Commit 8370edea ("bin2c: move bin2c in scripts/basic") moved bin2c
to the scripts/basic/ directory, incorrectly stating "Kexec wants to
use bin2c and it wants to use it really early in the build process.
See arch/x86/purgatory/ code in later patches."

Commit bdab125c ("Revert "kexec/purgatory: Add clean-up for
purgatory directory"") and commit d6605b6b ("x86/build: Remove
unnecessary preparation for purgatory") removed the redundant
purgatory build magic entirely.

That means that the move of bin2c was unnecessary in the first place.

fixdep is the only host program that deserves to sit in the
scripts/basic/ directory.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

Currently the code is split over various files with dma- prefixes in the
lib/ and drives/base directories, and the number of files keeps growing.
Move them into a single directory to keep the code together and remove
the file name prefixes.  To match the irq infrastructure this directory
is placed under the kernel/ directory.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Expose a new system call allowing each thread to register one userspace
memory area to be used as an ABI between kernel and user-space for two
purposes: user-space restartable sequences and quick access to read the
current CPU number value from user-space.

* Restartable sequences (per-cpu atomics)

Restartables sequences allow user-space to perform update operations on
per-cpu data without requiring heavy-weight atomic operations.

The restartable critical sections (percpu atomics) work has been started
by Paul Turner and Andrew Hunter. It lets the kernel handle restart of
critical sections. [1] [2] The re-implementation proposed here brings a
few simplifications to the ABI which facilitates porting to other
architectures and speeds up the user-space fast path.

Here are benchmarks of various rseq use-cases.

Test hardware:

arm32: ARMv7 Processor rev 4 (v7l) "Cubietruck", 2-core
x86-64: Intel E5-2630 v3@2.40GHz, 16-core, hyperthreading

The following benchmarks were all performed on a single thread.

* Per-CPU statistic counter increment

                getcpu+atomic (ns/op)    rseq (ns/op)    speedup
arm32:                344.0                 31.4          11.0
x86-64:                15.3                  2.0           7.7

* LTTng-UST: write event 32-bit header, 32-bit payload into tracer
             per-cpu buffer

                getcpu+atomic (ns/op)    rseq (ns/op)    speedup
arm32:               2502.0                 2250.0         1.1
x86-64:               117.4                   98.0         1.2

* liburcu percpu: lock-unlock pair, dereference, read/compare word

                getcpu+atomic (ns/op)    rseq (ns/op)    speedup
arm32:                751.0                 128.5          5.8
x86-64:                53.4                  28.6          1.9

* jemalloc memory allocator adapted to use rseq

Using rseq with per-cpu memory pools in jemalloc at Facebook (based on
rseq 2016 implementation):

The production workload response-time has 1-2% gain avg. latency, and
the P99 overall latency drops by 2-3%.

* Reading the current CPU number

Speeding up reading the current CPU number on which the caller thread is
running is done by keeping the current CPU number up do date within the
cpu_id field of the memory area registered by the thread. This is done
by making scheduler preemption set the TIF_NOTIFY_RESUME flag on the
current thread. Upon return to user-space, a notify-resume handler
updates the current CPU value within the registered user-space memory
area. User-space can then read the current CPU number directly from
memory.

Keeping the current cpu id in a memory area shared between kernel and
user-space is an improvement over current mechanisms available to read
the current CPU number, which has the following benefits over
alternative approaches:

- 35x speedup on ARM vs system call through glibc
- 20x speedup on x86 compared to calling glibc, which calls vdso
  executing a "lsl" instruction,
- 14x speedup on x86 compared to inlined "lsl" instruction,
- Unlike vdso approaches, this cpu_id value can be read from an inline
  assembly, which makes it a useful building block for restartable
  sequences.
- The approach of reading the cpu id through memory mapping shared
  between kernel and user-space is portable (e.g. ARM), which is not the
  case for the lsl-based x86 vdso.

On x86, yet another possible approach would be to use the gs segment
selector to point to user-space per-cpu data. This approach performs
similarly to the cpu id cache, but it has two disadvantages: it is
not portable, and it is incompatible with existing applications already
using the gs segment selector for other purposes.

Benchmarking various approaches for reading the current CPU number:

ARMv7 Processor rev 4 (v7l)
Machine model: Cubietruck
- Baseline (empty loop):                                    8.4 ns
- Read CPU from rseq cpu_id:                               16.7 ns
- Read CPU from rseq cpu_id (lazy register):               19.8 ns
- glibc 2.19-0ubuntu6.6 getcpu:                           301.8 ns
- getcpu system call:                                     234.9 ns

x86-64 Intel(R) Xeon(R) CPU E5-2630 v3 @ 2.40GHz:
- Baseline (empty loop):                                    0.8 ns
- Read CPU from rseq cpu_id:                                0.8 ns
- Read CPU from rseq cpu_id (lazy register):                0.8 ns
- Read using gs segment selector:                           0.8 ns
- "lsl" inline assembly:                                   13.0 ns
- glibc 2.19-0ubuntu6 getcpu:                              16.6 ns
- getcpu system call:                                      53.9 ns

- Speed (benchmark taken on v8 of patchset)

Running 10 runs of hackbench -l 100000 seems to indicate, contrary to
expectations, that enabling CONFIG_RSEQ slightly accelerates the
scheduler:

Configuration: 2 sockets * 8-core Intel(R) Xeon(R) CPU E5-2630 v3 @
2.40GHz (directly on hardware, hyperthreading disabled in BIOS, energy
saving disabled in BIOS, turboboost disabled in BIOS, cpuidle.off=1
kernel parameter), with a Linux v4.6 defconfig+localyesconfig,
restartable sequences series applied.

* CONFIG_RSEQ=n

avg.:      41.37 s
std.dev.:   0.36 s

* CONFIG_RSEQ=y

avg.:      40.46 s
std.dev.:   0.33 s

- Size

On x86-64, between CONFIG_RSEQ=n/y, the text size increase of vmlinux is
567 bytes, and the data size increase of vmlinux is 5696 bytes.

[1] https://lwn.net/Articles/650333/
[2] http://www.linuxplumbersconf.org/2013/ocw/system/presentations/1695/original/LPC%20-%20PerCpu%20Atomics.pdfSigned-off-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Watson <davejwatson@fb.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Chris Lameter <cl@linux.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Andrew Hunter <ahh@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Maurer <bmaurer@fb.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-api@vger.kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20151027235635.16059.11630.stgit@pjt-glaptop.roam.corp.google.com
Link: http://lkml.kernel.org/r/20150624222609.6116.86035.stgit@kitami.mtv.corp.google.com
Link: https://lkml.kernel.org/r/20180602124408.8430-3-mathieu.desnoyers@efficios.com

Currently, kernel/memremap.c contains generic code for supporting
memremap() (CONFIG_HAS_IOMEM) and devm_memremap_pages()
(CONFIG_ZONE_DEVICE). This causes ongoing build maintenance problems as
additions to memremap.c, especially for the ZONE_DEVICE case, need to be
careful about being placed in ifdef guards. Remove the need for these
ifdef guards by moving the ZONE_DEVICE support functions to their own
compilation unit.

Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Support in-kernel fault-injection framework via debugfs.
This allows you to inject a conditional error to specified
function using debugfs interfaces.

Here is the result of test script described in
Documentation/fault-injection/fault-injection.txt

  ===========
  # ./test_fail_function.sh
  1+0 records in
  1+0 records out
  1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.0227404 s, 46.1 MB/s
  btrfs-progs v4.4
  See http://btrfs.wiki.kernel.org for more information.

  Label:              (null)
  UUID:               bfa96010-12e9-4360-aed0-42eec7af5798
  Node size:          16384
  Sector size:        4096
  Filesystem size:    1001.00MiB
  Block group profiles:
    Data:             single            8.00MiB
    Metadata:         DUP              58.00MiB
    System:           DUP              12.00MiB
  SSD detected:       no
  Incompat features:  extref, skinny-metadata
  Number of devices:  1
  Devices:
     ID        SIZE  PATH
      1  1001.00MiB  /dev/loop2

  mount: mount /dev/loop2 on /opt/tmpmnt failed: Cannot allocate memory
  SUCCESS!
  ===========
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The entire file is now conditionally compiled only when CONFIG_MODULES is
enabled, and this this is a bool.  Just move this conditional to the
Makefile as its easier to read this way.

Link: http://lkml.kernel.org/r/20170810180618.22457-5-mcgrof@kernel.orgSigned-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Daniel Mentz <danielmentz@google.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "kmod: few code cleanups to split out umh code"

The usermode helper has a provenance from the old usb code which first
required a usermode helper.  Eventually this was shoved into kmod.c and
the kernel's modprobe calls was converted over eventually to share the
same code.  Over time the list of usermode helpers in the kernel has grown
-- so kmod is just but one user of the API.

This series is a simple logical cleanup which acknowledges the code
evolution of the usermode helper and shoves the UMH API into its own
dedicated file.  This way users of the API can later just include umh.h
instead of kmod.h.

Note despite the diff state the first patch really is just a code shove,
no functional changes are done there.  I did use git format-patch -M to
generate the patch, but in the end the split was not enough for git to
consider it a rename hence the large diffstat.

I've put this through 0-day and it gives me their machine compilation
blessings with all tests as OK.

This patch (of 4):

There's a slew of usermode helper users and kmod is just one of them.
Split out the usermode helper code into its own file to keep the logic and
focus split up.

This change provides no functional changes.

Link: http://lkml.kernel.org/r/20170810180618.22457-2-mcgrof@kernel.orgSigned-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Daniel Mentz <danielmentz@google.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Implement MEMBARRIER_CMD_PRIVATE_EXPEDITED with IPIs using cpumask built
from all runqueues for which current thread's mm is the same as the
thread calling sys_membarrier. It executes faster than the non-expedited
variant (no blocking). It also works on NOHZ_FULL configurations.

Scheduler-wise, it requires a memory barrier before and after context
switching between processes (which have different mm). The memory
barrier before context switch is already present. For the barrier after
context switch:

* Our TSO archs can do RELEASE without being a full barrier. Look at
  x86 spin_unlock() being a regular STORE for example.  But for those
  archs, all atomics imply smp_mb and all of them have atomic ops in
  switch_mm() for mm_cpumask(), and on x86 the CR3 load acts as a full
  barrier.

* From all weakly ordered machines, only ARM64 and PPC can do RELEASE,
  the rest does indeed do smp_mb(), so there the spin_unlock() is a full
  barrier and we're good.

* ARM64 has a very heavy barrier in switch_to(), which suffices.

* PPC just removed its barrier from switch_to(), but appears to be
  talking about adding something to switch_mm(). So add a
  smp_mb__after_unlock_lock() for now, until this is settled on the PPC
  side.

Changes since v3:
- Properly document the memory barriers provided by each architecture.

Changes since v2:
- Address comments from Peter Zijlstra,
- Add smp_mb__after_unlock_lock() after finish_lock_switch() in
  finish_task_switch() to add the memory barrier we need after storing
  to rq->curr. This is much simpler than the previous approach relying
  on atomic_dec_and_test() in mmdrop(), which actually added a memory
  barrier in the common case of switching between userspace processes.
- Return -EINVAL when MEMBARRIER_CMD_SHARED is used on a nohz_full
  kernel, rather than having the whole membarrier system call returning
  -ENOSYS. Indeed, CMD_PRIVATE_EXPEDITED is compatible with nohz_full.
  Adapt the CMD_QUERY mask accordingly.

Changes since v1:
- move membarrier code under kernel/sched/ because it uses the
  scheduler runqueue,
- only add the barrier when we switch from a kernel thread. The case
  where we switch from a user-space thread is already handled by
  the atomic_dec_and_test() in mmdrop().
- add a comment to mmdrop() documenting the requirement on the implicit
  memory barrier.

CC: Peter Zijlstra <peterz@infradead.org>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: Andrew Hunter <ahh@google.com>
CC: Maged Michael <maged.michael@gmail.com>
CC: gromer@google.com
CC: Avi Kivity <avi@scylladb.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: NDave Watson <davejwatson@fb.com>

Split SOFTLOCKUP_DETECTOR from LOCKUP_DETECTOR, and split
HARDLOCKUP_DETECTOR_PERF from HARDLOCKUP_DETECTOR.

LOCKUP_DETECTOR implies the general boot, sysctl, and programming
interfaces for the lockup detectors.

An architecture that wants to use a hard lockup detector must define
HAVE_HARDLOCKUP_DETECTOR_PERF or HAVE_HARDLOCKUP_DETECTOR_ARCH.

Alternatively an arch can define HAVE_NMI_WATCHDOG, which provides the
minimum arch_touch_nmi_watchdog, and it otherwise does its own thing and
does not implement the LOCKUP_DETECTOR interfaces.

sparc is unusual in that it has started to implement some of the
interfaces, but not fully yet.  It should probably be converted to a full
HAVE_HARDLOCKUP_DETECTOR_ARCH.

[npiggin@gmail.com: fix]
  Link: http://lkml.kernel.org/r/20170617223522.66c0ad88@roar.ozlabs.ibm.com
Link: http://lkml.kernel.org/r/20170616065715.18390-4-npiggin@gmail.comSigned-off-by: NNicholas Piggin <npiggin@gmail.com>
Reviewed-by: NDon Zickus <dzickus@redhat.com>
Reviewed-by: NBabu Moger <babu.moger@oracle.com>
Tested-by: Babu Moger <babu.moger@oracle.com>	[sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "kexec/fadump: remove dependency with CONFIG_KEXEC and
reuse crashkernel parameter for fadump", v4.

Traditionally, kdump is used to save vmcore in case of a crash.  Some
architectures like powerpc can save vmcore using architecture specific
support instead of kexec/kdump mechanism.  Such architecture specific
support also needs to reserve memory, to be used by dump capture kernel.
crashkernel parameter can be a reused, for memory reservation, by such
architecture specific infrastructure.

This patchset removes dependency with CONFIG_KEXEC for crashkernel
parameter and vmcoreinfo related code as it can be reused without kexec
support.  Also, crashkernel parameter is reused instead of
fadump_reserve_mem to reserve memory for fadump.

The first patch moves crashkernel parameter parsing and vmcoreinfo
related code under CONFIG_CRASH_CORE instead of CONFIG_KEXEC_CORE.  The
second patch reuses the definitions of append_elf_note() & final_note()
functions under CONFIG_CRASH_CORE in IA64 arch code.  The third patch
removes dependency on CONFIG_KEXEC for firmware-assisted dump (fadump)
in powerpc.  The next patch reuses crashkernel parameter for reserving
memory for fadump, instead of the fadump_reserve_mem parameter.  This
has the advantage of using all syntaxes crashkernel parameter supports,
for fadump as well.  The last patch updates fadump kernel documentation
about use of crashkernel parameter.

This patch (of 5):

Traditionally, kdump is used to save vmcore in case of a crash.  Some
architectures like powerpc can save vmcore using architecture specific
support instead of kexec/kdump mechanism.  Such architecture specific
support also needs to reserve memory, to be used by dump capture kernel.
crashkernel parameter can be a reused, for memory reservation, by such
architecture specific infrastructure.

But currently, code related to vmcoreinfo and parsing of crashkernel
parameter is built under CONFIG_KEXEC_CORE.  This patch introduces
CONFIG_CRASH_CORE and moves the above mentioned code under this config,
allowing code reuse without dependency on CONFIG_KEXEC.  There is no
functional change with this patch.

Link: http://lkml.kernel.org/r/149035338104.6881.4550894432615189948.stgit@hbathini.in.ibm.comSigned-off-by: NHari Bathini <hbathini@linux.vnet.ibm.com>
Acked-by: NDave Young <dyoung@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

They're growing to be too many and planned to get split further.  Move
them under their own directory.

 kernel/cgroup.c		-> kernel/cgroup/cgroup.c
 kernel/cgroup_freezer.c	-> kernel/cgroup/freezer.c
 kernel/cgroup_pids.c		-> kernel/cgroup/pids.c
 kernel/cpuset.c		-> kernel/cgroup/cpuset.c
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NAcked-by: Zefan Li <lizefan@huawei.com>

Separate hardlockup code from watchdog.c and move it to watchdog_hld.c.
It is mostly straight forward.  Remove everything inside
CONFIG_HARDLOCKUP_DETECTORS.  This code will go to file watchdog_hld.c.
Also update the makefile accordigly.

Link: http://lkml.kernel.org/r/1478034826-43888-3-git-send-email-babu.moger@oracle.comSigned-off-by: NBabu Moger <babu.moger@oracle.com>
Acked-by: NDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Josh Hunt <johunt@akamai.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The build system stopped generating ikconfig.h in v2.6.8. Remove an entry
for it in dontdiff. There's also a reference to it in a small comment.
Remove that comment too, as it is of little help in any case.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Limit per userns sysctls to only be opened for write by a holder
of CAP_SYS_RESOURCE.

Add all of the necessary boilerplate for having per user namespace
sysctls.
Acked-by: NKees Cook <keescook@chromium.org>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

CONFIG_MIPS32_N32=y but CONFIG_BINFMT_ELF disabled results in the
following linker errors:

  arch/mips/built-in.o: In function `elf_core_dump':
  binfmt_elfn32.c:(.text+0x23dbc): undefined reference to `elf_core_extra_phdrs'
  binfmt_elfn32.c:(.text+0x246e4): undefined reference to `elf_core_extra_data_size'
  binfmt_elfn32.c:(.text+0x248d0): undefined reference to `elf_core_write_extra_phdrs'
  binfmt_elfn32.c:(.text+0x24ac4): undefined reference to `elf_core_write_extra_data'

CONFIG_MIPS32_O32=y but CONFIG_BINFMT_ELF disabled results in the following
linker errors:

  arch/mips/built-in.o: In function `elf_core_dump':
  binfmt_elfo32.c:(.text+0x28a04): undefined reference to `elf_core_extra_phdrs'
  binfmt_elfo32.c:(.text+0x29330): undefined reference to `elf_core_extra_data_size'
  binfmt_elfo32.c:(.text+0x2951c): undefined reference to `elf_core_write_extra_phdrs'
  binfmt_elfo32.c:(.text+0x29710): undefined reference to `elf_core_write_extra_data'

This is because binfmt_elfn32 and binfmt_elfo32 are using symbols from
elfcore but for these configurations elfcore will not be built.

Fixed by making elfcore selectable by a separate config symbol which
unlike the current mechanism can also be used from other directories
than kernel/, then having each flavor of ELF that relies on elfcore.o,
select it in Kconfig, including CONFIG_MIPS32_N32 and CONFIG_MIPS32_O32
which fixes this issue.

Link: http://lkml.kernel.org/r/20160520141705.GA1913@linux-mips.orgSigned-off-by: NRalf Baechle <ralf@linux-mips.org>
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kcov provides code coverage collection for coverage-guided fuzzing
(randomized testing).  Coverage-guided fuzzing is a testing technique
that uses coverage feedback to determine new interesting inputs to a
system.  A notable user-space example is AFL
(http://lcamtuf.coredump.cx/afl/).  However, this technique is not
widely used for kernel testing due to missing compiler and kernel
support.

kcov does not aim to collect as much coverage as possible.  It aims to
collect more or less stable coverage that is function of syscall inputs.
To achieve this goal it does not collect coverage in soft/hard
interrupts and instrumentation of some inherently non-deterministic or
non-interesting parts of kernel is disbled (e.g.  scheduler, locking).

Currently there is a single coverage collection mode (tracing), but the
API anticipates additional collection modes.  Initially I also
implemented a second mode which exposes coverage in a fixed-size hash
table of counters (what Quentin used in his original patch).  I've
dropped the second mode for simplicity.

This patch adds the necessary support on kernel side.  The complimentary
compiler support was added in gcc revision 231296.

We've used this support to build syzkaller system call fuzzer, which has
found 90 kernel bugs in just 2 months:

  https://github.com/google/syzkaller/wiki/Found-Bugs

We've also found 30+ bugs in our internal systems with syzkaller.
Another (yet unexplored) direction where kcov coverage would greatly
help is more traditional "blob mutation".  For example, mounting a
random blob as a filesystem, or receiving a random blob over wire.

Why not gcov.  Typical fuzzing loop looks as follows: (1) reset
coverage, (2) execute a bit of code, (3) collect coverage, repeat.  A
typical coverage can be just a dozen of basic blocks (e.g.  an invalid
input).  In such context gcov becomes prohibitively expensive as
reset/collect coverage steps depend on total number of basic
blocks/edges in program (in case of kernel it is about 2M).  Cost of
kcov depends only on number of executed basic blocks/edges.  On top of
that, kernel requires per-thread coverage because there are always
background threads and unrelated processes that also produce coverage.
With inlined gcov instrumentation per-thread coverage is not possible.

kcov exposes kernel PCs and control flow to user-space which is
insecure.  But debugfs should not be mapped as user accessible.

Based on a patch by Quentin Casasnovas.

[akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
[akpm@linux-foundation.org: unbreak allmodconfig]
[akpm@linux-foundation.org: follow x86 Makefile layout standards]
Signed-off-by: NDmitry Vyukov <dvyukov@google.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: David Drysdale <drysdale@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The file cgroup-debug.c had been removed from commit fe693435
(cgroups: move the cgroup debug subsys into cgroup.c to access internal state).
Remain the CFLAGS_REMOVE_cgroup-debug.o = $(CC_FLAGS_FTRACE)
useless in kernel/Makefile.
Signed-off-by: NLi Bin <huawei.libin@huawei.com>
Acked-by: NZefan Li <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Here is an implementation of a new system call, sys_membarrier(), which
executes a memory barrier on all threads running on the system.  It is
implemented by calling synchronize_sched().  It can be used to
distribute the cost of user-space memory barriers asymmetrically by
transforming pairs of memory barriers into pairs consisting of
sys_membarrier() and a compiler barrier.  For synchronization primitives
that distinguish between read-side and write-side (e.g.  userspace RCU
[1], rwlocks), the read-side can be accelerated significantly by moving
the bulk of the memory barrier overhead to the write-side.

The existing applications of which I am aware that would be improved by
this system call are as follows:

* Through Userspace RCU library (http://urcu.so)
  - DNS server (Knot DNS) https://www.knot-dns.cz/
  - Network sniffer (http://netsniff-ng.org/)
  - Distributed object storage (https://sheepdog.github.io/sheepdog/)
  - User-space tracing (http://lttng.org)
  - Network storage system (https://www.gluster.org/)
  - Virtual routers (https://events.linuxfoundation.org/sites/events/files/slides/DPDK_RCU_0MQ.pdf)
  - Financial software (https://lkml.org/lkml/2015/3/23/189)

Those projects use RCU in userspace to increase read-side speed and
scalability compared to locking.  Especially in the case of RCU used by
libraries, sys_membarrier can speed up the read-side by moving the bulk of
the memory barrier cost to synchronize_rcu().

* Direct users of sys_membarrier
  - core dotnet garbage collector (https://github.com/dotnet/coreclr/issues/198)

Microsoft core dotnet GC developers are planning to use the mprotect()
side-effect of issuing memory barriers through IPIs as a way to implement
Windows FlushProcessWriteBuffers() on Linux.  They are referring to
sys_membarrier in their github thread, specifically stating that
sys_membarrier() is what they are looking for.

To explain the benefit of this scheme, let's introduce two example threads:

Thread A (non-frequent, e.g. executing liburcu synchronize_rcu())
Thread B (frequent, e.g. executing liburcu
rcu_read_lock()/rcu_read_unlock())

In a scheme where all smp_mb() in thread A are ordering memory accesses
with respect to smp_mb() present in Thread B, we can change each
smp_mb() within Thread A into calls to sys_membarrier() and each
smp_mb() within Thread B into compiler barriers "barrier()".

Before the change, we had, for each smp_mb() pairs:

Thread A                    Thread B
previous mem accesses       previous mem accesses
smp_mb()                    smp_mb()
following mem accesses      following mem accesses

After the change, these pairs become:

Thread A                    Thread B
prev mem accesses           prev mem accesses
sys_membarrier()            barrier()
follow mem accesses         follow mem accesses

As we can see, there are two possible scenarios: either Thread B memory
accesses do not happen concurrently with Thread A accesses (1), or they
do (2).

1) Non-concurrent Thread A vs Thread B accesses:

Thread A                    Thread B
prev mem accesses
sys_membarrier()
follow mem accesses
                            prev mem accesses
                            barrier()
                            follow mem accesses

In this case, thread B accesses will be weakly ordered. This is OK,
because at that point, thread A is not particularly interested in
ordering them with respect to its own accesses.

2) Concurrent Thread A vs Thread B accesses

Thread A                    Thread B
prev mem accesses           prev mem accesses
sys_membarrier()            barrier()
follow mem accesses         follow mem accesses

In this case, thread B accesses, which are ensured to be in program
order thanks to the compiler barrier, will be "upgraded" to full
smp_mb() by synchronize_sched().

* Benchmarks

On Intel Xeon E5405 (8 cores)
(one thread is calling sys_membarrier, the other 7 threads are busy
looping)

1000 non-expedited sys_membarrier calls in 33s =3D 33 milliseconds/call.

* User-space user of this system call: Userspace RCU library

Both the signal-based and the sys_membarrier userspace RCU schemes
permit us to remove the memory barrier from the userspace RCU
rcu_read_lock() and rcu_read_unlock() primitives, thus significantly
accelerating them. These memory barriers are replaced by compiler
barriers on the read-side, and all matching memory barriers on the
write-side are turned into an invocation of a memory barrier on all
active threads in the process. By letting the kernel perform this
synchronization rather than dumbly sending a signal to every process
threads (as we currently do), we diminish the number of unnecessary wake
ups and only issue the memory barriers on active threads. Non-running
threads do not need to execute such barrier anyway, because these are
implied by the scheduler context switches.

Results in liburcu:

Operations in 10s, 6 readers, 2 writers:

memory barriers in reader:    1701557485 reads, 2202847 writes
signal-based scheme:          9830061167 reads,    6700 writes
sys_membarrier:               9952759104 reads,     425 writes
sys_membarrier (dyn. check):  7970328887 reads,     425 writes

The dynamic sys_membarrier availability check adds some overhead to
the read-side compared to the signal-based scheme, but besides that,
sys_membarrier slightly outperforms the signal-based scheme. However,
this non-expedited sys_membarrier implementation has a much slower grace
period than signal and memory barrier schemes.

Besides diminishing the number of wake-ups, one major advantage of the
membarrier system call over the signal-based scheme is that it does not
need to reserve a signal. This plays much more nicely with libraries,
and with processes injected into for tracing purposes, for which we
cannot expect that signals will be unused by the application.

An expedited version of this system call can be added later on to speed
up the grace period. Its implementation will likely depend on reading
the cpu_curr()->mm without holding each CPU's rq lock.

This patch adds the system call to x86 and to asm-generic.

[1] http://urcu.so

membarrier(2) man page:

MEMBARRIER(2)              Linux Programmer's Manual             MEMBARRIER(2)

NAME
       membarrier - issue memory barriers on a set of threads

SYNOPSIS
       #include <linux/membarrier.h>

       int membarrier(int cmd, int flags);

DESCRIPTION
       The cmd argument is one of the following:

       MEMBARRIER_CMD_QUERY
              Query  the  set  of  supported commands. It returns a bitmask of
              supported commands.

       MEMBARRIER_CMD_SHARED
              Execute a memory barrier on all threads running on  the  system.
              Upon  return from system call, the caller thread is ensured that
              all running threads have passed through a state where all memory
              accesses  to  user-space  addresses  match program order between
              entry to and return from the system  call  (non-running  threads
              are de facto in such a state). This covers threads from all pro=E2=80=90
              cesses running on the system.  This command returns 0.

       The flags argument needs to be 0. For future extensions.

       All memory accesses performed  in  program  order  from  each  targeted
       thread is guaranteed to be ordered with respect to sys_membarrier(). If
       we use the semantic "barrier()" to represent a compiler barrier forcing
       memory  accesses  to  be performed in program order across the barrier,
       and smp_mb() to represent explicit memory barriers forcing full  memory
       ordering  across  the barrier, we have the following ordering table for
       each pair of barrier(), sys_membarrier() and smp_mb():

       The pair ordering is detailed as (O: ordered, X: not ordered):

                              barrier()   smp_mb() sys_membarrier()
              barrier()          X           X            O
              smp_mb()           X           O            O
              sys_membarrier()   O           O            O

RETURN VALUE
       On success, these system calls return zero.  On error, -1 is  returned,
       and errno is set appropriately. For a given command, with flags
       argument set to 0, this system call is guaranteed to always return the
       same value until reboot.

ERRORS
       ENOSYS System call is not implemented.

       EINVAL Invalid arguments.

Linux                             2015-04-15                     MEMBARRIER(2)
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nicholas Miell <nmiell@comcast.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Pranith Kumar <bobby.prani@gmail.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are two kexec load syscalls, kexec_load another and kexec_file_load.
 kexec_file_load has been splited as kernel/kexec_file.c.  In this patch I
split kexec_load syscall code to kernel/kexec.c.

And add a new kconfig option KEXEC_CORE, so we can disable kexec_load and
use kexec_file_load only, or vice verse.

The original requirement is from Ted Ts'o, he want kexec kernel signature
being checked with CONFIG_KEXEC_VERIFY_SIG enabled.  But kexec-tools use
kexec_load syscall can bypass the checking.

Vivek Goyal proposed to create a common kconfig option so user can compile
in only one syscall for loading kexec kernel.  KEXEC/KEXEC_FILE selects
KEXEC_CORE so that old config files still work.

Because there's general code need CONFIG_KEXEC_CORE, so I updated all the
architecture Kconfig with a new option KEXEC_CORE, and let KEXEC selects
KEXEC_CORE in arch Kconfig.  Also updated general kernel code with to
kexec_load syscall.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NDave Young <dyoung@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Petr Tesarik <ptesarik@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Split kexec_file syscall related code to another file kernel/kexec_file.c
so that the #ifdef CONFIG_KEXEC_FILE in kexec.c can be dropped.

Sharing variables and functions are moved to kernel/kexec_internal.h per
suggestion from Vivek and Petr.

[akpm@linux-foundation.org: fix bisectability]
[akpm@linux-foundation.org: declare the various arch_kexec functions]
[akpm@linux-foundation.org: fix build]
Signed-off-by: NDave Young <dyoung@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Petr Tesarik <ptesarik@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Existing users of ioremap_cache() are mapping memory that is known in
advance to not have i/o side effects.  These users are forced to cast
away the __iomem annotation, or otherwise neglect to fix the sparse
errors thrown when dereferencing pointers to this memory.  Provide
memremap() as a non __iomem annotated ioremap_*() in the case when
ioremap is otherwise a pointer to cacheable memory. Empirically,
ioremap_<cacheable-type>() call sites are seeking memory-like semantics
(e.g.  speculative reads, and prefetching permitted).

memremap() is a break from the ioremap implementation pattern of adding
a new memremap_<type>() for each mapping type and having silent
compatibility fall backs.  Instead, the implementation defines flags
that are passed to the central memremap() and if a mapping type is not
supported by an arch memremap returns NULL.

We introduce a memremap prototype as a trivial wrapper of
ioremap_cache() and ioremap_wt().  Later, once all ioremap_cache() and
ioremap_wt() usage has been removed from drivers we teach archs to
implement arch_memremap() with the ability to strictly enforce the
mapping type.

Cc: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Move certificate handling out of the kernel/ directory and into a certs/
directory to get all the weird stuff in one place and move the generated
signing keys into this directory.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Fix up the dependencies somewhat too, while we're at it.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Let the user explicitly provide a file containing trusted keys, instead of
just automatically finding files matching *.x509 in the build tree and
trusting whatever we find. This really ought to be an *explicit*
configuration, and the build rules for dealing with the files were
fairly painful too.

Fix applied from James Morris that removes an '=' from a macro definition
in kernel/Makefile as this is a feature that only exists from GNU make 3.82
onwards.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

The current rule for generating signing_key.priv and signing_key.x509 is
a classic example of a bad rule which has a tendency to break parallel
make. When invoked to create *either* target, it generates the other
target as a side-effect that make didn't predict.

So let's switch to using a single file signing_key.pem which contains
both key and certificate. That matches what we do in the case of an
external key specified by CONFIG_MODULE_SIG_KEY anyway, so it's also
slightly cleaner.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Where an external PEM file or PKCS#11 URI is given, we can get the cert
from it for ourselves instead of making the user drop signing_key.x509
in place for us.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

This is to be used to audit by executable path rules, but audit watches should
be able to share this code eventually.

At the moment the audit watch code is a lot more complex.  That code only
creates one fsnotify watch per parent directory.  That 'audit_parent' in
turn has a list of 'audit_watches' which contain the name, ino, dev of
the specific object we care about.  This just creates one fsnotify watch
per object we care about.  So if you watch 100 inodes in /etc this code
will create 100 fsnotify watches on /etc.  The audit_watch code will
instead create 1 fsnotify watch on /etc (the audit_parent) and then 100
individual watches chained from that fsnotify mark.

We should be able to convert the audit_watch code to do one fsnotify
mark per watch and simplify things/remove a whole lot of code.  After
that conversion we should be able to convert the audit_fsnotify code to
support that hierarchy if the optimization is necessary.

Move the access to the entry for audit_match_signal() to the beginning of
the audit_del_rule() function in case the entry found is the same one passed
in.  This will enable it to be used by audit_autoremove_mark_rule(),
kill_rules() and audit_remove_parent_watches().

This is a heavily modified and merged version of two patches originally
submitted by Eric Paris.

Cc: Peter Moody <peter@hda3.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
[PM: added a space after a declaration to keep ./scripts/checkpatch happy]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Adds a new single-purpose PIDs subsystem to limit the number of
tasks that can be forked inside a cgroup. Essentially this is an
implementation of RLIMIT_NPROC that applies to a cgroup rather than a
process tree.

However, it should be noted that organisational operations (adding and
removing tasks from a PIDs hierarchy) will *not* be prevented. Rather,
the number of tasks in the hierarchy cannot exceed the limit through
forking. This is due to the fact that, in the unified hierarchy, attach
cannot fail (and it is not possible for a task to overcome its PIDs
cgroup policy limit by attaching to a child cgroup -- even if migrating
mid-fork it must be able to fork in the parent first).

PIDs are fundamentally a global resource, and it is possible to reach
PID exhaustion inside a cgroup without hitting any reasonable kmemcg
policy. Once you've hit PID exhaustion, you're only in a marginally
better state than OOM. This subsystem allows PID exhaustion inside a
cgroup to be prevented.
Signed-off-by: NAleksa Sarai <cyphar@cyphar.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

It's a bug in our Makefile rules, make it show what the changing
certificate list was, and make it a warning so that people actually see
it.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change default key details to be more obviously unspecified.
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NJames Morris <james.l.morris@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are a lot of embedded systems that run most or all of their
functionality in init, running as root:root.  For these systems,
supporting multiple users is not necessary.

This patch adds a new symbol, CONFIG_MULTIUSER, that makes support for
non-root users, non-root groups, and capabilities optional.  It is enabled
under CONFIG_EXPERT menu.

When this symbol is not defined, UID and GID are zero in any possible case
and processes always have all capabilities.

The following syscalls are compiled out: setuid, setregid, setgid,
setreuid, setresuid, getresuid, setresgid, getresgid, setgroups,
getgroups, setfsuid, setfsgid, capget, capset.

Also, groups.c is compiled out completely.

In kernel/capability.c, capable function was moved in order to avoid
adding two ifdef blocks.

This change saves about 25 KB on a defconfig build.  The most minimal
kernels have total text sizes in the high hundreds of kB rather than
low MB.  (The 25k goes down a bit with allnoconfig, but not that much.

The kernel was booted in Qemu.  All the common functionalities work.
Adding users/groups is not possible, failing with -ENOSYS.

Bloat-o-meter output:
add/remove: 7/87 grow/shrink: 19/397 up/down: 1675/-26325 (-24650)

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NIulia Manda <iulia.manda21@gmail.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Tested-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the kernel is compiled with function tracer support the -pg compile option
is passed to gcc to generate extra code into the prologue of each function.

This patch replaces the "open-coded" -pg compile flag with a CC_FLAGS_FTRACE
makefile variable which architectures can override if a different option
should be used for code generation.
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Every kernel build that includes X.509 support prints out
a message like

 - Including cert signing_key.x509

This may be useful for some cases, but when doing automated
build tests, it just means noise.

To hide the message, this uses '$(kecho)' for printing the
message, which means we still see it when building with V=1,
but not at the normal level or when building with 'make -s'.
Signed-off-by: NArnd Bergmann <arnd@arnd.de>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

This commit introduces code for the live patching core.  It implements
an ftrace-based mechanism and kernel interface for doing live patching
of kernel and kernel module functions.

It represents the greatest common functionality set between kpatch and
kgraft and can accept patches built using either method.

This first version does not implement any consistency mechanism that
ensures that old and new code do not run together.  In practice, ~90% of
CVEs are safe to apply in this way, since they simply add a conditional
check.  However, any function change that can not execute safely with
the old version of the function can _not_ be safely applied in this
version.

[ jkosina@suse.cz: due to the number of contributions that got folded into
  this original patch from Seth Jennings, add SUSE's copyright as well, as
  discussed via e-mail ]
Signed-off-by: NSeth Jennings <sjenning@redhat.com>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: NMiroslav Benes <mbenes@suse.cz>
Reviewed-by: NPetr Mladek <pmladek@suse.cz>
Reviewed-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: NMiroslav Benes <mbenes@suse.cz>
Signed-off-by: NPetr Mladek <pmladek@suse.cz>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

All memory accounting and limiting has been switched over to the
lockless page counters.  Bye, res_counter!

[akpm@linux-foundation.org: update Documentation/cgroups/memory.txt]
[mhocko@suse.cz: ditch the last remainings of res_counter]
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NVladimir Davydov <vdavydov@parallels.com>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

introduce two configs:
- hidden CONFIG_BPF to select eBPF interpreter that classic socket filters
  depend on
- visible CONFIG_BPF_SYSCALL (default off) that tracing and sockets can use

that solves several problems:
- tracing and others that wish to use eBPF don't need to depend on NET.
  They can use BPF_SYSCALL to allow loading from userspace or select BPF
  to use it directly from kernel in NET-less configs.
- in 3.18 programs cannot be attached to events yet, so don't force it on
- when the rest of eBPF infra is there in 3.19+, it's still useful to
  switch it off to minimize kernel size

bloat-o-meter on x64 shows:
add/remove: 0/60 grow/shrink: 0/2 up/down: 0/-15601 (-15601)

tested with many different config combinations. Hopefully didn't miss anything.
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Acked-by: NDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch series does not do kernel signature verification yet.  I plan
to post another patch series for that.  Now distributions are already
signing PE/COFF bzImage with PKCS7 signature I plan to parse and verify
those signatures.

Primary goal of this patchset is to prepare groundwork so that kernel
image can be signed and signatures be verified during kexec load.  This
should help with two things.

- It should allow kexec/kdump on secureboot enabled machines.

- In general it can help even without secureboot. By being able to verify
  kernel image signature in kexec, it should help with avoiding module
  signing restrictions. Matthew Garret showed how to boot into a custom
  kernel, modify first kernel's memory and then jump back to old kernel and
  bypass any policy one wants to.

This patch (of 15):

Kexec wants to use bin2c and it wants to use it really early in the build
process. See arch/x86/purgatory/ code in later patches.

So move bin2c in scripts/basic so that it can be built very early and
be usable by arch/x86/purgatory/
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

BPF is used in several kernel components. This split creates logical boundary
between generic eBPF core and the rest

kernel/bpf/core.c: eBPF interpreter

net/core/filter.c: classic->eBPF converter, classic verifiers, socket filters

This patch only moves functions.
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>