irqchip/gic: Return an error if GIC initialisation fails

If the GIC initialisation fails, then currently we do not return an error
or clean-up afterwards. Although for root controllers, this failure may be
fatal anyway, for secondary controllers, it may not be fatal and so return
an error on failure and clean-up.

Update the functions gic_cpu_init() and gic_pm_init() to return an error
instead of calling BUG() and perform any necessary clean-up.

For non-banked GIC controllers, make sure that we free any memory
allocated if we fail to initialise the IRQ domain. Please note that
free_percpu() only frees memory if the pointer passed to it is not NULL
and so it is unnecessary to check if both pointers are valid or not.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 73 insertions, 26 deletions

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index a8cb86bea544..7cf138286442 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -467,7 +467,7 @@ static void __init gic_dist_init(struct gic_chip_data *gic)
         writel_relaxed(GICD_ENABLE, base + GIC_DIST_CTRL);
 }
 
-static void gic_cpu_init(struct gic_chip_data *gic)
+static int gic_cpu_init(struct gic_chip_data *gic)
 {
         void __iomem *dist_base = gic_data_dist_base(gic);
         void __iomem *base = gic_data_cpu_base(gic);
@@ -483,7 +483,9 @@ static void gic_cpu_init(struct gic_chip_data *gic)
                 /*
                  * Get what the GIC says our CPU mask is.
                  */
-                BUG_ON(cpu >= NR_GIC_CPU_IF);
+                if (WARN_ON(cpu >= NR_GIC_CPU_IF))
+                        return -EINVAL;
+
                 cpu_mask = gic_get_cpumask(gic);
                 gic_cpu_map[cpu] = cpu_mask;
 
@@ -500,6 +502,8 @@ static void gic_cpu_init(struct gic_chip_data *gic)
 
         writel_relaxed(GICC_INT_PRI_THRESHOLD, base + GIC_CPU_PRIMASK);
         gic_cpu_if_up(gic);
+
+        return 0;
 }
 
 int gic_cpu_if_down(unsigned int gic_nr)
@@ -713,26 +717,39 @@ static struct notifier_block gic_notifier_block = {
         .notifier_call = gic_notifier,
 };
 
-static void __init gic_pm_init(struct gic_chip_data *gic)
+static int __init gic_pm_init(struct gic_chip_data *gic)
 {
         gic->saved_ppi_enable = __alloc_percpu(DIV_ROUND_UP(32, 32) * 4,
                 sizeof(u32));
-        BUG_ON(!gic->saved_ppi_enable);
+        if (WARN_ON(!gic->saved_ppi_enable))
+                return -ENOMEM;
 
         gic->saved_ppi_active = __alloc_percpu(DIV_ROUND_UP(32, 32) * 4,
                 sizeof(u32));
-        BUG_ON(!gic->saved_ppi_active);
+        if (WARN_ON(!gic->saved_ppi_active))
+                goto free_ppi_enable;
 
         gic->saved_ppi_conf = __alloc_percpu(DIV_ROUND_UP(32, 16) * 4,
                 sizeof(u32));
-        BUG_ON(!gic->saved_ppi_conf);
+        if (WARN_ON(!gic->saved_ppi_conf))
+                goto free_ppi_active;
 
         if (gic == &gic_data[0])
                 cpu_pm_register_notifier(&gic_notifier_block);
+
+        return 0;
+
+free_ppi_active:
+        free_percpu(gic->saved_ppi_active);
+free_ppi_enable:
+        free_percpu(gic->saved_ppi_enable);
+
+        return -ENOMEM;
 }
 #else
-static void __init gic_pm_init(struct gic_chip_data *gic)
+static int __init gic_pm_init(struct gic_chip_data *gic)
 {
+        return 0;
 }
 #endif
 
@@ -1005,13 +1022,13 @@ static const struct irq_domain_ops gic_irq_domain_ops = {
         .unmap = gic_irq_domain_unmap,
 };
 
-static void __init __gic_init_bases(unsigned int gic_nr, int irq_start,
+static int __init __gic_init_bases(unsigned int gic_nr, int irq_start,
                            void __iomem *dist_base, void __iomem *cpu_base,
                            u32 percpu_offset, struct fwnode_handle *handle)
 {
         irq_hw_number_t hwirq_base;
         struct gic_chip_data *gic;
-        int gic_irqs, irq_base, i;
+        int gic_irqs, irq_base, i, ret;
 
         BUG_ON(gic_nr >= CONFIG_ARM_GIC_MAX_NR);
 
@@ -1026,7 +1043,7 @@ static void __init __gic_init_bases(unsigned int gic_nr, int irq_start,
                 gic->chip.irq_mask = gic_eoimode1_mask_irq;
                 gic->chip.irq_eoi = gic_eoimode1_eoi_irq;
                 gic->chip.irq_set_vcpu_affinity = gic_irq_set_vcpu_affinity;
-                gic->chip.name = "GICv2";
+                gic->chip.name = kasprintf(GFP_KERNEL, "GICv2");
         } else {
                 gic->chip.name = kasprintf(GFP_KERNEL, "GIC-%d", gic_nr);
         }
@@ -1036,17 +1053,16 @@ static void __init __gic_init_bases(unsigned int gic_nr, int irq_start,
                 gic->chip.irq_set_affinity = gic_set_affinity;
 #endif
 
-#ifdef CONFIG_GIC_NON_BANKED
-        if (percpu_offset) { /* Frankein-GIC without banked registers... */
+        if (IS_ENABLED(CONFIG_GIC_NON_BANKED) && percpu_offset) {
+                /* Frankein-GIC without banked registers... */
                 unsigned int cpu;
 
                 gic->dist_base.percpu_base = alloc_percpu(void __iomem *);
                 gic->cpu_base.percpu_base = alloc_percpu(void __iomem *);
                 if (WARN_ON(!gic->dist_base.percpu_base ||
                             !gic->cpu_base.percpu_base)) {
-                        free_percpu(gic->dist_base.percpu_base);
-                        free_percpu(gic->cpu_base.percpu_base);
-                        return;
+                        ret = -ENOMEM;
+                        goto error;
                 }
 
                 for_each_possible_cpu(cpu) {
@@ -1058,9 +1074,8 @@ static void __init __gic_init_bases(unsigned int gic_nr, int irq_start,
                 }
 
                 gic_set_base_accessor(gic, gic_get_percpu_base);
-        } else
-#endif
-        {                       /* Normal, sane GIC... */
+        } else {
+                /* Normal, sane GIC... */
                 WARN(percpu_offset,
                      "GIC_NON_BANKED not enabled, ignoring %08x offset!",
                      percpu_offset);
@@ -1110,8 +1125,10 @@ static void __init __gic_init_bases(unsigned int gic_nr, int irq_start,
                                         hwirq_base, &gic_irq_domain_ops, gic);
         }
 
-        if (WARN_ON(!gic->domain))
-                return;
+        if (WARN_ON(!gic->domain)) {
+                ret = -ENODEV;
+                goto error;
+        }
 
         if (gic_nr == 0) {
                 /*
@@ -1131,8 +1148,25 @@ static void __init __gic_init_bases(unsigned int gic_nr, int irq_start,
         }
 
         gic_dist_init(gic);
-        gic_cpu_init(gic);
-        gic_pm_init(gic);
+        ret = gic_cpu_init(gic);
+        if (ret)
+                goto error;
+
+        ret = gic_pm_init(gic);
+        if (ret)
+                goto error;
+
+        return 0;
+
+error:
+        if (IS_ENABLED(CONFIG_GIC_NON_BANKED) && percpu_offset) {
+                free_percpu(gic->dist_base.percpu_base);
+                free_percpu(gic->cpu_base.percpu_base);
+        }
+
+        kfree(gic->chip.name);
+
+        return ret;
 }
 
 void __init gic_init(unsigned int gic_nr, int irq_start,
@@ -1193,7 +1227,7 @@ gic_of_init(struct device_node *node, struct device_node *parent)
         void __iomem *cpu_base;
         void __iomem *dist_base;
         u32 percpu_offset;
-        int irq;
+        int irq, ret;
 
         if (WARN_ON(!node))
                 return -ENODEV;
@@ -1218,8 +1252,14 @@ gic_of_init(struct device_node *node, struct device_node *parent)
         if (of_property_read_u32(node, "cpu-offset", &percpu_offset))
                 percpu_offset = 0;
 
-        __gic_init_bases(gic_cnt, -1, dist_base, cpu_base, percpu_offset,
+        ret = __gic_init_bases(gic_cnt, -1, dist_base, cpu_base, percpu_offset,
                          &node->fwnode);
+        if (ret) {
+                iounmap(dist_base);
+                iounmap(cpu_base);
+                return ret;
+        }
+
         if (!gic_cnt)
                 gic_init_physaddr(node);
 
@@ -1308,7 +1348,7 @@ static int __init gic_v2_acpi_init(struct acpi_subtable_header *header,
         struct acpi_madt_generic_distributor *dist;
         void __iomem *cpu_base, *dist_base;
         struct fwnode_handle *domain_handle;
-        int count;
+        int count, ret;
 
         /* Collect CPU base addresses */
         count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
@@ -1351,7 +1391,14 @@ static int __init gic_v2_acpi_init(struct acpi_subtable_header *header,
                 return -ENOMEM;
         }
 
-        __gic_init_bases(0, -1, dist_base, cpu_base, 0, domain_handle);
+        ret = __gic_init_bases(0, -1, dist_base, cpu_base, 0, domain_handle);
+        if (ret) {
+                pr_err("Failed to initialise GIC\n");
+                irq_domain_free_fwnode(domain_handle);
+                iounmap(cpu_base);
+                iounmap(dist_base);
+                return ret;
+        }
 
         acpi_set_irq_model(ACPI_IRQ_MODEL_GIC, domain_handle);