From 33d86143595345a22819e95467c3fa6c61f1fb55 Mon Sep 17 00:00:00 2001
From: William Cohen <wcohen@redhat.com>
Date: Fri, 13 Aug 2021 08:58:07 +0800
Subject: [PATCH] Add bactrace support for RISC-V

---
 runtime/linux/runtime.h |  2 +-
 runtime/unwind/riscv.h  | 78 +++++++++++++++++++++++++++++++++++++++++
 runtime/unwind/unwind.h |  2 ++
 3 files changed, 81 insertions(+), 1 deletion(-)
 create mode 100644 runtime/unwind/riscv.h

diff --git a/runtime/linux/runtime.h b/runtime/linux/runtime.h
index e57d10a8a..880c1fa4a 100644
--- a/runtime/linux/runtime.h
+++ b/runtime/linux/runtime.h
@@ -199,7 +199,7 @@ static struct
    Only define STP_USE_DWARF_UNWINDER when STP_NEED_UNWIND_DATA,
    as set through a pragma:unwind in one of the [u]context-unwind.stp
    functions. */
-#if (defined(__arm__) || defined(__i386__) || defined(__x86_64__) || defined(__powerpc64__)) || defined (__s390x__) || defined(__aarch64__) || defined(__mips__)
+#if (defined(__arm__) || defined(__i386__) || defined(__x86_64__) || defined(__powerpc64__)) || defined (__s390x__) || defined(__aarch64__) || defined(__mips__) || defined(__riscv)
 #ifdef STP_NEED_UNWIND_DATA
 #ifndef STP_USE_DWARF_UNWINDER
 #define STP_USE_DWARF_UNWINDER
diff --git a/runtime/unwind/riscv.h b/runtime/unwind/riscv.h
new file mode 100644
index 000000000..62434cf29
--- /dev/null
+++ b/runtime/unwind/riscv.h
@@ -0,0 +1,78 @@
+/* -*- linux-c -*-
+ *
+ * RISC-V dwarf unwinder header file
+ *
+ * This file is part of systemtap, and is free software.  You can
+ * redistribute it and/or modify it under the terms of the GNU General
+ * Public License (GPL); either version 2, or (at your option) any
+ * later version.
+ */
+#ifndef _STP_RISCV_UNWIND_H
+#define _STP_RISCV_UNWIND_H
+
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+
+#define _stp_get_unaligned(ptr) (*(ptr))
+
+#define UNW_PC(frame)        (frame)->regs.epc
+#define UNW_SP(frame)        (frame)->regs.sp
+
+#define STACK_LIMIT(ptr)     (((ptr) - 1) & ~(THREAD_SIZE - 1))
+
+#define UNW_REGISTER_INFO \
+	PTREGS_INFO(epc), \
+	PTREGS_INFO(ra), \
+	PTREGS_INFO(sp), \
+	PTREGS_INFO(gp), \
+	PTREGS_INFO(tp), \
+	PTREGS_INFO(t0), \
+	PTREGS_INFO(t1), \
+	PTREGS_INFO(t2), \
+	PTREGS_INFO(s0), \
+	PTREGS_INFO(s1), \
+	PTREGS_INFO(a0), \
+	PTREGS_INFO(a1), \
+	PTREGS_INFO(a2), \
+	PTREGS_INFO(a3), \
+	PTREGS_INFO(a4), \
+	PTREGS_INFO(a5), \
+	PTREGS_INFO(a6), \
+	PTREGS_INFO(a7), \
+	PTREGS_INFO(s2), \
+	PTREGS_INFO(s3), \
+	PTREGS_INFO(s4), \
+	PTREGS_INFO(s5), \
+	PTREGS_INFO(s6), \
+	PTREGS_INFO(s7), \
+	PTREGS_INFO(s8), \
+	PTREGS_INFO(s9), \
+	PTREGS_INFO(s10), \
+	PTREGS_INFO(s11), \
+	PTREGS_INFO(t3), \
+	PTREGS_INFO(t4), \
+	PTREGS_INFO(t5), \
+	PTREGS_INFO(t6)
+
+#define UNW_PC_IDX 0
+#define UNW_SP_IDX 2
+
+/* Use default rules. The stack pointer should be set from the CFA.
+   And the instruction pointer should be set from the return address
+   column (which normally is the return register (regs[31]). */
+
+static inline void arch_unw_init_frame_info(struct unwind_frame_info *info,
+                                            /*const*/ struct pt_regs *regs,
+					    int sanitize)
+{
+	if (&info->regs == regs) { /* happens when unwinding kernel->user */
+		info->call_frame = 1;
+		return;
+	}
+
+	memset(info, 0, sizeof(*info));
+	/* XXX handle sanitize??? */
+	info->regs = *regs;
+}
+
+#endif /* _STP_RISCV_UNWIND_H */
diff --git a/runtime/unwind/unwind.h b/runtime/unwind/unwind.h
index 5c68a5f03..ce94ad3ec 100644
--- a/runtime/unwind/unwind.h
+++ b/runtime/unwind/unwind.h
@@ -36,6 +36,8 @@ struct unwind_frame_info
 #include "arm64.h"
 #elif defined (__mips__)
 #include "mips.h"
+#elif defined (__riscv)
+#include "riscv.h"
 #else
 #error "Unsupported dwarf unwind architecture"
 #endif
-- 
2.43.5