A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_spinlock_t data type, which allows to associate a
spinlock with the sequence counter. This enables lockdep to verify that
the spinlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-23-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_spinlock_t data type, which allows to associate a
spinlock with the sequence counter. This enables lockdep to verify that
the spinlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-22-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_spinlock_t data type, which allows to associate a
spinlock with the sequence counter. This enables lockdep to verify that
the spinlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Link: https://lkml.kernel.org/r/20200720155530.1173732-21-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_spinlock_t data type, which allows to associate a
spinlock with the sequence counter. This enables lockdep to verify that
the spinlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-20-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_spinlock_t data type, which allows to associate a
spinlock with the sequence counter. This enables lockdep to verify that
the spinlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-19-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_raw_spinlock_t data type, which allows to associate
a raw spinlock with the sequence counter. This enables lockdep to verify
that the raw spinlock used for writer serialization is held when the
write side critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-18-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. If the serialization primitive is
not disabling preemption implicitly, preemption has to be explicitly
disabled before entering the sequence counter write side critical
section.

A plain seqcount_t does not contain the information of which lock must
be held when entering a write side critical section.

Use the new seqcount_spinlock_t and seqcount_mutex_t data types instead,
which allow to associate a lock with the sequence counter. This enables
lockdep to verify that the lock used for writer serialization is held
when the write side critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-17-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_rwlock_t data type, which allows to associate a
rwlock with the sequence counter. This enables lockdep to verify that
the rwlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-16-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_spinlock_t data type, which allows to associate a
spinlock with the sequence counter. This enables lockdep to verify that
the spinlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-15-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_spinlock_t data type, which allows to associate a
spinlock with the sequence counter. This enables lockdep to verify that
the spinlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-14-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. If the serialization primitive is
not disabling preemption implicitly, preemption has to be explicitly
disabled before entering the sequence counter write side critical
section.

The dma-buf reservation subsystem uses plain sequence counters to manage
updates to reservations. Writer serialization is accomplished through a
wound/wait mutex.

Acquiring a wound/wait mutex does not disable preemption, so this needs
to be done manually before and after the write side critical section.

Use the newly-added seqcount_ww_mutex_t instead:

  - It associates the ww_mutex with the sequence count, which enables
    lockdep to validate that the write side critical section is properly
    serialized.

  - It removes the need to explicitly add preempt_disable/enable()
    around the write side critical section because the write_begin/end()
    functions for this new data type automatically do this.

If lockdep is disabled this ww_mutex lock association is compiled out
and has neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lkml.kernel.org/r/20200720155530.1173732-13-a.darwish@linutronix.de

Commit 3c3b177a ("reservation: add support for read-only access
using rcu") introduced a sequence counter to manage updates to
reservations. Back then, the reservation object initializer
reservation_object_init() was always inlined.

Having the sequence counter initialization inlined meant that each of
the call sites would have a different lockdep class key, which would've
broken lockdep's deadlock detection. The aforementioned commit thus
introduced, and exported, a custom seqcount lockdep class key and name.

The commit 8735f168 ("dma-buf: cleanup reservation_object_init...")
transformed the reservation object initializer to a normal non-inlined C
function. seqcount_init(), which automatically defines the seqcount
lockdep class key and must be called non-inlined, can now be safely used.

Remove the seqcount custom lockdep class key, name, and export. Use
seqcount_init() inside the dma reservation object initializer.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lkml.kernel.org/r/20200720155530.1173732-12-a.darwish@linutronix.de

Parent commit, "seqlock: Extend seqcount API with associated locks",
introduced a big number of multi-line macros that are newline-escaped
at 72 columns.

For overall cohesion, align the earlier-existing macros similarly.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-11-a.darwish@linutronix.de

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. If the serialization primitive is
not disabling preemption implicitly, preemption has to be explicitly
disabled before entering the write side critical section.

There is no built-in debugging mechanism to verify that the lock used
for writer serialization is held and preemption is disabled. Some usage
sites like dma-buf have explicit lockdep checks for the writer-side
lock, but this covers only a small portion of the sequence counter usage
in the kernel.

Add new sequence counter types which allows to associate a lock to the
sequence counter at initialization time. The seqcount API functions are
extended to provide appropriate lockdep assertions depending on the
seqcount/lock type.

For sequence counters with associated locks that do not implicitly
disable preemption, preemption protection is enforced in the sequence
counter write side functions. This removes the need to explicitly add
preempt_disable/enable() around the write side critical sections: the
write_begin/end() functions for these new sequence counter types
automatically do this.

Introduce the following seqcount types with associated locks:

     seqcount_spinlock_t
     seqcount_raw_spinlock_t
     seqcount_rwlock_t
     seqcount_mutex_t
     seqcount_ww_mutex_t

Extend the seqcount read and write functions to branch out to the
specific seqcount_LOCKTYPE_t implementation at compile-time. This avoids
kernel API explosion per each new seqcount_LOCKTYPE_t added. Add such
compile-time type detection logic into a new, internal, seqlock header.

Document the proper seqcount_LOCKTYPE_t usage, and rationale, at
Documentation/locking/seqlock.rst.

If lockdep is disabled, this lock association is compiled out and has
neither storage size nor runtime overhead.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-10-a.darwish@linutronix.de

Preemption must be disabled before entering a sequence count write side
critical section.  Failing to do so, the seqcount read side can preempt
the write side section and spin for the entire scheduler tick.  If that
reader belongs to a real-time scheduling class, it can spin forever and
the kernel will livelock.

Assert through lockdep that preemption is disabled for seqcount writers.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-9-a.darwish@linutronix.de

Asserting that preemption is enabled or disabled is a critical sanity
check.  Developers are usually reluctant to add such a check in a
fastpath as reading the preemption count can be costly.

Extend the lockdep API with macros asserting that preemption is disabled
or enabled. If lockdep is disabled, or if the underlying architecture
does not support kernel preemption, this assert has no runtime overhead.

References: f54bb2ec ("locking/lockdep: Add IRQs disabled/enabled assertion APIs: ...")
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-8-a.darwish@linutronix.de

raw_seqcount_begin() has the same code as raw_read_seqcount(), with the
exception of masking the sequence counter's LSB before returning it to
the caller.

Note, raw_seqcount_begin() masks the counter's LSB before returning it
to the caller so that read_seqcount_retry() can fail if the counter is
odd -- without the overhead of an extra branching instruction.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-7-a.darwish@linutronix.de

seqlock.h is now included by kernel's RST documentation, but a small
number of the the exported seqlock.h functions are kernel-doc annotated.

Add kernel-doc for all seqlock.h exported APIs.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-6-a.darwish@linutronix.de

The seqlock.h seqcount_t and seqlock_t API definitions are presented in
the chronological order of their development rather than the order that
makes most sense to readers. This makes it hard to follow and understand
the header file code.

Group and reorder all of the exported seqlock.h functions according to
their function.

First, group together the seqcount_t standard read path functions:

    - __read_seqcount_begin()
    - raw_read_seqcount_begin()
    - read_seqcount_begin()

since each function is implemented exactly in terms of the one above
it. Then, group the special-case seqcount_t readers on their own as:

    - raw_read_seqcount()
    - raw_seqcount_begin()

since the only difference between the two functions is that the second
one masks the sequence counter LSB while the first one does not. Note
that raw_seqcount_begin() can actually be implemented in terms of
raw_read_seqcount(), which will be done in a follow-up commit.

Then, group the seqcount_t write path functions, instead of injecting
unrelated seqcount_t latch functions between them, and order them as:

    - raw_write_seqcount_begin()
    - raw_write_seqcount_end()
    - write_seqcount_begin_nested()
    - write_seqcount_begin()
    - write_seqcount_end()
    - raw_write_seqcount_barrier()
    - write_seqcount_invalidate()

which is the expected natural order. This also isolates the seqcount_t
latch functions into their own area, at the end of the sequence counters
section, and before jumping to the next one: sequential locks
(seqlock_t).

Do a similar grouping and reordering for seqlock_t "locking" readers vs.
the "conditionally locking or lockless" ones.

No implementation code was changed in any of the reordering above.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-5-a.darwish@linutronix.de

The seqcount_t latch reader example at the raw_write_seqcount_latch()
kernel-doc comment ends the latch read section with a manual smp memory
barrier and sequence counter comparison.

This is technically correct, but it is suboptimal: read_seqcount_retry()
already contains the same logic of an smp memory barrier and sequence
counter comparison.

End the latch read critical section example with read_seqcount_retry().
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-4-a.darwish@linutronix.de

Align the code samples and note sections inside kernel-doc comments with
tabs. This way they can be properly parsed and rendered by Sphinx. It
also makes the code samples easier to read from text editors.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-3-a.darwish@linutronix.de

Proper documentation for the design and usage of sequence counters and
sequential locks does not exist. Complete the seqlock.h documentation as
follows:

  - Divide all documentation on a seqcount_t vs. seqlock_t basis. The
    description for both mechanisms was intermingled, which is incorrect
    since the usage constrains for each type are vastly different.

  - Add an introductory paragraph describing the internal design of, and
    rationale for, sequence counters.

  - Document seqcount_t writer non-preemptibility requirement, which was
    not previously documented anywhere, and provide a clear rationale.

  - Provide template code for seqcount_t and seqlock_t initialization
    and reader/writer critical sections.

  - Recommend using seqlock_t by default. It implicitly handles the
    serialization and non-preemptibility requirements of writers.

At seqlock.h:

  - Remove references to brlocks as they've long been removed from the
    kernel.

  - Remove references to gcc-3.x since the kernel's minimum supported
    gcc version is 4.9.

References: 0f6ed63b ("no need to keep brlock macros anymore...")
References: 6ec4476a ("Raise gcc version requirement to 4.9")
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-2-a.darwish@linutronix.de

This patch breaks a header loop involving qspinlock_types.h.
The issue is that qspinlock_types.h includes atomic.h, which then
eventually includes kernel.h which could lead back to the original
file via spinlock_types.h.

As ATOMIC_INIT is now defined by linux/types.h, there is no longer
any need to include atomic.h from qspinlock_types.h.  This also
allows the CONFIG_PARAVIRT hack to be removed since it was trying
to prevent exactly this loop.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/20200729123316.GC7047@gondor.apana.org.au

This patch moves ATOMIC_INIT from asm/atomic.h into linux/types.h.
This allows users of atomic_t to use ATOMIC_INIT without having to
include atomic.h as that way may lead to header loops.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/20200729123105.GB7047@gondor.apana.org.au

Currently lockdep_types.h includes list.h without actually using any
of its macros or functions.  All it needs are the type definitions
which were moved into types.h long ago.  This potentially causes
inclusion loops because both are included by many core header
files.

This patch moves the list.h inclusion into lockdep.h.  Note that
we could probably remove it completely but that could potentially
result in compile failures should any end users not include list.h
directly and also be unlucky enough to not get list.h via some other
header file.
Reported-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://lkml.kernel.org/r/20200716063649.GA23065@gondor.apana.org.au

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge tag 'perf-tools-fixes-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into master

Pull perf tooling fixes from Arnaldo Carvalho de Melo:

 - Update hashmap.h from libbpf and kvm.h from x86's kernel UAPI.

 - Set opt->set in libsubcmd's OPT_CALLBACK_SET(). This fixes
   'perf record --switch-output-event event-name' usage"

* tag 'perf-tools-fixes-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
  tools arch kvm: Sync kvm headers with the kernel sources
  perf tools: Sync hashmap.h with libbpf's
  libsubcmd: Fix OPT_CALLBACK_SET()

Merge tag 'x86-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master

Pull x86 fixes from Thomas Gleixner:
 "A pile of fixes for x86:

   - Fix the I/O bitmap invalidation on XEN PV, which was overlooked in
     the recent ioperm/iopl rework. This caused the TSS and XEN's I/O
     bitmap to get out of sync.

   - Use the proper vectors for HYPERV.

   - Make disabling of stack protector for the entry code work with GCC
     builds which enable stack protector by default. Removing the option
     is not sufficient, it needs an explicit -fno-stack-protector to
     shut it off.

   - Mark check_user_regs() noinstr as it is called from noinstr code.
     The missing annotation causes it to be placed in the text section
     which makes it instrumentable.

   - Add the missing interrupt disable in exc_alignment_check()

   - Fixup a XEN_PV build dependency in the 32bit entry code

   - A few fixes to make the Clang integrated assembler happy

   - Move EFI stub build to the right place for out of tree builds

   - Make prepare_exit_to_usermode() static. It's not longer called from
     ASM code"

* tag 'x86-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Don't add the EFI stub to targets
  x86/entry: Actually disable stack protector
  x86/ioperm: Fix io bitmap invalidation on Xen PV
  x86: math-emu: Fix up 'cmp' insn for clang ias
  x86/entry: Fix vectors to IDTENTRY_SYSVEC for CONFIG_HYPERV
  x86/entry: Add compatibility with IAS
  x86/entry/common: Make prepare_exit_to_usermode() static
  x86/entry: Mark check_user_regs() noinstr
  x86/traps: Disable interrupts in exc_aligment_check()
  x86/entry/32: Fix XEN_PV build dependency

Merge tag 'timers-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master

Pull timer fixes from Thomas Gleixner:
 "Two fixes for the timer wheel:

   - A timer which is already expired at enqueue time can set the
     base->next_expiry value backwards. As a consequence base->clk can
     be set back as well. This can lead to timers expiring early. Add a
     sanity check to prevent this.

   - When a timer is queued with an expiry time beyond the wheel
     capacity then it should be queued in the bucket of the last wheel
     level which is expiring last.

     The code adjusted the expiry time to the maximum wheel capacity,
     which is only correct when the wheel clock is 0. Aside of that the
     check whether the delta is larger than wheel capacity does not
     check the delta, it checks the expiry value itself. As a result
     timers can expire at random.

     Fix this by checking the right variable and adjust expiry time so
     it becomes base->clock plus capacity which places it into the
     outmost bucket in the last wheel level"

* tag 'timers-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timer: Fix wheel index calculation on last level
  timer: Prevent base->clk from moving backward

Merge tag 'sched-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master

Pull scheduler fixes from Thomas Gleixner:
 "A set of scheduler fixes:

   - Plug a load average accounting race which was introduced with a
     recent optimization casing load average to show bogus numbers.

   - Fix the rseq CPU id initialization for new tasks. sched_fork() does
     not update the rseq CPU id so the id is the stale id of the parent
     task, which can cause user space data corruption.

   - Handle a 0 return value of task_h_load() correctly in the load
     balancer, which does not decrease imbalance and therefore pulls
     until the maximum number of loops is reached, which might be all
     tasks just created by a fork bomb"

* tag 'sched-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: handle case of task_h_load() returning 0
  sched: Fix unreliable rseq cpu_id for new tasks
  sched: Fix loadavg accounting race

Merge tag 'irq-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master

Pull irq fixes from Thomas Gleixner:
 "Two fixes for the interrupt subsystem:

   - Make the handling of the firmware node consistent and do not free
     the node after the domain has been created successfully. The core
     code stores a pointer to it which can lead to a use after free or
     double free.

     This used to "work" because the pointer was not stored when the
     initial code was written, but at some point later it was required
     to store it. Of course nobody noticed that the existing users break
     that way.

   - Handle affinity setting on inactive interrupts correctly when
     hierarchical irq domains are enabled.

     When interrupts are inactive with the modern hierarchical irqdomain
     design, the interrupt chips are not necessarily in a state where
     affinity changes can be handled. The legacy irq chip design allowed
     this because interrupts are immediately fully initialized at
     allocation time. X86 has a hacky workaround for this, but other
     implementations do not.

     This cased malfunction on GIC-V3. Instead of playing whack a mole
     to find all affected drivers, change the core code to store the
     requested affinity setting and then establish it when the interrupt
     is allocated, which makes the X86 hack go away"

* tag 'irq-urgent-2020-07-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/affinity: Handle affinity setting on inactive interrupts correctly
  irqdomain/treewide: Keep firmware node unconditionally allocated

Pull USB fixes from Greg KH:
 "Here are a few small USB fixes, and one thunderbolt fix, for 5.8-rc6.

  Nothing huge in here, just the normal collection of gadget, dwc2/3,
  serial, and other minor USB driver fixes and id additions. Full
  details are in the shortlog.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'usb-5.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: serial: iuu_phoenix: fix memory corruption
  USB: c67x00: fix use after free in c67x00_giveback_urb
  usb: gadget: function: fix missing spinlock in f_uac1_legacy
  usb: gadget: udc: atmel: fix uninitialized read in debug printk
  usb: gadget: udc: atmel: remove outdated comment in usba_ep_disable()
  usb: dwc2: Fix shutdown callback in platform
  usb: cdns3: trace: fix some endian issues
  usb: cdns3: ep0: fix some endian issues
  usb: gadget: udc: gr_udc: fix memleak on error handling path in gr_ep_init()
  usb: gadget: fix langid kernel-doc warning in usbstring.c
  usb: dwc3: pci: add support for the Intel Jasper Lake
  usb: dwc3: pci: add support for the Intel Tiger Lake PCH -H variant
  usb: chipidea: core: add wakeup support for extcon
  USB: serial: option: add Quectel EG95 LTE modem
  thunderbolt: Fix path indices used in USB3 tunnel discovery
  USB: serial: ch341: add new Product ID for CH340
  USB: serial: option: add GosunCn GM500 series
  USB: serial: cypress_m8: enable Simply Automated UPB PIM

Pull dma-mapping fixes from Christoph Hellwig:
 "Ensure we always have fully addressable memory in the dma coherent
  pool (Nicolas Saenz Julienne)"

* tag 'dma-mapping-5.8-6' of git://git.infradead.org/users/hch/dma-mapping:
  dma-pool: do not allocate pool memory from CMA
  dma-pool: make sure atomic pool suits device
  dma-pool: introduce dma_guess_pool()
  dma-pool: get rid of dma_in_atomic_pool()
  dma-direct: provide function to check physical memory area validity

vmlinux-objs-y is added to targets, which currently means that the EFI
stub gets added to the targets as well. It shouldn't be added since it
is built elsewhere.

This confuses Makefile.build which interprets the EFI stub as a target
	$(obj)/$(objtree)/drivers/firmware/efi/libstub/lib.a
and will create drivers/firmware/efi/libstub/ underneath
arch/x86/boot/compressed, to hold this supposed target, if building
out-of-tree. [0]

Fix this by pulling the stub out of vmlinux-objs-y into efi-obj-y.

[0] See scripts/Makefile.build near the end:
    # Create directories for object files if they do not exist
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lkml.kernel.org/r/20200715032631.1562882-1-nivedita@alum.mit.edu

Some builds of GCC enable stack protector by default. Simply removing
the arguments is not sufficient to disable stack protector, as the stack
protector for those GCC builds must be explicitly disabled. Remove the
argument removals and add -fno-stack-protector. Additionally include
missed x32 argument updates, and adjust whitespace for readability.

Fixes: 20355e5f ("x86/entry: Exclude low level entry code from sanitizing")
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/202006261333.585319CA6B@keescook

Pull SCSI fix from James Bottomley:
 "One small driver fix. Although the one liner makes it sound like a
  cosmetic change, it's a regression fix for the megaraid_sas driver"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: megaraid_sas: Remove undefined ENABLE_IRQ_POLL macro

Merge tag 'hwmon-for-v5.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging into master

Pull hwmon fixes from Guenter Roeck:

 - Using SCT on some Tohsiba drives causes firmware hangs. Disable its
   use in the drivetemp driver.

 - Handle potential buffer overflows in scmi and aspeed-pwm-tacho
   driver.

 - Energy reporting does not work well on all AMD CPUs. Restrict
   amd_energy to known working models.

 - Enable reading the CPU temperature on NCT6798D using undocumented
   registers.

 - Fix read errors seen if PEC is enabled in adm1275 driver.

 - Fix setting the pwm1_enable in emc2103 driver.

* tag 'hwmon-for-v5.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (drivetemp) Avoid SCT usage on Toshiba DT01ACA family drives
  hwmon: (scmi) Fix potential buffer overflow in scmi_hwmon_probe()
  hwmon: (nct6775) Accept PECI Calibration as temperature source for NCT6798D
  hwmon: (adm1275) Make sure we are reading enough data for different chips
  hwmon: (emc2103) fix unable to change fan pwm1_enable attribute
  hwmon: (amd_energy) match for supported models
  hwmon: (aspeed-pwm-tacho) Avoid possible buffer overflow

Merge tag 'riscv-for-linus-5.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux into master

Pull RISC-V fixes from Palmer Dabbelt:
 "Two fixes:

   - 16KiB kernel stacks on rv64, which fixes a lot of crashes.

   - Rolling an mmiowb() into the scheduler, which when combined with
     Will's fix to the mmiowb()-on-spinlock should fix the PREEMPT
     issues we've been seeing"

* tag 'riscv-for-linus-5.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Upgrade smp_mb__after_spinlock() to iorw,iorw
  riscv: use 16KB kernel stack on 64-bit