1 files changed, 33 insertions, 0 deletions
diff --git a/drivers/hwtracing/coresight/coresight-self-hosted-trace.h b/drivers/hwtracing/coresight/coresight-self-hosted-trace.h
new file mode 100644
index 000000000000..53840a2c41f2
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-self-hosted-trace.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Arm v8 Self-Hosted trace support.
+ *
+ * Copyright (C) 2021 ARM Ltd.
+ */
+
+#ifndef __CORESIGHT_SELF_HOSTED_TRACE_H
+#define __CORESIGHT_SELF_HOSTED_TRACE_H
+
+#include <asm/sysreg.h>
+
+static inline u64 read_trfcr(void)
+{
+	return read_sysreg_s(SYS_TRFCR_EL1);
+}
+
+static inline void write_trfcr(u64 val)
+{
+	write_sysreg_s(val, SYS_TRFCR_EL1);
+	isb();
+}
+
+static inline u64 cpu_prohibit_trace(void)
+{
+	u64 trfcr = read_trfcr();
+
+	/* Prohibit tracing at EL0 & the kernel EL */
+	write_trfcr(trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE));
+	/* Return the original value of the TRFCR */
+	return trfcr;
+}
+#endif /*  __CORESIGHT_SELF_HOSTED_TRACE_H */