The GIC (v2 at least) has a bit in the TYPER register to indicate whether the GIC

supports the Security Extensions or not. This bit is not the same as the CPU one.
Currently we are not checking for either before trying to write to the special
registers.  This can lead to problems on hardware or simulators that do not
provide the security extensions.  Add the missing checks. Their interactions with
the CPU flag is not entirely clear to me but using a macro will make it easier
to quickly adjust the condition once the CPU bits are sorted as well.

Reviewed by:	br
Sponsored by:	DARPA/AFRL
Differential Revision:	https://reviews.freebsd.org/D6397

2 files changed, 10 insertions, 4 deletions

diff --git a/sys/arm64/arm64/gic.c b/sys/arm64/arm64/gic.c
index 2140086..68b7cab 100644
--- a/sys/arm64/arm64/gic.c
+++ b/sys/arm64/arm64/gic.c
@@ -94,6 +94,11 @@ __FBSDID("$FreeBSD$");
 #define	GIC_LAST_PPI		31	/* core) peripheral interrupts. */
 #define	GIC_FIRST_SPI		32	/* Irqs 32+ are shared peripherals. */
 
+/* TYPER Registers */
+#define	GICD_TYPER_SECURITYEXT	0x400
+#define	GIC_SUPPORT_SECEXT(_sc)	\
+    ((_sc->typer & GICD_TYPER_SECURITYEXT) == GICD_TYPER_SECURITYEXT)
+
 /* First bit is a polarity bit (0 - low, 1 - high) */
 #define GICD_ICFGR_POL_LOW	(0 << 0)
 #define GICD_ICFGR_POL_HIGH	(1 << 0)
@@ -164,7 +169,7 @@ gic_init_secondary(device_t dev)
 		gic_d_write_4(sc, GICD_IPRIORITYR(i >> 2), 0);
 
 	/* Set all the interrupts to be in Group 0 (secure) */
-	for (i = 0; i < sc->nirqs; i += 32) {
+	for (i = 0; GIC_SUPPORT_SECEXT(sc) && i < sc->nirqs; i += 32) {
 		gic_d_write_4(sc, GICD_IGROUPR(i >> 5), 0);
 	}
 
@@ -221,8 +226,8 @@ arm_gic_attach(device_t dev)
 	gic_d_write_4(sc, GICD_CTLR, 0x00);
 
 	/* Get the number of interrupts */
-	sc->nirqs = gic_d_read_4(sc, GICD_TYPER);
-	sc->nirqs = 32 * ((sc->nirqs & 0x1f) + 1);
+	sc->typer = gic_d_read_4(sc, GICD_TYPER);
+	sc->nirqs = 32 * ((sc->typer & 0x1f) + 1);
 
 	arm_register_root_pic(dev, sc->nirqs);
 
@@ -257,7 +262,7 @@ arm_gic_attach(device_t dev)
 	}
 
 	/* Set all the interrupts to be in Group 0 (secure) */
-	for (i = 0; i < sc->nirqs; i += 32) {
+	for (i = 0; GIC_SUPPORT_SECEXT(sc) && i < sc->nirqs; i += 32) {
 		gic_d_write_4(sc, GICD_IGROUPR(i >> 5), 0);
 	}
 
diff --git a/sys/arm64/arm64/gic.h b/sys/arm64/arm64/gic.h
index d22d43b..a8ba6a8 100644
--- a/sys/arm64/arm64/gic.h
+++ b/sys/arm64/arm64/gic.h
@@ -49,6 +49,7 @@ struct arm_gic_softc {
 	uint8_t			ver;
 	struct mtx		mutex;
 	uint32_t		nirqs;
+	uint32_t		typer;
 };
 
 DECLARE_CLASS(arm_gicv2m_driver);