diff mbox series

[5.4,43/62] genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP

Message ID 20210816125429.678050593@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH Aug. 16, 2021, 1:02 p.m. UTC 
From: Thomas Gleixner <tglx@linutronix.de>

commit 826da771291fc25a428e871f9e7fb465e390f852 upstream.

X86 IO/APIC and MSI interrupts (when used without interrupts remapping)
require that the affinity setup on startup is done before the interrupt is
enabled for the first time as the non-remapped operation mode cannot safely
migrate enabled interrupts from arbitrary contexts. Provide a new irq chip
flag which allows affected hardware to request this.

This has to be opt-in because there have been reports in the past that some
interrupt chips cannot handle affinity setting before startup.

Fixes: 18404756765c ("genirq: Expose default irq affinity mask (take 3)")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210729222542.779791738@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/irq.h |    2 ++
 kernel/irq/chip.c   |    5 ++++-
 2 files changed, 6 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -542,6 +542,7 @@  struct irq_chip {
  * IRQCHIP_EOI_THREADED:	Chip requires eoi() on unmask in threaded mode
  * IRQCHIP_SUPPORTS_LEVEL_MSI	Chip can provide two doorbells for Level MSIs
  * IRQCHIP_SUPPORTS_NMI:	Chip can deliver NMIs, only for root irqchips
+ * IRQCHIP_AFFINITY_PRE_STARTUP:      Default affinity update before startup
  */
 enum {
 	IRQCHIP_SET_TYPE_MASKED		= (1 <<  0),
@@ -553,6 +554,7 @@  enum {
 	IRQCHIP_EOI_THREADED		= (1 <<  6),
 	IRQCHIP_SUPPORTS_LEVEL_MSI	= (1 <<  7),
 	IRQCHIP_SUPPORTS_NMI		= (1 <<  8),
+	IRQCHIP_AFFINITY_PRE_STARTUP	= (1 << 10),
 };
 
 #include <linux/irqdesc.h>
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -265,8 +265,11 @@  int irq_startup(struct irq_desc *desc, b
 	} else {
 		switch (__irq_startup_managed(desc, aff, force)) {
 		case IRQ_STARTUP_NORMAL:
+			if (d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP)
+				irq_setup_affinity(desc);
 			ret = __irq_startup(desc);
-			irq_setup_affinity(desc);
+			if (!(d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP))
+				irq_setup_affinity(desc);
 			break;
 		case IRQ_STARTUP_MANAGED:
 			irq_do_set_affinity(d, aff, false);