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Anand K Mistry fe71988834 proc: provide details on indirect branch speculation
Similar to speculation store bypass, show information about the indirect
branch speculation mode of a task in /proc/$pid/status.

For testing/benchmarking, I needed to see whether IB (Indirect Branch)
speculation (see Spectre-v2) is enabled on a task, to see whether an
IBPB instruction should be executed on an address space switch.
Unfortunately, this information isn't available anywhere else and
currently the only way to get it is to hack the kernel to expose it
(like this change).  It also helped expose a bug with conditional IB
speculation on certain CPUs.

Another place this could be useful is to audit the system when using
sanboxing.  With this change, I can confirm that seccomp-enabled
process have IB speculation force disabled as expected when the kernel
command line parameter `spectre_v2_user=seccomp`.

Since there's already a 'Speculation_Store_Bypass' field, I used that
as precedent for adding this one.

[amistry@google.com: remove underscores from field name to workaround documentation issue]
  Link: https://lkml.kernel.org/r/20201106131015.v2.1.I7782b0cedb705384a634cfd8898eb7523562da99@changeid

Link: https://lkml.kernel.org/r/20201030172731.1.I7782b0cedb705384a634cfd8898eb7523562da99@changeid
Signed-off-by: Anand K Mistry <amistry@google.com>
Cc: Anthony Steinhauser <asteinhauser@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Anand K Mistry <amistry@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alexey Gladkov <gladkov.alexey@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 22:46:15 -08:00
arch alpha: replace bogus in_interrupt() 2020-12-15 22:46:15 -08:00
block Scheduler updates: 2020-12-14 18:29:11 -08:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: aegis128 - avoid spurious references crypto_aegis128_update_simd 2020-12-04 18:16:53 +11:00
Documentation proc: provide details on indirect branch speculation 2020-12-15 22:46:15 -08:00
drivers pci-v5.11-changes 2020-12-15 16:49:59 -08:00
fs proc: provide details on indirect branch speculation 2020-12-15 22:46:15 -08:00
include pci-v5.11-changes 2020-12-15 16:49:59 -08:00
init Merge branch 'akpm' (patches from Andrew) 2020-12-15 12:53:37 -08:00
ipc Merge branch 'akpm' (patches from Andrew) 2020-12-15 12:53:37 -08:00
kernel ACPI updates for 5.11-rc1 2020-12-15 16:39:06 -08:00
lib ACPI updates for 5.11-rc1 2020-12-15 16:39:06 -08:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm/memory_hotplug: quieting offline operation 2020-12-15 22:46:15 -08:00
net Networking updates for 5.11 2020-12-15 13:22:29 -08:00
samples samples/bpf: Fix possible hang in xdpsock with multiple threads 2020-12-10 23:13:43 +01:00
scripts Networking updates for 5.11 2020-12-15 13:22:29 -08:00
security Networking updates for 5.11 2020-12-15 13:22:29 -08:00
sound ACPI updates for 5.11-rc1 2020-12-15 16:39:06 -08:00
tools Power management updates for 5.11-rc1 2020-12-15 16:30:31 -08:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt kvm: x86/mmu: Support dirty logging for the TDP MMU 2020-10-23 03:42:13 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-12-11 22:29:38 -08:00
Kbuild
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS pci-v5.11-changes 2020-12-15 16:49:59 -08:00
Makefile Linux 5.10 2020-12-13 14:41:30 -08:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.