1 files changed, 79 insertions, 0 deletions
diff --git a/arch/riscv/lib/stacktrace.c b/arch/riscv/lib/stacktrace.c
new file mode 100644
index 0000000000..663938019e
--- /dev/null
+++ b/arch/riscv/lib/stacktrace.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2008 ARM Limited
+ * Copyright (C) 2014 Regents of the University of California
+ * Copyright (C) 2021 Ahmad Fatoum, Pengutronix
+ *
+ * Framepointer assisted stack unwinder
+ */
+
+#include <linux/kernel.h>
+#include <printk.h>
+#include <asm/unwind.h>
+#include <asm/ptrace.h>
+#include <asm-generic/memory_layout.h>
+#include <asm/sections.h>
+
+struct stackframe {
+	unsigned long fp;
+	unsigned long ra;
+};
+
+static void dump_backtrace_entry(unsigned long where, unsigned long from)
+{
+#ifdef CONFIG_KALLSYMS
+	printf("[<%08lx>] (%pS) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
+#else
+	printf("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
+#endif
+}
+
+static int unwind_frame(struct stackframe *frame, unsigned long *sp)
+{
+	unsigned long low, high;
+	unsigned long fp = frame->fp;
+
+	low = *sp;
+	high = ALIGN(low, STACK_SIZE);
+
+	if (fp < low || fp > high - sizeof(struct stackframe) || fp & 0x7)
+		return -1;
+
+	*frame = *((struct stackframe *)fp - 1);
+	*sp = fp;
+
+	return 0;
+}
+
+void unwind_backtrace(const struct pt_regs *regs)
+{
+        struct stackframe frame = {};
+	register unsigned long current_sp asm ("sp");
+	unsigned long sp = 0;
+
+	if (regs) {
+		frame.fp = frame_pointer(regs);
+		frame.ra = regs->ra;
+	} else {
+		sp = current_sp;
+		frame.fp = (unsigned long)__builtin_frame_address(0);
+		frame.ra = (unsigned long)unwind_backtrace;
+	}
+
+	printf("Call trace:\n");
+	for (;;) {
+		unsigned long where = frame.ra;
+		int ret;
+
+		ret = unwind_frame(&frame, &sp);
+		if (ret < 0)
+			break;
+
+		dump_backtrace_entry(where, frame.ra);
+	}
+}
+
+void dump_stack(void)
+{
+	unwind_backtrace(NULL);
+}