[PATCH V3 -next] powerpc: kernel/time.c - cleanup warnings

[PATCH V3 -next] powerpc: kernel/time.c - cleanup warnings

[He Ying]

We found these warnings in arch/powerpc/kernel/time.c as follows:
warning: symbol 'decrementer_max' was not declared. Should it be static?
warning: symbol 'rtc_lock' was not declared. Should it be static?
warning: symbol 'dtl_consumer' was not declared. Should it be static?

Declare 'decrementer_max' in powerpc asm/time.h.
Include linux/mc146818rtc.h in powerpc kernel/time.c where 'rtc_lock'
is declared. And remove duplicated declaration of 'rtc_lock' in powerpc
platforms/chrp/time.c because it has included linux/mc146818rtc.h.
Move 'dtl_consumer' definition behind "include <asm/dtl.h>" because it
is declared there.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: He Ying <heying24@huawei.com>
---
V2:
- Instead of including linux/mc146818rtc.h in powerpc kernel/time.c, declare
  rtc_lock in powerpc asm/time.h.
V3:
- Recover to V1, that is including linux/mc146818rtc.h in powerpc
  kernel/time.c. And remove duplicated declaration of 'rtc_lock' in powerpc
  platforms/chrp/time.c because it has included linux/mc146818rtc.h.

 arch/powerpc/include/asm/time.h    | 1 +
 arch/powerpc/kernel/time.c         | 9 ++++-----
 arch/powerpc/platforms/chrp/time.c | 2 --
 3 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/include/asm/time.h b/arch/powerpc/include/asm/time.h
index 8dd3cdb25338..2cd2b50bedda 100644
--- a/arch/powerpc/include/asm/time.h
+++ b/arch/powerpc/include/asm/time.h
@@ -22,6 +22,7 @@ extern unsigned long tb_ticks_per_jiffy;
 extern unsigned long tb_ticks_per_usec;
 extern unsigned long tb_ticks_per_sec;
 extern struct clock_event_device decrementer_clockevent;
+extern u64 decrementer_max;
 
 
 extern void generic_calibrate_decr(void);
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index b67d93a609a2..ac81f043bf49 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -55,8 +55,9 @@
 #include <linux/sched/cputime.h>
 #include <linux/sched/clock.h>
 #include <linux/processor.h>
-#include <asm/trace.h>
+#include <linux/mc146818rtc.h>
 
+#include <asm/trace.h>
 #include <asm/interrupt.h>
 #include <asm/io.h>
 #include <asm/nvram.h>
@@ -150,10 +151,6 @@ bool tb_invalid;
 u64 __cputime_usec_factor;
 EXPORT_SYMBOL(__cputime_usec_factor);
 
-#ifdef CONFIG_PPC_SPLPAR
-void (*dtl_consumer)(struct dtl_entry *, u64);
-#endif
-
 static void calc_cputime_factors(void)
 {
 	struct div_result res;
@@ -179,6 +176,8 @@ static inline unsigned long read_spurr(unsigned long tb)
 
 #include <asm/dtl.h>
 
+void (*dtl_consumer)(struct dtl_entry *, u64);
+
 /*
  * Scan the dispatch trace log and count up the stolen time.
  * Should be called with interrupts disabled.
diff --git a/arch/powerpc/platforms/chrp/time.c b/arch/powerpc/platforms/chrp/time.c
index acde7bbe0716..b94dfd5090d8 100644
--- a/arch/powerpc/platforms/chrp/time.c
+++ b/arch/powerpc/platforms/chrp/time.c
@@ -30,8 +30,6 @@
 
 #include <platforms/chrp/chrp.h>
 
-extern spinlock_t rtc_lock;
-
 #define NVRAM_AS0  0x74
 #define NVRAM_AS1  0x75
 #define NVRAM_DATA 0x77
-- 
2.17.1

Re: [PATCH V3 -next] powerpc: kernel/time.c - cleanup warnings

[Alexandre Belloni]

On 24/03/2021 05:09:39-0400, He Ying wrote:
> We found these warnings in arch/powerpc/kernel/time.c as follows:
> warning: symbol 'decrementer_max' was not declared. Should it be static?
> warning: symbol 'rtc_lock' was not declared. Should it be static?
> warning: symbol 'dtl_consumer' was not declared. Should it be static?
> 
> Declare 'decrementer_max' in powerpc asm/time.h.
> Include linux/mc146818rtc.h in powerpc kernel/time.c where 'rtc_lock'
> is declared. And remove duplicated declaration of 'rtc_lock' in powerpc
> platforms/chrp/time.c because it has included linux/mc146818rtc.h.
> Move 'dtl_consumer' definition behind "include <asm/dtl.h>" because it
> is declared there.
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: He Ying <heying24@huawei.com>
> ---
> V2:
> - Instead of including linux/mc146818rtc.h in powerpc kernel/time.c, declare
>   rtc_lock in powerpc asm/time.h.
> V3:
> - Recover to V1, that is including linux/mc146818rtc.h in powerpc
>   kernel/time.c. And remove duplicated declaration of 'rtc_lock' in powerpc
>   platforms/chrp/time.c because it has included linux/mc146818rtc.h.
> 
>  arch/powerpc/include/asm/time.h    | 1 +
>  arch/powerpc/kernel/time.c         | 9 ++++-----
>  arch/powerpc/platforms/chrp/time.c | 2 --
>  3 files changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/time.h b/arch/powerpc/include/asm/time.h
> index 8dd3cdb25338..2cd2b50bedda 100644
> --- a/arch/powerpc/include/asm/time.h
> +++ b/arch/powerpc/include/asm/time.h
> @@ -22,6 +22,7 @@ extern unsigned long tb_ticks_per_jiffy;
>  extern unsigned long tb_ticks_per_usec;
>  extern unsigned long tb_ticks_per_sec;
>  extern struct clock_event_device decrementer_clockevent;
> +extern u64 decrementer_max;
>  
>  
>  extern void generic_calibrate_decr(void);
> diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
> index b67d93a609a2..ac81f043bf49 100644
> --- a/arch/powerpc/kernel/time.c
> +++ b/arch/powerpc/kernel/time.c
> @@ -55,8 +55,9 @@
>  #include <linux/sched/cputime.h>
>  #include <linux/sched/clock.h>
>  #include <linux/processor.h>
> -#include <asm/trace.h>
> +#include <linux/mc146818rtc.h>

I'm fine with that but I really think my suggestion to make the rtc_lock
local to the platforms was better because it is only used to synchronize
between concurrent invocations of chrp_set_rtc_time or
maple_set_rtc_time. The rtc core will never do that and the only case
would be concurrent calls to rtc_ops.set_time and
update_persistent_clock64 (which should also be removed at some point).

>  
> +#include <asm/trace.h>
>  #include <asm/interrupt.h>
>  #include <asm/io.h>
>  #include <asm/nvram.h>
> @@ -150,10 +151,6 @@ bool tb_invalid;
>  u64 __cputime_usec_factor;
>  EXPORT_SYMBOL(__cputime_usec_factor);
>  
> -#ifdef CONFIG_PPC_SPLPAR
> -void (*dtl_consumer)(struct dtl_entry *, u64);
> -#endif
> -
>  static void calc_cputime_factors(void)
>  {
>  	struct div_result res;
> @@ -179,6 +176,8 @@ static inline unsigned long read_spurr(unsigned long tb)
>  
>  #include <asm/dtl.h>
>  
> +void (*dtl_consumer)(struct dtl_entry *, u64);
> +
>  /*
>   * Scan the dispatch trace log and count up the stolen time.
>   * Should be called with interrupts disabled.
> diff --git a/arch/powerpc/platforms/chrp/time.c b/arch/powerpc/platforms/chrp/time.c
> index acde7bbe0716..b94dfd5090d8 100644
> --- a/arch/powerpc/platforms/chrp/time.c
> +++ b/arch/powerpc/platforms/chrp/time.c
> @@ -30,8 +30,6 @@
>  
>  #include <platforms/chrp/chrp.h>
>  
> -extern spinlock_t rtc_lock;
> -
>  #define NVRAM_AS0  0x74
>  #define NVRAM_AS1  0x75
>  #define NVRAM_DATA 0x77
> -- 
> 2.17.1
> 

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH V3 -next] powerpc: kernel/time.c - cleanup warnings

[Christophe Leroy]

Le 24/03/2021 à 10:09, He Ying a écrit :
> We found these warnings in arch/powerpc/kernel/time.c as follows:
> warning: symbol 'decrementer_max' was not declared. Should it be static?
> warning: symbol 'rtc_lock' was not declared. Should it be static?
> warning: symbol 'dtl_consumer' was not declared. Should it be static?
> 
> Declare 'decrementer_max' in powerpc asm/time.h.
> Include linux/mc146818rtc.h in powerpc kernel/time.c where 'rtc_lock'
> is declared. And remove duplicated declaration of 'rtc_lock' in powerpc
> platforms/chrp/time.c because it has included linux/mc146818rtc.h.
> Move 'dtl_consumer' definition behind "include <asm/dtl.h>" because it
> is declared there.
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: He Ying <heying24@huawei.com>

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>

> ---
> V2:
> - Instead of including linux/mc146818rtc.h in powerpc kernel/time.c, declare
>    rtc_lock in powerpc asm/time.h.
> V3:
> - Recover to V1, that is including linux/mc146818rtc.h in powerpc
>    kernel/time.c. And remove duplicated declaration of 'rtc_lock' in powerpc
>    platforms/chrp/time.c because it has included linux/mc146818rtc.h.
> 
>   arch/powerpc/include/asm/time.h    | 1 +
>   arch/powerpc/kernel/time.c         | 9 ++++-----
>   arch/powerpc/platforms/chrp/time.c | 2 --
>   3 files changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/time.h b/arch/powerpc/include/asm/time.h
> index 8dd3cdb25338..2cd2b50bedda 100644
> --- a/arch/powerpc/include/asm/time.h
> +++ b/arch/powerpc/include/asm/time.h
> @@ -22,6 +22,7 @@ extern unsigned long tb_ticks_per_jiffy;
>   extern unsigned long tb_ticks_per_usec;
>   extern unsigned long tb_ticks_per_sec;
>   extern struct clock_event_device decrementer_clockevent;
> +extern u64 decrementer_max;
>   
>   
>   extern void generic_calibrate_decr(void);
> diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
> index b67d93a609a2..ac81f043bf49 100644
> --- a/arch/powerpc/kernel/time.c
> +++ b/arch/powerpc/kernel/time.c
> @@ -55,8 +55,9 @@
>   #include <linux/sched/cputime.h>
>   #include <linux/sched/clock.h>
>   #include <linux/processor.h>
> -#include <asm/trace.h>
> +#include <linux/mc146818rtc.h>
>   
> +#include <asm/trace.h>
>   #include <asm/interrupt.h>
>   #include <asm/io.h>
>   #include <asm/nvram.h>
> @@ -150,10 +151,6 @@ bool tb_invalid;
>   u64 __cputime_usec_factor;
>   EXPORT_SYMBOL(__cputime_usec_factor);
>   
> -#ifdef CONFIG_PPC_SPLPAR
> -void (*dtl_consumer)(struct dtl_entry *, u64);
> -#endif
> -
>   static void calc_cputime_factors(void)
>   {
>   	struct div_result res;
> @@ -179,6 +176,8 @@ static inline unsigned long read_spurr(unsigned long tb)
>   
>   #include <asm/dtl.h>
>   
> +void (*dtl_consumer)(struct dtl_entry *, u64);
> +
>   /*
>    * Scan the dispatch trace log and count up the stolen time.
>    * Should be called with interrupts disabled.
> diff --git a/arch/powerpc/platforms/chrp/time.c b/arch/powerpc/platforms/chrp/time.c
> index acde7bbe0716..b94dfd5090d8 100644
> --- a/arch/powerpc/platforms/chrp/time.c
> +++ b/arch/powerpc/platforms/chrp/time.c
> @@ -30,8 +30,6 @@
>   
>   #include <platforms/chrp/chrp.h>
>   
> -extern spinlock_t rtc_lock;
> -
>   #define NVRAM_AS0  0x74
>   #define NVRAM_AS1  0x75
>   #define NVRAM_DATA 0x77
> 

Re: [PATCH V3 -next] powerpc: kernel/time.c - cleanup warnings

[Christophe Leroy]

Le 24/03/2021 à 10:29, Alexandre Belloni a écrit :
> On 24/03/2021 05:09:39-0400, He Ying wrote:
>> We found these warnings in arch/powerpc/kernel/time.c as follows:
>> warning: symbol 'decrementer_max' was not declared. Should it be static?
>> warning: symbol 'rtc_lock' was not declared. Should it be static?
>> warning: symbol 'dtl_consumer' was not declared. Should it be static?
>>
>> Declare 'decrementer_max' in powerpc asm/time.h.
>> Include linux/mc146818rtc.h in powerpc kernel/time.c where 'rtc_lock'
>> is declared. And remove duplicated declaration of 'rtc_lock' in powerpc
>> platforms/chrp/time.c because it has included linux/mc146818rtc.h.
>> Move 'dtl_consumer' definition behind "include <asm/dtl.h>" because it
>> is declared there.
>>
>> Reported-by: Hulk Robot <hulkci@huawei.com>
>> Signed-off-by: He Ying <heying24@huawei.com>
>> ---
>> V2:
>> - Instead of including linux/mc146818rtc.h in powerpc kernel/time.c, declare
>>    rtc_lock in powerpc asm/time.h.
>> V3:
>> - Recover to V1, that is including linux/mc146818rtc.h in powerpc
>>    kernel/time.c. And remove duplicated declaration of 'rtc_lock' in powerpc
>>    platforms/chrp/time.c because it has included linux/mc146818rtc.h.
>>
>>   arch/powerpc/include/asm/time.h    | 1 +
>>   arch/powerpc/kernel/time.c         | 9 ++++-----
>>   arch/powerpc/platforms/chrp/time.c | 2 --
>>   3 files changed, 5 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/time.h b/arch/powerpc/include/asm/time.h
>> index 8dd3cdb25338..2cd2b50bedda 100644
>> --- a/arch/powerpc/include/asm/time.h
>> +++ b/arch/powerpc/include/asm/time.h
>> @@ -22,6 +22,7 @@ extern unsigned long tb_ticks_per_jiffy;
>>   extern unsigned long tb_ticks_per_usec;
>>   extern unsigned long tb_ticks_per_sec;
>>   extern struct clock_event_device decrementer_clockevent;
>> +extern u64 decrementer_max;
>>   
>>   
>>   extern void generic_calibrate_decr(void);
>> diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
>> index b67d93a609a2..ac81f043bf49 100644
>> --- a/arch/powerpc/kernel/time.c
>> +++ b/arch/powerpc/kernel/time.c
>> @@ -55,8 +55,9 @@
>>   #include <linux/sched/cputime.h>
>>   #include <linux/sched/clock.h>
>>   #include <linux/processor.h>
>> -#include <asm/trace.h>
>> +#include <linux/mc146818rtc.h>
> 
> I'm fine with that but I really think my suggestion to make the rtc_lock
> local to the platforms was better because it is only used to synchronize
> between concurrent invocations of chrp_set_rtc_time or
> maple_set_rtc_time. The rtc core will never do that and the only case
> would be concurrent calls to rtc_ops.set_time and
> update_persistent_clock64 (which should also be removed at some point).

I agree but I think it must be done carefully. If the lock is local to the driver really and without 
a link with the RTC core, then the lock var should probably be static. But then we'll have name 
conflict with the global rtc_lock which is declared in <linux/mc146818rtc.h>

All this is not easy, and I like your idea in the other mail to really clean up the rtc core and 
remove this global rtc_lock completely.

For the time being I guess the fix provided by this patch is just semantic and is just fine as is, 
as there is no real bug behind the messages from sparse.

Christophe

Re: [PATCH V3 -next] powerpc: kernel/time.c - cleanup warnings

[heying (H)]

Dear Alexandre,


在 2021/3/24 17:29, Alexandre Belloni 写道:
> On 24/03/2021 05:09:39-0400, He Ying wrote:
>> We found these warnings in arch/powerpc/kernel/time.c as follows:
>> warning: symbol 'decrementer_max' was not declared. Should it be static?
>> warning: symbol 'rtc_lock' was not declared. Should it be static?
>> warning: symbol 'dtl_consumer' was not declared. Should it be static?
>>
>> Declare 'decrementer_max' in powerpc asm/time.h.
>> Include linux/mc146818rtc.h in powerpc kernel/time.c where 'rtc_lock'
>> is declared. And remove duplicated declaration of 'rtc_lock' in powerpc
>> platforms/chrp/time.c because it has included linux/mc146818rtc.h.
>> Move 'dtl_consumer' definition behind "include <asm/dtl.h>" because it
>> is declared there.
>>
>> Reported-by: Hulk Robot <hulkci@huawei.com>
>> Signed-off-by: He Ying <heying24@huawei.com>
>> ---
>> V2:
>> - Instead of including linux/mc146818rtc.h in powerpc kernel/time.c, declare
>>    rtc_lock in powerpc asm/time.h.
>> V3:
>> - Recover to V1, that is including linux/mc146818rtc.h in powerpc
>>    kernel/time.c. And remove duplicated declaration of 'rtc_lock' in powerpc
>>    platforms/chrp/time.c because it has included linux/mc146818rtc.h.
>>
>>   arch/powerpc/include/asm/time.h    | 1 +
>>   arch/powerpc/kernel/time.c         | 9 ++++-----
>>   arch/powerpc/platforms/chrp/time.c | 2 --
>>   3 files changed, 5 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/time.h b/arch/powerpc/include/asm/time.h
>> index 8dd3cdb25338..2cd2b50bedda 100644
>> --- a/arch/powerpc/include/asm/time.h
>> +++ b/arch/powerpc/include/asm/time.h
>> @@ -22,6 +22,7 @@ extern unsigned long tb_ticks_per_jiffy;
>>   extern unsigned long tb_ticks_per_usec;
>>   extern unsigned long tb_ticks_per_sec;
>>   extern struct clock_event_device decrementer_clockevent;
>> +extern u64 decrementer_max;
>>   
>>   
>>   extern void generic_calibrate_decr(void);
>> diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
>> index b67d93a609a2..ac81f043bf49 100644
>> --- a/arch/powerpc/kernel/time.c
>> +++ b/arch/powerpc/kernel/time.c
>> @@ -55,8 +55,9 @@
>>   #include <linux/sched/cputime.h>
>>   #include <linux/sched/clock.h>
>>   #include <linux/processor.h>
>> -#include <asm/trace.h>
>> +#include <linux/mc146818rtc.h>
> I'm fine with that but I really think my suggestion to make the rtc_lock
> local to the platforms was better because it is only used to synchronize
> between concurrent invocations of chrp_set_rtc_time or
> maple_set_rtc_time. The rtc core will never do that and the only case
> would be concurrent calls to rtc_ops.set_time and
> update_persistent_clock64 (which should also be removed at some point).

Many thanks for your suggestion. As you suggest, rtc_lock should be 
local to platforms.

Does it mean not only powerpc but also all other platforms should adapt 
this change?

It might be a big change. I have no idea if that's OK. What are other 
maintainers' opinions?


Thanks.

Re: [PATCH V3 -next] powerpc: kernel/time.c - cleanup warnings

[Alexandre Belloni]

On 24/03/2021 17:46:19+0800, heying (H) wrote:
> Many thanks for your suggestion. As you suggest, rtc_lock should be local to
> platforms.
> 
> Does it mean not only powerpc but also all other platforms should adapt this
> change?

Not all the other ones, in the current state, x86 still needs it. I'll
work on that. Again, the patch is fine as is.

Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>



-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com