[PATCH 1/2] clocksource/drivers/imx-sysctr: mark two variable with __ro_after_init

[PATCH 1/2] clocksource/drivers/imx-sysctr: mark two variable with __ro_after_init

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@nxp.com>

sys_ctr_base and cmpcr will not be updated after init, so mark
as __ro_after_init.

Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/clocksource/timer-imx-sysctr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clocksource/timer-imx-sysctr.c b/drivers/clocksource/timer-imx-sysctr.c
index 18b90fc56bfc..2b309af11266 100644
--- a/drivers/clocksource/timer-imx-sysctr.c
+++ b/drivers/clocksource/timer-imx-sysctr.c
@@ -20,8 +20,8 @@
 
 #define SYS_CTR_CLK_DIV		0x3
 
-static void __iomem *sys_ctr_base;
-static u32 cmpcr;
+static void __iomem *sys_ctr_base __ro_after_init;
+static u32 cmpcr __ro_after_init;
 
 static void sysctr_timer_enable(bool enable)
 {
-- 
2.25.1


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[PATCH 2/2] clocksource: timer-imx-sysctr: set cpumask to cpu_possible_mask

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@nxp.com>

Actually we have CLOCK_EVT_FEAT_DYNIRQ, the irq affinity will be runtime
changed and no issue. But the system counter timer is not tied to CPU0,
so use cpu_possible_mask here.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/clocksource/timer-imx-sysctr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clocksource/timer-imx-sysctr.c b/drivers/clocksource/timer-imx-sysctr.c
index 2b309af11266..55a8e198d2a1 100644
--- a/drivers/clocksource/timer-imx-sysctr.c
+++ b/drivers/clocksource/timer-imx-sysctr.c
@@ -119,7 +119,7 @@ static struct timer_of to_sysctr = {
 
 static void __init sysctr_clockevent_init(void)
 {
-	to_sysctr.clkevt.cpumask = cpumask_of(0);
+	to_sysctr.clkevt.cpumask = cpu_possible_mask;
 
 	clockevents_config_and_register(&to_sysctr.clkevt,
 					timer_of_rate(&to_sysctr),
-- 
2.25.1


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Re: [PATCH 2/2] clocksource: timer-imx-sysctr: set cpumask to cpu_possible_mask

[Daniel Lezcano]

On 01/12/2021 13:50, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> Actually we have CLOCK_EVT_FEAT_DYNIRQ, the irq affinity will be runtime
> changed and no issue. But the system counter timer is not tied to CPU0,
> so use cpu_possible_mask here.

Did you mean:

"There is no reason to tie the system counter timer to CPU0, change its
affinity to cpu_possible_mask.

Moreover, the timer has the flag CLOCK_EVT_FEAT_DYNIRQ set, changing to
cpu_possibl_mask will reduce the number of wakeups related to the system
timer"

?

Note you may want to explain why 'there is no reason'


> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/clocksource/timer-imx-sysctr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clocksource/timer-imx-sysctr.c b/drivers/clocksource/timer-imx-sysctr.c
> index 2b309af11266..55a8e198d2a1 100644
> --- a/drivers/clocksource/timer-imx-sysctr.c
> +++ b/drivers/clocksource/timer-imx-sysctr.c
> @@ -119,7 +119,7 @@ static struct timer_of to_sysctr = {
>  
>  static void __init sysctr_clockevent_init(void)
>  {
> -	to_sysctr.clkevt.cpumask = cpumask_of(0);
> +	to_sysctr.clkevt.cpumask = cpu_possible_mask;
>  
>  	clockevents_config_and_register(&to_sysctr.clkevt,
>  					timer_of_rate(&to_sysctr),
> 


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Re: [PATCH 1/2] clocksource/drivers/imx-sysctr: mark two variable with __ro_after_init

[Kees Cook]

On Wed, Dec 01, 2021 at 08:50:29PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> sys_ctr_base and cmpcr will not be updated after init, so mark
> as __ro_after_init.
> 
> Cc: Kees Cook <keescook@chromium.org>
> Signed-off-by: Peng Fan <peng.fan@nxp.com>

Always nice to get more of these. :)

Reviewed-by: Kees Cook <keescook@chromium.org>

Thanks!

-Kees

> ---
>  drivers/clocksource/timer-imx-sysctr.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clocksource/timer-imx-sysctr.c b/drivers/clocksource/timer-imx-sysctr.c
> index 18b90fc56bfc..2b309af11266 100644
> --- a/drivers/clocksource/timer-imx-sysctr.c
> +++ b/drivers/clocksource/timer-imx-sysctr.c
> @@ -20,8 +20,8 @@
>  
>  #define SYS_CTR_CLK_DIV		0x3
>  
> -static void __iomem *sys_ctr_base;
> -static u32 cmpcr;
> +static void __iomem *sys_ctr_base __ro_after_init;
> +static u32 cmpcr __ro_after_init;
>  
>  static void sysctr_timer_enable(bool enable)
>  {
> -- 
> 2.25.1
> 

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RE: [PATCH 2/2] clocksource: timer-imx-sysctr: set cpumask to cpu_possible_mask

[Peng Fan]

> Subject: Re: [PATCH 2/2] clocksource: timer-imx-sysctr: set cpumask to
> cpu_possible_mask
> 
> On 01/12/2021 13:50, Peng Fan (OSS) wrote:
> > From: Peng Fan <peng.fan@nxp.com>
> >
> > Actually we have CLOCK_EVT_FEAT_DYNIRQ, the irq affinity will be
> > runtime changed and no issue. But the system counter timer is not tied
> > to CPU0, so use cpu_possible_mask here.
> 
> Did you mean:
> 
> "There is no reason to tie the system counter timer to CPU0, change its
> affinity to cpu_possible_mask.
> 
> Moreover, the timer has the flag CLOCK_EVT_FEAT_DYNIRQ set, changing to
> cpu_possibl_mask will reduce the number of wakeups related to the system
> timer"

The syctr interrupt could be set affinity to any cores in the SoC. Default affinity
is set to cpu 0.

This timer will be used as broadcast timer on all the i.MX SoCs. Because DYNIRQ
flag set, the core time framework will runtime set the interrupt affinity to the cores
that needs to wake up and the cpumask will runtime set to the core that will be
wake up. So even the sysctr initialization use cpumask 0, there is no issue,
the current patch is just use cpu_possible_mask to show the fact that the
timer supports routed to all the cpu cores and nothing else.

Thanks,
Peng.

> 
> ?
> 
> Note you may want to explain why 'there is no reason'
> 
> 
> > Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > ---
> >  drivers/clocksource/timer-imx-sysctr.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/clocksource/timer-imx-sysctr.c
> > b/drivers/clocksource/timer-imx-sysctr.c
> > index 2b309af11266..55a8e198d2a1 100644
> > --- a/drivers/clocksource/timer-imx-sysctr.c
> > +++ b/drivers/clocksource/timer-imx-sysctr.c
> > @@ -119,7 +119,7 @@ static struct timer_of to_sysctr = {
> >
> >  static void __init sysctr_clockevent_init(void)  {
> > -	to_sysctr.clkevt.cpumask = cpumask_of(0);
> > +	to_sysctr.clkevt.cpumask = cpu_possible_mask;
> >
> >  	clockevents_config_and_register(&to_sysctr.clkevt,
> >  					timer_of_rate(&to_sysctr),
> >
> 
> 
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Re: [PATCH 1/2] clocksource/drivers/imx-sysctr: mark two variable with __ro_after_init

[Daniel Lezcano]

On 01/12/2021 13:50, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> sys_ctr_base and cmpcr will not be updated after init, so mark
> as __ro_after_init.
> 
> Cc: Kees Cook <keescook@chromium.org>
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/clocksource/timer-imx-sysctr.c | 4 ++--

Applied, thanks


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RE: [PATCH 1/2] clocksource/drivers/imx-sysctr: mark two variable with __ro_after_init

[Peng Fan]

Hi Daniel,

> Subject: Re: [PATCH 1/2] clocksource/drivers/imx-sysctr: mark two variable
> with __ro_after_init
> 
> On 01/12/2021 13:50, Peng Fan (OSS) wrote:
> > From: Peng Fan <peng.fan@nxp.com>
> >
> > sys_ctr_base and cmpcr will not be updated after init, so mark as
> > __ro_after_init.
> >
> > Cc: Kees Cook <keescook@chromium.org>
> > Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > ---
> >  drivers/clocksource/timer-imx-sysctr.c | 4 ++--
> 
> Applied, thanks

I not see this patch in your tree.
https://git.linaro.org/people/daniel.lezcano/linux.git/log/?h=timers/drivers/next

Thanks,
Peng.

> 
> 
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Re: [PATCH 1/2] clocksource/drivers/imx-sysctr: mark two variable with __ro_after_init

[Daniel Lezcano]

On 14/12/2021 09:25, Peng Fan wrote:
> Hi Daniel,
> 
>> Subject: Re: [PATCH 1/2] clocksource/drivers/imx-sysctr: mark two variable
>> with __ro_after_init
>>
>> On 01/12/2021 13:50, Peng Fan (OSS) wrote:
>>> From: Peng Fan <peng.fan@nxp.com>
>>>
>>> sys_ctr_base and cmpcr will not be updated after init, so mark as
>>> __ro_after_init.
>>>
>>> Cc: Kees Cook <keescook@chromium.org>
>>> Signed-off-by: Peng Fan <peng.fan@nxp.com>
>>> ---
>>>  drivers/clocksource/timer-imx-sysctr.c | 4 ++--
>>
>> Applied, thanks
> 
> I not see this patch in your tree.
> https://git.linaro.org/people/daniel.lezcano/linux.git/log/?h=timers/drivers/next


You should see it now

Thanks

  -- Daniel


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