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irqchip/ls-extirq: Fix invalid wait context by avoiding to use regmap 

The irqchip->irq_set_type method is called by __irq_set_trigger() under
the desc->lock raw spinlock.

The ls-extirq implementation, ls_extirq_irq_set_type(), uses an MMIO
regmap created by of_syscon_register(), which uses plain spinlocks
(the kind that are sleepable on RT).

Therefore, this is an invalid locking scheme for which we get a kernel
splat stating just that ("[ BUG: Invalid wait context ]"), because the
context in which the plain spinlock may sleep is atomic due to the raw
spinlock. We need to go raw spinlocks all the way.

Make this driver ioremap its INTPCR register on its own, and stop
relying on syscon to provide a regmap.

Fixes: 0dcd9f8727 ("irqchip: Add support for Layerscape external interrupt lines")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
[maz: trimmed down commit log]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220728144254.175385-1-vladimir.oltean@nxp.com
This commit is contained in:
Vladimir Oltean 2022-07-28 17:42:54 +03:00 committed by Marc Zyngier
parent 732d69c80c
commit 1b00adce8a
1 changed files with 63 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

87
drivers/irqchip/irq-ls-extirq.c
View File

@ -6,8 +6,7 @@
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include <dt-bindings/interrupt-controller/arm-gic.h>
@ -16,13 +15,41 @@
#define LS1021A_SCFGREVCR 0x200
struct ls_extirq_data {
struct regmap *syscon;
u32 intpcr;
void __iomem *intpcr;
raw_spinlock_t lock;
bool big_endian;
bool is_ls1021a_or_ls1043a;
u32 nirq;
struct irq_fwspec map[MAXIRQ];
};
static void ls_extirq_intpcr_rmw(struct ls_extirq_data *priv, u32 mask,
u32 value)
{
u32 intpcr;
/*
* Serialize concurrent calls to ls_extirq_set_type() from multiple
* IRQ descriptors, making sure the read-modify-write is atomic.
*/
raw_spin_lock(&priv->lock);
if (priv->big_endian)
intpcr = ioread32be(priv->intpcr);
else
intpcr = ioread32(priv->intpcr);
intpcr &= ~mask;
intpcr |= value;
if (priv->big_endian)
iowrite32be(intpcr, priv->intpcr);
else
iowrite32(intpcr, priv->intpcr);
raw_spin_unlock(&priv->lock);
}
static int
ls_extirq_set_type(struct irq_data *data, unsigned int type)
{
@ -51,7 +78,8 @@ ls_extirq_set_type(struct irq_data *data, unsigned int type)
default:
return -EINVAL;
}
regmap_update_bits(priv->syscon, priv->intpcr, mask, value);
ls_extirq_intpcr_rmw(priv, mask, value);
return irq_chip_set_type_parent(data, type);
}
@ -143,7 +171,6 @@ ls_extirq_parse_map(struct ls_extirq_data *priv, struct device_node *node)
static int __init
ls_extirq_of_init(struct device_node *node, struct device_node *parent)
{
struct irq_domain *domain, *parent_domain;
struct ls_extirq_data *priv;
int ret;
@ -151,40 +178,52 @@ ls_extirq_of_init(struct device_node *node, struct device_node *parent)
parent_domain = irq_find_host(parent);
if (!parent_domain) {
pr_err("Cannot find parent domain\n");
return -ENODEV;
ret = -ENODEV;
goto err_irq_find_host;
}
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->syscon = syscon_node_to_regmap(node->parent);
if (IS_ERR(priv->syscon)) {
ret = PTR_ERR(priv->syscon);
pr_err("Failed to lookup parent regmap\n");
goto out;
if (!priv) {
ret = -ENOMEM;
goto err_alloc_priv;
}
ret = of_property_read_u32(node, "reg", &priv->intpcr);
if (ret) {
pr_err("Missing INTPCR offset value\n");
goto out;
/*
* All extirq OF nodes are under a scfg/syscon node with
* the 'ranges' property
*/
priv->intpcr = of_iomap(node, 0);
if (!priv->intpcr) {
pr_err("Cannot ioremap OF node %pOF\n", node);
ret = -ENOMEM;
goto err_iomap;
}
ret = ls_extirq_parse_map(priv, node);
if (ret)
goto out;
goto err_parse_map;
priv->big_endian = of_device_is_big_endian(parent);
priv->is_ls1021a_or_ls1043a = of_device_is_compatible(node, "fsl,ls1021a-extirq") ||
of_device_is_compatible(node, "fsl,ls1043a-extirq");
raw_spin_lock_init(&priv->lock);
domain = irq_domain_add_hierarchy(parent_domain, 0, priv->nirq, node,
&extirq_domain_ops, priv);
if (!domain)
if (!domain) {
ret = -ENOMEM;
goto err_add_hierarchy;
}
out:
if (ret)
kfree(priv);
return 0;
err_add_hierarchy:
err_parse_map:
iounmap(priv->intpcr);
err_iomap:
kfree(priv);
err_alloc_priv:
err_irq_find_host:
return ret;
}