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-rw-r--r--arch/arm/kernel/stacktrace.c96
1 files changed, 96 insertions, 0 deletions
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
new file mode 100644
index 0000000..fc650f6
--- /dev/null
+++ b/arch/arm/kernel/stacktrace.c
@@ -0,0 +1,96 @@
+#include <linux/module.h>
+#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 < (low + 12) || 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;
+}
+EXPORT_SYMBOL(walk_stackframe);
+
+#ifdef CONFIG_STACKTRACE
+struct stack_trace_data {
+ struct stack_trace *trace;
+ unsigned int no_sched_functions;
+ unsigned int skip;
+};
+
+static int save_trace(struct stackframe *frame, void *d)
+{
+ struct stack_trace_data *data = d;
+ struct stack_trace *trace = data->trace;
+ unsigned long addr = frame->lr;
+
+ if (data->no_sched_functions && in_sched_functions(addr))
+ return 0;
+ if (data->skip) {
+ data->skip--;
+ return 0;
+ }
+
+ trace->entries[trace->nr_entries++] = addr;
+
+ return trace->nr_entries >= trace->max_entries;
+}
+
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+ struct stack_trace_data data;
+ unsigned long fp, base;
+
+ data.trace = trace;
+ data.skip = trace->skip;
+ base = (unsigned long)task_stack_page(tsk);
+
+ if (tsk != current) {
+#ifdef CONFIG_SMP
+ /*
+ * What guarantees do we have here that 'tsk'
+ * is not running on another CPU?
+ */
+ BUG();
+#else
+ data.no_sched_functions = 1;
+ fp = thread_saved_fp(tsk);
+#endif
+ } else {
+ data.no_sched_functions = 0;
+ asm("mov %0, fp" : "=r" (fp));
+ }
+
+ walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+
+void save_stack_trace(struct stack_trace *trace)
+{
+ save_stack_trace_tsk(current, trace);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+#endif
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