clk: zynqmp: fix compile testing without ZYNQMP_FIRMWARE

Commit Message

Arnd Bergmann April 21, 2021, 1:48 p.m. UTC

From: Arnd Bergmann <[e-mail]>

When the firmware code is disabled, the incomplete error handling
in the clk driver causes compile-time warnings:

drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
  147 |         rate =  parent_rate * fbdiv;
      |                 ~~~~~~~~~~~~^~~~~~~
In function 'zynqmp_pll_get_mode',
    inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
   61 |         return ret_payload[1];
      |                ~~~~~~~~~~~^~~
drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
   53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
      |             ^~~~~~~~~~~
drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
   57 |         return val;
      |                ^~~

As it was apparently intentional to support this for compile testing
purposes, change the code to have just enough error handling for the
compiler to not notice the remaining bugs.

Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
Signed-off-by: Arnd Bergmann <[e-mail]>
---
 drivers/clk/zynqmp/clk-mux-zynqmp.c | 4 +++-
 drivers/clk/zynqmp/pll.c            | 8 ++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

Comments

Punit Agrawal April 22, 2021, 5:48 a.m. UTC | #1

Hi Arnd,

Thanks for the fix.

Arnd Bergmann <[e-mail]> writes:

> From: Arnd Bergmann <[e-mail]>
>
> When the firmware code is disabled, the incomplete error handling
> in the clk driver causes compile-time warnings:
>
> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
> drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
>   147 |         rate =  parent_rate * fbdiv;
>       |                 ~~~~~~~~~~~~^~~~~~~
> In function 'zynqmp_pll_get_mode',
>     inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
> drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
>    61 |         return ret_payload[1];
>       |                ~~~~~~~~~~~^~~
> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
> drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
>    53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
>       |             ^~~~~~~~~~~
> drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
> drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
>    57 |         return val;
>       |                ^~~


Not sure what I am missing but I couldn't reproduce these warnings. I
tried a few different ways to toggle CONFIG_ZYNQMP_FIRMWARE.

Regardless...

> As it was apparently intentional to support this for compile testing
> purposes, change the code to have just enough error handling for the
> compiler to not notice the remaining bugs.
>
> Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
> Signed-off-by: Arnd Bergmann <[e-mail]>
> ---
>  drivers/clk/zynqmp/clk-mux-zynqmp.c | 4 +++-
>  drivers/clk/zynqmp/pll.c            | 8 ++++++--
>  2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/zynqmp/clk-mux-zynqmp.c b/drivers/clk/zynqmp/clk-mux-zynqmp.c
> index 06194149be83..2afded3c7c11 100644
> --- a/drivers/clk/zynqmp/clk-mux-zynqmp.c
> +++ b/drivers/clk/zynqmp/clk-mux-zynqmp.c
> @@ -50,9 +50,11 @@ static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
>  
>  	ret = zynqmp_pm_clock_getparent(clk_id, &val);
>  
> -	if (ret)
> +	if (ret) {
>  		pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
>  			     __func__, clk_name, ret);
> +		return ret;
> +	}
>  
>  	return val;
>  }
> diff --git a/drivers/clk/zynqmp/pll.c b/drivers/clk/zynqmp/pll.c
> index abe6afbf3407..67d2a2d260c1 100644
> --- a/drivers/clk/zynqmp/pll.c
> +++ b/drivers/clk/zynqmp/pll.c
> @@ -54,9 +54,11 @@ static inline enum pll_mode zynqmp_pll_get_mode(struct clk_hw *hw)
>  	int ret;
>  
>  	ret = zynqmp_pm_get_pll_frac_mode(clk_id, ret_payload);
> -	if (ret)
> +	if (ret) {
>  		pr_warn_once("%s() PLL get frac mode failed for %s, ret = %d\n",
>  			     __func__, clk_name, ret);
> +		return ret;
> +	}
>  
>  	return ret_payload[1];
>  }
> @@ -140,9 +142,11 @@ static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
>  	int ret;
>  
>  	ret = zynqmp_pm_clock_getdivider(clk_id, &fbdiv);
> -	if (ret)
> +	if (ret) {
>  		pr_warn_once("%s() get divider failed for %s, ret = %d\n",
>  			     __func__, clk_name, ret);
> +		return -1ul;
> +	}
>  
>  	rate =  parent_rate * fbdiv;
>  	if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {

The changes make sense in that the functions error out sensibly when the
zynqmp firmware driver is not enabled.

Acked-by: Punit Agrawal <[e-mail]>

Punit

Michal Simek April 22, 2021, 10:54 a.m. UTC | #2

Hi,

On 4/22/21 7:48 AM, Punit Agrawal wrote:
> Hi Arnd,
> 
> Thanks for the fix.
> 
> Arnd Bergmann <[e-mail]> writes:
> 
>> From: Arnd Bergmann <[e-mail]>
>>
>> When the firmware code is disabled, the incomplete error handling
>> in the clk driver causes compile-time warnings:
>>
>> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
>> drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
>>   147 |         rate =  parent_rate * fbdiv;
>>       |                 ~~~~~~~~~~~~^~~~~~~
>> In function 'zynqmp_pll_get_mode',
>>     inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
>> drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
>>    61 |         return ret_payload[1];
>>       |                ~~~~~~~~~~~^~~
>> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
>> drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
>>    53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
>>       |             ^~~~~~~~~~~
>> drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
>> drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
>>    57 |         return val;
>>       |                ^~~
> 
> 
> Not sure what I am missing but I couldn't reproduce these warnings. I
> tried a few different ways to toggle CONFIG_ZYNQMP_FIRMWARE.
> 
> Regardless...

Me too. Can you share your .config file?

> 
>> As it was apparently intentional to support this for compile testing
>> purposes, change the code to have just enough error handling for the
>> compiler to not notice the remaining bugs.
>>
>> Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
>> Signed-off-by: Arnd Bergmann <[e-mail]>
>> ---
>>  drivers/clk/zynqmp/clk-mux-zynqmp.c | 4 +++-
>>  drivers/clk/zynqmp/pll.c            | 8 ++++++--
>>  2 files changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/clk/zynqmp/clk-mux-zynqmp.c b/drivers/clk/zynqmp/clk-mux-zynqmp.c
>> index 06194149be83..2afded3c7c11 100644
>> --- a/drivers/clk/zynqmp/clk-mux-zynqmp.c
>> +++ b/drivers/clk/zynqmp/clk-mux-zynqmp.c
>> @@ -50,9 +50,11 @@ static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
>>  
>>  	ret = zynqmp_pm_clock_getparent(clk_id, &val);
>>  
>> -	if (ret)
>> +	if (ret) {
>>  		pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
>>  			     __func__, clk_name, ret);
>> +		return ret;

return should be u8 and this can be negative value. That's why I think
this should be fixed differently and all users should be checked that it
is handled like that.


>> +	}
>>  
>>  	return val;
>>  }
>> diff --git a/drivers/clk/zynqmp/pll.c b/drivers/clk/zynqmp/pll.c
>> index abe6afbf3407..67d2a2d260c1 100644
>> --- a/drivers/clk/zynqmp/pll.c
>> +++ b/drivers/clk/zynqmp/pll.c
>> @@ -54,9 +54,11 @@ static inline enum pll_mode zynqmp_pll_get_mode(struct clk_hw *hw)
>>  	int ret;
>>  
>>  	ret = zynqmp_pm_get_pll_frac_mode(clk_id, ret_payload);
>> -	if (ret)
>> +	if (ret) {
>>  		pr_warn_once("%s() PLL get frac mode failed for %s, ret = %d\n",
>>  			     __func__, clk_name, ret);
>> +		return ret;
>> +	}

Return should be enum pll_mode which is 0 or 1 which is likely not done
here.

>>  
>>  	return ret_payload[1];
>>  }
>> @@ -140,9 +142,11 @@ static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
>>  	int ret;
>>  
>>  	ret = zynqmp_pm_clock_getdivider(clk_id, &fbdiv);
>> -	if (ret)
>> +	if (ret) {
>>  		pr_warn_once("%s() get divider failed for %s, ret = %d\n",
>>  			     __func__, clk_name, ret);
>> +		return -1ul;
>> +	}

Same here.


>>  
>>  	rate =  parent_rate * fbdiv;
>>  	if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {
> 
> The changes make sense in that the functions error out sensibly when the
> zynqmp firmware driver is not enabled.
> 
> Acked-by: Punit Agrawal <[e-mail]>

I think code should be checked that these error values are handled how
they should be handled.

Thanks,
Michal

Punit Agrawal April 23, 2021, 6:37 a.m. UTC | #3

Michal Simek <[e-mail]> writes:

> Hi,
>
> On 4/22/21 7:48 AM, Punit Agrawal wrote:
>> Hi Arnd,
>> 
>> Thanks for the fix.
>> 
>> Arnd Bergmann <[e-mail]> writes:
>> 
>>> From: Arnd Bergmann <[e-mail]>
>>>
>>> When the firmware code is disabled, the incomplete error handling
>>> in the clk driver causes compile-time warnings:
>>>
>>> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
>>> drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
>>>   147 |         rate =  parent_rate * fbdiv;
>>>       |                 ~~~~~~~~~~~~^~~~~~~
>>> In function 'zynqmp_pll_get_mode',
>>>     inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
>>> drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
>>>    61 |         return ret_payload[1];
>>>       |                ~~~~~~~~~~~^~~
>>> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
>>> drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
>>>    53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
>>>       |             ^~~~~~~~~~~
>>> drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
>>> drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
>>>    57 |         return val;
>>>       |                ^~~
>> 
>> 
>> Not sure what I am missing but I couldn't reproduce these warnings. I
>> tried a few different ways to toggle CONFIG_ZYNQMP_FIRMWARE.
>> 
>> Regardless...
>
> Me too. Can you share your .config file?
>
>> 
>>> As it was apparently intentional to support this for compile testing
>>> purposes, change the code to have just enough error handling for the
>>> compiler to not notice the remaining bugs.
>>>
>>> Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
>>> Signed-off-by: Arnd Bergmann <[e-mail]>
>>> ---
>>>  drivers/clk/zynqmp/clk-mux-zynqmp.c | 4 +++-
>>>  drivers/clk/zynqmp/pll.c            | 8 ++++++--
>>>  2 files changed, 9 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/clk/zynqmp/clk-mux-zynqmp.c b/drivers/clk/zynqmp/clk-mux-zynqmp.c
>>> index 06194149be83..2afded3c7c11 100644
>>> --- a/drivers/clk/zynqmp/clk-mux-zynqmp.c
>>> +++ b/drivers/clk/zynqmp/clk-mux-zynqmp.c
>>> @@ -50,9 +50,11 @@ static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
>>>  
>>>  	ret = zynqmp_pm_clock_getparent(clk_id, &val);
>>>  
>>> -	if (ret)
>>> +	if (ret) {
>>>  		pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
>>>  			     __func__, clk_name, ret);
>>> +		return ret;
>
> return should be u8 and this can be negative value. That's why I think
> this should be fixed differently and all users should be checked that it
> is handled like that.
>
>
>>> +	}
>>>  
>>>  	return val;
>>>  }
>>> diff --git a/drivers/clk/zynqmp/pll.c b/drivers/clk/zynqmp/pll.c
>>> index abe6afbf3407..67d2a2d260c1 100644
>>> --- a/drivers/clk/zynqmp/pll.c
>>> +++ b/drivers/clk/zynqmp/pll.c
>>> @@ -54,9 +54,11 @@ static inline enum pll_mode zynqmp_pll_get_mode(struct clk_hw *hw)
>>>  	int ret;
>>>  
>>>  	ret = zynqmp_pm_get_pll_frac_mode(clk_id, ret_payload);
>>> -	if (ret)
>>> +	if (ret) {
>>>  		pr_warn_once("%s() PLL get frac mode failed for %s, ret = %d\n",
>>>  			     __func__, clk_name, ret);
>>> +		return ret;
>>> +	}
>
> Return should be enum pll_mode which is 0 or 1 which is likely not done
> here.
>
>>>  
>>>  	return ret_payload[1];
>>>  }
>>> @@ -140,9 +142,11 @@ static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
>>>  	int ret;
>>>  
>>>  	ret = zynqmp_pm_clock_getdivider(clk_id, &fbdiv);
>>> -	if (ret)
>>> +	if (ret) {
>>>  		pr_warn_once("%s() get divider failed for %s, ret = %d\n",
>>>  			     __func__, clk_name, ret);
>>> +		return -1ul;
>>> +	}
>
> Same here.
>
>
>>>  
>>>  	rate =  parent_rate * fbdiv;
>>>  	if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {
>> 
>> The changes make sense in that the functions error out sensibly when the
>> zynqmp firmware driver is not enabled.
>> 
>> Acked-by: Punit Agrawal <[e-mail]>
>
> I think code should be checked that these error values are handled how
> they should be handled.

I only looked at it from the point of view of getting rid of the
warnings - based on the commit log, Arnd's patch is only taking care of
the compiler warnings when the driver is built with
CONFIG_COMPILE_TEST=y and likely CONFIG_ZYNQMP_FIRMWARE=n.

In practice, the code should not be hit at runtime due to the dependency
on the firmware driver. Even then, a better fix would indeed be taking
the returned values at call sites into account.

[...]

Stephen Boyd April 30, 2021, 2:17 a.m. UTC | #4

Quoting Punit Agrawal (2021-04-22 23:37:25)
> Michal Simek <[e-mail]> writes:
> >
> >
> >>>  
> >>>     rate =  parent_rate * fbdiv;
> >>>     if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {
> >> 
> >> The changes make sense in that the functions error out sensibly when the
> >> zynqmp firmware driver is not enabled.
> >> 
> >> Acked-by: Punit Agrawal <[e-mail]>
> >
> > I think code should be checked that these error values are handled how
> > they should be handled.
> 
> I only looked at it from the point of view of getting rid of the
> warnings - based on the commit log, Arnd's patch is only taking care of
> the compiler warnings when the driver is built with
> CONFIG_COMPILE_TEST=y and likely CONFIG_ZYNQMP_FIRMWARE=n.

The subject line basically says this.

> 
> In practice, the code should not be hit at runtime due to the dependency
> on the firmware driver. Even then, a better fix would indeed be taking
> the returned values at call sites into account.

Still needs to be fixed. If a better patch is sent I would apply it, but
if that isn't going to happen I'll apply this one.

Michal Simek June 21, 2021, 1:15 p.m. UTC | #5

On 4/30/21 4:17 AM, Stephen Boyd wrote:
> Quoting Punit Agrawal (2021-04-22 23:37:25)
>> Michal Simek <[e-mail]> writes:
>>>
>>>
>>>>>  
>>>>>     rate =  parent_rate * fbdiv;
>>>>>     if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {
>>>>
>>>> The changes make sense in that the functions error out sensibly when the
>>>> zynqmp firmware driver is not enabled.
>>>>
>>>> Acked-by: Punit Agrawal <[e-mail]>
>>>
>>> I think code should be checked that these error values are handled how
>>> they should be handled.
>>
>> I only looked at it from the point of view of getting rid of the
>> warnings - based on the commit log, Arnd's patch is only taking care of
>> the compiler warnings when the driver is built with
>> CONFIG_COMPILE_TEST=y and likely CONFIG_ZYNQMP_FIRMWARE=n.
> 
> The subject line basically says this.
> 
>>
>> In practice, the code should not be hit at runtime due to the dependency
>> on the firmware driver. Even then, a better fix would indeed be taking
>> the returned values at call sites into account.
> 
> Still needs to be fixed. If a better patch is sent I would apply it, but
> if that isn't going to happen I'll apply this one.

I have sent v2 version based on what I have found how that error values
should look like. Please take a look at v2.
https://lore.kernel.org/linux-clk/fdee[e-mail]/

Thanks,
Michal

Patch

diff --git a/drivers/clk/zynqmp/clk-mux-zynqmp.c b/drivers/clk/zynqmp/clk-mux-zynqmp.c
index 06194149be83..2afded3c7c11 100644
--- a/drivers/clk/zynqmp/clk-mux-zynqmp.c
+++ b/drivers/clk/zynqmp/clk-mux-zynqmp.c
@@ -50,9 +50,11 @@  static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
 
 	ret = zynqmp_pm_clock_getparent(clk_id, &val);
 
-	if (ret)
+	if (ret) {
 		pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
 			     __func__, clk_name, ret);
+		return ret;
+	}
 
 	return val;
 }
diff --git a/drivers/clk/zynqmp/pll.c b/drivers/clk/zynqmp/pll.c
index abe6afbf3407..67d2a2d260c1 100644
--- a/drivers/clk/zynqmp/pll.c
+++ b/drivers/clk/zynqmp/pll.c
@@ -54,9 +54,11 @@  static inline enum pll_mode zynqmp_pll_get_mode(struct clk_hw *hw)
 	int ret;
 
 	ret = zynqmp_pm_get_pll_frac_mode(clk_id, ret_payload);
-	if (ret)
+	if (ret) {
 		pr_warn_once("%s() PLL get frac mode failed for %s, ret = %d\n",
 			     __func__, clk_name, ret);
+		return ret;
+	}
 
 	return ret_payload[1];
 }
@@ -140,9 +142,11 @@  static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
 	int ret;
 
 	ret = zynqmp_pm_clock_getdivider(clk_id, &fbdiv);
-	if (ret)
+	if (ret) {
 		pr_warn_once("%s() get divider failed for %s, ret = %d\n",
 			     __func__, clk_name, ret);
+		return -1ul;
+	}
 
 	rate =  parent_rate * fbdiv;
 	if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {