Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/csky/kernel/stacktrace.c b/arch/csky/kernel/stacktrace.c
new file mode 100644
index 0000000..fec777a
--- /dev/null
+++ b/arch/csky/kernel/stacktrace.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. */
+
+#include <linux/sched/debug.h>
+#include <linux/sched/task_stack.h>
+#include <linux/stacktrace.h>
+#include <linux/ftrace.h>
+
+void save_stack_trace(struct stack_trace *trace)
+{
+ save_stack_trace_tsk(current, trace);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+ unsigned long *fp, *stack_start, *stack_end;
+ unsigned long addr;
+ int skip = trace->skip;
+ int savesched;
+ int graph_idx = 0;
+
+ if (tsk == current) {
+ asm volatile("mov %0, r8\n":"=r"(fp));
+ savesched = 1;
+ } else {
+ fp = (unsigned long *)thread_saved_fp(tsk);
+ savesched = 0;
+ }
+
+ addr = (unsigned long) fp & THREAD_MASK;
+ stack_start = (unsigned long *) addr;
+ stack_end = (unsigned long *) (addr + THREAD_SIZE);
+
+ while (fp > stack_start && fp < stack_end) {
+ unsigned long lpp, fpp;
+
+ fpp = fp[0];
+ lpp = fp[1];
+ if (!__kernel_text_address(lpp))
+ break;
+ else
+ lpp = ftrace_graph_ret_addr(tsk, &graph_idx, lpp, NULL);
+
+ if (savesched || !in_sched_functions(lpp)) {
+ if (skip) {
+ skip--;
+ } else {
+ trace->entries[trace->nr_entries++] = lpp;
+ if (trace->nr_entries >= trace->max_entries)
+ break;
+ }
+ }
+ fp = (unsigned long *)fpp;
+ }
+}
+EXPORT_SYMBOL_GPL(save_stack_trace_tsk);