Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / xtensa / kernel / stacktrace.c

diff --git a/kernel/arch/xtensa/kernel/stacktrace.c b/kernel/arch/xtensa/kernel/stacktrace.c
new file mode 100644 (file)
index 0000000..7d2c317
--- /dev/null
+++ b/kernel/arch/xtensa/kernel/stacktrace.c
@@ -0,0 +1,120 @@
+/*
+ * arch/xtensa/kernel/stacktrace.c
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2001 - 2013 Tensilica Inc.
+ */
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+
+#include <asm/stacktrace.h>
+#include <asm/traps.h>
+
+void walk_stackframe(unsigned long *sp,
+               int (*fn)(struct stackframe *frame, void *data),
+               void *data)
+{
+       unsigned long a0, a1;
+       unsigned long sp_end;
+
+       a1 = (unsigned long)sp;
+       sp_end = ALIGN(a1, THREAD_SIZE);
+
+       spill_registers();
+
+       while (a1 < sp_end) {
+               struct stackframe frame;
+
+               sp = (unsigned long *)a1;
+
+               a0 = *(sp - 4);
+               a1 = *(sp - 3);
+
+               if (a1 <= (unsigned long)sp)
+                       break;
+
+               frame.pc = MAKE_PC_FROM_RA(a0, a1);
+               frame.sp = a1;
+
+               if (fn(&frame, data))
+                       return;
+       }
+}
+
+#ifdef CONFIG_STACKTRACE
+
+struct stack_trace_data {
+       struct stack_trace *trace;
+       unsigned skip;
+};
+
+static int stack_trace_cb(struct stackframe *frame, void *data)
+{
+       struct stack_trace_data *trace_data = data;
+       struct stack_trace *trace = trace_data->trace;
+
+       if (trace_data->skip) {
+               --trace_data->skip;
+               return 0;
+       }
+       if (!kernel_text_address(frame->pc))
+               return 0;
+
+       trace->entries[trace->nr_entries++] = frame->pc;
+       return trace->nr_entries >= trace->max_entries;
+}
+
+void save_stack_trace_tsk(struct task_struct *task, struct stack_trace *trace)
+{
+       struct stack_trace_data trace_data = {
+               .trace = trace,
+               .skip = trace->skip,
+       };
+       walk_stackframe(stack_pointer(task), stack_trace_cb, &trace_data);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
+
+void save_stack_trace(struct stack_trace *trace)
+{
+       save_stack_trace_tsk(current, trace);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+
+#endif
+
+#ifdef CONFIG_FRAME_POINTER
+
+struct return_addr_data {
+       unsigned long addr;
+       unsigned skip;
+};
+
+static int return_address_cb(struct stackframe *frame, void *data)
+{
+       struct return_addr_data *r = data;
+
+       if (r->skip) {
+               --r->skip;
+               return 0;
+       }
+       if (!kernel_text_address(frame->pc))
+               return 0;
+       r->addr = frame->pc;
+       return 1;
+}
+
+unsigned long return_address(unsigned level)
+{
+       struct return_addr_data r = {
+               .skip = level + 1,
+       };
+       walk_stackframe(stack_pointer(NULL), return_address_cb, &r);
+       return r.addr;
+}
+EXPORT_SYMBOL(return_address);
+
+#endif