Ftrace_graph_ret_addr 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
hasn't been modified, the unchanged value of 'ret' is returned.
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
---
arch/loongarch/include/asm/ftrace.h | 3 +++
arch/loongarch/include/asm/unwind.h | 1 +
arch/loongarch/kernel/ftrace_dyn.c | 2 +-
arch/loongarch/kernel/unwind_guess.c | 4 +++-
arch/loongarch/kernel/unwind_prologue.c | 11 +++++++++--
5 files changed, 17 insertions(+), 4 deletions(-)
@@ -6,6 +6,8 @@
#ifndef _ASM_LOONGARCH_FTRACE_H
#define _ASM_LOONGARCH_FTRACE_H
+#define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1]))
+
#ifdef CONFIG_FUNCTION_TRACER
#define MCOUNT_INSN_SIZE 4 /* sizeof mcount call */
@@ -33,6 +35,7 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
#endif
#ifdef CONFIG_DYNAMIC_FTRACE
+#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
return addr;
@@ -21,6 +21,7 @@ struct unwind_state {
struct stack_info stack_info;
struct task_struct *task;
bool first, error, is_ftrace;
+ int graph_idx;
unsigned long sp, pc, ra;
};
@@ -140,7 +140,7 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent)
old = *parent;
- if (!function_graph_enter(old, self_addr, 0, NULL))
+ if (!function_graph_enter(old, self_addr, 0, parent))
*parent = return_hooker;
}
@@ -2,6 +2,7 @@
/*
* Copyright (C) 2022 Loongson Technology Corporation Limited
*/
+#include <linux/ftrace.h>
#include <linux/kernel.h>
#include <asm/unwind.h>
@@ -53,7 +54,8 @@ bool unwind_next_frame(struct unwind_state *state)
state->sp < info->end;
state->sp += sizeof(unsigned long)) {
addr = *(unsigned long *)(state->sp);
-
+ state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ addr, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
if (__kernel_text_address(addr))
return true;
}
@@ -2,6 +2,7 @@
/*
* Copyright (C) 2022 Loongson Technology Corporation Limited
*/
+#include <linux/ftrace.h>
#include <linux/kallsyms.h>
#include <asm/inst.h>
@@ -30,6 +31,8 @@ static bool unwind_by_guess(struct unwind_state *state)
state->sp < info->end;
state->sp += sizeof(unsigned long)) {
addr = *(unsigned long *)(state->sp);
+ state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ addr, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
if (__kernel_text_address(addr))
return true;
}
@@ -171,8 +174,11 @@ bool unwind_next_frame(struct unwind_state *state)
break;
case UNWINDER_PROLOGUE:
- if (unwind_by_prologue(state))
+ if (unwind_by_prologue(state)) {
+ state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ state->pc, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
return true;
+ }
if (info->type == STACK_TYPE_IRQ &&
info->end == state->sp) {
@@ -182,8 +188,9 @@ bool unwind_next_frame(struct unwind_state *state)
if (user_mode(regs) || !__kernel_text_address(pc))
return false;
- state->pc = pc;
state->sp = regs->regs[3];
+ state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ pc, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
state->ra = regs->regs[1];
state->first = true;
get_stack_info(state->sp, state->task, info);