Re: [PATCH v2 28/34] ARM: mmu32: Add pte_flags_to_pmd()

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 17.05.23 11:03, Sascha Hauer wrote:
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  arch/arm/cpu/mmu_32.c | 35 +++++++++++++++++++++++++++++------
>  1 file changed, 29 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm/cpu/mmu_32.c b/arch/arm/cpu/mmu_32.c
> index 4abaab7d87..0af89ac39c 100644
> --- a/arch/arm/cpu/mmu_32.c
> +++ b/arch/arm/cpu/mmu_32.c
> @@ -187,30 +187,53 @@ static u32 pmd_flags_to_pte(u32 pmd)
>  	return pte;
>  }
>  
> +static u32 pte_flags_to_pmd(u32 pte)
> +{
> +	u32 pmd = 0;
> +
> +	if (pte & PTE_BUFFERABLE)
> +		pmd |= PMD_SECT_BUFFERABLE;
> +	if (pte & PTE_CACHEABLE)
> +		pmd |= PMD_SECT_CACHEABLE;
> +
> +	if (cpu_architecture() >= CPU_ARCH_ARMv7) {
> +		if (pte & PTE_EXT_NG)
> +			pmd |= PMD_SECT_nG;
> +		if (pte & PTE_EXT_XN)
> +			pmd |= PMD_SECT_XN;

Note that at least,  <asm/pgtable.h> claims these bits are v6+:

#define PTE_EXT_XN		(1 << 0)	/* v6 */
#define PMD_SECT_nG		(1 << 17)	/* v6 */


> +
> +		/* TEX[2:0] */
> +		pmd |= ((pte >> 6) & 7) << 12;
> +		/* AP[1:0] */
> +		pmd |= ((pte >> 4) & 0x3) << 10;
> +		/* AP[2] */
> +		pmd |= ((pte >> 9) & 0x1) << 15;
> +	} else {
> +		pmd |= PMD_SECT_AP_WRITE | PMD_SECT_AP_READ;
> +	}
> +
> +	return pmd;
> +}
> +
>  int arch_remap_range(void *start, size_t size, unsigned flags)
>  {
>  	u32 addr = (u32)start;
>  	u32 pte_flags;
> -	u32 pgd_flags;
>  
>  	BUG_ON(!IS_ALIGNED(addr, PAGE_SIZE));
>  
>  	switch (flags) {
>  	case MAP_CACHED:
>  		pte_flags = pte_flags_cached;
> -		pgd_flags = PMD_SECT_DEF_CACHED;
>  		break;
>  	case MAP_UNCACHED:
>  		pte_flags = pte_flags_uncached;
> -		pgd_flags = pgd_flags_uncached;
>  		break;
>  	case MAP_FAULT:
>  		pte_flags = 0x0;
> -		pgd_flags = 0x0;
>  		break;
>  	case ARCH_MAP_WRITECOMBINE:
>  		pte_flags = pte_flags_wc;
> -		pgd_flags = pgd_flags_wc;
>  		break;
>  	default:
>  		return -EINVAL;
> @@ -228,7 +251,7 @@ int arch_remap_range(void *start, size_t size, unsigned flags)
>  			 * replace it with a section
>  			 */
>  			chunk = PGDIR_SIZE;
> -			*pgd = addr | pgd_flags;
> +			*pgd = addr | pte_flags_to_pmd(pte_flags) | PMD_TYPE_SECT;
>  			dma_flush_range(pgd, sizeof(*pgd));
>  		} else {
>  			unsigned int num_ptes;

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