commit f8b8404337de4e2466e2e1139ea68b1f8295974f upstream.

This patch reworks the UEFI anti-bricking code, including an effective
reversion of cc5a080c and 31ff2f20. It turns out that calling
QueryVariableInfo() from boot services results in some firmware
implementations jumping to physical addresses even after entering virtual
mode, so until we have 1:1 mappings for UEFI runtime space this isn't
going to work so well.

Reverting these gets us back to the situation where we'd refuse to create
variables on some systems because they classify deleted variables as "used"
until the firmware triggers a garbage collection run, which they won't do
until they reach a lower threshold. This results in it being impossible to
install a bootloader, which is unhelpful.

Feedback from Samsung indicates that the firmware doesn't need more than
5KB of storage space for its own purposes, so that seems like a reasonable
threshold. However, there's still no guarantee that a platform will attempt
garbage collection merely because it drops below this threshold. It seems
that this is often only triggered if an attempt to write generates a
genuine EFI_OUT_OF_RESOURCES error. We can force that by attempting to
create a variable larger than the remaining space. This should fail, but if
it somehow succeeds we can then immediately delete it.

I've tested this on the UEFI machines I have available, but I don't have
a Samsung and so can't verify that it avoids the bricking problem.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Lee, Chun-Y <jlee@suse.com> [ dummy variable cleanup ]
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 * The EFI variable anti-bricking algorithm merged in -rc8 broke booting
   on some Apple machines because they implement EFI spec 1.10, which
   doesn't provide a QueryVariableInfo() runtime function and the logic
   used to check for the existence of that function was insufficient.
   Fix from Josh Boyer.

 * The anti-bricking algorithm also introduced a compiler warning on
   32-bit. Fix from Borislav Petkov.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

We need to check the runtime sys_table for the EFI version the firmware
specifies instead of just checking for a NULL QueryVariableInfo.  Older
implementations of EFI don't have QueryVariableInfo but the runtime is
a smaller structure, so the pointer to it may be pointing off into garbage.

This is apparently the case with several Apple firmwares that support EFI
1.10, and the current check causes them to no longer boot.  Fix based on
a suggestion from Matthew Garrett.

Signed-off-by: Josh Boyer <jwboyer@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Fix this:

arch/x86/boot/compressed/eboot.c: In function ‘setup_efi_vars’:
arch/x86/boot/compressed/eboot.c:269:2: warning: passing argument 1 of ‘efi_call_phys’ makes pointer from integer without a cast [enabled by default]
In file included from arch/x86/boot/compressed/eboot.c:12:0:
/w/kernel/linux/arch/x86/include/asm/efi.h:8:33: note: expected ‘void *’ but argument is of type ‘long unsigned int’

after cc5a080c5d40 ("efi: Pass boot services variable info to runtime
code").

Reported-by: Paul Bolle <pebolle@tiscali.nl>
Cc: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Matt Fleming (1):
      x86, efivars: firmware bug workarounds should be in platform
      code

Matthew Garrett (3):
      Move utf16 functions to kernel core and rename
      efi: Pass boot services variable info to runtime code
      efi: Distinguish between "remaining space" and actually used
      space

Richard Weinberger (2):
      x86,efi: Check max_size only if it is non-zero.
      x86,efi: Implement efi_no_storage_paranoia parameter

Sergey Vlasov (2):
      x86/Kconfig: Make EFI select UCS2_STRING
      efi: Export efi_query_variable_store() for efivars.ko

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

EFI variables can be flagged as being accessible only within boot services.
This makes it awkward for us to figure out how much space they use at
runtime. In theory we could figure this out by simply comparing the results
from QueryVariableInfo() to the space used by all of our variables, but
that fails if the platform doesn't garbage collect on every boot. Thankfully,
calling QueryVariableInfo() while still inside boot services gives a more
reliable answer. This patch passes that information from the EFI boot stub
up to the efi platform code.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

eboot.o and efi_stub_$(BITS).o didn't get added to "targets", and hence
their .cmd files don't get included by the build machinery, leading to
the files always getting rebuilt.

Rather than adding the two files individually, take the opportunity and
add $(VMLINUX_OBJS) to "targets" instead, thus allowing the assignment
at the top of the file to be shrunk quite a bit.

At the same time, remove a pointless flags override line - the variable
assigned to was misspelled anyway, and the options added are
meaningless for assembly sources.

[ hpa: the patch is not minimal, but I am taking it for -urgent anyway
  since the excess impact of the patch seems to be small enough. ]

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/515C5D2502000078000CA6AD@nat28.tlf.novell.com
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Pull x86/EFI changes from Peter Anvin:

 - Improve the initrd handling in the EFI boot stub by allowing forward
   slashes in the pathname - from Chun-Yi Lee.

 - Cleanup code duplication in the EFI mixed kernel/firmware code - from
   Satoru Takeuchi.

 - efivarfs bug fixes for more strict filename validation, with lots of
   input from Al Viro.

* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, efi: remove duplicate code in setup_arch() by using, efi_is_native()
  efivarfs: guid part of filenames are case-insensitive
  efivarfs: Validate filenames much more aggressively
  efivarfs: Use sizeof() instead of magic number
  x86, efi: Allow slash in file path of initrd

Pull x86 mm changes from Peter Anvin:
 "This is a huge set of several partly interrelated (and concurrently
  developed) changes, which is why the branch history is messier than
  one would like.

  The *really* big items are two humonguous patchsets mostly developed
  by Yinghai Lu at my request, which completely revamps the way we
  create initial page tables.  In particular, rather than estimating how
  much memory we will need for page tables and then build them into that
  memory -- a calculation that has shown to be incredibly fragile -- we
  now build them (on 64 bits) with the aid of a "pseudo-linear mode" --
  a #PF handler which creates temporary page tables on demand.

  This has several advantages:

  1. It makes it much easier to support things that need access to data
     very early (a followon patchset uses this to load microcode way
     early in the kernel startup).

  2. It allows the kernel and all the kernel data objects to be invoked
     from above the 4 GB limit.  This allows kdump to work on very large
     systems.

  3. It greatly reduces the difference between Xen and native (Xen's
     equivalent of the #PF handler are the temporary page tables created
     by the domain builder), eliminating a bunch of fragile hooks.

  The patch series also gets us a bit closer to W^X.

  Additional work in this pull is the 64-bit get_user() work which you
  were also involved with, and a bunch of cleanups/speedups to
  __phys_addr()/__pa()."

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (105 commits)
  x86, mm: Move reserving low memory later in initialization
  x86, doc: Clarify the use of asm("%edx") in uaccess.h
  x86, mm: Redesign get_user with a __builtin_choose_expr hack
  x86: Be consistent with data size in getuser.S
  x86, mm: Use a bitfield to mask nuisance get_user() warnings
  x86/kvm: Fix compile warning in kvm_register_steal_time()
  x86-32: Add support for 64bit get_user()
  x86-32, mm: Remove reference to alloc_remap()
  x86-32, mm: Remove reference to resume_map_numa_kva()
  x86-32, mm: Rip out x86_32 NUMA remapping code
  x86/numa: Use __pa_nodebug() instead
  x86: Don't panic if can not alloc buffer for swiotlb
  mm: Add alloc_bootmem_low_pages_nopanic()
  x86, 64bit, mm: hibernate use generic mapping_init
  x86, 64bit, mm: Mark data/bss/brk to nx
  x86: Merge early kernel reserve for 32bit and 64bit
  x86: Add Crash kernel low reservation
  x86, kdump: Remove crashkernel range find limit for 64bit
  memblock: Add memblock_mem_size()
  x86, boot: Not need to check setup_header version for setup_data
  ...

Pull x86 bootup changes from Ingo Molnar:
 "Deal with bootloaders which fail to initialize unknown fields in
  boot_params to zero, by sanitizing boot params passed in.

  This unbreaks versions of kexec-utils.  Other bootloaders do not
  appear to show sensitivity to this change, but it's a possibility for
  breakage nevertheless."

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, boot: Sanitize boot_params if not zeroed on creation