powerpc: Fix DABR match on hash based systems

commit f23ab3efb1b30cc5c5ef5ae4ef294ed467f30675 upstream.

Commit 398a719d34a1 ("powerpc/mm: Update bits used to skip hash_page")
mistakenly dropped the DSISR_DABRMATCH bit from the mask of bit tested
to skip trying to hash a page.

As a result, the DABR matches would no longer be detected.

This adds it back. We open code it in the 2 places where it matters
rather than fold it into DSISR_BAD_FAULT_32S/64S because this isn't
technically a bad fault and while we would never hit it with the
current code, I prefer if page_fault_is_bad() didn't trigger on these.

Fixes: 398a719d34a1 ("powerpc/mm: Update bits used to skip hash_page")
Cc: stable@vger.kernel.org # v4.14
Tested-by: Pedro Miraglia Franco de Carvalho <pedromfc@br.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index e9f72ab..e91b40a 100644 (file)
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1617,7 +1617,7 @@ USE_TEXT_SECTION()
        .balign IFETCH_ALIGN_BYTES
 do_hash_page:
        #ifdef CONFIG_PPC_STD_MMU_64
-       lis     r0,DSISR_BAD_FAULT_64S@h
+       lis     r0,(DSISR_BAD_FAULT_64S|DSISR_DABRMATCH)@h
        ori     r0,r0,DSISR_BAD_FAULT_64S@l
        and.    r0,r4,r0                /* weird error? */
        bne-    handle_page_fault       /* if not, try to insert a HPTE */

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 8c54166..29b2fed 100644 (file)
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -388,7 +388,7 @@ DataAccess:
        EXCEPTION_PROLOG
        mfspr   r10,SPRN_DSISR
        stw     r10,_DSISR(r11)
-       andis.  r0,r10,DSISR_BAD_FAULT_32S@h
+       andis.  r0,r10,(DSISR_BAD_FAULT_32S|DSISR_DABRMATCH)@h
        bne     1f                      /* if not, try to put a PTE */
        mfspr   r4,SPRN_DAR             /* into the hash table */
        rlwinm  r3,r10,32-15,21,21      /* DSISR_STORE -> _PAGE_RW */