Subject: Re: [PATCH v4 1/4] powerpc/mm: refactor radix physical page mapping

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Wed, 04 Jan 2017 10:34:25 +0530

Reza Arbab <[email-masked]> writes:

> Move the page mapping code in radix_init_pgtable() into a separate
> function that will also be used for memory hotplug.
>
> The current goto loop progressively decreases its mapping size as it
> covers the tail of a range whose end is unaligned. Change this to a for
> loop which can do the same for both ends of the range.
>

We lost the below in the change.

		pr_info("Mapping range 0x%lx - 0x%lx with 0x%lx\n",
			(unsigned long)base, (unsigned long)end,
			linear_page_size);

Is there a way to dump the range and the size with which we mapped that
range ?

> Signed-off-by: Reza Arbab <[email-masked]>
> ---
>  arch/powerpc/mm/pgtable-radix.c | 69 ++++++++++++++++++-----------------------
>  1 file changed, 31 insertions(+), 38 deletions(-)
>
> diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
> index 623a0dc..5cee6d1 100644
> --- a/arch/powerpc/mm/pgtable-radix.c
> +++ b/arch/powerpc/mm/pgtable-radix.c
> @@ -107,54 +107,47 @@ int radix__map_kernel_page(unsigned long ea, unsigned long pa,
>  	return 0;
>  }
>
> +static int __meminit create_physical_mapping(unsigned long start,
> +					     unsigned long end)
> +{
> +	unsigned long mapping_size;
> +
> +	start = _ALIGN_UP(start, PAGE_SIZE);
> +	for (; start < end; start += mapping_size) {
> +		unsigned long gap = end - start;
> +		int rc;
> +
> +		if (IS_ALIGNED(start, PUD_SIZE) && gap >= PUD_SIZE &&
> +		    mmu_psize_defs[MMU_PAGE_1G].shift)
> +			mapping_size = PUD_SIZE;
> +		else if (IS_ALIGNED(start, PMD_SIZE) && gap >= PMD_SIZE &&
> +			 mmu_psize_defs[MMU_PAGE_2M].shift)
> +			mapping_size = PMD_SIZE;
> +		else
> +			mapping_size = PAGE_SIZE;
> +
> +		rc = radix__map_kernel_page((unsigned long)__va(start), start,
> +					    PAGE_KERNEL_X, mapping_size);
> +		if (rc)
> +			return rc;
> +	}
> +
> +	return 0;
> +}
> +
>  static void __init radix_init_pgtable(void)
>  {
> -	int loop_count;
> -	u64 base, end, start_addr;
>  	unsigned long rts_field;
>  	struct memblock_region *reg;
> -	unsigned long linear_page_size;
>
>  	/* We don't support slb for radix */
>  	mmu_slb_size = 0;
>  	/*
>  	 * Create the linear mapping, using standard page size for now
>  	 */
> -	loop_count = 0;
> -	for_each_memblock(memory, reg) {
> -
> -		start_addr = reg->base;
> -
> -redo:
> -		if (loop_count < 1 && mmu_psize_defs[MMU_PAGE_1G].shift)
> -			linear_page_size = PUD_SIZE;
> -		else if (loop_count < 2 && mmu_psize_defs[MMU_PAGE_2M].shift)
> -			linear_page_size = PMD_SIZE;
> -		else
> -			linear_page_size = PAGE_SIZE;
> -
> -		base = _ALIGN_UP(start_addr, linear_page_size);
> -		end = _ALIGN_DOWN(reg->base + reg->size, linear_page_size);
> -
> -		pr_info("Mapping range 0x%lx - 0x%lx with 0x%lx\n",
> -			(unsigned long)base, (unsigned long)end,
> -			linear_page_size);
> -
> -		while (base < end) {
> -			radix__map_kernel_page((unsigned long)__va(base),
> -					      base, PAGE_KERNEL_X,
> -					      linear_page_size);
> -			base += linear_page_size;
> -		}
> -		/*
> -		 * map the rest using lower page size
> -		 */
> -		if (end < reg->base + reg->size) {
> -			start_addr = end;
> -			loop_count++;
> -			goto redo;
> -		}
> -	}
> +	for_each_memblock(memory, reg)
> +		WARN_ON(create_physical_mapping(reg->base,
> +						reg->base + reg->size));
>  	/*
>  	 * Allocate Partition table and process table for the
>  	 * host.
> -- 
> 1.8.3.1