From ba4b5fb19165823051008e09ca0cbe34915974cf Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Mon, 16 Dec 2019 11:24:57 +0000
Subject: [PATCH] irqchip/gic-v3: Only provision redistributors that are
 enabled in ACPI

commit 926b5dfa6b8dc666ff398044af6906b156e1d949 upstream.

We currently allocate redistributor region structures for
individual redistributors when ACPI doesn't present us with
compact MMIO regions covering multiple redistributors.

It turns out that we allocate these structures even when
the redistributor is flagged as disabled by ACPI. It works
fine until someone actually tries to tarse one of these
structures, and access the corresponding MMIO region.

Instead, track the number of enabled redistributors, and
only allocate what is required. This makes sure that there
is no invalid data to misuse.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reported-by: Heyi Guo <guoheyi@huawei.com>
Tested-by: Heyi Guo <guoheyi@huawei.com>
Link: https://lore.kernel.org/r/20191216062745.63397-1-guoheyi@huawei.com
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index f3e44d6d9255..c09c1eea3319 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1572,6 +1572,7 @@ static struct
 	struct redist_region *redist_regs;
 	u32 nr_redist_regions;
 	bool single_redist;
+	int enabled_rdists;
 	u32 maint_irq;
 	int maint_irq_mode;
 	phys_addr_t vcpu_base;
@@ -1666,8 +1667,10 @@ static int __init gic_acpi_match_gicc(union acpi_subtable_headers *header,
 	 * If GICC is enabled and has valid gicr base address, then it means
 	 * GICR base is presented via GICC
 	 */
-	if ((gicc->flags & ACPI_MADT_ENABLED) && gicc->gicr_base_address)
+	if ((gicc->flags & ACPI_MADT_ENABLED) && gicc->gicr_base_address) {
+		acpi_data.enabled_rdists++;
 		return 0;
+	}
 
 	/*
 	 * It's perfectly valid firmware can pass disabled GICC entry, driver
@@ -1697,8 +1700,10 @@ static int __init gic_acpi_count_gicr_regions(void)
 
 	count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
 				      gic_acpi_match_gicc, 0);
-	if (count > 0)
+	if (count > 0) {
 		acpi_data.single_redist = true;
+		count = acpi_data.enabled_rdists;
+	}
 
 	return count;
 }
-- 
2.7.4