The migitation control is simpler to implement in architecture code as it
avoids the extra function call to check the mode. Aside of that having an
explicit seccomp enabled mode in the architecture mitigations would require
even more workarounds.

Move it into architecture code and provide a weak function in the seccomp
code. Remove the 'which' argument as this allows the architecture to decide
which mitigations are relevant for seccomp.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

If a seccomp user is not interested in Speculative Store Bypass mitigation
by default, it can set the new SECCOMP_FILTER_FLAG_SPEC_ALLOW flag when
adding filters.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Use PR_SPEC_FORCE_DISABLE in seccomp() because seccomp does not allow to
widen restrictions.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

For certain use cases it is desired to enforce mitigations so they cannot
be undone afterwards. That's important for loader stubs which want to
prevent a child from disabling the mitigation again. Will also be used for
seccomp(). The extra state preserving of the prctl state for SSB is a
preparatory step for EBPF dymanic speculation control.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

There's no reason for these to be changed after boot.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

When speculation flaw mitigations are opt-in (via prctl), using seccomp
will automatically opt-in to these protections, since using seccomp
indicates at least some level of sandboxing is desired.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

As done with seccomp and no_new_privs, also show speculation flaw
mitigation state in /proc/$pid/status.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Adjust arch_prctl_get/set_spec_ctrl() to operate on tasks other than
current.

This is needed both for /proc/$pid/status queries and for seccomp (since
thread-syncing can trigger seccomp in non-current threads).
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Add prctl based control for Speculative Store Bypass mitigation and make it
the default mitigation for Intel and AMD.

Andi Kleen provided the following rationale (slightly redacted):

 There are multiple levels of impact of Speculative Store Bypass:

 1) JITed sandbox.
    It cannot invoke system calls, but can do PRIME+PROBE and may have call
    interfaces to other code

 2) Native code process.
    No protection inside the process at this level.

 3) Kernel.

 4) Between processes. 

 The prctl tries to protect against case (1) doing attacks.

 If the untrusted code can do random system calls then control is already
 lost in a much worse way. So there needs to be system call protection in
 some way (using a JIT not allowing them or seccomp). Or rather if the
 process can subvert its environment somehow to do the prctl it can already
 execute arbitrary code, which is much worse than SSB.

 To put it differently, the point of the prctl is to not allow JITed code
 to read data it shouldn't read from its JITed sandbox. If it already has
 escaped its sandbox then it can already read everything it wants in its
 address space, and do much worse.

 The ability to control Speculative Store Bypass allows to enable the
 protection selectively without affecting overall system performance.

Based on an initial patch from Tim Chen. Completely rewritten.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The Speculative Store Bypass vulnerability can be mitigated with the
Reduced Data Speculation (RDS) feature. To allow finer grained control of
this eventually expensive mitigation a per task mitigation control is
required.

Add a new TIF_RDS flag and put it into the group of TIF flags which are
evaluated for mismatch in switch_to(). If these bits differ in the previous
and the next task, then the slow path function __switch_to_xtra() is
invoked. Implement the TIF_RDS dependent mitigation control in the slow
path.

If the prctl for controlling Speculative Store Bypass is disabled or no
task uses the prctl then there is no overhead in the switch_to() fast
path.

Update the KVM related speculation control functions to take TID_RDS into
account as well.

Based on a patch from Tim Chen. Completely rewritten.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Add two new prctls to control aspects of speculation related vulnerabilites
and their mitigations to provide finer grained control over performance
impacting mitigations.

PR_GET_SPECULATION_CTRL returns the state of the speculation misfeature
which is selected with arg2 of prctl(2). The return value uses bit 0-2 with
the following meaning:

Bit  Define           Description
0    PR_SPEC_PRCTL    Mitigation can be controlled per task by
                      PR_SET_SPECULATION_CTRL
1    PR_SPEC_ENABLE   The speculation feature is enabled, mitigation is
                      disabled
2    PR_SPEC_DISABLE  The speculation feature is disabled, mitigation is
                      enabled

If all bits are 0 the CPU is not affected by the speculation misfeature.

If PR_SPEC_PRCTL is set, then the per task control of the mitigation is
available. If not set, prctl(PR_SET_SPECULATION_CTRL) for the speculation
misfeature will fail.

PR_SET_SPECULATION_CTRL allows to control the speculation misfeature, which
is selected by arg2 of prctl(2) per task. arg3 is used to hand in the
control value, i.e. either PR_SPEC_ENABLE or PR_SPEC_DISABLE.

The common return values are:

EINVAL  prctl is not implemented by the architecture or the unused prctl()
        arguments are not 0
ENODEV  arg2 is selecting a not supported speculation misfeature

PR_SET_SPECULATION_CTRL has these additional return values:

ERANGE  arg3 is incorrect, i.e. it's not either PR_SPEC_ENABLE or PR_SPEC_DISABLE
ENXIO   prctl control of the selected speculation misfeature is disabled

The first supported controlable speculation misfeature is
PR_SPEC_STORE_BYPASS. Add the define so this can be shared between
architectures.

Based on an initial patch from Tim Chen and mostly rewritten.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Having everything in nospec-branch.h creates a hell of dependencies when
adding the prctl based switching mechanism. Move everything which is not
required in nospec-branch.h to spec-ctrl.h and fix up the includes in the
relevant files.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

Expose the CPUID.7.EDX[31] bit to the guest, and also guard against various
combinations of SPEC_CTRL MSR values.

The handling of the MSR (to take into account the host value of SPEC_CTRL
Bit(2)) is taken care of in patch:

  KVM/SVM/VMX/x86/spectre_v2: Support the combination of guest and host IBRS
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

AMD does not need the Speculative Store Bypass mitigation to be enabled.

The parameters for this are already available and can be done via MSR
C001_1020. Each family uses a different bit in that MSR for this.

[ tglx: Expose the bit mask via a variable and move the actual MSR fiddling
  	into the bugs code as that's the right thing to do and also required
	to prepare for dynamic enable/disable ]
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

Intel and AMD SPEC_CTRL (0x48) MSR semantics may differ in the
future (or in fact use different MSRs for the same functionality).

As such a run-time mechanism is required to whitelist the appropriate MSR
values.

[ tglx: Made the variable __ro_after_init ]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

Intel CPUs expose methods to:

 - Detect whether RDS capability is available via CPUID.7.0.EDX[31],

 - The SPEC_CTRL MSR(0x48), bit 2 set to enable RDS.

 - MSR_IA32_ARCH_CAPABILITIES, Bit(4) no need to enable RRS.

With that in mind if spec_store_bypass_disable=[auto,on] is selected set at
boot-time the SPEC_CTRL MSR to enable RDS if the platform requires it.

Note that this does not fix the KVM case where the SPEC_CTRL is exposed to
guests which can muck with it, see patch titled :
 KVM/SVM/VMX/x86/spectre_v2: Support the combination of guest and host IBRS.

And for the firmware (IBRS to be set), see patch titled:
 x86/spectre_v2: Read SPEC_CTRL MSR during boot and re-use reserved bits

[ tglx: Distangled it from the intel implementation and kept the call order ]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

Contemporary high performance processors use a common industry-wide
optimization known as "Speculative Store Bypass" in which loads from
addresses to which a recent store has occurred may (speculatively) see an
older value. Intel refers to this feature as "Memory Disambiguation" which
is part of their "Smart Memory Access" capability.

Memory Disambiguation can expose a cache side-channel attack against such
speculatively read values. An attacker can create exploit code that allows
them to read memory outside of a sandbox environment (for example,
malicious JavaScript in a web page), or to perform more complex attacks
against code running within the same privilege level, e.g. via the stack.

As a first step to mitigate against such attacks, provide two boot command
line control knobs:

 nospec_store_bypass_disable
 spec_store_bypass_disable=[off,auto,on]

By default affected x86 processors will power on with Speculative
Store Bypass enabled. Hence the provided kernel parameters are written
from the point of view of whether to enable a mitigation or not.
The parameters are as follows:

 - auto - Kernel detects whether your CPU model contains an implementation
	  of Speculative Store Bypass and picks the most appropriate
	  mitigation.

 - on   - disable Speculative Store Bypass
 - off  - enable Speculative Store Bypass

[ tglx: Reordered the checks so that the whole evaluation is not done
  	when the CPU does not support RDS ]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

Add the CPU feature bit CPUID.7.0.EDX[31] which indicates whether the CPU
supports Reduced Data Speculation.

[ tglx: Split it out from a later patch ]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

Add the sysfs file for the new vulerability. It does not do much except
show the words 'Vulnerable' for recent x86 cores.

Intel cores prior to family 6 are known not to be vulnerable, and so are
some Atoms and some Xeon Phi.

It assumes that older Cyrix, Centaur, etc. cores are immune.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

A guest may modify the SPEC_CTRL MSR from the value used by the
kernel. Since the kernel doesn't use IBRS, this means a value of zero is
what is needed in the host.

But the 336996-Speculative-Execution-Side-Channel-Mitigations.pdf refers to
the other bits as reserved so the kernel should respect the boot time
SPEC_CTRL value and use that.

This allows to deal with future extensions to the SPEC_CTRL interface if
any at all.

Note: This uses wrmsrl() instead of native_wrmsl(). I does not make any
difference as paravirt will over-write the callq *0xfff.. with the wrmsrl
assembler code.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

The 336996-Speculative-Execution-Side-Channel-Mitigations.pdf refers to all
the other bits as reserved. The Intel SDM glossary defines reserved as
implementation specific - aka unknown.

As such at bootup this must be taken it into account and proper masking for
the bits in use applied.

A copy of this document is available at
https://bugzilla.kernel.org/show_bug.cgi?id=199511

[ tglx: Made x86_spec_ctrl_base __ro_after_init ]
Suggested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

Those SysFS functions have a similar preamble, as such make common
code to handle them.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

Combine the various logic which goes through all those
x86_cpu_id matching structures in one function.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

The macro is not type safe and I did look for why that "g" constraint for
the asm doesn't work: it's because the asm is more fundamentally wrong.

It does

        movl %[val], %%eax

but "val" isn't a 32-bit value, so then gcc will pass it in a register, 
and generate code like

        movl %rsi, %eax

and gas will complain about a nonsensical 'mov' instruction (it's moving a 
64-bit register to a 32-bit one).

Passing it through memory will just hide the real bug - gcc still thinks 
the memory location is 64-bit, but the "movl" will only load the first 32 
bits and it all happens to work because x86 is little-endian.

Convert it to a type safe inline function with a little trick which hands
the feature into the ALTERNATIVE macro.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

The recent commt which addresses the x86_phys_bits corruption with
encrypted memory on CPUID reload after a microcode update lost the reload
of CPUID_8000_0008_EBX as well.

As a consequence IBRS and IBRS_FW are not longer detected

Restore the behaviour by bringing the reload of CPUID_8000_0008_EBX
back. This restore has a twist due to the convoluted way the cpuid analysis
works:

CPUID_8000_0008_EBX is used by AMD to enumerate IBRB, IBRS, STIBP. On Intel
EBX is not used. But the speculation control code sets the AMD bits when
running on Intel depending on the Intel specific speculation control
bits. This was done to use the same bits for alternatives.

The change which moved the 8000_0008 evaluation out of get_cpu_cap() broke
this nasty scheme due to ordering. So that on Intel the store to
CPUID_8000_0008_EBX clears the IBRB, IBRS, STIBP bits which had been set
before by software.

So the actual CPUID_8000_0008_EBX needs to go back to the place where it
was and the phys/virt address space calculation cannot touch it.

In hindsight this should have used completely synthetic bits for IBRB,
IBRS, STIBP instead of reusing the AMD bits, but that's for 4.18.

/me needs to find time to cleanup that steaming pile of ...

Fixes: d94a155c ("x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption")
Reported-by: Jörg Otte <jrg.otte@gmail.com>
Reported-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jörg Otte <jrg.otte@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: kirill.shutemov@linux.intel.com
Cc: Borislav Petkov <bp@alien8.de
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1805021043510.1668@nanos.tec.linutronix.de

Pull x86 fixes from Thomas Gleixner:
 "Another set of x86 related updates:

   - Fix the long broken x32 version of the IPC user space headers which
     was noticed by Arnd Bergman in course of his ongoing y2038 work.
     GLIBC seems to have non broken private copies of these headers so
     this went unnoticed.

   - Two microcode fixlets which address some more fallout from the
     recent modifications in that area:

      - Unconditionally save the microcode patch, which was only saved
        when CPU_HOTPLUG was enabled causing failures in the late
        loading mechanism

      - Make the later loader synchronization finally work under all
        circumstances. It was exiting early and causing timeout failures
        due to a missing synchronization point.

   - Do not use mwait_play_dead() on AMD systems to prevent excessive
     power consumption as the CPU cannot go into deep power states from
     there.

   - Address an annoying sparse warning due to lost type qualifiers of
     the vmemmap and vmalloc base address constants.

   - Prevent reserving crash kernel region on Xen PV as this leads to
     the wrong perception that crash kernels actually work there which
     is not the case. Xen PV has its own crash mechanism handled by the
     hypervisor.

   - Add missing TLB cpuid values to the table to make the printout on
     certain machines correct.

   - Enumerate the new CLDEMOTE instruction

   - Fix an incorrect SPDX identifier

   - Remove stale macros"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ipc: Fix x32 version of shmid64_ds and msqid64_ds
  x86/setup: Do not reserve a crash kernel region if booted on Xen PV
  x86/cpu/intel: Add missing TLB cpuid values
  x86/smpboot: Don't use mwait_play_dead() on AMD systems
  x86/mm: Make vmemmap and vmalloc base address constants unsigned long
  x86/vector: Remove the unused macro FPU_IRQ
  x86/vector: Remove the macro VECTOR_OFFSET_START
  x86/cpufeatures: Enumerate cldemote instruction
  x86/microcode: Do not exit early from __reload_late()
  x86/microcode/intel: Save microcode patch unconditionally
  x86/jailhouse: Fix incorrect SPDX identifier

Pull x86 pti fixes from Thomas Gleixner:
 "A set of updates for the x86/pti related code:

   - Preserve r8-r11 in int $0x80. r8-r11 need to be preserved, but the
     int$80 entry code removed that quite some time ago. Make it correct
     again.

   - A set of fixes for the Global Bit work which went into 4.17 and
     caused a bunch of interesting regressions:

      - Triggering a BUG in the page attribute code due to a missing
        check for early boot stage

      - Warnings in the page attribute code about holes in the kernel
        text mapping which are caused by the freeing of the init code.
        Handle such holes gracefully.

      - Reduce the amount of kernel memory which is set global to the
        actual text and do not incidentally overlap with data.

      - Disable the global bit when RANDSTRUCT is enabled as it
        partially defeats the hardening.

      - Make the page protection setup correct for vma->page_prot
        population again. The adjustment of the protections fell through
        the crack during the Global bit rework and triggers warnings on
        machines which do not support certain features, e.g. NX"

* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/entry/64/compat: Preserve r8-r11 in int $0x80
  x86/pti: Filter at vma->vm_page_prot population
  x86/pti: Disallow global kernel text with RANDSTRUCT
  x86/pti: Reduce amount of kernel text allowed to be Global
  x86/pti: Fix boot warning from Global-bit setting
  x86/pti: Fix boot problems from Global-bit setting

Pull timer fixes from Thomas Gleixner:
 "Two fixes from the timer departement:

   - Fix a long standing issue in the NOHZ tick code which causes RB
     tree corruption, delayed timers and other malfunctions. The cause
     for this is code which modifies the expiry time of an enqueued
     hrtimer.

   - Revert the CLOCK_MONOTONIC/CLOCK_BOOTTIME unification due to
     regression reports. Seems userspace _is_ relying on the documented
     behaviour despite our hope that it wont"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME
  tick/sched: Do not mess with an enqueued hrtimer

Pull perf fixes from Thomas Gleixner:
 "The perf update contains the following bits:

  x86:
   - Prevent setting freeze_on_smi on PerfMon V1 CPUs to avoid #GP

  perf stat:
   - Keep the '/' event modifier separator in fallback, for example when
     fallbacking from 'cpu/cpu-cycles/' to user level only, where it
     should become 'cpu/cpu-cycles/u' and not 'cpu/cpu-cycles/:u' (Jiri
     Olsa)

   - Fix PMU events parsing rule, improving error reporting for invalid
     events (Jiri Olsa)

   - Disable write_backward and other event attributes for !group events
     in a group, fixing, for instance this group: '{cycles,msr/aperf/}:S'
     that has leader sampling (:S) and where just the 'cycles', the
     leader event, should have the write_backward attribute set, in this
     case it all fails because the PMU where 'msr/aperf/' lives doesn't
     accepts write_backward style sampling (Jiri Olsa)

   - Only fall back group read for leader (Kan Liang)

   - Fix core PMU alias list for x86 platform (Kan Liang)

   - Print out hint for mixed PMU group error (Kan Liang)

   - Fix duplicate PMU name for interval print (Kan Liang)

  Core:
   - Set main kernel end address properly when reading kernel and module
     maps (Namhyung Kim)

  perf mem:
   - Fix incorrect entries and add missing man options (Sangwon Hong)

  s/390:
   - Remove s390 specific strcmp_cpuid_cmp function (Thomas Richter)

   - Adapt 'perf test' case record+probe_libc_inet_pton.sh for s390

   - Fix s390 undefined record__auxtrace_init() return value in 'perf
     record' (Thomas Richter)"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Don't enable freeze-on-smi for PerfMon V1
  perf stat: Fix duplicate PMU name for interval print
  perf evsel: Only fall back group read for leader
  perf stat: Print out hint for mixed PMU group error
  perf pmu: Fix core PMU alias list for X86 platform
  perf record: Fix s390 undefined record__auxtrace_init() return value
  perf mem: Document incorrect and missing options
  perf evsel: Disable write_backward for leader sampling group events
  perf pmu: Fix pmu events parsing rule
  perf stat: Keep the / modifier separator in fallback
  perf test: Adapt test case record+probe_libc_inet_pton.sh for s390
  perf list: Remove s390 specific strcmp_cpuid_cmp function
  perf machine: Set main kernel end address properly

Pull ext4 fixes from Ted Ts'o:
 "Fix misc bugs and a regression for ext4"

* tag 'for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: add MODULE_SOFTDEP to ensure crc32c is included in the initramfs
  ext4: fix bitmap position validation
  ext4: set h_journal if there is a failure starting a reserved handle
  ext4: prevent right-shifting extents beyond EXT_MAX_BLOCKS

The comment claims that this helper will try not to loose bits, but for
64bit long it looses the high bits before hashing 64bit long into 32bit
int.  Use the helper hash_long() to do the right thing for 64bit long.
For 32bit long, there is no change.

All the callers of end_name_hash() either assign the result to
qstr->hash, which is u32 or return the result as an int value (e.g.
full_name_hash()).  Change the helper return type to int to conform to
its users.

[ It took me a while to apply this, because my initial reaction to it
  was - incorrectly - that it could make for slower code.

  After having looked more at it, I take back all my complaints about
  the patch, Amir was right and I was mis-reading things or just being
  stupid.

  I also don't worry too much about the possible performance impact of
  this on 64-bit, since most architectures that actually care about
  performance end up not using this very much (the dcache code is the
  most performance-critical, but the word-at-a-time case uses its own
  hashing anyway).

  So this ends up being mostly used for filesystems that do their own
  degraded hashing (usually because they want a case-insensitive
  comparison function).

  A _tiny_ worry remains, in that not everybody uses DCACHE_WORD_ACCESS,
  and then this potentially makes things more expensive on 64-bit
  architectures with slow or lacking multipliers even for the normal
  case.

  That said, realistically the only such architecture I can think of is
  PA-RISC. Nobody really cares about performance on that, it's more of a
  "look ma, I've got warts^W an odd machine" platform.

  So the patch is fine, and all my initial worries were just misplaced
  from not looking at this properly.   - Linus ]
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The AFFS filesystem is still in use by m68k community (Link #2), but as
there was no code activity and no maintainer, the filesystem appeared on
the list of candidates for staging/removal (Link #1).

I volunteer to act as a maintainer of AFFS to collect any fixes that
might show up and to guard fs/affs/ against another spring cleaning.

Link: https://lkml.kernel.org/r/20180425154602.GA8546@bombadil.infradead.org
Link: https://lkml.kernel.org/r/1613268.lKBQxPXt8J@merkaba
CC: Martin Steigerwald <martin@lichtvoll.de>
CC: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull i2c fixes from Wolfram Sang:

 - two driver fixes

 - better parameter check for the core

 - Documentation updates

 - part of a tree-wide HAS_DMA cleanup

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: sprd: Fix the i2c count issue
  i2c: sprd: Prevent i2c accesses after suspend is called
  i2c: dev: prevent ZERO_SIZE_PTR deref in i2cdev_ioctl_rdwr()
  Documentation/i2c: adopt kernel commenting style in examples
  Documentation/i2c: sync docs with current state of i2c-tools
  Documentation/i2c: whitespace cleanup
  i2c: Remove depends on HAS_DMA in case of platform dependency

Pull crypto fixes from Herbert Xu:

 - crypto API regression that may cause sporadic alloc failures

 - double-free bug in drbg

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: drbg - set freed buffers to NULL
  crypto: api - fix finding algorithm currently being tested

Pull cifs fixes from Steve French:
 "A few security related fixes for SMB3, most importantly for SMB3.11
  encryption"

* tag '4.17-rc2-smb3' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: smbd: Avoid allocating iov on the stack
  cifs: smbd: Don't use RDMA read/write when signing is used
  SMB311: Fix reconnect
  SMB3: Fix 3.11 encryption to Windows and handle encrypted smb3 tcon
  CIFS: set *resp_buf_type to NO_BUFFER on error

Pull powerpc fixes from Michael Ellerman:
 "A bunch of fixes, mostly for existing code and going to stable.

  Our memory hot-unplug path wasn't flushing the cache before removing
  memory. That is a problem now that we are doing memory hotplug on bare
  metal.

  Three fixes for the NPU code that supports devices connected via
  NVLink (ie. GPUs). The main one tweaks the TLB flush algorithm to
  avoid soft lockups for large flushes.

  A fix for our memory error handling where we would loop infinitely,
  returning back to the bad access and hard lockup the CPU.

  Fixes for the OPAL RTC driver, which wasn't handling some error cases
  correctly.

  A fix for a hardlockup in the powernv cpufreq driver.

  And finally two fixes to our smp_send_stop(), required due to a recent
  change to use it on shutdown.

  Thanks to: Alistair Popple, Balbir Singh, Laurentiu Tudor, Mahesh
  Salgaonkar, Mark Hairgrove, Nicholas Piggin, Rashmica Gupta, Shilpasri
  G Bhat"

* tag 'powerpc-4.17-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/kvm/booke: Fix altivec related build break
  powerpc: Fix deadlock with multiple calls to smp_send_stop
  cpufreq: powernv: Fix hardlockup due to synchronous smp_call in timer interrupt
  powerpc: Fix smp_send_stop NMI IPI handling
  rtc: opal: Fix OPAL RTC driver OPAL_BUSY loops
  powerpc/mce: Fix a bug where mce loops on memory UE.
  powerpc/powernv/npu: Do a PID GPU TLB flush when invalidating a large address range
  powerpc/powernv/npu: Prevent overwriting of pnv_npu2_init_contex() callback parameters
  powerpc/powernv/npu: Add lock to prevent race in concurrent context init/destroy
  powerpc/powernv/memtrace: Let the arch hotunplug code flush cache
  powerpc/mm: Flush cache on memory hot(un)plug

Pull KVM fixes from Radim Krčmář:
 "ARM:
   - PSCI selection API, a leftover from 4.16 (for stable)
   - Kick vcpu on active interrupt affinity change
   - Plug a VMID allocation race on oversubscribed systems
   - Silence debug messages
   - Update Christoffer's email address (linaro -> arm)

  x86:
   - Expose userspace-relevant bits of a newly added feature
   - Fix TLB flushing on VMX with VPID, but without EPT"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  x86/headers/UAPI: Move DISABLE_EXITS KVM capability bits to the UAPI
  kvm: apic: Flush TLB after APIC mode/address change if VPIDs are in use
  arm/arm64: KVM: Add PSCI version selection API
  KVM: arm/arm64: vgic: Kick new VCPU on interrupt migration
  arm64: KVM: Demote SVE and LORegion warnings to debug only
  MAINTAINERS: Update e-mail address for Christoffer Dall
  KVM: arm/arm64: Close VMID generation race

Pull arm64 fixes from Will Deacon:
 "Nothing too bad, but the spectre updates to smatch identified a few
  places that may need sanitising so we've got those covered.

  Details:

   - Close some potential spectre-v1 vulnerabilities found by smatch

   - Add missing list sentinel for CPUs that don't require KPTI

   - Removal of unused 'addr' parameter for I/D cache coherency

   - Removal of redundant set_fs(KERNEL_DS) calls in ptrace

   - Fix single-stepping state machine handling in response to kernel
     traps

   - Clang support for 128-bit integers

   - Avoid instrumenting our out-of-line atomics in preparation for
     enabling LSE atomics by default in 4.18"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: avoid instrumenting atomic_ll_sc.o
  KVM: arm/arm64: vgic: fix possible spectre-v1 in vgic_mmio_read_apr()
  KVM: arm/arm64: vgic: fix possible spectre-v1 in vgic_get_irq()
  arm64: fix possible spectre-v1 in ptrace_hbp_get_event()
  arm64: support __int128 with clang
  arm64: only advance singlestep for user instruction traps
  arm64/kernel: rename module_emit_adrp_veneer->module_emit_veneer_for_adrp
  arm64: ptrace: remove addr_limit manipulation
  arm64: mm: drop addr parameter from sync icache and dcache
  arm64: add sentinel to kpti_safe_list

Pull modules fix from Jessica Yu:
 "Fix display of module section addresses in sysfs, which were getting
  hashed with %pK and breaking tools like perf"

* tag 'modules-for-v4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  module: Fix display of wrong module .text address