[tip: irq/core] irqchip/gic-v3: Warn about inconsistent implementations of extended ranges

[tip-bot2 for Marc Zyngier]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     ad5a78d3da81836c88d1f2d53310484462660997
Gitweb:        https://git.kernel.org/tip/ad5a78d3da81836c88d1f2d53310484462660997
Author:        Marc Zyngier <maz@xxxxxxxxxx>
AuthorDate:    Thu, 25 Jul 2019 15:30:51 +01:00
Committer:     Marc Zyngier <maz@xxxxxxxxxx>
CommitterDate: Tue, 20 Aug 2019 10:23:35 +01:00

irqchip/gic-v3: Warn about inconsistent implementations of extended ranges

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 <maz@xxxxxxxxxx>
---
 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 d3727e8..8af08dd 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 9ec3349..5cc10cf 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