Re: [RFC] m68k: Enable memtest kernel parameter

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Finn,

it looks as though early_memtest() does skip allocated and unmapped 
areas, so I'd say this looks fine.

Cheers,

	Michael


On 13/09/21 15:40, Michael Schmitz wrote:
> Hi Finn,
>
> On 13/09/21 13:34, Finn Thain wrote:
>>
>> This appears to work on Aranym, QEMU and the Quadra 630 I have here.
>> It is completely untested on Coldfire etc. I don't even know whether the
>> right memory mappings are in place for this to actually work as intended.
>
> The comment just above the section from paging_init() in your patch
> states that all physical memory is mapped into kernel virtual address
> space. I don't think that mapping is contiguous though.
>
>> Would someone take a look please?
>>
>> diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
>> index 6e40f7f29ebc..d87e12b4855b 100644
>> --- a/arch/m68k/Kconfig
>> +++ b/arch/m68k/Kconfig
>> @@ -9,6 +9,7 @@ config M68K
>>      select ARCH_HAVE_NMI_SAFE_CMPXCHG if RMW_INSNS
>>      select ARCH_MIGHT_HAVE_PC_PARPORT if ISA
>>      select ARCH_NO_PREEMPT if !COLDFIRE
>> +    select ARCH_USE_MEMTEST
>>      select ARCH_WANT_IPC_PARSE_VERSION
>>      select BINFMT_FLAT_ARGVP_ENVP_ON_STACK
>>      select DMA_DIRECT_REMAP if HAS_DMA && MMU && !COLDFIRE
>> diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
>> index 3a653f0a4188..d6301a094fc1 100644
>> --- a/arch/m68k/mm/motorola.c
>> +++ b/arch/m68k/mm/motorola.c
>> @@ -455,6 +455,8 @@ void __init paging_init(void)
>>
>>      flush_tlb_all();
>>
>> +    early_memtest(min_addr, max_addr);
>> +
>>      /*
>>       * initialize the bad page table and bad page to point
>>       * to a couple of allocated pages
>>
>
> I'd rather start that from availmem, not from min_addr ... I'm amazed
> this works - I'd expect the kernel text segment to get trashed by the
> memory test routines.
>
> Cheers,
>
>     Michael