Re: [PATCH 00/16] irqchip: harden initialization error paths

[Nam Cao <namcao@linutronix.de>]

Thomas Gleixner <tglx@kernel.org> writes:
> A lot of these "fixes" are purely cosmetic and create a false sense of
> correctness because if the initialization of the root interrupt
> controller of a system fails then machine won't boot at all.
>
> So instead of adding tons of cleanups we rather go and analyze which
> controllers are actually root controllers and therefore essential for
> the machine to boot. For those the only valid error handling is:

PLIC is one of those. I will send a patch.

Nam

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index 5b0dac104814..0fbecaf0d317 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -643,13 +643,11 @@ static int plic_probe(struct fwnode_handle *fwnode)
 
 	error = plic_parse_nr_irqs_and_contexts(fwnode, &nr_irqs, &nr_contexts, &gsi_base, &id);
 	if (error)
-		goto fail_free_regs;
+		return error;
 
 	priv = kzalloc_obj(*priv);
-	if (!priv) {
-		error = -ENOMEM;
-		goto fail_free_regs;
-	}
+	if (!priv)
+		return -ENOMEM;
 
 	priv->fwnode = fwnode;
 	priv->plic_quirks = plic_quirks;
@@ -668,10 +666,8 @@ static int plic_probe(struct fwnode_handle *fwnode)
 	priv->acpi_plic_id = id;
 
 	priv->prio_save = bitmap_zalloc(nr_irqs, GFP_KERNEL);
-	if (!priv->prio_save) {
-		error = -ENOMEM;
-		goto fail_free_priv;
-	}
+	if (!priv->prio_save)
+		return -ENOMEM;
 
 	for (i = 0; i < nr_contexts; i++) {
 		error = plic_parse_context_parent(fwnode, i, &parent_hwirq, &cpu,
@@ -735,10 +731,8 @@ static int plic_probe(struct fwnode_handle *fwnode)
 
 		handler->enable_save = kcalloc(priv->irq_groups, sizeof(*handler->enable_save),
 					       GFP_KERNEL);
-		if (!handler->enable_save) {
-			error = -ENOMEM;
-			goto fail_cleanup_contexts;
-		}
+		if (!handler->enable_save)
+			return -ENOMEM;
 done:
 		for_each_device_irq(hwirq, priv) {
 			plic_toggle(handler, hwirq, 0);
@@ -748,10 +742,8 @@ static int plic_probe(struct fwnode_handle *fwnode)
 	}
 
 	priv->irqdomain = irq_domain_create_linear(fwnode, nr_irqs, &plic_irqdomain_ops, priv);
-	if (WARN_ON(!priv->irqdomain)) {
-		error = -ENOMEM;
-		goto fail_cleanup_contexts;
-	}
+	if (!priv->irqdomain)
+		return -ENOMEM;
 
 	/*
 	 * We can have multiple PLIC instances so setup global state
@@ -799,33 +791,13 @@ static int plic_probe(struct fwnode_handle *fwnode)
 	pr_info("%pfwP: mapped %d interrupts with %d handlers for %d contexts.\n",
 		fwnode, nr_irqs, nr_handlers, nr_contexts);
 	return 0;
-
-fail_cleanup_contexts:
-	for (i = 0; i < nr_contexts; i++) {
-		if (plic_parse_context_parent(fwnode, i, &parent_hwirq, &cpu, priv->acpi_plic_id))
-			continue;
-		if (parent_hwirq != RV_IRQ_EXT || cpu < 0)
-			continue;
-
-		handler = per_cpu_ptr(&plic_handlers, cpu);
-		handler->present = false;
-		handler->hart_base = NULL;
-		handler->enable_base = NULL;
-		kfree(handler->enable_save);
-		handler->enable_save = NULL;
-		handler->priv = NULL;
-	}
-	bitmap_free(priv->prio_save);
-fail_free_priv:
-	kfree(priv);
-fail_free_regs:
-	iounmap(regs);
-	return error;
 }
 
 static int plic_platform_probe(struct platform_device *pdev)
 {
-	return plic_probe(pdev->dev.fwnode);
+	if (plic_probe(pdev->dev.fwnode))
+		panic("Failed to initialize root interrupt controller\n");
+	return 0;
 }
 
 static struct platform_driver plic_driver = {
@@ -842,7 +814,10 @@ builtin_platform_driver(plic_driver);
 static int __init plic_early_probe(struct device_node *node,
 				   struct device_node *parent)
 {
-	return plic_probe(&node->fwnode);
+	if (plic_probe(&node->fwnode))
+		panic("Failed to initialize root interrupt controller\n");
+	return 0;
 }
 
 IRQCHIP_DECLARE(riscv, "allwinner,sun20i-d1-plic", plic_early_probe);