Blackfin: add preliminary support for STACKTRACE

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

2 files changed, 54 insertions, 0 deletions

diff --git a/arch/blackfin/kernel/Makefile b/arch/blackfin/kernel/Makefile
index fd4d4328a0f2..a66dda4f4b1f 100644
--- a/arch/blackfin/kernel/Makefile
+++ b/arch/blackfin/kernel/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_MODULES)                += module.o
 obj-$(CONFIG_KGDB)                   += kgdb.o
 obj-$(CONFIG_KGDB_TESTS)             += kgdb_test.o
 obj-$(CONFIG_EARLY_PRINTK)           += early_printk.o
+obj-$(CONFIG_STACKTRACE)             += stacktrace.o
 
 # the kgdb test puts code into L2 and without linker
 # relaxation, we need to force long calls to/from it
diff --git a/arch/blackfin/kernel/stacktrace.c b/arch/blackfin/kernel/stacktrace.c
new file mode 100644
index 000000000000..30301e1eace5
--- /dev/null
+++ b/arch/blackfin/kernel/stacktrace.c
@@ -0,0 +1,53 @@
+/*
+ * Blackfin stacktrace code (mostly copied from avr32)
+ *
+ * Copyright 2009 Analog Devices Inc.
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <linux/thread_info.h>
+#include <linux/module.h>
+
+register unsigned long current_frame_pointer asm("FP");
+
+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);