[PATCH 2/5] irqchip/gic-v3: Support secure-donated non-secure SGIs

Sudeep Holla
2026-04-12T17:05:47Z

Parse secure-donated SGI ranges from the firmware, reject invalid
interrupt specifiers, and allow devicetree consumers to map only the
SGIs explicitly donated by the secure side to non-secure software.

Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
---
drivers/irqchip/irq-gic-v3.c | 86 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 86 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 20f13b686ab2..cc7720d9fb0e 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -35,6 +35,8 @@
#include <asm/smp_plat.h>
#include <asm/virt.h>

+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
#include "irq-gic-common.h"

static u8 dist_prio_irq __ro_after_init = GICV3_PRIO_IRQ;
@@ -65,6 +67,7 @@ struct gic_chip_data {
u64 flags;
bool has_rss;
unsigned int ppi_nr;
+ u16 donated_sgi_mask;
struct partition_affinity *parts;
unsigned int nr_parts;
};
@@ -95,6 +98,7 @@ static bool nmi_support_forbidden;
* with hwirq IDs, is simplified by accounting for all 16.
*/
#define SGI_NR 16
+#define GIC_SGI_IPI_NR 8

/*
* The behaviours of RPR and PMR registers differ depending on the value of
@@ -119,6 +123,74 @@ static bool nmi_support_forbidden;
*/
static DEFINE_STATIC_KEY_FALSE(supports_pseudo_nmis);

+static bool gic_sgi_is_donated_to_ns(unsigned int sgi)
+{
+ return sgi < SGI_NR && (gic_data.donated_sgi_mask & BIT(sgi));
+}
+
+static int __init gic_of_init_donated_sgi_ranges(struct device_node *node)
+{
+ const char *propname = "arm,secure-donated-ns-sgi-ranges";
+ int count, i;
+ u32 *ranges;
+ u16 mask = 0;
+
+ count = of_property_count_u32_elems(node, propname);
+ if (count < 0) {
+ if (count == -EINVAL)
+ return 0;
+
+ pr_err("%pOF: unable to read %s\n", node, propname);
+ return count;
+ }
+
+ if (!count)
+ return 0;
+
+ if (count % 2) {
+ pr_err("%pOF: %s must contain <sgi span> pairs\n",
+ node, propname);
+ return -EINVAL;
+ }
+
+ ranges = kcalloc(count, sizeof(*ranges), GFP_KERNEL);
+ if (!ranges)
+ return -ENOMEM;
+
+ if (of_property_read_u32_array(node, propname, ranges, count)) {
+ pr_err("%pOF: unable to read %s\n", node, propname);
+ kfree(ranges);
+ return -EINVAL;
+ }
+
+ for (i = 0; i < count; i += 2) {
+ u32 sgi = ranges[i];
+ u32 span = ranges[i + 1];
+ u32 end;
+
+ if (sgi < GIC_SGI_IPI_NR || sgi >= SGI_NR || !span || span > 8) {
+ pr_err("%pOF: invalid SGI range <%u %u> in %s\n",
+ node, sgi, span, propname);
+ kfree(ranges);
+ return -EINVAL;
+ }
+
+ end = sgi + span;
+ if (end > SGI_NR) {
+ pr_err("%pOF: SGI range <%u %u> exceeds SGI space in %s\n",
+ node, sgi, span, propname);
+ kfree(ranges);
+ return -EINVAL;
+ }
+
+ mask |= GENMASK(end - 1, sgi);
+ }
+
+ kfree(ranges);
+ gic_data.donated_sgi_mask = mask;
+ return 0;
+}
+
static u32 gic_get_pribits(void)
{
u32 pribits;
@@ -1614,6 +1686,12 @@ static int gic_irq_domain_translate(struct irq_domain *d,
case 3: /* EPPI */
*hwirq = fwspec->param[1] + EPPI_BASE_INTID;
break;
+ case GIC_SGI: /* SGI */
+ if (!gic_sgi_is_donated_to_ns(fwspec->param[1]))
+ return -EINVAL;
+
+ *hwirq = fwspec->param[1];
+ break;
case GIC_IRQ_TYPE_LPI: /* LPI */
*hwirq = fwspec->param[1];
break;
@@ -1623,6 +1701,10 @@ static int gic_irq_domain_translate(struct irq_domain *d,

*type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;

+ if (fwspec->param[0] == GIC_SGI &&
+ *type != IRQ_TYPE_EDGE_RISING)
+ return -EINVAL;
+
/*
* Make it clear that broken DTs are... broken.
*/
@@ -2239,6 +2321,10 @@ static int __init gic_of_init(struct device_node *node, struct device_node *pare

gic_enable_of_quirks(node, gic_quirks, &gic_data);

+ err = gic_of_init_donated_sgi_ranges(node);
+ if (err)
+ goto out_unmap_rdist;
+
err = gic_init_bases(dist_phys_base, dist_base, rdist_regs,
nr_redist_regions, redist_stride, &node->fwnode);
if (err)

--
2.43.0