powerpc/powernv: Support firmware disable of RFI flush

Some versions of firmware will have a setting that can be configured
to disable the RFI flush, add support for it.

Fixes: 6e032b350cd1 ("powerpc/powernv: Check device-tree for RFI flush settings")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(cherry picked from commit eb0a2d2620ae431c543963c8c7f08f597366fc60)

CVE-2018-3639 (powerpc)

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index ee6f026f202bd59b859a6ec71067ebda30449b4e..953645013a42a9383c1e3b60381bad7cdf07a30d 100644 (file)
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -79,6 +79,10 @@ static void pnv_setup_rfi_flush(void)
                if (np && of_property_read_bool(np, "disabled"))
                        enable--;
 
+               np = of_get_child_by_name(fw_features, "speculation-policy-favor-security");
+               if (np && of_property_read_bool(np, "disabled"))
+                       enable = 0;
+
                of_node_put(np);
                of_node_put(fw_features);
        }