Re: [PATCH v2 1/4] powerpc/mmu: do MMU type discovery before crashkernel reservation

[Ritesh Harjani (IBM) <ritesh.list@gmail.com>]

Minor nits

Sourabh Jain <sourabhjain@linux.ibm.com> writes:

> Crashkernel reservation on high memory depends on the MMU type, so
> finalize the MMU type before calling arch_reserve_crashkernel().
>
> With the changes introduced here, early_radix_enabled() becomes usable
> and will be used in arch_reserve_crashkernel() in the upcoming patch.
>
> early_radix_enabled() depends on cur_cpu_spec->mmu_features to find
> out if the radix MMU is enabled. The radix MMU bit in mmu_features is
> discovered from the FDT and kernel configs. To make sure the MMU type is
> finalized before arch_reserve_crashkernel() is called, the function that
> scans the FDT and sets mmu_features, along with some bits from
> mmu_early_type_finalize(), has been moved above
> arch_reserve_crashkernel().
>

Can you also add a short description of why can't we move
arch_reserve_crashkernel() to a later point instead of breaking
mmu_early_init_devtree() and moving the xx_type_finalize() part above?

If I am not wrong, it is since move_device_tree() checks whether the FDT
overlaps the crash kernel reservation. So arch_reserve_crashkernel()
must be called before move_device_tree().


> Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
> ---
>  arch/powerpc/include/asm/book3s/64/mmu.h |  1 +
>  arch/powerpc/include/asm/mmu.h           |  1 +
>  arch/powerpc/kernel/prom.c               | 28 +++++++++++++-----------
>  arch/powerpc/mm/init_64.c                | 27 ++++++++++++++---------
>  4 files changed, 34 insertions(+), 23 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
> index 48631365b48c..7a3b2ff02041 100644
> --- a/arch/powerpc/include/asm/book3s/64/mmu.h
> +++ b/arch/powerpc/include/asm/book3s/64/mmu.h
> @@ -208,6 +208,7 @@ extern int mmu_vmemmap_psize;
>  
>  /* MMU initialization */
>  void mmu_early_init_devtree(void);
> +void mmu_early_type_finalize(void);

can you rename this as mmu_early_init_type().

Otherwise the change looks good to me. With the above 2 addressed, feel
free to add:

Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>