Re: [patch V5 07/15] scripts/gdb: Update x86 interrupts to the array based storage

[Radu Rendec <radu@rendec.net>]

On Wed, 2026-04-01 at 23:52 +0200, Thomas Gleixner wrote:
> From: Thomas Gleixner <tglx@kernel.org>
> 
> x86 changed the interrupt statistics from a struct with individual members
> to an counter array. It also provides a corresponding info array with the
> strings for prefix and description and an indicator to skip the entry.
> 
> Update the already out of sync GDB script to use the counter and the info
> array, which keeps the GDB script in sync automatically.
> 
> Signed-off-by: Thomas Gleixner <tglx@kernel.org>
> Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
> ---
> V5: Bring the show_err_irq() back as it is used on mips
>     Fix the index calculation for the show bitmap so it works with more than one
>     unsigned long.
> V4: Adopted to irq_stat_count_show bitmap and removed the duplicate ERR/MIS output
> V3: New patch - Radu
> ---
>  scripts/gdb/linux/interrupts.py |   81 +++++++++++-----------------------------
>  1 file changed, 23 insertions(+), 58 deletions(-)
> --- a/scripts/gdb/linux/interrupts.py
> +++ b/scripts/gdb/linux/interrupts.py
> @@ -90,71 +90,29 @@ irq_desc_type = utils.CachedType("struct
>  
>      return text
>  
> -def show_irq_err_count(prec):
> -    cnt = utils.gdb_eval_or_none("irq_err_count")
> -    text = ""
> -    if cnt is not None:
> -        text += "%*s: %10u\n" % (prec, "ERR", cnt['counter'])
> -    return text
> -

Nit: show_irq_err_count() is unchanged, and I see no obvious reason to
move it down below. Keeping it here would exclude it from the patch
altogether, making the patch shorter and easier to read/review.

> -def x86_show_irqstat(prec, pfx, field, desc):
> -    irq_stat = gdb.parse_and_eval("&irq_stat")
> +def x86_show_irqstat(prec, pfx, idx, desc):
> +    irq_stat = gdb.parse_and_eval("&irq_stat.counts[%d]" %idx)
>      text = "%*s: " % (prec, pfx)
>      for cpu in cpus.each_online_cpu():
>          stat = cpus.per_cpu(irq_stat, cpu)
> -        text += "%10u " % (stat[field])
> -    text += "  %s\n" % (desc)
> -    return text
> -
> -def x86_show_mce(prec, var, pfx, desc):
> -    pvar = gdb.parse_and_eval(var)
> -    text = "%*s: " % (prec, pfx)
> -    for cpu in cpus.each_online_cpu():
> -        text += "%10u " % (cpus.per_cpu(pvar, cpu).dereference())
> -    text += "  %s\n" % (desc)
> +        text += "%10u " % (stat.dereference())

Something is wrong here. The counters for the arch specific interrupts
are not aligned with the generic ones. Sample from my VM setup:

(gdb) lx-interruptlist 
           CPU0       CPU1       CPU2       CPU3       
  1:          0         0         9         0   IO-APIC    1-edge      i8042
  4:          0         0         0       267   IO-APIC    4-edge      ttyS0
  9:          0         0         0         0   IO-APIC    9-fasteoi   acpi
 12:          0        15         0         0   IO-APIC   12-edge      i8042
[...]
NMI:          0          0          0          0   Non-maskable interrupts
LOC:       3925       3997       4281       3972   Local timer interrupts
PMI:          0          0          0          0   Performance monitoring interrupts
[...]

If I remove the space in "%10u " it becomes aligned but then the
description is no longer aligned.

> +    text += desc
>      return text
>  
>  def x86_show_interupts(prec):
> -    text = x86_show_irqstat(prec, "NMI", '__nmi_count', 'Non-maskable interrupts')
> +    info_type = gdb.lookup_type('struct irq_stat_info')
> +    info = gdb.parse_and_eval('irq_stat_info')
> +    bitmap = gdb.parse_and_eval('irq_stat_count_show')
> +    bitsperlong = 8 * int(bitmap.type.target().sizeof)
>  
> -    if constants.LX_CONFIG_X86_LOCAL_APIC:
> -        text += x86_show_irqstat(prec, "LOC", 'apic_timer_irqs', "Local timer interrupts")
> -        text += x86_show_irqstat(prec, "SPU", 'irq_spurious_count', "Spurious interrupts")
> -        text += x86_show_irqstat(prec, "PMI", 'apic_perf_irqs', "Performance monitoring interrupts")
> -        text += x86_show_irqstat(prec, "IWI", 'apic_irq_work_irqs', "IRQ work interrupts")
> -        text += x86_show_irqstat(prec, "RTR", 'icr_read_retry_count', "APIC ICR read retries")
> -        if utils.gdb_eval_or_none("x86_platform_ipi_callback") is not None:
> -            text += x86_show_irqstat(prec, "PLT", 'x86_platform_ipis', "Platform interrupts")
> -
> -    if constants.LX_CONFIG_SMP:
> -        text += x86_show_irqstat(prec, "RES", 'irq_resched_count', "Rescheduling interrupts")
> -        text += x86_show_irqstat(prec, "CAL", 'irq_call_count', "Function call interrupts")
> -        text += x86_show_irqstat(prec, "TLB", 'irq_tlb_count', "TLB shootdowns")
> -
> -    if constants.LX_CONFIG_X86_THERMAL_VECTOR:
> -        text += x86_show_irqstat(prec, "TRM", 'irq_thermal_count', "Thermal events interrupts")
> -
> -    if constants.LX_CONFIG_X86_MCE_THRESHOLD:
> -        text += x86_show_irqstat(prec, "THR", 'irq_threshold_count', "Threshold APIC interrupts")
> -
> -    if constants.LX_CONFIG_X86_MCE_AMD:
> -        text += x86_show_irqstat(prec, "DFR", 'irq_deferred_error_count', "Deferred Error APIC interrupts")
> -
> -    if constants.LX_CONFIG_X86_MCE:
> -        text += x86_show_mce(prec, "&mce_exception_count", "MCE", "Machine check exceptions")
> -        text += x86_show_mce(prec, "&mce_poll_count", "MCP", "Machine check polls")
> -
> -    text += show_irq_err_count(prec)
> -
> -    if constants.LX_CONFIG_X86_IO_APIC:
> -        cnt = utils.gdb_eval_or_none("irq_mis_count")
> -        if cnt is not None:
> -            text += "%*s: %10u\n" % (prec, "MIS", cnt['counter'])
> -
> -    if constants.LX_CONFIG_KVM:
> -        text += x86_show_irqstat(prec, "PIN", 'kvm_posted_intr_ipis', 'Posted-interrupt notification event')
> -        text += x86_show_irqstat(prec, "NPI", 'kvm_posted_intr_nested_ipis', 'Nested posted-interrupt event')
> -        text += x86_show_irqstat(prec, "PIW", 'kvm_posted_intr_wakeup_ipis', 'Posted-interrupt wakeup event')
> +    text = ""
> +    for idx in range(int(info.type.sizeof / info_type.sizeof)):
> +        show = bitmap[int(idx / bitsperlong)]
> +        if not show & 1 << int(idx % bitsperlong):
> +            continue
> +        pfx = info[idx]['symbol'].string()
> +        desc = info[idx]['text'].string()
> +        text += x86_show_irqstat(prec, pfx, idx, desc)
>  
>      return text
>  
> @@ -187,6 +145,13 @@ irq_desc_type = utils.CachedType("struct
>      text += "%*s: %10lu\n" % (prec, "ERR", gdb.parse_and_eval("irq_err_count"))
>      return text
>  
> +def show_irq_err_count(prec):
> +    cnt = utils.gdb_eval_or_none("irq_err_count")
> +    text = ""
> +    if cnt is not None:
> +        text += "%*s: %10u\n" % (prec, "ERR", cnt['counter'])
> +    return text
> +
>  def arch_show_interrupts(prec):
>      text = ""
>      if utils.is_target_arch("x86"):