On Sat, 2016-20-02 at 17:58:37 UTC, Ben Hutchings wrote:

Soft dirty bit support was only implemented for 64-bit Book3S, and
32-bit configurations currently fail to build.

Fixes: 7207f43665b8 ("powerpc/mm: Add page soft dirty tracking")
References: https://buildd.debian.org/status/fetch.php?pkg=linux&arch=powerpc&ver=4.5%7Erc4-1%7Eexp1&stamp=1455791718
Signed-off-by: Ben Hutchings <redacted>

Thanks for the patch Ben.

I merged a similar but not identical patch into my fixes branch last week, and
Linus merged it over the weekend. Let me know if it isn't sufficient for you:

  https://git.kernel.org/torvalds/c/19f97c983071

cheers