1 files changed, 139 insertions, 37 deletions

diff --git a/arch/csky/kernel/stacktrace.c b/arch/csky/kernel/stacktrace.c
index fec777a643f1..92809e1da723 100644
--- a/arch/csky/kernel/stacktrace.c
+++ b/arch/csky/kernel/stacktrace.c
@@ -1,57 +1,159 @@
 // 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>
+#include <linux/ptrace.h>
 
-void save_stack_trace(struct stack_trace *trace)
+#ifdef CONFIG_FRAME_POINTER
+
+struct stackframe {
+	unsigned long fp;
+	unsigned long ra;
+};
+
+void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
+			     bool (*fn)(unsigned long, void *), void *arg)
 {
-	save_stack_trace_tsk(current, trace);
+	unsigned long fp, sp, pc;
+
+	if (regs) {
+		fp = frame_pointer(regs);
+		sp = user_stack_pointer(regs);
+		pc = instruction_pointer(regs);
+	} else if (task == NULL || task == current) {
+		const register unsigned long current_sp __asm__ ("sp");
+		const register unsigned long current_fp __asm__ ("r8");
+		fp = current_fp;
+		sp = current_sp;
+		pc = (unsigned long)walk_stackframe;
+	} else {
+		/* task blocked in __switch_to */
+		fp = thread_saved_fp(task);
+		sp = thread_saved_sp(task);
+		pc = thread_saved_lr(task);
+	}
+
+	for (;;) {
+		unsigned long low, high;
+		struct stackframe *frame;
+
+		if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))
+			break;
+
+		/* Validate frame pointer */
+		low = sp;
+		high = ALIGN(sp, THREAD_SIZE);
+		if (unlikely(fp < low || fp > high || fp & 0x3))
+			break;
+		/* Unwind stack frame */
+		frame = (struct stackframe *)fp;
+		sp = fp;
+		fp = frame->fp;
+		pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
+					   (unsigned long *)(fp - 8));
+	}
 }
-EXPORT_SYMBOL_GPL(save_stack_trace);
 
-void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+#else /* !CONFIG_FRAME_POINTER */
+
+static void notrace walk_stackframe(struct task_struct *task,
+	struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
 {
-	unsigned long *fp, *stack_start, *stack_end;
-	unsigned long addr;
-	int skip = trace->skip;
-	int savesched;
-	int graph_idx = 0;
+	unsigned long sp, pc;
+	unsigned long *ksp;
 
-	if (tsk == current) {
-		asm volatile("mov %0, r8\n":"=r"(fp));
-		savesched = 1;
+	if (regs) {
+		sp = user_stack_pointer(regs);
+		pc = instruction_pointer(regs);
+	} else if (task == NULL || task == current) {
+		const register unsigned long current_sp __asm__ ("sp");
+		sp = current_sp;
+		pc = (unsigned long)walk_stackframe;
 	} else {
-		fp = (unsigned long *)thread_saved_fp(tsk);
-		savesched = 0;
+		/* task blocked in __switch_to */
+		sp = thread_saved_sp(task);
+		pc = thread_saved_lr(task);
 	}
 
-	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;
+	if (unlikely(sp & 0x3))
+		return;
 
-		fpp = fp[0];
-		lpp = fp[1];
-		if (!__kernel_text_address(lpp))
+	ksp = (unsigned long *)sp;
+	while (!kstack_end(ksp)) {
+		if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
 			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;
+		pc = (*ksp++) - 0x4;
 	}
 }
+#endif /* CONFIG_FRAME_POINTER */
+
+static bool print_trace_address(unsigned long pc, void *arg)
+{
+	print_ip_sym(pc);
+	return false;
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	pr_cont("Call Trace:\n");
+	walk_stackframe(task, NULL, print_trace_address, NULL);
+}
+
+static bool save_wchan(unsigned long pc, void *arg)
+{
+	if (!in_sched_functions(pc)) {
+		unsigned long *p = arg;
+		*p = pc;
+		return true;
+	}
+	return false;
+}
+
+unsigned long get_wchan(struct task_struct *task)
+{
+	unsigned long pc = 0;
+
+	if (likely(task && task != current && task->state != TASK_RUNNING))
+		walk_stackframe(task, NULL, save_wchan, &pc);
+	return pc;
+}
+
+#ifdef CONFIG_STACKTRACE
+static bool __save_trace(unsigned long pc, void *arg, bool nosched)
+{
+	struct stack_trace *trace = arg;
+
+	if (unlikely(nosched && in_sched_functions(pc)))
+		return false;
+	if (unlikely(trace->skip > 0)) {
+		trace->skip--;
+		return false;
+	}
+
+	trace->entries[trace->nr_entries++] = pc;
+	return (trace->nr_entries >= trace->max_entries);
+}
+
+static bool save_trace(unsigned long pc, void *arg)
+{
+	return __save_trace(pc, arg, false);
+}
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer.
+ */
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+	walk_stackframe(tsk, NULL, save_trace, trace);
+}
 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
+
+void save_stack_trace(struct stack_trace *trace)
+{
+	save_stack_trace_tsk(NULL, trace);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+
+#endif /* CONFIG_STACKTRACE */