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powerpc: Fix DABR match on hash based systems

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commit f23ab3efb1 upstream.

Commit 398a719d34 ("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: 398a719d34 ("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>
This commit is contained in:
Benjamin Herrenschmidt
2017-11-10 12:15:00 +11:00
committed by Greg Kroah-Hartman
parent 3b09911d3b
commit 40be210c83
2 changed files with 2 additions and 2 deletions
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2
arch/powerpc/kernel/exceptions-64s.S
View File

@@ -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 */

2
arch/powerpc/kernel/head_32.S
View File

@@ -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 */