Support ftrace on NDS32 architecture

new file mode 100644
index 0000000..bac7657
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_NDS32_FTRACE_H
+#define __ASM_NDS32_FTRACE_H
+
+#ifdef CONFIG_FUNCTION_TRACER
+
+#define HAVE_FUNCTION_GRAPH_FP_TEST
+
+#define MCOUNT_ADDR ((unsigned long)(_mcount))
+/* mcount call is composed of three instructions:
+ * sethi + ori + jral
+ */
+#define MCOUNT_INSN_SIZE 12
+
+extern void _mcount(unsigned long parent_ip);
+
+#endif /* CONFIG_FUNCTION_TRACER */
+
+#endif /* __ASM_NDS32_FTRACE_H */

new file mode 100644
index 0000000..563f64c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/ftrace.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+
+extern void (*ftrace_trace_function)(unsigned long, unsigned long,
+				     struct ftrace_ops*, struct pt_regs*);
+
+noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
+				  struct ftrace_ops *op, struct pt_regs *regs)
+{
+	__asm__ ("");  /* avoid to optimize as pure function */
+}
+
+noinline void _mcount(unsigned long parent_ip)
+{
+	/* save all state by the compiler prologue */
+
+	unsigned long ip = (unsigned long)__builtin_return_address(0);
+
+	if (ftrace_trace_function != ftrace_stub)
+		ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip,
+				      NULL, NULL);
+
+	/* restore all state by the compiler epilogue */
+}
+EXPORT_SYMBOL(_mcount);

81 lines not on this page · raw message

index bac7657..2f96cc9 100644
@@ -15,6 +15,32 @@
 
 extern void _mcount(unsigned long parent_ip);
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+#define FTRACE_ADDR ((unsigned long)_ftrace_caller)
+
+#ifdef __NDS32_EL__
+#define INSN_NOP		0x09000040
+#define INSN_SIZE(insn)		(((insn & 0x00000080) == 0) ? 4 : 2)
+#define IS_SETHI(insn)		((insn & 0x000000fe) == 0x00000046)
+#define ENDIAN_CONVERT(insn)	be32_to_cpu(insn)
+#else /* __NDS32_EB__ */
+#define INSN_NOP		0x40000009
+#define INSN_SIZE(insn)		(((insn & 0x80000000) == 0) ? 4 : 2)
+#define IS_SETHI(insn)		((insn & 0xfe000000) == 0x46000000)
+#define ENDIAN_CONVERT(insn)	(insn)
+#endif
+
+extern void _ftrace_caller(unsigned long parent_ip);
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+	return addr;
+}
+struct dyn_arch_ftrace {
+};
+
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
 #endif /* CONFIG_FUNCTION_TRACER */
 
 #endif /* __ASM_NDS32_FTRACE_H */

180 lines not on this page · raw message

index 3ca676b..a646a83 100644
@@ -74,6 +74,14 @@ void _ftrace_caller(unsigned long parent_ip)
 		"nop			\n\t"
 		"nop			\n\t");
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	/* a placeholder for the call to ftrace_graph_caller */
+	__asm__ __volatile__ (
+		"ftrace_graph_call:	\n\t"
+		"nop			\n\t"
+		"nop			\n\t"
+		"nop			\n\t");
+#endif
 	/* restore all state needed by the compiler epilogue */
 }
 

@@ -258,4 +266,32 @@ void __naked return_to_handler(void)
 		"lmw.bim $r0,[$sp],$r1,#0x0  \n\t");
 }
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern unsigned long ftrace_graph_call;
+
+static int ftrace_modify_graph_caller(bool enable)
+{
+	unsigned long pc = (unsigned long)&ftrace_graph_call;
+	unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+	unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+
+	ftrace_gen_call_insn(call_insn, (unsigned long)ftrace_graph_caller);
+
+	if (enable)
+		return ftrace_modify_code(pc, nop_insn, call_insn, true);
+	else
+		return ftrace_modify_code(pc, call_insn, nop_insn, true);
+}
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+	return ftrace_modify_graph_caller(true);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+	return ftrace_modify_graph_caller(false);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */

index 8b231e9..36bc870 100644
@@ -4,6 +4,7 @@
 #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)
 {

@@ -16,6 +17,7 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 	unsigned long *fpn;
 	int skip = trace->skip;
 	int savesched;
+	int graph_idx = 0;
 
 	if (tsk == current) {
 		__asm__ __volatile__("\tori\t%0, $fp, #0\n":"=r"(fpn));

@@ -33,6 +35,8 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 		fpp = fpn[FP_OFFSET];
 		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) {

index f0e9743..7684c8f 100644
@@ -8,6 +8,7 @@
 #include <linux/kdebug.h>
 #include <linux/sched/task_stack.h>
 #include <linux/uaccess.h>
+#include <linux/ftrace.h>
 
 #include <asm/proc-fns.h>
 #include <asm/unistd.h>

@@ -94,28 +95,6 @@ static void dump_instr(struct pt_regs *regs)
 	set_fs(fs);
 }
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-#include <linux/ftrace.h>
-static void
-get_real_ret_addr(unsigned long *addr, struct task_struct *tsk, int *graph)
-{
-	if (*addr == (unsigned long)return_to_handler) {
-		int index = tsk->curr_ret_stack;
-
-		if (tsk->ret_stack && index >= *graph) {
-			index -= *graph;
-			*addr = tsk->ret_stack[index].ret;
-			(*graph)++;
-		}
-	}
-}
-#else
-static inline void
-get_real_ret_addr(unsigned long *addr, struct task_struct *tsk, int *graph)
-{
-}
-#endif
-
 #define LOOP_TIMES (100)
 static void __dump(struct task_struct *tsk, unsigned long *base_reg)
 {

@@ -126,7 +105,8 @@ static void __dump(struct task_struct *tsk, unsigned long *base_reg)
 		while (!kstack_end(base_reg)) {
 			ret_addr = *base_reg++;
 			if (__kernel_text_address(ret_addr)) {
-				get_real_ret_addr(&ret_addr, tsk, &graph);
+				ret_addr = ftrace_graph_ret_addr(
+						tsk, &graph, ret_addr, NULL);
 				print_ip_sym(ret_addr);
 			}
 			if (--cnt < 0)

@@ -145,7 +125,9 @@ static void __dump(struct task_struct *tsk, unsigned long *base_reg)
 			next_fp = base_reg[FP_OFFSET];
 #endif
 			if (__kernel_text_address(ret_addr)) {
-				get_real_ret_addr(&ret_addr, tsk, &graph);
+
+				ret_addr = ftrace_graph_ret_addr(
+						tsk, &graph, ret_addr, NULL);
 				print_ip_sym(ret_addr);
 			}
 			if (--cnt < 0)