lkml.org 
[lkml]   [2022]   [Jan]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v5 1/6] powercap/drivers/dtpm: Move dtpm table from init to data section
From
Date

Hi Ulf,

thanks for your comments

On 31/12/2021 14:33, Ulf Hansson wrote:
> On Sat, 18 Dec 2021 at 14:00, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
>>
>> The dtpm table is used to let the different dtpm backends to register
>> their setup callbacks in a single place and preventing to export
>> multiple functions all around the kernel. That allows the dtpm code to
>> be self-encapsulated.
>
> Well, that's not entirely true. The dtpm code and its backends (or
> ops, whatever we call them) are already maintained from a single
> place, the /drivers/powercap/* directory. I assume we intend to keep
> it like this going forward too, right?

Hopefully we can add more devices like the battery or the backlight, but
I'm not sure they will be in drivers/powercap.

> That is also what patch4 with the devfreq backend continues to conform to.
>
>>
>> The dtpm hierarchy will be passed as a parameter by a platform
>> specific code and that will lead to the creation of the different dtpm
>> nodes.
>>
>> The function creating the hierarchy could be called from a module at
>> init time or when it is loaded. However, at this moment the table is
>> already freed as it belongs to the init section and the creation will
>> lead to a invalid memory access.
>>
>> Fix this by moving the table to the data section.
>
> With the above said, I find it a bit odd to put a table in the data
> section like this. Especially, since the only remaining argument for
> why, is to avoid exporting functions, which isn't needed anyway.
>
> I mean, it would be silly if we should continue to put subsystem
> specific tables in here, to just let them contain a set of subsystem
> specific callbacks.

Do you have an alternative without introducing cyclic dependencies ?



>> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
>
> Kind regards
> Uffe
>
>> ---
>> include/asm-generic/vmlinux.lds.h | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
>> index 42f3866bca69..50d494d94d6c 100644
>> --- a/include/asm-generic/vmlinux.lds.h
>> +++ b/include/asm-generic/vmlinux.lds.h
>> @@ -362,7 +362,8 @@
>> BRANCH_PROFILE() \
>> TRACE_PRINTKS() \
>> BPF_RAW_TP() \
>> - TRACEPOINT_STR()
>> + TRACEPOINT_STR() \
>> + DTPM_TABLE()
>>
>> /*
>> * Data section helpers
>> @@ -723,7 +724,6 @@
>> ACPI_PROBE_TABLE(irqchip) \
>> ACPI_PROBE_TABLE(timer) \
>> THERMAL_TABLE(governor) \
>> - DTPM_TABLE() \
>> EARLYCON_TABLE() \
>> LSM_TABLE() \
>> EARLY_LSM_TABLE() \
>> --
>> 2.25.1
>>


--
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog

\
 
 \ /
  Last update: 2022-01-04 09:59    [W:0.110 / U:1.388 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site