[PATCH 4.9 35/61] powerpc/powernv: Set or clear security feature flags

Greg Kroah-Hartman
2018-06-05T17:05:54Z

From: Michael Ellerman <mpe@ellerman.id.au>

commit 77addf6e95c8689e478d607176b399a6242a777e upstream.

Now that we have feature flags for security related things, set or
clear them based on what we see in the device tree provided by
firmware.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/platforms/powernv/setup.c | 56 +++++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)

--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -37,9 +37,63 @@
#include <asm/smp.h>
#include <asm/tm.h>
#include <asm/setup.h>
+#include <asm/security_features.h>

#include "powernv.h"

+
+static bool fw_feature_is(const char *state, const char *name,
+ struct device_node *fw_features)
+{
+ struct device_node *np;
+ bool rc = false;
+
+ np = of_get_child_by_name(fw_features, name);
+ if (np) {
+ rc = of_property_read_bool(np, state);
+ of_node_put(np);
+ }
+
+ return rc;
+}
+
+static void init_fw_feat_flags(struct device_node *np)
+{
+ if (fw_feature_is("enabled", "inst-spec-barrier-ori31,31,0", np))
+ security_ftr_set(SEC_FTR_SPEC_BAR_ORI31);
+
+ if (fw_feature_is("enabled", "fw-bcctrl-serialized", np))
+ security_ftr_set(SEC_FTR_BCCTRL_SERIALISED);
+
+ if (fw_feature_is("enabled", "inst-spec-barrier-ori31,31,0", np))
+ security_ftr_set(SEC_FTR_L1D_FLUSH_ORI30);
+
+ if (fw_feature_is("enabled", "inst-l1d-flush-trig2", np))
+ security_ftr_set(SEC_FTR_L1D_FLUSH_TRIG2);
+
+ if (fw_feature_is("enabled", "fw-l1d-thread-split", np))
+ security_ftr_set(SEC_FTR_L1D_THREAD_PRIV);
+
+ if (fw_feature_is("enabled", "fw-count-cache-disabled", np))
+ security_ftr_set(SEC_FTR_COUNT_CACHE_DISABLED);
+
+ /*
+ * The features below are enabled by default, so we instead look to see
+ * if firmware has *disabled* them, and clear them if so.
+ */
+ if (fw_feature_is("disabled", "speculation-policy-favor-security", np))
+ security_ftr_clear(SEC_FTR_FAVOUR_SECURITY);
+
+ if (fw_feature_is("disabled", "needs-l1d-flush-msr-pr-0-to-1", np))
+ security_ftr_clear(SEC_FTR_L1D_FLUSH_PR);
+
+ if (fw_feature_is("disabled", "needs-l1d-flush-msr-hv-1-to-0", np))
+ security_ftr_clear(SEC_FTR_L1D_FLUSH_HV);
+
+ if (fw_feature_is("disabled", "needs-spec-barrier-for-bound-checks", np))
+ security_ftr_clear(SEC_FTR_BNDS_CHK_SPEC_BAR);
+}
+
static void pnv_setup_rfi_flush(void)
{
struct device_node *np, *fw_features;
@@ -55,6 +109,8 @@ static void pnv_setup_rfi_flush(void)
of_node_put(np);

if (fw_features) {
+ init_fw_feat_flags(fw_features);
+
np = of_get_child_by_name(fw_features, "inst-l1d-flush-trig2");
if (np && of_property_read_bool(np, "enabled"))
type = L1D_FLUSH_MTTRIG;