[PATCH v1 1/1] riscv: mm: call best_map_size many times during linear-mapping

[Qinglin Pan]

Hi Alex,

On 11/15/22 11:38 PM, Alexandre Ghiti wrote:
> Hi Qinglin,
> 
> On 06/10/2022 04:12, panqinglin2020 at iscas.ac.cn wrote:
>> From: Qinglin Pan <panqinglin2020 at iscas.ac.cn>
>>
>> Modify the best_map_size function to give map_size many times instead
>> of only once, so a memory region can be mapped by both PMD_SIZE and
>> PAGE_SIZE.
>>
>> Signed-off-by: Qinglin Pan <panqinglin2020 at iscas.ac.cn>
>> ---
>>   arch/riscv/mm/init.c | 9 +++++----
>>   1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
>> index b56a0a75533f..1b76d3fe4e26 100644
>> --- a/arch/riscv/mm/init.c
>> +++ b/arch/riscv/mm/init.c
>> @@ -673,10 +673,11 @@ void __init create_pgd_mapping(pgd_t *pgdp,
>>   static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t 
>> size)
>>   {
>>       /* Upgrade to PMD_SIZE mappings whenever possible */
>> -    if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
>> -        return PAGE_SIZE;
>> +    base &= PMD_SIZE - 1;
>> +    if (!base && size >= PMD_SIZE)
>> +        return PMD_SIZE;
>> -    return PMD_SIZE;
>> +    return PAGE_SIZE;
>>   }
>>   #ifdef CONFIG_XIP_KERNEL
>> @@ -1111,9 +1112,9 @@ static void __init setup_vm_final(void)
>>           if (end >= __pa(PAGE_OFFSET) + memory_limit)
>>               end = __pa(PAGE_OFFSET) + memory_limit;
>> -        map_size = best_map_size(start, end - start);
>>           for (pa = start; pa < end; pa += map_size) {
>>               va = (uintptr_t)__va(pa);
>> +            map_size = best_map_size(pa, end - pa);
>>               create_pgd_mapping(swapper_pg_dir, va, pa, map_size,
>>                          pgprot_from_va(va));
> 
> 
> It works fine for me, so you can add:
> 
> Reviewed-by: Alexandre Ghiti <alexghiti at rivosinc.com>
> Tested-by: Alexandre Ghiti <alexghiti at rivosinc.com>
> 
> FYI, I'm working right now on using hugepages of 1GB for the linear 
> mapping.
> 
> Thanks,
> 
> Alex

Got it. Thanks a lot for your revew and test.

Thanks,
Qinglin