From: Vladimir Oltean <vladimir.oltean@nxp.com>
To: Mark Brown <broonie@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Lee Jones <lee.jones@linaro.org>, Arnd Bergmann <arnd@arndb.de>,
Thomas Gleixner <tglx@linutronix.de>,
Marc Zyngier <maz@kernel.org>,
Hou Zhiqiang <Zhiqiang.Hou@nxp.com>, Biwen Li <biwen.li@nxp.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] regmap: teach regmap to use raw spinlocks if requested in the config
Date: Wed, 25 Aug 2021 23:50:40 +0300 [thread overview]
Message-ID: <20210825205041.927788-2-vladimir.oltean@nxp.com> (raw)
In-Reply-To: <20210825205041.927788-1-vladimir.oltean@nxp.com>
Some drivers might access regmap in a context where a raw spinlock is
held. An example is drivers/irqchip/irq-ls-extirq.c, which calls
regmap_update_bits() from struct irq_chip :: irq_set_type, which is a
method called by __irq_set_trigger() under the desc->lock raw spin lock.
Since desc->lock is a raw spin lock and the regmap internal lock for
mmio is a plain spinlock (which can become sleepable on RT), this is an
invalid locking scheme and we get a splat stating that this is a
"[ BUG: Invalid wait context ]".
It seems reasonable for regmap to have an option use a raw spinlock too,
so add that in the config such that drivers can request it.
Suggested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
drivers/base/regmap/internal.h | 4 ++++
drivers/base/regmap/regmap.c | 35 +++++++++++++++++++++++++++++-----
include/linux/regmap.h | 2 ++
3 files changed, 36 insertions(+), 5 deletions(-)
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 0097696c31de..b1905916f7af 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -53,6 +53,10 @@ struct regmap {
spinlock_t spinlock;
unsigned long spinlock_flags;
};
+ struct {
+ raw_spinlock_t raw_spinlock;
+ unsigned long raw_spinlock_flags;
+ };
};
regmap_lock lock;
regmap_unlock unlock;
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index fe3e38dd5324..e7ae477d2fcf 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -533,6 +533,23 @@ __releases(&map->spinlock)
spin_unlock_irqrestore(&map->spinlock, map->spinlock_flags);
}
+static void regmap_lock_raw_spinlock(void *__map)
+__acquires(&map->raw_spinlock)
+{
+ struct regmap *map = __map;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&map->raw_spinlock, flags);
+ map->raw_spinlock_flags = flags;
+}
+
+static void regmap_unlock_raw_spinlock(void *__map)
+__releases(&map->raw_spinlock)
+{
+ struct regmap *map = __map;
+ raw_spin_unlock_irqrestore(&map->raw_spinlock, map->raw_spinlock_flags);
+}
+
static void dev_get_regmap_release(struct device *dev, void *res)
{
/*
@@ -770,11 +787,19 @@ struct regmap *__regmap_init(struct device *dev,
} else {
if ((bus && bus->fast_io) ||
config->fast_io) {
- spin_lock_init(&map->spinlock);
- map->lock = regmap_lock_spinlock;
- map->unlock = regmap_unlock_spinlock;
- lockdep_set_class_and_name(&map->spinlock,
- lock_key, lock_name);
+ if (config->use_raw_spinlock) {
+ raw_spin_lock_init(&map->raw_spinlock);
+ map->lock = regmap_lock_raw_spinlock;
+ map->unlock = regmap_unlock_raw_spinlock;
+ lockdep_set_class_and_name(&map->raw_spinlock,
+ lock_key, lock_name);
+ } else {
+ spin_lock_init(&map->spinlock);
+ map->lock = regmap_lock_spinlock;
+ map->unlock = regmap_unlock_spinlock;
+ lockdep_set_class_and_name(&map->spinlock,
+ lock_key, lock_name);
+ }
} else {
mutex_init(&map->mutex);
map->lock = regmap_lock_mutex;
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index f5f08dd0a116..7a3cda794501 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -344,6 +344,7 @@ typedef void (*regmap_unlock)(void *);
* @ranges: Array of configuration entries for virtual address ranges.
* @num_ranges: Number of range configuration entries.
* @use_hwlock: Indicate if a hardware spinlock should be used.
+ * @use_raw_spinlock: Indicate if a raw spinlock should be used.
* @hwlock_id: Specify the hardware spinlock id.
* @hwlock_mode: The hardware spinlock mode, should be HWLOCK_IRQSTATE,
* HWLOCK_IRQ or 0.
@@ -403,6 +404,7 @@ struct regmap_config {
unsigned int num_ranges;
bool use_hwlock;
+ bool use_raw_spinlock;
unsigned int hwlock_id;
unsigned int hwlock_mode;
--
2.25.1
next prev parent reply other threads:[~2021-08-25 20:51 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-25 20:50 [PATCH 0/2] Use raw spinlocks in the ls-extirq driver Vladimir Oltean
2021-08-25 20:50 ` Vladimir Oltean [this message]
2021-08-26 23:01 ` [PATCH 1/2] regmap: teach regmap to use raw spinlocks if requested in the config Thomas Gleixner
2021-08-27 16:12 ` Vladimir Oltean
2021-08-27 19:59 ` Thomas Gleixner
2021-08-30 10:49 ` Vladimir Oltean
2021-08-30 11:02 ` Rasmus Villemoes
2021-08-30 12:42 ` Mark Brown
2021-08-30 12:19 ` Mark Brown
2021-08-30 14:16 ` Thomas Gleixner
2021-09-01 16:05 ` Mark Brown
2021-09-02 8:35 ` Thomas Gleixner
2021-08-25 20:50 ` [PATCH 2/2] mfd: syscon: request a regmap with raw spinlocks for some devices Vladimir Oltean
2021-08-25 21:24 ` Arnd Bergmann
2021-08-25 22:00 ` Vladimir Oltean
2021-08-26 9:24 ` Arnd Bergmann
2021-08-26 13:57 ` Vladimir Oltean
2021-08-26 14:48 ` Arnd Bergmann
2021-09-06 9:18 ` Lee Jones
2021-08-26 12:51 ` (subset) [PATCH 0/2] Use raw spinlocks in the ls-extirq driver Mark Brown
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210825205041.927788-2-vladimir.oltean@nxp.com \
--to=vladimir.oltean@nxp.com \
--cc=Zhiqiang.Hou@nxp.com \
--cc=arnd@arndb.de \
--cc=biwen.li@nxp.com \
--cc=broonie@kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=lee.jones@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=maz@kernel.org \
--cc=rafael@kernel.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).