diff options
| -rw-r--r-- | include/linux/ftrace.h | 10 | ||||
| -rw-r--r-- | kernel/trace/trace_functions_graph.c | 58 |
2 files changed, 68 insertions, 0 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 483e02a50d37..6f93ac46e7f0 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -814,6 +814,9 @@ extern int ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, unsigned long frame_pointer, unsigned long *retp); +unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, + unsigned long ret, unsigned long *retp); + /* * Sometimes we don't want to trace a function with the function * graph tracer but we want them to keep traced by the usual function @@ -875,6 +878,13 @@ static inline int task_curr_ret_stack(struct task_struct *tsk) return -1; } +static inline unsigned long +ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret, + unsigned long *retp) +{ + return ret; +} + static inline void pause_graph_tracing(void) { } static inline void unpause_graph_tracing(void) { } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index f7212ec643e2..0cbe38a844fa 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -284,6 +284,64 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer) return ret; } +/** + * ftrace_graph_ret_addr - convert a potentially modified stack return address + * to its original value + * + * This function can be called by stack unwinding code to convert a found stack + * return address ('ret') to its original value, in case the function graph + * tracer has modified it to be 'return_to_handler'. If the address hasn't + * been modified, the unchanged value of 'ret' is returned. + * + * 'idx' is a state variable which should be initialized by the caller to zero + * before the first call. + * + * 'retp' is a pointer to the return address on the stack. It's ignored if + * the arch doesn't have HAVE_FUNCTION_GRAPH_RET_ADDR_PTR defined. + */ +#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR +unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, + unsigned long ret, unsigned long *retp) +{ + int index = task->curr_ret_stack; + int i; + + if (ret != (unsigned long)return_to_handler) + return ret; + + if (index < -1) + index += FTRACE_NOTRACE_DEPTH; + + if (index < 0) + return ret; + + for (i = 0; i <= index; i++) + if (task->ret_stack[i].retp == retp) + return task->ret_stack[i].ret; + + return ret; +} +#else /* !HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */ +unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, + unsigned long ret, unsigned long *retp) +{ + int task_idx; + + if (ret != (unsigned long)return_to_handler) + return ret; + + task_idx = task->curr_ret_stack; + + if (!task->ret_stack || task_idx < *idx) + return ret; + + task_idx -= *idx; + (*idx)++; + + return task->ret_stack[task_idx].ret; +} +#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */ + int __trace_graph_entry(struct trace_array *tr, struct ftrace_graph_ent *trace, unsigned long flags, |