Subject: [PATCH v2 10/12] irqchip/gic-v3: Warn about inconsistent implementations of extended ranges

From: Marc Zyngier <[email-masked]>
Date: Tue, 6 Aug 2019 11:01:19 +0100

As is it usual for the GIC, it isn't disallowed to put together a system
that is majorly inconsistent, with a distributor supporting the
extended ranges while some of the CPUs don't.

Kindly tell the user that things are sailing isn't going to be smooth.

Signed-off-by: Marc Zyngier <[email-masked]>
---
 drivers/irqchip/irq-gic-v3.c       | 5 +++++
 include/linux/irqchip/arm-gic-v3.h | 1 +
 2 files changed, 6 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index f53e58d398ba..334a10d9dbfb 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1014,6 +1014,11 @@ static void gic_cpu_init(void)
 
 	gic_enable_redist(true);
 
+	WARN((gic_data.ppi_nr > 16 || GIC_ESPI_NR != 0) &&
+	     !(gic_read_ctlr() & ICC_CTLR_EL1_ExtRange),
+	     "Distributor has extended ranges, but CPU%d doesn't\n",
+	     smp_processor_id());
+
 	rbase = gic_data_rdist_sgi_base();
 
 	/* Configure SGIs/PPIs as non-secure Group-1 */
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index 9ec3349dee04..5cc10cf7cb3e 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -496,6 +496,7 @@
 #define ICC_CTLR_EL1_A3V_SHIFT		15
 #define ICC_CTLR_EL1_A3V_MASK		(0x1 << ICC_CTLR_EL1_A3V_SHIFT)
 #define ICC_CTLR_EL1_RSS		(0x1 << 18)
+#define ICC_CTLR_EL1_ExtRange		(0x1 << 19)
 #define ICC_PMR_EL1_SHIFT		0
 #define ICC_PMR_EL1_MASK		(0xff << ICC_PMR_EL1_SHIFT)
 #define ICC_BPR0_EL1_SHIFT		0
-- 
2.20.1

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