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Subject[PATCH 1/2] pinctrl: armada-37xx: make irq_lock a raw spinlock to avoid invalid wait context
Date
The irqchip->irq_set_type method is called by __irq_set_trigger() under
the desc->lock raw spinlock.

The armada-37xx implementation, armada_37xx_irq_set_type(), takes a
plain spinlock, the kind that becomes 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.

Replace the driver's irq_lock with a raw spinlock, to disable preemption
even on RT.

Fixes: 2f227605394b ("pinctrl: armada-37xx: Add irqchip support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
drivers/pinctrl/mvebu/pinctrl-armada-37xx.c | 38 ++++++++++-----------
1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c b/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c
index a140b6bfbfaa..8fddc67271b4 100644
--- a/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c
+++ b/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c
@@ -102,7 +102,7 @@ struct armada_37xx_pinctrl {
struct device *dev;
struct gpio_chip gpio_chip;
struct irq_chip irq_chip;
- spinlock_t irq_lock;
+ raw_spinlock_t irq_lock;
struct pinctrl_desc pctl;
struct pinctrl_dev *pctl_dev;
struct armada_37xx_pin_group *groups;
@@ -523,9 +523,9 @@ static void armada_37xx_irq_ack(struct irq_data *d)
unsigned long flags;

armada_37xx_irq_update_reg(&reg, d);
- spin_lock_irqsave(&info->irq_lock, flags);
+ raw_spin_lock_irqsave(&info->irq_lock, flags);
writel(d->mask, info->base + reg);
- spin_unlock_irqrestore(&info->irq_lock, flags);
+ raw_spin_unlock_irqrestore(&info->irq_lock, flags);
}

static void armada_37xx_irq_mask(struct irq_data *d)
@@ -536,10 +536,10 @@ static void armada_37xx_irq_mask(struct irq_data *d)
unsigned long flags;

armada_37xx_irq_update_reg(&reg, d);
- spin_lock_irqsave(&info->irq_lock, flags);
+ raw_spin_lock_irqsave(&info->irq_lock, flags);
val = readl(info->base + reg);
writel(val & ~d->mask, info->base + reg);
- spin_unlock_irqrestore(&info->irq_lock, flags);
+ raw_spin_unlock_irqrestore(&info->irq_lock, flags);
}

static void armada_37xx_irq_unmask(struct irq_data *d)
@@ -550,10 +550,10 @@ static void armada_37xx_irq_unmask(struct irq_data *d)
unsigned long flags;

armada_37xx_irq_update_reg(&reg, d);
- spin_lock_irqsave(&info->irq_lock, flags);
+ raw_spin_lock_irqsave(&info->irq_lock, flags);
val = readl(info->base + reg);
writel(val | d->mask, info->base + reg);
- spin_unlock_irqrestore(&info->irq_lock, flags);
+ raw_spin_unlock_irqrestore(&info->irq_lock, flags);
}

static int armada_37xx_irq_set_wake(struct irq_data *d, unsigned int on)
@@ -564,14 +564,14 @@ static int armada_37xx_irq_set_wake(struct irq_data *d, unsigned int on)
unsigned long flags;

armada_37xx_irq_update_reg(&reg, d);
- spin_lock_irqsave(&info->irq_lock, flags);
+ raw_spin_lock_irqsave(&info->irq_lock, flags);
val = readl(info->base + reg);
if (on)
val |= (BIT(d->hwirq % GPIO_PER_REG));
else
val &= ~(BIT(d->hwirq % GPIO_PER_REG));
writel(val, info->base + reg);
- spin_unlock_irqrestore(&info->irq_lock, flags);
+ raw_spin_unlock_irqrestore(&info->irq_lock, flags);

return 0;
}
@@ -583,7 +583,7 @@ static int armada_37xx_irq_set_type(struct irq_data *d, unsigned int type)
u32 val, reg = IRQ_POL;
unsigned long flags;

- spin_lock_irqsave(&info->irq_lock, flags);
+ raw_spin_lock_irqsave(&info->irq_lock, flags);
armada_37xx_irq_update_reg(&reg, d);
val = readl(info->base + reg);
switch (type) {
@@ -607,11 +607,11 @@ static int armada_37xx_irq_set_type(struct irq_data *d, unsigned int type)
break;
}
default:
- spin_unlock_irqrestore(&info->irq_lock, flags);
+ raw_spin_unlock_irqrestore(&info->irq_lock, flags);
return -EINVAL;
}
writel(val, info->base + reg);
- spin_unlock_irqrestore(&info->irq_lock, flags);
+ raw_spin_unlock_irqrestore(&info->irq_lock, flags);

return 0;
}
@@ -626,7 +626,7 @@ static int armada_37xx_edge_both_irq_swap_pol(struct armada_37xx_pinctrl *info,

regmap_read(info->regmap, INPUT_VAL + 4*reg_idx, &l);

- spin_lock_irqsave(&info->irq_lock, flags);
+ raw_spin_lock_irqsave(&info->irq_lock, flags);
p = readl(info->base + IRQ_POL + 4 * reg_idx);
if ((p ^ l) & (1 << bit_num)) {
/*
@@ -647,7 +647,7 @@ static int armada_37xx_edge_both_irq_swap_pol(struct armada_37xx_pinctrl *info,
ret = -1;
}

- spin_unlock_irqrestore(&info->irq_lock, flags);
+ raw_spin_unlock_irqrestore(&info->irq_lock, flags);
return ret;
}

@@ -664,11 +664,11 @@ static void armada_37xx_irq_handler(struct irq_desc *desc)
u32 status;
unsigned long flags;

- spin_lock_irqsave(&info->irq_lock, flags);
+ raw_spin_lock_irqsave(&info->irq_lock, flags);
status = readl_relaxed(info->base + IRQ_STATUS + 4 * i);
/* Manage only the interrupt that was enabled */
status &= readl_relaxed(info->base + IRQ_EN + 4 * i);
- spin_unlock_irqrestore(&info->irq_lock, flags);
+ raw_spin_unlock_irqrestore(&info->irq_lock, flags);
while (status) {
u32 hwirq = ffs(status) - 1;
u32 virq = irq_find_mapping(d, hwirq +
@@ -695,12 +695,12 @@ static void armada_37xx_irq_handler(struct irq_desc *desc)

update_status:
/* Update status in case a new IRQ appears */
- spin_lock_irqsave(&info->irq_lock, flags);
+ raw_spin_lock_irqsave(&info->irq_lock, flags);
status = readl_relaxed(info->base +
IRQ_STATUS + 4 * i);
/* Manage only the interrupt that was enabled */
status &= readl_relaxed(info->base + IRQ_EN + 4 * i);
- spin_unlock_irqrestore(&info->irq_lock, flags);
+ raw_spin_unlock_irqrestore(&info->irq_lock, flags);
}
}
chained_irq_exit(chip, desc);
@@ -731,7 +731,7 @@ static int armada_37xx_irqchip_register(struct platform_device *pdev,
struct device *dev = &pdev->dev;
unsigned int i, nr_irq_parent;

- spin_lock_init(&info->irq_lock);
+ raw_spin_lock_init(&info->irq_lock);

nr_irq_parent = of_irq_count(np);
if (!nr_irq_parent) {
--
2.34.1
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