From f16fb1ecc5a1cb2f7cc595179d1fe55e711e599f Mon Sep 17 00:00:00 2001
From: Russell King <rmk@dyn-67.arm.linux.org.uk>
Date: Sat, 28 Apr 2007 09:59:37 +0100
Subject: [ARM] Add stacktrace support and make oprofile use it
Add support for stacktrace. Use the new stacktrace code with
oprofile instead of it's version; there's no point having
multiple versions of stacktracing in the kernel.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/kernel/stacktrace.c | 73 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 73 insertions(+)
create mode 100644 arch/arm/kernel/stacktrace.c
(limited to 'arch/arm/kernel/stacktrace.c')
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
new file mode 100644
index 000000000000..77ef35efaa8d
--- /dev/null
+++ b/arch/arm/kernel/stacktrace.c
@@ -0,0 +1,73 @@
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+
+#include "stacktrace.h"
+
+int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high,
+ int (*fn)(struct stackframe *, void *), void *data)
+{
+ struct stackframe *frame;
+
+ do {
+ /*
+ * Check current frame pointer is within bounds
+ */
+ if ((fp - 12) < low || fp + 4 >= high)
+ break;
+
+ frame = (struct stackframe *)(fp - 12);
+
+ if (fn(frame, data))
+ break;
+
+ /*
+ * Update the low bound - the next frame must always
+ * be at a higher address than the current frame.
+ */
+ low = fp + 4;
+ fp = frame->fp;
+ } while (fp);
+
+ return 0;
+}
+
+#ifdef CONFIG_STACKTRACE
+struct stack_trace_data {
+ struct stack_trace *trace;
+ unsigned int skip;
+};
+
+static int save_trace(struct stackframe *frame, void *d)
+{
+ struct stack_trace_data *data = d;
+ struct stack_trace *trace = data->trace;
+
+ if (data->skip) {
+ data->skip--;
+ return 0;
+ }
+
+ trace->entries[trace->nr_entries++] = frame->lr;
+
+ return trace->nr_entries >= trace->max_entries;
+}
+
+void save_stack_trace(struct stack_trace *trace, struct task_struct *task)
+{
+ struct stack_trace_data data;
+ unsigned long fp, base;
+
+ data.trace = trace;
+ data.skip = trace->skip;
+
+ if (task) {
+ base = (unsigned long)task_stack_page(task);
+ fp = 0; /* FIXME */
+ } else {
+ base = (unsigned long)task_stack_page(current);
+ asm("mov %0, fp" : "=r" (fp));
+ }
+
+ walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);
+}
+#endif
--
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