From 981e9728390b401404c36241e2ce6bd4cfcb723d Mon Sep 17 00:00:00 2001
From: Aidan MacDonald <amachronic@protonmail.com>
Date: Mon, 16 May 2022 14:33:26 +0100
Subject: mips: add native backtrace implementation

Should make debugging crashes on native MIPS targets far easier.
This is by no means a 100% complete or robust implementation but
it seems to handle the vast majority of functions.

Change-Id: Id5f430270e02b5092b79026b6876675c784aa649
---
 lib/mipsunwinder/backtrace-mipsunwinder.h | 65 +++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 lib/mipsunwinder/backtrace-mipsunwinder.h

(limited to 'lib/mipsunwinder/backtrace-mipsunwinder.h')

diff --git a/lib/mipsunwinder/backtrace-mipsunwinder.h b/lib/mipsunwinder/backtrace-mipsunwinder.h
new file mode 100644
index 0000000000..4d6288b5fe
--- /dev/null
+++ b/lib/mipsunwinder/backtrace-mipsunwinder.h
@@ -0,0 +1,65 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2022 Aidan MacDonald
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#ifndef BACKTRACE_MIPSUNWINDER_H
+#define BACKTRACE_MIPSUNWINDER_H
+
+/*#define MIPSUNWINDER_DEBUG*/
+
+#include <stdint.h>
+
+enum {
+    MIPSBT_RA,
+    MIPSBT_NREG,
+};
+
+struct mips_bt_context {
+    void* pc;
+    void* sp;
+    int depth;
+    uint32_t valid;
+    uint32_t reg[MIPSBT_NREG];
+#ifdef MIPSUNWINDER_DEBUG
+    void(*debugf)(void*, const char*, ...);
+    void* debug_arg;
+#endif
+};
+
+int mips_bt_step(struct mips_bt_context* ctx);
+void mips_bt_start(struct mips_bt_context* ctx);
+
+#ifdef MIPSUNWINDER_DEBUG
+# define mips_bt_debug(ctx, ...) \
+    do { struct mips_bt_context* __ctx = ctx; \
+         if(__ctx->debugf) \
+             __ctx->debugf(__ctx->debug_arg, __VA_ARGS__);\
+    } while(0)
+#else
+# define mips_bt_debug(...) do { } while(0)
+#endif
+
+/* NOTE: ignores pcAddr and spAddr, backtrace starts from caller */
+void rb_backtrace(int pcAddr, int spAddr, unsigned* line);
+
+/* given struct mips_bt_context argument, print stack traceback */
+void rb_backtrace_ctx(void* arg, unsigned* line);
+
+#endif /* BACKTRACE_MIPSUNWINDER_H */
-- 
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