powerpc/mm: Fix _PAGE_COHERENT support on classic ppc32 HW

The following commit:

commit 64b3d0e8122b422e879b23d42f9e0e8efbbf9744
Author: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date:   Thu Dec 18 19:13:51 2008 +0000

    powerpc/mm: Rework usage of _PAGE_COHERENT/NO_CACHE/GUARDED

broke setting of the _PAGE_COHERENT bit in the PPC HW PTE.  Since we now
actually set _PAGE_COHERENT in the Linux PTE we shouldn't be clearing it
out before we propogate it to the PPC HW PTE.

Reported-by: Martyn Welch <martyn.welch@gefanuc.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S
index 67850ec..14af8ce 100644 (file)
--- a/arch/powerpc/mm/hash_low_32.S
+++ b/arch/powerpc/mm/hash_low_32.S
@@ -320,7 +320,7 @@ _GLOBAL(create_hpte)
        and     r8,r8,r0                /* writable if _RW & _DIRTY */
        rlwimi  r5,r5,32-1,30,30        /* _PAGE_USER -> PP msb */
        rlwimi  r5,r5,32-2,31,31        /* _PAGE_USER -> PP lsb */
-       ori     r8,r8,0xe14             /* clear out reserved bits and M */
+       ori     r8,r8,0xe04             /* clear out reserved bits */
        andc    r8,r5,r8                /* PP = user? (rw&dirty? 2: 3): 0 */
 BEGIN_FTR_SECTION
        rlwinm  r8,r8,0,~_PAGE_COHERENT /* clear M (coherence not required) */