lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:	Thu, 10 Jul 2014 15:32:25 +0200
From:	Tomeu Vizoso <tomeu.vizoso@...labora.com>
To:	Stephen Warren <swarren@...dotorg.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Mike Turquette <mturquette@...aro.org>, rabin@....in,
	linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, tomasz.figa@...il.com
Cc:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>,
	Tomeu Vizoso <tomeu.vizoso@...labora.com>
Subject: [RFC v3 4/5] clk: per-user clock accounting for debug

When a clock has multiple users, the WARNING on imbalance of
enable/disable may not show the guilty party since although they may
have commited the error earlier, the warning is emitted later when some
other user, presumably innocent, disables the clock.

Provide per-user clock enable/disable accounting and disabler tracking
in order to help debug these problems.

Based on previous work by Rabin Vincent <rabin@....in>.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@...labora.com>
---
 drivers/clk/clk.c           | 35 +++++++++++++++++++++++++++++++----
 drivers/clk/clk.h           |  3 ++-
 drivers/clk/clkdev.c        | 16 ++++++++++++----
 include/linux/clk-private.h |  4 ++++
 4 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index cc1d09b..9d51900 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -568,7 +568,8 @@ static int clk_disable_unused(void)
 }
 late_initcall_sync(clk_disable_unused);
 
-struct clk *__clk_create_clk(struct clk_core *clk_core)
+struct clk *__clk_create_clk(struct clk_core *clk_core, const char *dev,
+			     const char *con)
 {
 	struct clk *clk;
 
@@ -581,6 +582,8 @@ struct clk *__clk_create_clk(struct clk_core *clk_core)
 		return ERR_PTR(-ENOMEM);
 
 	clk->core = clk_core;
+	clk->dev_id = dev;
+	clk->con_id = con;
 
 	return clk;
 }
@@ -955,7 +958,20 @@ EXPORT_SYMBOL_GPL(clk_provider_disable);
  */
 void clk_disable(struct clk *clk_user)
 {
-	clk_provider_disable(clk_to_clk_core(clk_user));
+	struct clk_core *clk = clk_to_clk_core(clk_user);
+	unsigned long flags;
+
+	flags = clk_enable_lock();
+	if (!WARN(clk_user->enable_count == 0,
+		  "incorrect disable clk dev %s con %s last disabler %pF\n",
+		  clk_user->dev_id, clk_user->con_id, clk_user->last_disable)) {
+
+		clk_user->last_disable = __builtin_return_address(0);
+		clk_user->enable_count--;
+
+		__clk_disable(clk);
+	}
+	clk_enable_unlock(flags);
 }
 EXPORT_SYMBOL_GPL(clk_disable);
 
@@ -1016,7 +1032,17 @@ EXPORT_SYMBOL_GPL(clk_provider_enable);
  */
 int clk_enable(struct clk *clk_user)
 {
-	return clk_provider_enable(clk_to_clk_core(clk_user));
+	struct clk_core *clk = clk_to_clk_core(clk_user);
+	unsigned long flags;
+	int ret;
+
+	flags = clk_enable_lock();
+	ret = __clk_enable(clk);
+	if (!ret)
+		clk_user->enable_count++;
+	clk_enable_unlock(flags);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(clk_enable);
 
@@ -1692,8 +1718,9 @@ EXPORT_SYMBOL_GPL(clk_provider_get_parent);
 struct clk *clk_get_parent(struct clk *clk_user)
 {
 	struct clk_core *clk = clk_to_clk_core(clk_user);
+	struct clk_core *parent = clk_provider_get_parent(clk);
 
-	return __clk_create_clk(clk_provider_get_parent(clk));
+	return __clk_create_clk(parent, clk_user->dev_id, clk_user->con_id);
 }
 EXPORT_SYMBOL_GPL(clk_get_parent);
 
diff --git a/drivers/clk/clk.h b/drivers/clk/clk.h
index 4d7398f..3987594 100644
--- a/drivers/clk/clk.h
+++ b/drivers/clk/clk.h
@@ -23,5 +23,6 @@ static inline struct clk_core *clk_to_clk_core(struct clk *clk)
 {
 	return clk->core;
 }
-struct clk *__clk_create_clk(struct clk_core *clk_core);
+struct clk *__clk_create_clk(struct clk_core *clk_core, const char *dev,
+			     const char *con);
 #endif
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 10020b2..6ea91bf 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -76,7 +76,9 @@ struct clk_core *of_clk_provider_get(struct device_node *np, int index)
 
 struct clk *of_clk_get(struct device_node *np, int index)
 {
-	return __clk_create_clk(of_clk_provider_get(np, index));
+	struct clk_core *clk = of_clk_provider_get(np, index);
+
+	return __clk_create_clk(clk, np->full_name, NULL);
 }
 EXPORT_SYMBOL(of_clk_get);
 
@@ -128,7 +130,9 @@ struct clk_core *of_clk_provider_get_by_name(struct device_node *np, const char
  */
 struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
 {
-	return __clk_create_clk(of_clk_provider_get_by_name(np, name));
+	struct clk_core *clk = of_clk_provider_get_by_name(np, name);
+
+	return __clk_create_clk(clk, np->full_name, NULL);
 }
 EXPORT_SYMBOL(of_clk_get_by_name);
 #endif
@@ -195,7 +199,9 @@ EXPORT_SYMBOL_GPL(clk_provider_get_sys);
 
 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
 {
-	return __clk_create_clk(clk_provider_get_sys(dev_id, con_id));
+	struct clk_core *clk = clk_provider_get_sys(dev_id, con_id);
+
+	return __clk_create_clk(clk, dev_id, con_id);
 }
 EXPORT_SYMBOL(clk_get_sys);
 
@@ -218,7 +224,9 @@ EXPORT_SYMBOL(clk_provider_get);
 
 struct clk *clk_get(struct device *dev, const char *con_id)
 {
-	return __clk_create_clk(clk_provider_get(dev, con_id));
+	const char *dev_id = dev ? dev_name(dev) : NULL;
+
+	return __clk_create_clk(clk_provider_get(dev, con_id), dev_id, con_id);
 }
 EXPORT_SYMBOL(clk_get);
 
diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
index 2c1ece9..9657fc8 100644
--- a/include/linux/clk-private.h
+++ b/include/linux/clk-private.h
@@ -57,6 +57,10 @@ struct clk_core {
 
 struct clk {
 	struct clk_core	*core;
+	unsigned int	enable_count;
+	const char	*dev_id;
+	const char	*con_id;
+	void		*last_disable;
 };
 
 /*
-- 
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists