linux-toradex.git/kernel/irq/proc.c, branch v6.11-rc2

genirq/proc: Simplify irqdesc::kstat_irqs handling further

2024-06-03T09:48:29+00:00

Interrupts which have no action and chained interrupts can be
ignored due to the following reasons (as per tglx's comment):

  1) Interrupts which have no action are completely uninteresting as
     there is no real information attached.

  2) Chained interrupts do not have a count at all.

So there is no point to evaluate the number of accounted interrupts before
checking for non-requested or chained interrupts.

Remove the any_count logic and simply check whether the interrupt
descriptor has the kstat_irqs member populated.

[ tglx: Adapted to upstream changes ]

Suggested-by: Thomas Gleixner 
Signed-off-by: Adrian Huang 
Signed-off-by: Thomas Gleixner 
Tested-by: Jiwei Sun 
Link: https://lore.kernel.org/r/20240515100632.1419-1-ahuang12@lenovo.com
Link: https://lore.kernel.org/lkml/87h6f0knau.ffs@tglx/

genirq: Avoid summation loops for /proc/interrupts

2024-04-12T15:08:05+00:00

show_interrupts() unconditionally accumulates the per CPU interrupt
statistics to determine whether an interrupt was ever raised.

This can be avoided for all interrupts which are not strictly per CPU
and not of type NMI because those interrupts provide already an
accumulated counter. The required logic is already implemented in
kstat_irqs().

Split the inner access logic out of kstat_irqs() and use it for
kstat_irqs() and show_interrupts() to avoid the accumulation loop
when possible.

Originally-by: Thomas Gleixner 
Signed-off-by: Bitao Hu 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Liu Song 
Reviewed-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20240411074134.30922-4-yaoma@linux.alibaba.com

genirq: Convert kstat_irqs to a struct

2024-04-12T15:08:05+00:00

The irq_desc::kstat_irqs member is a per-CPU variable of type int, which is
only capable of counting. A snapshot mechanism for interrupt statistics
will be added soon, which requires an additional variable to store the
snapshot.

To facilitate expansion, convert kstat_irqs here to a struct containing
only the count.

Originally-by: Thomas Gleixner 
Signed-off-by: Bitao Hu 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20240411074134.30922-2-yaoma@linux.alibaba.com

proc: remove PDE_DATA() completely

2022-01-22T06:33:37+00:00

Remove PDE_DATA() completely and replace it with pde_data().

[akpm@linux-foundation.org: fix naming clash in drivers/nubus/proc.c]
[akpm@linux-foundation.org: now fix it properly]

Link: https://lkml.kernel.org/r/20211124081956.87711-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song 
Acked-by: Christian Brauner 
Cc: Alexey Dobriyan 
Cc: Alexey Gladkov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

genirq: Improve "hwirq" output in /proc and /sys/

2021-07-30T21:07:31+00:00

The HW IRQ numbers generated by the PCI MSI layer can be quite large
on a pSeries machine when running under the IBM Hypervisor and they
appear as negative. Use '%lu' instead to show them correctly.

Signed-off-by: Cédric Le Goater 
Signed-off-by: Thomas Gleixner

kernel: Initialize cpumask before parsing

2021-04-10T11:35:54+00:00

KMSAN complains that new_value at cpumask_parse_user() from
write_irq_affinity() from irq_affinity_proc_write() is uninitialized.

  [  148.133411][ T5509] =====================================================
  [  148.135383][ T5509] BUG: KMSAN: uninit-value in find_next_bit+0x325/0x340
  [  148.137819][ T5509]
  [  148.138448][ T5509] Local variable ----new_value.i@irq_affinity_proc_write created at:
  [  148.140768][ T5509]  irq_affinity_proc_write+0xc3/0x3d0
  [  148.142298][ T5509]  irq_affinity_proc_write+0xc3/0x3d0
  [  148.143823][ T5509] =====================================================

Since bitmap_parse() from cpumask_parse_user() calls find_next_bit(),
any alloc_cpumask_var() + cpumask_parse_user() sequence has possibility
that find_next_bit() accesses uninitialized cpu mask variable. Fix this
problem by replacing alloc_cpumask_var() with zalloc_cpumask_var().

Signed-off-by: Tetsuo Handa 
Signed-off-by: Thomas Gleixner 
Acked-by: Steven Rostedt (VMware) 
Link: https://lore.kernel.org/r/20210401055823.3929-1-penguin-kernel@I-love.SAKURA.ne.jp

genirq: Annotate irq stats data races

2020-12-15T15:19:30+00:00

Both the per cpu stats and the accumulated count are accessed lockless and
can be concurrently modified. That's intentional and the stats are a rough
estimate anyway. Annotate them with data_race().

Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20201210194043.067097663@linutronix.de

genirq: Allow interrupts to be excluded from /proc/interrupts

2020-09-13T16:04:38+00:00

A number of architectures implement IPI statistics directly,
duplicating the core kstat_irqs accounting. As we move IPIs to
being actual IRQs, we would end-up with a confusing display
in /proc/interrupts (where the IPIs would appear twice).

In order to solve this, allow interrupts to be flagged as
"hidden", which excludes them from /proc/interrupts.

Reviewed-by: Valentin Schneider 
Signed-off-by: Marc Zyngier

genirq/proc: Reject invalid affinity masks (again)

2020-02-14T08:43:17+00:00

Qian Cai reported that the WARN_ON() in the x86/msi affinity setting code,
which catches cases where the affinity setting is not done on the CPU which
is the current target of the interrupt, triggers during CPU hotplug stress
testing.

It turns out that the warning which was added with the commit addressing
the MSI affinity race unearthed yet another long standing bug.

If user space writes a bogus affinity mask, i.e. it contains no online CPUs,
then it calls irq_select_affinity_usr(). This was introduced for ALPHA in

  eee45269b0f5 ("[PATCH] Alpha: convert to generic irq framework (generic part)")

and subsequently made available for all architectures in

  18404756765c ("genirq: Expose default irq affinity mask (take 3)")

which introduced the circumvention of the affinity setting restrictions for
interrupt which cannot be moved in process context.

The whole exercise is bogus in various aspects:

  1) If the interrupt is already started up then there is absolutely
     no point to honour a bogus interrupt affinity setting from user
     space. The interrupt is already assigned to an online CPU and it
     does not make any sense to reassign it to some other randomly
     chosen online CPU.

  2) If the interupt is not yet started up then there is no point
     either. A subsequent startup of the interrupt will invoke
     irq_setup_affinity() anyway which will chose a valid target CPU.

So the only correct solution is to just return -EINVAL in case user space
wrote an affinity mask which does not contain any online CPUs, except for
ALPHA which has it's own magic sauce for this.

Fixes: 18404756765c ("genirq: Expose default irq affinity mask (take 3)")
Reported-by: Qian Cai 
Signed-off-by: Thomas Gleixner 
Tested-by: Qian Cai 
Link: https://lkml.kernel.org/r/878sl8xdbm.fsf@nanos.tec.linutronix.de

proc: convert everything to "struct proc_ops"

2020-02-04T03:05:26+00:00

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

	llseek		=> proc_lseek
	unlocked_ioctl	=> proc_ioctl

	xxx		=> proc_xxx

	delete ".owner = THIS_MODULE" line

[akpm@linux-foundation.org: fix drivers/isdn/capi/kcapi_proc.c]
[sfr@canb.auug.org.au: fix kernel/sched/psi.c]
  Link: http://lkml.kernel.org/r/20200122180545.36222f50@canb.auug.org.au
Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2
Signed-off-by: Alexey Dobriyan 
Signed-off-by: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds