Re: [PATCH 3/4] mm: Make GENERIC_PTDUMP dependent on MMU

[Anshuman Khandual]

On 2/13/25 16:53, Steven Price wrote:
> On 13/02/2025 04:09, Anshuman Khandual wrote:
>> There is no page table dump without a MMU. Make this dependency at generic
>> level and drop the same from riscv platform instead.
>>
>> Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
>> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Cc: linux-mm@xxxxxxxxx
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> 
> As Christophe has pointed out - this is broken. The select will override
> the dependency you've added in GENERIC_PTDUMP. Generally have "depends
> on" for symbols that are "select"ed is broken. I'd suggest just dropping
> this patch.

Agreed, will drop this patch. Thanks Steven and Christophe for the
explanation here regarding correct usage regarding the "select"'s
construct.

> 
> Steve
> 
>> ---
>>  arch/riscv/Kconfig | 2 +-
>>  mm/Kconfig.debug   | 1 +
>>  2 files changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
>> index 7612c52e9b1e..c4cdba6460b8 100644
>> --- a/arch/riscv/Kconfig
>> +++ b/arch/riscv/Kconfig
>> @@ -112,7 +112,7 @@ config RISCV
>>  	select GENERIC_IRQ_SHOW_LEVEL
>>  	select GENERIC_LIB_DEVMEM_IS_ALLOWED
>>  	select GENERIC_PCI_IOMAP
>> -	select GENERIC_PTDUMP if MMU
>> +	select GENERIC_PTDUMP
>>  	select GENERIC_SCHED_CLOCK
>>  	select GENERIC_SMP_IDLE_THREAD
>>  	select GENERIC_TIME_VSYSCALL if MMU && 64BIT
>> diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
>> index a51a1149909a..c08406760d29 100644
>> --- a/mm/Kconfig.debug
>> +++ b/mm/Kconfig.debug
>> @@ -214,6 +214,7 @@ config DEBUG_WX
>>  	  If in doubt, say "Y".
>>  
>>  config GENERIC_PTDUMP
>> +	depends on MMU
>>  	bool
>>  
>>  config PTDUMP_CORE
>