[PATCH 5/8] x86/dumpstack/ftrace: convert dump_trace() callbacks to use ftrace_graph_ret_addr()

From: Josh Poimboeuf
Date: Fri Aug 19 2016 - 07:53:28 EST


Convert print_context_stack() and print_context_stack_bp() to use the
arch-independent ftrace_graph_ret_addr() helper.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/kernel/dumpstack.c | 65 +++++++++++++++------------------------------
1 file changed, 22 insertions(+), 43 deletions(-)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 5f49c04..9bf3d02 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -38,38 +38,6 @@ void printk_address(unsigned long address)
pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address);
}

-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-static void
-print_ftrace_graph_addr(unsigned long addr, void *data,
- const struct stacktrace_ops *ops,
- struct task_struct *task, int *graph)
-{
- unsigned long ret_addr;
- int index;
-
- if (addr != (unsigned long)return_to_handler)
- return;
-
- index = task->curr_ret_stack;
-
- if (!task->ret_stack || index < *graph)
- return;
-
- index -= *graph;
- ret_addr = task->ret_stack[index].ret;
-
- ops->address(data, ret_addr, 1);
-
- (*graph)++;
-}
-#else
-static inline void
-print_ftrace_graph_addr(unsigned long addr, void *data,
- const struct stacktrace_ops *ops,
- struct task_struct *task, int *graph)
-{ }
-#endif
-
/*
* x86-64 can have up to three kernel stacks:
* process stack
@@ -107,18 +75,24 @@ print_context_stack(struct task_struct *task,
stack = (unsigned long *)task_stack_page(task);

while (valid_stack_ptr(task, stack, sizeof(*stack), end)) {
- unsigned long addr;
+ unsigned long addr = *stack;

- addr = *stack;
if (__kernel_text_address(addr)) {
+ unsigned long real_addr;
+ int reliable = 0;
+
if ((unsigned long) stack == bp + sizeof(long)) {
- ops->address(data, addr, 1);
+ reliable = 1;
frame = frame->next_frame;
bp = (unsigned long) frame;
- } else {
- ops->address(data, addr, 0);
}
- print_ftrace_graph_addr(addr, data, ops, task, graph);
+
+ ops->address(data, addr, reliable);
+
+ real_addr = ftrace_graph_ret_addr(task, graph, addr,
+ stack);
+ if (real_addr != addr)
+ ops->address(data, real_addr, 1);
}
stack++;
}
@@ -133,19 +107,24 @@ print_context_stack_bp(struct task_struct *task,
unsigned long *end, int *graph)
{
struct stack_frame *frame = (struct stack_frame *)bp;
- unsigned long *ret_addr = &frame->return_address;
+ unsigned long *retp = &frame->return_address;

- while (valid_stack_ptr(task, ret_addr, sizeof(*ret_addr), end)) {
- unsigned long addr = *ret_addr;
+ while (valid_stack_ptr(task, retp, sizeof(*retp), end)) {
+ unsigned long addr = *retp;
+ unsigned long real_addr;

if (!__kernel_text_address(addr))
break;

if (ops->address(data, addr, 1))
break;
+
+ real_addr = ftrace_graph_ret_addr(task, graph, addr, retp);
+ if (real_addr != addr)
+ ops->address(data, real_addr, 1);
+
frame = frame->next_frame;
- ret_addr = &frame->return_address;
- print_ftrace_graph_addr(addr, data, ops, task, graph);
+ retp = &frame->return_address;
}

return (unsigned long)frame;
--
2.7.4