Hexagon: Add basic stacktrace functionality for Hexagon architecture.

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 66 insertions, 0 deletions

diff --git a/arch/hexagon/kernel/stacktrace.c b/arch/hexagon/kernel/stacktrace.c
new file mode 100644
index 000000000000..11c597b2ac59
--- /dev/null
+++ b/arch/hexagon/kernel/stacktrace.c
@@ -0,0 +1,66 @@
+/*
+ * Stacktrace support for Hexagon
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <linux/thread_info.h>
+#include <linux/module.h>
+
+register unsigned long current_frame_pointer asm("r30");
+
+struct stackframe {
+        unsigned long fp;
+        unsigned long rets;
+};
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer.
+ */
+void save_stack_trace(struct stack_trace *trace)
+{
+        unsigned long low, high;
+        unsigned long fp;
+        struct stackframe *frame;
+        int skip = trace->skip;
+
+        low = (unsigned long)task_stack_page(current);
+        high = low + THREAD_SIZE;
+        fp = current_frame_pointer;
+
+        while (fp >= low && fp <= (high - sizeof(*frame))) {
+                frame = (struct stackframe *)fp;
+
+                if (skip) {
+                        skip--;
+                } else {
+                        trace->entries[trace->nr_entries++] = frame->rets;
+                        if (trace->nr_entries >= trace->max_entries)
+                                break;
+                }
+
+                /*
+                 * The next frame must be at a higher address than the
+                 * current frame.
+                 */
+                low = fp + sizeof(*frame);
+                fp = frame->fp;
+        }
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);