[SRU][Trusty][PULL] Update to upstream's implementation of Spectre v1 mitigation (LP: #1774181)

[Juerg Haefliger]

BugLink: https://bugs.launchpad.net/bugs/1774181

Xenial/Trusty/Precise are currently lacking full support of upstream's Spectre
v1 mitigation. Add the missing patches and merge them with Ubuntu's current
implementation.

== SRU Justification ==
Ubuntu's Spectre v1 mitigation is based on the original embargoed patchset
which introduced a barrier macro to prevent speculation beyond array boundaries
for user controlled indices. What eventually landed in upstream is slightly
different and uses a barrier macro in combination with a masking solution (plus
syscall table and user pointer sanitation). During the updates to newer stable
upstream versions, all those patches were skipped. After reviewing them, we
want to bring them back and merge them with the current implementation which
brings us back in sync with upstream stable.

== Fix ==
Add all the missing Spectre v1 patches from upstream stable 4.4.118 to 4.4.131.
Where appropriate, replace Ubuntu's additional barriers with the masking macro.

== Regression Potential ==
Low. The patches have been in upstream for quite a while now and we keep the
speculation barriers that are currently in Ubuntu but not in upstream.

== Test Case ==
TBD.

Compile-tested all supported architectures.

Signed-off-by: Juerg Haefliger <juergh at canonical.com>
---

The following changes since commit ae41eb7e6e1f4431c8a6d98578588d15b7240bf8:

  fscache: Fix hanging wait on page discarded by writeback (2018-06-18 17:44:37 +0200)

are available in the Git repository at:

  git://git.launchpad.net/~juergh/+git/trusty-linux lp1774181

for you to fetch changes up to 182dabb3ee807633a0a11e8bbac93a64d111fdd3:

  UBUNTU: SAUCE: filter: Use barrier_nospec() instead of osb() (2018-06-28 16:08:50 +0200)

----------------------------------------------------------------
Ben Hutchings (1):
      x86/syscall: Sanitize syscall table de-references under speculation

Dan Williams (9):
      array_index_nospec: Sanitize speculative array de-references
      x86: Implement array_index_mask_nospec
      x86: Introduce barrier_nospec
      x86/get_user: Use pointer masking to limit speculation
      vfs, fdtable: Prevent bounds-check bypass via speculative execution
      nl80211: Sanitize array index in parse_txq_params
      x86/spectre: Report get_user mitigation for spectre_v1
      x86/kvm: Update spectre-v1 mitigation
      nospec: Kill array_index_nospec_mask_check()

Juerg Haefliger (3):
      UBUNTU: SAUCE: Replace osb() calls with array_index_nospec()
      UBUNTU: SAUCE: Rename osb() to barrier_nospec()
      UBUNTU: SAUCE: filter: Use barrier_nospec() instead of osb()

Mark Rutland (1):
      Documentation: Document array_index_nospec

Rasmus Villemoes (1):
      nospec: Allow index argument to have const-qualified type

Will Deacon (1):
      nospec: Move array_index_nospec() parameter checking into separate macro

 Documentation/speculation.txt            | 90 ++++++++++++++++++++++++++++++++
 arch/arm/include/asm/barrier.h           |  3 --
 arch/arm64/include/asm/barrier.h         |  3 --
 arch/powerpc/include/asm/barrier.h       |  3 +-
 arch/s390/include/asm/barrier.h          | 13 +++--
 arch/x86/ia32/ia32entry.S                | 36 ++++++++-----
 arch/x86/include/asm/barrier.h           | 32 ++++++++++--
 arch/x86/kernel/cpu/bugs.c               | 10 +---
 arch/x86/kernel/entry_32.S               |  4 ++
 arch/x86/kernel/entry_64.S               | 16 +++---
 arch/x86/kvm/vmx.c                       | 15 ++++--
 arch/x86/lib/getuser.S                   | 10 ++++
 drivers/media/usb/uvc/uvc_v4l2.c         |  5 +-
 drivers/net/wireless/ath/carl9170/main.c |  3 +-
 drivers/scsi/qla2xxx/qla_mr.c            |  5 +-
 fs/udf/misc.c                            | 13 ++---
 include/asm-generic/barrier.h            | 11 ----
 include/linux/fdtable.h                  |  3 +-
 include/linux/nospec.h                   | 53 +++++++++++++++++++
 kernel/user_namespace.c                  |  3 +-
 net/core/filter.c                        |  5 +-
 net/wireless/nl80211.c                   |  9 ++--
 22 files changed, 268 insertions(+), 77 deletions(-)
 create mode 100644 Documentation/speculation.txt