github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-07 06:17:02 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

irqchip/jcore-aic: Fix lost IPIs on SMP

Browse Source 
Since commit bdf4e2ac29 ("genirq: Allow per-cpu interrupt sharing for
non-overlapping affinities"), handle_percpu_devid_irq() only runs an
action whose affinity mask contains the current CPU. Only actions set up
through the percpu_devid request functions have such a mask.

handle_jcore_irq() passes every per-CPU interrupt to
handle_percpu_devid_irq(). The J2 IPI is not a percpu_devid interrupt.
j2_prepare_cpus() requests it with request_irq() and IRQF_PERCPU, so its
action has no affinity mask and cpumask_test_cpu() reads through a NULL
pointer. J2 has no MMU to catch this. The read returns whatever is at
address 0, the action is not found, and IPIs are dropped as spurious
("Spurious percpu IRQ20 on CPU1", printed once).

Pass only percpu_devid interrupts (the PIT) to handle_percpu_devid_irq()
and the other per-CPU interrupts to handle_percpu_irq() again, as before
commit d7e3fd6582 ("irqchip/jcore-aic, clocksource/drivers/jcore: Fix
jcore-pit interrupt request").

Found with a two-CPU J2 model simulated from the J-Core RTL. Without
this change the boot stalls with both CPUs idle shortly after
"smp: Brought up 1 node, 2 CPUs". With it, the boot reaches userspace.

Fixes: bdf4e2ac29 ("genirq: Allow per-cpu interrupt sharing for non-overlapping affinities")
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Assisted-by: LLM
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260928035408.25871-1-kmehltretter@gmail.com
This commit is contained in:
Karl Mehltretter 2026-09-28 05:54:08 +02:00 committed by Thomas Gleixner
parent 0ca21fe111
commit f556f008f7
1 changed files with 3 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/irqchip/irq-jcore-aic.c
View File

@ -37,8 +37,10 @@ static struct irq_chip jcore_aic;
static void handle_jcore_irq(struct irq_desc *desc)
{
if (irqd_is_per_cpu(irq_desc_get_irq_data(desc)))
if (irq_is_percpu_devid(irq_desc_get_irq(desc)))
handle_percpu_devid_irq(desc);
else if (irqd_is_per_cpu(irq_desc_get_irq_data(desc)))
handle_percpu_irq(desc);
else
handle_simple_irq(desc);
}