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

[Andrew Jones]

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>