[Crash-utility] [PATCH] s390x: Allow HW Change-bit override for page table entries

[Dave Anderson]

----- Original Message -----
> Hi Dave,
> 
> s390x: Allow HW Change-bit override for page table entries
> 
> The HW Change-bit override (0x100) is used now for s390x. This patch allows
> page table entries that have set this bit.
> 
> Signed-off-by: Michael Holzheu <holzheu at linux.vnet.ibm.com>

Hi Michael,

I've queued this for crash-6.1.1, but can you confirm that
there will not be any backwards-compatibility issues here?

Dave


> ---
>  s390x.c |    7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> --- a/s390x.c
> +++ b/s390x.c
> @@ -600,11 +600,10 @@ static ulong _kl_pg_table_deref_s390x(ul
>  	readmem(table + offset, KVADDR, &entry, sizeof(entry), "entry",
>  		FAULT_ON_ERROR);
>  	/*
> -	 * Return zero if the page table entry has any of the reserved bits
> -	 * set (0x900) or the invalid bit (0x400) is set and it is not a
> -	 * swap entry.
> +	 * Return zero if the page table entry has the reserved (0x800) or
> +	 * the invalid (0x400) bit set and it is not a swap entry.
>  	 */
> -	if ((entry & 0xd00ULL) && !swap_entry(entry))
> +	if ((entry & 0xc00ULL) && !swap_entry(entry))
>  		return 0;
>  	/* Page table entry is valid and well formed. */
>  	return entry;
>