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Date: Mon, 18 Apr 2022 00:51:54 +0800
From: Schspa Shi <schspa@...il.com>
To: andy.shevchenko@...il.com
Cc: brgl@...ev.pl, f.fainelli@...il.com, fancer.lancer@...il.com,
hoan@...amperecomputing.com, linus.walleij@...aro.org,
linux-arm-kernel@...ts.infradead.org, linux-gpio@...r.kernel.org,
linux-kernel@...r.kernel.org, opendmb@...il.com, schspa@...il.com
Subject: [PATCH v2 01/15] gpio: use raw spinlock for gpio chip shadowed data
In case of PREEMPT_RT, there is a raw_spinlock -> spinlock dependency
as the lockdep report shows.
__irq_set_handler
irq_get_desc_buslock
__irq_get_desc_lock
raw_spin_lock_irqsave(&desc->lock, *flags); // raw spinlock get here
__irq_do_set_handler
mask_ack_irq
dwapb_irq_ack
spin_lock_irqsave(&gc->bgpio_lock, flags); // sleep able spinlock
irq_put_desc_busunlock
Replace with a raw lock to avoid BUGs. This lock is only used to access
registers, and It's safe to replace with the raw lock without bad
influence.
[ 15.090359][ T1] =============================
[ 15.090365][ T1] [ BUG: Invalid wait context ]
[ 15.090373][ T1] 5.10.59-rt52-00983-g186a6841c682-dirty #3 Not tainted
[ 15.090386][ T1] -----------------------------
[ 15.090392][ T1] swapper/0/1 is trying to lock:
[ 15.090402][ T1] 70ff00018507c188 (&gc->bgpio_lock){....}-{3:3}, at: _raw_spin_lock_irqsave+0x1c/0x28
[ 15.090470][ T1] other info that might help us debug this:
[ 15.090477][ T1] context-{5:5}
[ 15.090485][ T1] 3 locks held by swapper/0/1:
[ 15.090497][ T1] #0: c2ff0001816de1a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock+0x98/0x104
[ 15.090553][ T1] #1: ffff90001485b4b8 (irq_domain_mutex){+.+.}-{4:4}, at: irq_domain_associate+0xbc/0x6d4
[ 15.090606][ T1] #2: 4bff000185d7a8e0 (lock_class){....}-{2:2}, at: _raw_spin_lock_irqsave+0x1c/0x28
[ 15.090654][ T1] stack backtrace:
[ 15.090661][ T1] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.10.59-rt52-00983-g186a6841c682-dirty #3
[ 15.090682][ T1] Hardware name: Horizon Robotics Journey 5 DVB (DT)
[ 15.090692][ T1] Call trace:
......
[ 15.090811][ T1] _raw_spin_lock_irqsave+0x1c/0x28
[ 15.090828][ T1] dwapb_irq_ack+0xb4/0x300
[ 15.090846][ T1] __irq_do_set_handler+0x494/0xb2c
[ 15.090864][ T1] __irq_set_handler+0x74/0x114
[ 15.090881][ T1] irq_set_chip_and_handler_name+0x44/0x58
[ 15.090900][ T1] gpiochip_irq_map+0x210/0x644
......
Changelog:
v1 -> v2:
- Reduce the useless stacktrace.
- Split to series of patches
Link: https://lore.kernel.org/all/20220415165505.30383-1-schspa@gmail.com/
Signed-off-by: Schspa Shi <schspa@...il.com>
---
drivers/gpio/gpio-mmio.c | 22 +++++++++++-----------
include/linux/gpio/driver.h | 2 +-
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/drivers/gpio/gpio-mmio.c b/drivers/gpio/gpio-mmio.c
index c335a0309ba3..d9dff3dc92ae 100644
--- a/drivers/gpio/gpio-mmio.c
+++ b/drivers/gpio/gpio-mmio.c
@@ -220,7 +220,7 @@ static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
unsigned long mask = bgpio_line2mask(gc, gpio);
unsigned long flags;
- spin_lock_irqsave(&gc->bgpio_lock, flags);
+ raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
if (val)
gc->bgpio_data |= mask;
@@ -229,7 +229,7 @@ static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
gc->write_reg(gc->reg_dat, gc->bgpio_data);
- spin_unlock_irqrestore(&gc->bgpio_lock, flags);
+ raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}
static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
@@ -248,7 +248,7 @@ static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
unsigned long mask = bgpio_line2mask(gc, gpio);
unsigned long flags;
- spin_lock_irqsave(&gc->bgpio_lock, flags);
+ raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
if (val)
gc->bgpio_data |= mask;
@@ -257,7 +257,7 @@ static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
gc->write_reg(gc->reg_set, gc->bgpio_data);
- spin_unlock_irqrestore(&gc->bgpio_lock, flags);
+ raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}
static void bgpio_multiple_get_masks(struct gpio_chip *gc,
@@ -286,7 +286,7 @@ static void bgpio_set_multiple_single_reg(struct gpio_chip *gc,
unsigned long flags;
unsigned long set_mask, clear_mask;
- spin_lock_irqsave(&gc->bgpio_lock, flags);
+ raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
bgpio_multiple_get_masks(gc, mask, bits, &set_mask, &clear_mask);
@@ -295,7 +295,7 @@ static void bgpio_set_multiple_single_reg(struct gpio_chip *gc,
gc->write_reg(reg, gc->bgpio_data);
- spin_unlock_irqrestore(&gc->bgpio_lock, flags);
+ raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}
static void bgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
@@ -347,7 +347,7 @@ static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
{
unsigned long flags;
- spin_lock_irqsave(&gc->bgpio_lock, flags);
+ raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
gc->bgpio_dir &= ~bgpio_line2mask(gc, gpio);
@@ -356,7 +356,7 @@ static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
if (gc->reg_dir_out)
gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);
- spin_unlock_irqrestore(&gc->bgpio_lock, flags);
+ raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
return 0;
}
@@ -387,7 +387,7 @@ static void bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
{
unsigned long flags;
- spin_lock_irqsave(&gc->bgpio_lock, flags);
+ raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
gc->bgpio_dir |= bgpio_line2mask(gc, gpio);
@@ -396,7 +396,7 @@ static void bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
if (gc->reg_dir_out)
gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);
- spin_unlock_irqrestore(&gc->bgpio_lock, flags);
+ raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}
static int bgpio_dir_out_dir_first(struct gpio_chip *gc, unsigned int gpio,
@@ -610,7 +610,7 @@ int bgpio_init(struct gpio_chip *gc, struct device *dev,
if (gc->bgpio_bits > BITS_PER_LONG)
return -EINVAL;
- spin_lock_init(&gc->bgpio_lock);
+ raw_spin_lock_init(&gc->bgpio_lock);
gc->parent = dev;
gc->label = dev_name(dev);
gc->base = -1;
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 874aabd270c9..ff8247a19f57 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -445,7 +445,7 @@ struct gpio_chip {
void __iomem *reg_dir_in;
bool bgpio_dir_unreadable;
int bgpio_bits;
- spinlock_t bgpio_lock;
+ raw_spinlock_t bgpio_lock;
unsigned long bgpio_data;
unsigned long bgpio_dir;
#endif /* CONFIG_GPIO_GENERIC */
--
2.24.3 (Apple Git-128)
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