by Linus add explicit __visible to the asmlinkage users.
This marks all functions visible to assembler.

Tree sweep for arch/x86/*

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1398984278-29319-3-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/crypto/sha1_avx2_x86_64_asm.S introduced _end as a local
symbol, which broke the build under certain circumstances.  Although
the wisdom of _end as a local symbol can definitely be questioned, the
build should not break for that reason.

Thus, filter the output of nm to only get global symbols of
appropriate type.

Reported-by: Andy Lutomirski <luto@amacapital.net>
Cc: Chandramouli Narayanan <mouli@linux.intel.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/n/tip-uxm3j3w3odglcwhafwq5tjqu@git.kernel.org

Pull x86 fixes from Peter Anvin:
 "This is a collection of minor fixes for x86, plus the IRET information
  leak fix (forbid the use of 16-bit segments in 64-bit mode)"

NOTE! We may have to relax the "forbid the use of 16-bit segments in
64-bit mode" part, since there may be people who still run and depend on
16-bit Windows binaries under Wine.

But I'm taking this in the current unconditional form for now to see who
(if anybody) screams bloody murder.  Maybe nobody cares.  And maybe
we'll have to update it with some kind of runtime enablement (like our
vm.mmap_min_addr tunable that people who run dosemu/qemu/wine already
need to tweak).

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels
  efi: Pass correct file handle to efi_file_{read,close}
  x86/efi: Correct EFI boot stub use of code32_start
  x86/efi: Fix boot failure with EFI stub
  x86/platform/hyperv: Handle VMBUS driver being a module
  x86/apic: Reinstate error IRQ Pentium erratum 3AP workaround
  x86, CMCI: Add proper detection of end of CMCI storms

Pull EFI fixes from Matt Fleming:

"* Fix EFI boot regression introduced during the merge window where the
   firmware was reading random values from the stack because we were
   passing a pointer to the wrong object type.

 * Kernel corruption has been reported when booting with the EFI boot
   stub which was tracked down to setting a bogus value for
   bp->hdr.code32_start, resulting in corruption during relocation.

 * Olivier Martin reported that the wrong file handles were being passed
   to efi_file_(read|close), which works for x86 by luck due to the way
   that the FAT driver is implemented, but doesn't work on ARM."

Signed-off-by: Ingo Molnar <mingo@kernel.org>

We're currently passing the file handle for the root file system to
efi_file_read() and efi_file_close(), instead of the file handle for the
file we wish to read/close.

While this has worked up until now, it seems that it has only been by
pure luck. Olivier explains,

 "The issue is the UEFI Fat driver might return the same function for
  'fh->read()' and 'h->read()'. While in our case it does not work with
  a different implementation of EFI_SIMPLE_FILE_SYSTEM_PROTOCOL. In our
  case, we return a different pointer when reading a directory and
  reading a file."

Fixing this actually clears up the two functions because we can drop one
of the arguments, and instead only pass a file 'handle' argument.

Reported-by: Olivier Martin <olivier.martin@arm.com>
Reviewed-by: Olivier Martin <olivier.martin@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

code32_start should point at the start of the protected mode code, and
*not* at the beginning of the bzImage. This is much easier to do in
assembly so document that callers of make_boot_params() need to fill out
code32_start.

The fallout from this bug is that we would end up relocating the image
but copying the image at some offset, resulting in what appeared to be
memory corruption.

Reported-by: Thomas Bächler <thomas@archlinux.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

commit 54b52d872680 ("x86/efi: Build our own EFI services pointer
table") introduced a regression because the 64-bit file_size()
implementation passed a pointer to a 32-bit data object, instead of a
pointer to a 64-bit object.

Because the firmware treats the object as 64-bits regardless it was
reading random values from the stack for the upper 32-bits.

This resulted in people being unable to boot their machines, after
seeing the following error messages,

    Failed to get file info size
    Failed to alloc highmem for files

Reported-by: Dzmitry Sledneu <dzmitry.sledneu@gmail.com>
Reported-by: Koen Kooi <koen@dominion.thruhere.net>
Tested-by: Koen Kooi <koen@dominion.thruhere.net>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Pull x86 boot changes from Peter Anvin:
 "This patchset is a set of cleanups aiming at librarize some of the
  common code from the boot environments.  We currently have three
  different "little environments" (boot, boot/compressed, and
  realmode/rm) in x86, and we are likely to soon get a fourth one
  (kexec/purgatory, which will have to be integrated in the kernel to
  support secure kexec).  This is primarily a cleanup in the
  anticipation of the latter.

  While Vivek implemented this, he ran into some bugs, in particular the
  memcmp implementation for when gcc punts from using the builtin would
  have a misnamed symbol, causing compilation errors if we were ever
  unlucky enough that gcc didn't want to inline the test"

* 'x86/boot' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, boot: Move memset() definition in compressed/string.c
  x86, boot: Move memcmp() into string.h and string.c
  x86, boot: Move optimized memcpy() 32/64 bit versions to compressed/string.c
  x86, boot: Create a separate string.h file to provide standard string functions
  x86, boot: Undef memcmp before providing a new definition

Pull x86 EFI changes from Ingo Molnar:
 "The main changes:

  - Add debug code to the dump EFI pagetable - Borislav Petkov

  - Make 1:1 runtime mapping robust when booting on machines with lots
    of memory - Borislav Petkov

  - Move the EFI facilities bits out of 'x86_efi_facility' and into
    efi.flags which is the standard architecture independent place to
    keep EFI state, by Matt Fleming.

  - Add 'EFI mixed mode' support: this allows 64-bit kernels to be
    booted from 32-bit firmware.  This needs a bootloader that supports
    the 'EFI handover protocol'.  By Matt Fleming"

* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits)
  x86, efi: Abstract x86 efi_early calls
  x86/efi: Restore 'attr' argument to query_variable_info()
  x86/efi: Rip out phys_efi_get_time()
  x86/efi: Preserve segment registers in mixed mode
  x86/boot: Fix non-EFI build
  x86, tools: Fix up compiler warnings
  x86/efi: Re-disable interrupts after calling firmware services
  x86/boot: Don't overwrite cr4 when enabling PAE
  x86/efi: Wire up CONFIG_EFI_MIXED
  x86/efi: Add mixed runtime services support
  x86/efi: Firmware agnostic handover entry points
  x86/efi: Split the boot stub into 32/64 code paths
  x86/efi: Add early thunk code to go from 64-bit to 32-bit
  x86/efi: Build our own EFI services pointer table
  efi: Add separate 32-bit/64-bit definitions
  x86/efi: Delete dead code when checking for non-native
  x86/mm/pageattr: Always dump the right page table in an oops
  x86, tools: Consolidate #ifdef code
  x86/boot: Cleanup header.S by removing some #ifdefs
  efi: Use NULL instead of 0 for pointer
  ...