From: Aneesh Kumar K.V Date: Wed, 13 Aug 2014 07:02:03 +0000 (+0530) Subject: powerpc/mm: Use read barrier when creating real_pte X-Git-Tag: v3.2.64~172 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f9b211847bfb9c50483c7b62875e9aefbbce6f78;p=pandora-kernel.git powerpc/mm: Use read barrier when creating real_pte commit 85c1fafd7262e68ad821ee1808686b1392b1167d upstream. On ppc64 we support 4K hash pte with 64K page size. That requires us to track the hash pte slot information on a per 4k basis. We do that by storing the slot details in the second half of pte page. The pte bit _PAGE_COMBO is used to indicate whether the second half need to be looked while building real_pte. We need to use read memory barrier while doing that so that load of hidx is not reordered w.r.t _PAGE_COMBO check. On the store side we already do a lwsync in __hash_page_4K Signed-off-by: Aneesh Kumar K.V Signed-off-by: Benjamin Herrenschmidt [bwh: Backported to 3.2: include to ensure smp_rmb() is defined; cell_defconfig fails to build without this] Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed