1 files changed, 98 insertions, 0 deletions
diff --git a/lib/extensions/spe/spe.c b/lib/extensions/spe/spe.c
new file mode 100644
index 0000000..d747efc
--- /dev/null
+++ b/lib/extensions/spe/spe.c
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2017-2022, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdbool.h>
+
+#include <arch.h>
+#include <arch_helpers.h>
+#include <lib/el3_runtime/pubsub.h>
+#include <lib/extensions/spe.h>
+
+static inline void psb_csync(void)
+{
+	/*
+	 * The assembler does not yet understand the psb csync mnemonic
+	 * so use the equivalent hint instruction.
+	 */
+	__asm__ volatile("hint #17");
+}
+
+bool spe_supported(void)
+{
+	uint64_t features;
+
+	features = read_id_aa64dfr0_el1() >> ID_AA64DFR0_PMS_SHIFT;
+	return (features & ID_AA64DFR0_PMS_MASK) > 0ULL;
+}
+
+void spe_enable(bool el2_unused)
+{
+	uint64_t v;
+
+	if (!spe_supported())
+		return;
+
+	if (el2_unused) {
+		/*
+		 * MDCR_EL2.TPMS (ARM v8.2): Do not trap statistical
+		 * profiling controls to EL2.
+		 *
+		 * MDCR_EL2.E2PB (ARM v8.2): SPE enabled in Non-secure
+		 * state. Accesses to profiling buffer controls at
+		 * Non-secure EL1 are not trapped to EL2.
+		 */
+		v = read_mdcr_el2();
+		v &= ~MDCR_EL2_TPMS;
+		v |= MDCR_EL2_E2PB(MDCR_EL2_E2PB_EL1);
+		write_mdcr_el2(v);
+	}
+
+	/*
+	 * MDCR_EL2.NSPB (ARM v8.2): SPE enabled in Non-secure state
+	 * and disabled in secure state. Accesses to SPE registers at
+	 * S-EL1 generate trap exceptions to EL3.
+	 *
+	 * MDCR_EL3.EnPMSN (ARM v8.7): Do not trap access to PMSNEVFR_EL1
+	 * register at NS-EL1 or NS-EL2 to EL3 if FEAT_SPEv1p2 is implemented.
+	 * Setting this bit to 1 doesn't have any effect on it when
+	 * FEAT_SPEv1p2 not implemented.
+	 */
+	v = read_mdcr_el3();
+	v |= MDCR_NSPB(MDCR_NSPB_EL1) | MDCR_EnPMSN_BIT;
+	write_mdcr_el3(v);
+}
+
+void spe_disable(void)
+{
+	uint64_t v;
+
+	if (!spe_supported())
+		return;
+
+	/* Drain buffered data */
+	psb_csync();
+	dsbnsh();
+
+	/* Disable profiling buffer */
+	v = read_pmblimitr_el1();
+	v &= ~(1ULL << 0);
+	write_pmblimitr_el1(v);
+	isb();
+}
+
+static void *spe_drain_buffers_hook(const void *arg)
+{
+	if (!spe_supported())
+		return (void *)-1;
+
+	/* Drain buffered data */
+	psb_csync();
+	dsbnsh();
+
+	return (void *)0;
+}
+
+SUBSCRIBE_TO_EVENT(cm_entering_secure_world, spe_drain_buffers_hook);