linux.git/kernel/irq/proc.c, branch v6.12

genirq/proc: Change the return value for set affinity permission error

2024-08-29T14:42:06+00:00

Currently, when the affinity of an irq cannot be set due to lack of
permission, the write_irq_affinity() returns the error code -EIO.

Change the return value to -EPERM as that reflects the cause of error
correctly.

Signed-off-by: Jeff Xie 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/20240826145805.5938-1-jeff.xie@linux.dev

genirq/proc: Use irq_move_pending() in show_irq_affinity()

2024-08-29T14:42:06+00:00

irq_move_pending() encapsulates irqd_is_setaffinity_pending() depending on
CONFIG_GENERIC_PENDING_IRQ.

Replace the open coded #ifdeffery with it.

Signed-off-by: Jinjie Ruan 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/20240829111522.230595-1-ruanjinjie@huawei.com

genirq/proc: Correctly set file permissions for affinity control files

2024-08-29T14:41:42+00:00

The kernel already knows at the time of interrupt allocation whether
affinity of an interrupt can be controlled by userspace or not.

It still creates all related procfs control files with read/write
permissions. That's inconsistent and non-intuitive for system
administrators and tools.

Therefore set the file permissions to read-only for such interrupts.

[ tglx: Massage change log, fixed UP build ]

Signed-off-by: Jeff Xie 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/20240825131911.107119-1-jeff.xie@linux.dev

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