[PATCH v2 09/11] powerpc: powernv: Annotate data races in opal events
From: Rohan McLure <hidden>
Date: 2023-05-10 03:41:57
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
The kopald thread handles opal events as they appear, but by polling a static bit-vector in last_outstanding_events. Annotate these data races accordingly. We are not at risk of missing events, but use of READ_ONCE, WRITE_ONCE will assist readers in seeing that kopald only consumes the events it is aware of when it is scheduled. Also removes extraneous KCSAN warnings. Signed-off-by: Rohan McLure <redacted> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/platforms/powernv/opal-irqchip.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/opal-irqchip.c b/arch/powerpc/platforms/powernv/opal-irqchip.c
index d55652b5f6fa..f9a7001dacb7 100644
--- a/arch/powerpc/platforms/powernv/opal-irqchip.c
+++ b/arch/powerpc/platforms/powernv/opal-irqchip.c@@ -59,7 +59,7 @@ void opal_handle_events(void) cond_resched(); } - last_outstanding_events = 0; + WRITE_ONCE(last_outstanding_events, 0); if (opal_poll_events(&events) != OPAL_SUCCESS) return; e = be64_to_cpu(events) & opal_event_irqchip.mask;
@@ -69,7 +69,7 @@ void opal_handle_events(void) bool opal_have_pending_events(void) { - if (last_outstanding_events & opal_event_irqchip.mask) + if (READ_ONCE(last_outstanding_events) & opal_event_irqchip.mask) return true; return false; }
@@ -124,7 +124,7 @@ static irqreturn_t opal_interrupt(int irq, void *data) __be64 events; opal_handle_interrupt(virq_to_hw(irq), &events); - last_outstanding_events = be64_to_cpu(events); + WRITE_ONCE(last_outstanding_events, be64_to_cpu(events)); if (opal_have_pending_events()) opal_wake_poller();
--
2.37.2