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Subject[PATCH 6/6] nds32/stack: Get real return address by using ftrace_graph_ret_addr
Date
Function graph tracer has modified the return address to
'return_to_handler' on stack, and provide the 'ftrace_graph_ret_addr' to
get the real return address.

Signed-off-by: Zong Li <zong@andestech.com>
---
arch/nds32/kernel/stacktrace.c | 4 ++++
arch/nds32/kernel/traps.c | 30 ++++++------------------------
2 files changed, 10 insertions(+), 24 deletions(-)

diff --git a/arch/nds32/kernel/stacktrace.c b/arch/nds32/kernel/stacktrace.c
index 8b231e9..36bc870 100644
--- a/arch/nds32/kernel/stacktrace.c
+++ b/arch/nds32/kernel/stacktrace.c
@@ -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) {
diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c
index f0e9743..7684c8f 100644
--- a/arch/nds32/kernel/traps.c
+++ b/arch/nds32/kernel/traps.c
@@ -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)
--
2.7.4
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