[AVR32] Implement stacktrace support

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

3 files changed, 57 insertions, 0 deletions

diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index b108dd83f234..599ec166d833 100644
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -24,6 +24,9 @@ config GENERIC_GPIO
 config GENERIC_HARDIRQS
         def_bool y
 
+config STACKTRACE_SUPPORT
+        def_bool y
+
 config HARDIRQS_SW_RESEND
         def_bool y
 
diff --git a/arch/avr32/kernel/Makefile b/arch/avr32/kernel/Makefile
index 989fcd1fef7e..2d6d48f35f69 100644
--- a/arch/avr32/kernel/Makefile
+++ b/arch/avr32/kernel/Makefile
@@ -11,3 +11,4 @@ obj-y				+= signal.o sys_avr32.o process.o time.o
 obj-y                           += init_task.o switch_to.o cpu.o
 obj-$(CONFIG_MODULES)           += module.o avr32_ksyms.o
 obj-$(CONFIG_KPROBES)           += kprobes.o
+obj-$(CONFIG_STACKTRACE)        += stacktrace.o
diff --git a/arch/avr32/kernel/stacktrace.c b/arch/avr32/kernel/stacktrace.c
new file mode 100644
index 000000000000..9a68190bbffd
--- /dev/null
+++ b/arch/avr32/kernel/stacktrace.c
@@ -0,0 +1,53 @@
+/*
+ * Stack trace management functions
+ *
+ * Copyright (C) 2007 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <linux/thread_info.h>
+
+register unsigned long current_frame_pointer asm("r7");
+
+struct stackframe {
+        unsigned long lr;
+        unsigned long fp;
+};
+
+/*
+ * 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 - 8)) {
+                frame = (struct stackframe *)fp;
+
+                if (skip) {
+                        skip--;
+                } else {
+                        trace->entries[trace->nr_entries++] = frame->lr;
+                        if (trace->nr_entries >= trace->max_entries)
+                                break;
+                }
+
+                /*
+                 * The next frame must be at a higher address than the
+                 * current frame.
+                 */
+                low = fp + 8;
+                fp = frame->fp;
+        }
+}