Re: [PATCH v17 21/23] arm64: mm: Convert mm/dump.c to use walk_page_range()

[Steven Price]

On 16/02/2020 16:25, Ard Biesheuvel wrote:
> On Wed, 18 Dec 2019 at 17:25, Steven Price <steven.price@xxxxxxx> wrote:
>>
>> Now walk_page_range() can walk kernel page tables, we can switch the
>> arm64 ptdump code over to using it, simplifying the code.
>>
>> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
>> Signed-off-by: Steven Price <steven.price@xxxxxxx>
> 
> I did not realize this at the time, but this patch removes the ability
> to dump the EFI page tables on 32-bit ARM. Was that intentional?

No that wasn't intentional, but I can't instantly see how this change
affects 32-bit ARM.

<snip (files in arch/arm64)>
>> diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
>> index 899b803842bb..9dda2602c862 100644
>> --- a/drivers/firmware/efi/arm-runtime.c
>> +++ b/drivers/firmware/efi/arm-runtime.c
>> @@ -27,7 +27,7 @@
>>
>>  extern u64 efi_system_table;
>>
>> -#ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
>> +#if defined(CONFIG_PTDUMP_DEBUGFS) && defined(CONFIG_ARM64)

The previous define was *ARM64* so should never have been true when
building for arm. The new condition should be equivalent (arm64 &&
ptdump enabled).

Am I missing something?

Steve