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

[Qinglin Pan]

Hi Palmer,

Is there anything I need to change about this patch? :)

Thanks,
Qinglin

On 10/6/22 8:28 PM, Andrew Jones wrote:
> On Thu, Oct 06, 2022 at 10:12:23AM +0800, 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));
>> -- 
>> 2.35.1
>>
> 
> Reviewed-by: Andrew Jones <ajones at ventanamicro.com>