[PATCH 3/3] irqchip/gic-v3: Don't register a redistributor that was never counted

[Fuad Tabba <fuad.tabba@linux.dev>]

gic_acpi_match_gicc() counts only the enabled GICCs with a non-zero
gicr_base_address, and that count sizes redist_regs[], but
gic_acpi_parse_madt_gicc() registers every enabled one. For an enabled
GICC with a zero GICR base, gic_acpi_register_redist() therefore writes
a struct redist_region past the end of the array.

Commit fa2dabe57220e ("irqchip/gic-v3: Don't return errors from
gic_acpi_match_gicc()") removed the check that kept the two consistent;
its message says such entries are still caught by gic_populate_rdist(),
but that runs from gic_cpu_init(), after the write. Skip the entry
instead.

Fixes: fa2dabe57220e ("irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc()")
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
---
 drivers/irqchip/irq-gic-v3.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 6e1fa5b247fc4..fb6a0570fb154 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -2344,6 +2344,12 @@ gic_acpi_parse_madt_gicc(union acpi_subtable_headers *header,
 		return 0;
 	}
 
+	/* Not counted by gic_acpi_match_gicc(), so there is no slot for it */
+	if (!gicc->gicr_base_address) {
+		pr_warn(FW_BUG "GICC entry with ACPI UID %u has no GICR base address\n", gicc->uid);
+		return 0;
+	}
+
 	redist_base = ioremap(gicc->gicr_base_address, size);
 	if (!redist_base)
 		return -ENOMEM;
-- 
2.39.5