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

[Steven Price]

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.

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