irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d20564e0dc ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240408074609.3170807-1-arnd@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202311191229.55QXHVc6-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d20564e0dc ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240408074609.3170807-1-arnd@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202311191229.55QXHVc6-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d20564e0dc ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240408074609.3170807-1-arnd@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202311191229.55QXHVc6-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d20564e0dc ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240408074609.3170807-1-arnd@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202311191229.55QXHVc6-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d20564e0dc ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240408074609.3170807-1-arnd@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202311191229.55QXHVc6-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d20564e0dc ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240408074609.3170807-1-arnd@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202311191229.55QXHVc6-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d20564e0dc ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240408074609.3170807-1-arnd@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202311191229.55QXHVc6-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d20564e0dc ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240408074609.3170807-1-arnd@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202311191229.55QXHVc6-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d20564e0dc ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240408074609.3170807-1-arnd@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202311191229.55QXHVc6-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument

irqflags: Explicitly ignore lockdep_hrtimer_exit() argument

commit c1d11fc2c8320871b40730991071dd0a0b405bc8 upstream.

When building with 'make W=1' but CONFIG_TRACE_IRQFLAGS=n, the
unused argument to lockdep_hrtimer_exit() causes a warning:

kernel/time/hrtimer.c:1655:14: error: variable 'expires_in_hardirq' set but not used [-Werror=unused-but-set-variable]

This is intentional behavior, so add a cast to void to shut up the warning.

Fixes: 73d20564e0dc ("hrtimer: Don't dereference the hrtimer pointer after the callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240408074609.3170807-1-arnd@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202311191229.55QXHVc6-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

locking: Introduce __cleanup() based infrastructure

Use __attribute__((__cleanup__(func))) to build:

- simple auto-release pointers using __free()

- 'classes' with constructor and destructor sem

locking: Introduce __cleanup() based infrastructure

Use __attribute__((__cleanup__(func))) to build:

- simple auto-release pointers using __free()

- 'classes' with constructor and destructor semantics for
scope-based resource management.

- lock guards based on the above classes.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230612093537.614161713%40infradead.org

show more ...

lockdep: Fix -Wunused-parameter for _THIS_IP_

While looking into a bug related to the compiler's handling of addresses
of labels, I noticed some uses of _THIS_IP_ seemed unused in lockdep.
Drive by

lockdep: Fix -Wunused-parameter for _THIS_IP_

While looking into a bug related to the compiler's handling of addresses
of labels, I noticed some uses of _THIS_IP_ seemed unused in lockdep.
Drive by cleanup.

-Wunused-parameter:
kernel/locking/lockdep.c:1383:22: warning: unused parameter 'ip'
kernel/locking/lockdep.c:4246:48: warning: unused parameter 'ip'
kernel/locking/lockdep.c:4844:19: warning: unused parameter 'ip'

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20220314221909.2027027-1-ndesaulniers@google.com

show more ...

lockdep: Remove softirq accounting on PREEMPT_RT.

There is not really a softirq context on PREEMPT_RT. Softirqs on
PREEMPT_RT are always invoked within the context of a threaded
interrupt handler o

lockdep: Remove softirq accounting on PREEMPT_RT.

There is not really a softirq context on PREEMPT_RT. Softirqs on
PREEMPT_RT are always invoked within the context of a threaded
interrupt handler or within ksoftirqd. The "in-softirq" context is
preemptible and is protected by a per-CPU lock to ensure mutual
exclusion.

There is no difference on PREEMPT_RT between spin_lock_irq() and
spin_lock() because the former does not disable interrupts. Therefore
if a lock is used in_softirq() and locked once with spin_lock_irq()
then lockdep will report this with "inconsistent {SOFTIRQ-ON-W} ->
{IN-SOFTIRQ-W} usage".

Teach lockdep that we don't really do softirqs on -RT.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20211129174654.668506-6-bigeasy@linutronix.de

show more ...

lockdep: Fix -Wunused-parameter for _THIS_IP_

[ Upstream commit 8b023accc8df70e72f7704d29fead7ca914d6837 ]

While looking into a bug related to the compiler's handling of addresses
of labels, I noti

lockdep: Fix -Wunused-parameter for _THIS_IP_

[ Upstream commit 8b023accc8df70e72f7704d29fead7ca914d6837 ]

While looking into a bug related to the compiler's handling of addresses
of labels, I noticed some uses of _THIS_IP_ seemed unused in lockdep.
Drive by cleanup.

-Wunused-parameter:
kernel/locking/lockdep.c:1383:22: warning: unused parameter 'ip'
kernel/locking/lockdep.c:4246:48: warning: unused parameter 'ip'
kernel/locking/lockdep.c:4844:19: warning: unused parameter 'ip'

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20220314221909.2027027-1-ndesaulniers@google.com
Stable-dep-of: 54c3931957f6 ("tracing: hold caller_addr to hardirq_{enable,disable}_ip")
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

lockdep: report broken irq restoration

We generally expect local_irq_save() and local_irq_restore() to be
paired and sanely nested, and so local_irq_restore() expects to be
called with irqs disabled

lockdep: report broken irq restoration

We generally expect local_irq_save() and local_irq_restore() to be
paired and sanely nested, and so local_irq_restore() expects to be
called with irqs disabled. Thus, within local_irq_restore() we only
trace irq flag changes when unmasking irqs.

This means that a sequence such as:

| local_irq_disable();
| local_irq_save(flags);
| local_irq_enable();
| local_irq_restore(flags);

... is liable to break things, as the local_irq_restore() would mask
irqs without tracing this change. Similar problems may exist for
architectures whose arch_irq_restore() function depends on being called
with irqs disabled.

We don't consider such sequences to be a good idea, so let's define
those as forbidden, and add tooling to detect such broken cases.

This patch adds debug code to WARN() when raw_local_irq_restore() is
called with irqs enabled. As raw_local_irq_restore() is expected to pair
with raw_local_irq_save(), it should never be called with irqs enabled.

To avoid the possibility of circular header dependencies between
irqflags.h and bug.h, the warning is handled in a separate C file.

The new code is all conditional on a new CONFIG_DEBUG_IRQFLAGS symbol
which is independent of CONFIG_TRACE_IRQFLAGS. As noted above such cases
will confuse lockdep, so CONFIG_DEBUG_LOCKDEP now selects
CONFIG_DEBUG_IRQFLAGS.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210111153707.10071-1-mark.rutland@arm.com

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irq_work: Optimize irq_work_single()

Trade one atomic op for a full memory barrier.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.or

irq_work: Optimize irq_work_single()

Trade one atomic op for a full memory barrier.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

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irq_work: Cleanup

Get rid of the __call_single_node union and clean up the API a little
to avoid external code relying on the structure layout as much.

Signed-off-by: Peter Zijlstra (Intel) <peterz

irq_work: Cleanup

Get rid of the __call_single_node union and clean up the API a little
to avoid external code relying on the structure layout as much.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

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lockdep: Only trace IRQ edges

Problem:

raw_local_irq_save(); // software state on
local_irq_save(); // software state off
...
local_irq_restore(); // software state still off, because we do

lockdep: Only trace IRQ edges

Problem:

raw_local_irq_save(); // software state on
local_irq_save(); // software state off
...
local_irq_restore(); // software state still off, because we don't enable IRQs
raw_local_irq_restore(); // software state still off, *whoopsie*

existing instances:

- lock_acquire()
raw_local_irq_save()
__lock_acquire()
arch_spin_lock(&graph_lock)
pv_wait() := kvm_wait() (same or worse for Xen/HyperV)
local_irq_save()

- trace_clock_global()
raw_local_irq_save()
arch_spin_lock()
pv_wait() := kvm_wait()
local_irq_save()

- apic_retrigger_irq()
raw_local_irq_save()
apic->send_IPI() := default_send_IPI_single_phys()
local_irq_save()

Possible solutions:

A) make it work by enabling the tracing inside raw_*()
B) make it work by keeping tracing disabled inside raw_*()
C) call it broken and clean it up now

Now, given that the only reason to use the raw_* variant is because you don't
want tracing. Therefore A) seems like a weird option (although it can be done).
C) is tempting, but OTOH it ends up converting a _lot_ of code to raw just
because there is one raw user, this strips the validation/tracing off for all
the other users.

So we pick B) and declare any code that ends up doing:

raw_local_irq_save()
local_irq_save()
lockdep_assert_irqs_disabled();

broken. AFAICT this problem has existed forever, the only reason it came
up is because commit: 859d069ee1dd ("lockdep: Prepare for NMI IRQ
state tracking") changed IRQ tracing vs lockdep recursion and the
first instance is fairly common, the other cases hardly ever happen.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[rewrote changelog]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200723105615.1268126-1-npiggin@gmail.com

show more ...

locking/lockdep: Cleanup

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Ack

locking/lockdep: Cleanup

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.546087214@infradead.org

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lockdep: Use raw_cpu_*() for per-cpu variables

Sven reported that commit a21ee6055c30 ("lockdep: Change
hardirq{s_enabled,_context} to per-cpu variables") caused trouble on
s390 because their this_c

lockdep: Use raw_cpu_*() for per-cpu variables

Sven reported that commit a21ee6055c30 ("lockdep: Change
hardirq{s_enabled,_context} to per-cpu variables") caused trouble on
s390 because their this_cpu_*() primitives disable preemption which
then lands back tracing.

On the one hand, per-cpu ops should use preempt_*able_notrace() and
raw_local_irq_*(), on the other hand, we can trivialy use raw_cpu_*()
ops for this.

Fixes: a21ee6055c30 ("lockdep: Change hardirq{s_enabled,_context} to per-cpu variables")
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200821085348.192346882@infradead.org

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lockdep: Refactor IRQ trace events fields into struct

Refactor the IRQ trace events fields, used for printing information
about the IRQ trace events, into a separate struct 'irqtrace_events'.

This

lockdep: Refactor IRQ trace events fields into struct

Refactor the IRQ trace events fields, used for printing information
about the IRQ trace events, into a separate struct 'irqtrace_events'.

This improves readability by separating the information only used in
reporting, as well as enables (simplified) storing/restoring of
irqtrace_events snapshots.

No functional change intended.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200729110916.3920464-1-elver@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

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lockdep: Remove lockdep_hardirq{s_enabled,_context}() argument

Now that the macros use per-cpu data, we no longer need the argument.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Rev

lockdep: Remove lockdep_hardirq{s_enabled,_context}() argument

Now that the macros use per-cpu data, we no longer need the argument.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200623083721.571835311@infradead.org

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lockdep: Change hardirq{s_enabled,_context} to per-cpu variables

Currently all IRQ-tracking state is in task_struct, this means that
task_struct needs to be defined before we use it.

Especially for

lockdep: Change hardirq{s_enabled,_context} to per-cpu variables

Currently all IRQ-tracking state is in task_struct, this means that
task_struct needs to be defined before we use it.

Especially for lockdep_assert_irq*() this can lead to header-hell.

Move the hardirq state into per-cpu variables to avoid the task_struct
dependency.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200623083721.512673481@infradead.org

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x86/entry: Rename trace_hardirqs_off_prepare()

The typical pattern for trace_hardirqs_off_prepare() is:

ENTRY
lockdep_hardirqs_off(); // because hardware
... do entry magic
instrument

x86/entry: Rename trace_hardirqs_off_prepare()

The typical pattern for trace_hardirqs_off_prepare() is:

ENTRY
lockdep_hardirqs_off(); // because hardware
... do entry magic
instrumentation_begin();
trace_hardirqs_off_prepare();
... do actual work
trace_hardirqs_on_prepare();
lockdep_hardirqs_on_prepare();
instrumentation_end();
... do exit magic
lockdep_hardirqs_on();

which shows that it's named wrong, rename it to
trace_hardirqs_off_finish(), as it concludes the hardirq_off transition.

Also, given that the above is the only correct order, make the traditional
all-in-one trace_hardirqs_off() follow suit.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200529213321.415774872@infradead.org

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lockdep: Prepare for noinstr sections

Force inlining and prevent instrumentation of all sorts by marking the
functions which are invoked from low level entry code with 'noinstr'.

Split the irqflags

lockdep: Prepare for noinstr sections

Force inlining and prevent instrumentation of all sorts by marking the
functions which are invoked from low level entry code with 'noinstr'.

Split the irqflags tracking into two parts. One which does the heavy
lifting while RCU is watching and the final one which can be invoked after
RCU is turned off.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134100.484532537@linutronix.de

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