Re: [PATCH v1 2/2] s390/pgtable: introduce _REGION3_ENTRY_HARDWARE_BITS_LARGE

Heiko Carstens
2024-04-26T08:57:24Z

On Thu, Apr 25, 2024 at 03:05:55PM +0200, Claudio Imbrenda wrote:
> For completeness, introduce _REGION3_ENTRY_HARDWARE_BITS_LARGE,
> containing the hardware bits used for large puds.
>
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
> arch/s390/include/asm/pgtable.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index 3da2995fd196..5c0f840eee2a 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -262,6 +262,7 @@ static inline int is_module_addr(void *addr)
> #define _REGION3_ENTRY (_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_LENGTH)
> #define _REGION3_ENTRY_EMPTY (_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID)
>
> +#define _REGION3_ENTRY_HARDWARE_BITS_LARGE 0xffffffff8000073cUL

_REGION_ENTRY_HARDWARE_BITS is missing too. :)

And this definition also raises the question if the definition of
_SEGMENT_ENTRY_HARDWARE_BITS_LARGE should be changed so it also includes
the table type bits, which it probably should.

These masks are really a bit randomly defined and assume that the
ACCF-Validity control bit is never set, and therefore the ACC bitfield can
be assumed to be software bits (and they are used as such for format 1
segment table entries).

But the ACCF bit is also a hardware bit in any case... oh well.