From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Turquette Subject: Re: [Patch 1/3] clk: fix clk_mux_get_parent return's signed value Date: Wed, 29 May 2013 00:21:18 -0700 Message-ID: <20130529072118.6058.14433@quantum> References: <1367475929-32166-1-git-send-email-ambresh@ti.com> <1367475929-32166-2-git-send-email-ambresh@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1367475929-32166-2-git-send-email-ambresh@ti.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org Cc: Nishanth Menon , Rajendra , linux-kernel@vger.kernel.org, Tero Kristo , Ambresh K , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: linux-omap@vger.kernel.org Quoting Ambresh K (2013-05-01 23:25:27) > From: Ambresh K > > If for some reason, the value read from clksel field return > erroneous due to HW bug or improper configuration, then > clk_mux_get_parent should return appropriate error's. > clksel is an omap-centric term. How about: "clk_mux_get_parent should return an error if the value read from the register is erroneous." The general approach looks good to me. Can you submit a V2 which removes all of the clksel-isms and updates definitions for .get_parent functions to avoid the warnings you mentioned in the cover letter? You might find cocinelle useful for that last task. Regards, Mike > Currently if the value read is greater than the number of > available parents clk_mux_get_parent return's signed error > which will result in NULL pointer dereferencing in the > calling functions. > > Signed-off-by: Ambresh K > --- > drivers/clk/clk-mux.c | 2 +- > drivers/clk/clk.c | 12 +++++++++++- > include/linux/clk-provider.h | 4 ++-- > 3 files changed, 14 insertions(+), 4 deletions(-) > > diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c > index 25b1734..be0857e 100644 > --- a/drivers/clk/clk-mux.c > +++ b/drivers/clk/clk-mux.c > @@ -29,7 +29,7 @@ > > #define to_clk_mux(_hw) container_of(_hw, struct clk_mux, hw) > > -static u8 clk_mux_get_parent(struct clk_hw *hw) > +static int clk_mux_get_parent(struct clk_hw *hw) > { > struct clk_mux *mux = to_clk_mux(hw); > int num_parents = __clk_get_num_parents(hw->clk); > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > index 934cfd1..c187321 100644 > --- a/drivers/clk/clk.c > +++ b/drivers/clk/clk.c > @@ -1281,7 +1281,7 @@ EXPORT_SYMBOL_GPL(clk_get_parent); > static struct clk *__clk_init_parent(struct clk *clk) > { > struct clk *ret = NULL; > - u8 index; > + int index; > > /* handle the trivial cases */ > > @@ -1309,6 +1309,11 @@ static struct clk *__clk_init_parent(struct clk *clk) > */ > > index = clk->ops->get_parent(clk->hw); > + if (index < 0) { > + pr_err("%s: clk(%s) invalid parent clk_sel index(%d)\n", > + __func__, clk->name, index); > + goto out; > + } > > if (!clk->parents) > clk->parents = > @@ -1632,6 +1637,11 @@ int __clk_init(struct device *dev, struct clk *clk) > hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) { > if (orphan->ops->get_parent) { > i = orphan->ops->get_parent(orphan->hw); > + if (i < 0) { > + pr_err("%s: orphan clk(%s) invalid parent\n", > + __func__, orphan->name); > + continue; > + } > if (!strcmp(clk->name, orphan->parent_names[i])) > __clk_reparent(orphan, clk); > continue; > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h > index 1186098..96337a1 100644 > --- a/include/linux/clk-provider.h > +++ b/include/linux/clk-provider.h > @@ -80,7 +80,7 @@ struct clk_hw; > * supported by the clock. > * > * @get_parent: Queries the hardware to determine the parent of a clock. The > - * return value is a u8 which specifies the index corresponding to > + * return value which specifies the index corresponding to > * the parent clock. This index can be applied to either the > * .parent_names or .parents arrays. In short, this function > * translates the parent value read from hardware into an array > @@ -127,7 +127,7 @@ struct clk_ops { > long (*round_rate)(struct clk_hw *hw, unsigned long, > unsigned long *); > int (*set_parent)(struct clk_hw *hw, u8 index); > - u8 (*get_parent)(struct clk_hw *hw); > + int (*get_parent)(struct clk_hw *hw); > int (*set_rate)(struct clk_hw *hw, unsigned long, > unsigned long); > void (*init)(struct clk_hw *hw); > -- > 1.7.4.1