linux-kernel - [PATCH 4.9 38/94] powerpc/spufs: Fix hash faults for kernel regions

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Date:   Mon,  5 Jun 2017 18:17:14 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jeremy Kerr <jk@...abs.org>,
        Sombat Tragolgosol <sombat3960@...il.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 4.9 38/94] powerpc/spufs: Fix hash faults for kernel regions

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jeremy Kerr <jk@...abs.org>

commit d75e4919cc0b6fbcbc8d6654ef66d87a9dbf1526 upstream.

Commit ac29c64089b7 ("powerpc/mm: Replace _PAGE_USER with
_PAGE_PRIVILEGED") swapped _PAGE_USER for _PAGE_PRIVILEGED, and
introduced check_pte_access() which denied kernel access to
non-_PAGE_PRIVILEGED pages.

However, it didn't add _PAGE_PRIVILEGED to the hash fault handler
for spufs' kernel accesses, so the DMAs required to establish SPE
memory no longer work.

This change adds _PAGE_PRIVILEGED to the hash fault handler for
kernel accesses.

Fixes: ac29c64089b7 ("powerpc/mm: Replace _PAGE_USER with _PAGE_PRIVILEGED")
Signed-off-by: Jeremy Kerr <jk@...abs.org>
Reported-by: Sombat Tragolgosol <sombat3960@...il.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/powerpc/platforms/cell/spu_base.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/arch/powerpc/platforms/cell/spu_base.c
+++ b/arch/powerpc/platforms/cell/spu_base.c
@@ -197,7 +197,9 @@ static int __spu_trap_data_map(struct sp
 	    (REGION_ID(ea) != USER_REGION_ID)) {
 
 		spin_unlock(&spu->register_lock);
-		ret = hash_page(ea, _PAGE_PRESENT | _PAGE_READ, 0x300, dsisr);
+		ret = hash_page(ea,
+				_PAGE_PRESENT | _PAGE_READ | _PAGE_PRIVILEGED,
+				0x300, dsisr);
 		spin_lock(&spu->register_lock);
 
 		if (!ret) {