Re: [Patch 1/3] clk: fix clk_mux_get_parent return's signed value

[Mike Turquette]

On Mon, Jun 3, 2013 at 11:27 PM, Ambresh K <ambresh@xxxxxx> wrote:
>
>>
>> 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."
>>
>
> Make sense, will fix it.
>
>> 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.
>>
>
> Thanks!
> Will fix them and add your ack to it?

Great, thanks!  Don't worry about the Ack.  I'll take the patch
through the clk tree so it will have my SoB.

Regards,
Mike

>
>
>> 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 <ambresh@xxxxxx>
>>> ---
>>>  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
>>
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