linux-kernel - [PATCH v2 5/8] clk: call the clock init() callback before any other ops callback

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 linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 14 Feb 2018 14:43:37 +0100
From:   Jerome Brunet <jbrunet@...libre.com>
To:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     Jerome Brunet <jbrunet@...libre.com>, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 5/8] clk: call the clock init() callback before any other ops callback

Some clocks may need to initialize things, whatever it is, before
being able to properly operate. Move the .init() call before any
other callback, such recalc_rate() or get_phase(), so the clock
is properly setup before being used.

Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
---

Stephen, Mike,

This change is addressing a problem I have with clock driver I'm working
on. This driver needs the .init() callback to run first is order to answer
correctly .get_phase(). It does not address an existing issue, not one
that I'm aware of at least. This is why I did not put a Fixes tag.

In any case, it makes sense to run init before running anything else.

 drivers/clk/clk.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index cca05ea2c058..9d56be6ead39 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2929,6 +2929,17 @@ static int __clk_core_init(struct clk_core *core)
 		core->orphan = true;
 	}
 
+	/*
+	 * optional platform-specific magic
+	 *
+	 * The .init callback is not used by any of the basic clock types, but
+	 * exists for weird hardware that must perform initialization magic.
+	 * Please consider other ways of solving initialization problems before
+	 * using this callback, as its use is discouraged.
+	 */
+	if (core->ops->init)
+		core->ops->init(core->hw);
+
 	/*
 	 * Set clk's accuracy.  The preferred method is to use
 	 * .recalc_accuracy. For simple clocks and lazy developers the default
@@ -3006,17 +3017,6 @@ static int __clk_core_init(struct clk_core *core)
 		}
 	}
 
-	/*
-	 * optional platform-specific magic
-	 *
-	 * The .init callback is not used by any of the basic clock types, but
-	 * exists for weird hardware that must perform initialization magic.
-	 * Please consider other ways of solving initialization problems before
-	 * using this callback, as its use is discouraged.
-	 */
-	if (core->ops->init)
-		core->ops->init(core->hw);
-
 	kref_init(&core->ref);
 out:
 	clk_pm_runtime_put(core);
-- 
2.14.3