[PATCH RFC 1/8] stacktrace: Change callback prototype to pass more information

[He Zhe]

Currently stack_trace_consume_fn can only have pc of each frame of the
stack. Copying-beyond-the-frame-detection also needs fp of current and
previous frame. Other detection algorithm in the future may need more
information of the frame.

We define a frame_info to include them all.


Signed-off-by: He Zhe <zhe.he at windriver.com>
---
 include/linux/stacktrace.h |  9 ++++++++-
 kernel/stacktrace.c        | 10 +++++-----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
index 97455880ac41..5a61bfafe6f0 100644
--- a/include/linux/stacktrace.h
+++ b/include/linux/stacktrace.h
@@ -10,15 +10,22 @@ struct pt_regs;
 
 #ifdef CONFIG_ARCH_STACKWALK
 
+struct frame_info {
+	unsigned long pc;
+	unsigned long fp;
+	unsigned long prev_fp;
+};
+
 /**
  * stack_trace_consume_fn - Callback for arch_stack_walk()
  * @cookie:	Caller supplied pointer handed back by arch_stack_walk()
  * @addr:	The stack entry address to consume
+ * @fi:	The frame information to consume
  *
  * Return:	True, if the entry was consumed or skipped
  *		False, if there is no space left to store
  */
-typedef bool (*stack_trace_consume_fn)(void *cookie, unsigned long addr);
+typedef bool (*stack_trace_consume_fn)(void *cookie, struct frame_info *fi);
 /**
  * arch_stack_walk - Architecture specific function to walk the stack
  * @consume_entry:	Callback which is invoked by the architecture code for
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 9ed5ce989415..2d0a2812e92b 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -79,7 +79,7 @@ struct stacktrace_cookie {
 	unsigned int	len;
 };
 
-static bool stack_trace_consume_entry(void *cookie, unsigned long addr)
+static bool stack_trace_consume_entry(void *cookie, struct frame_info *fi)
 {
 	struct stacktrace_cookie *c = cookie;
 
@@ -90,15 +90,15 @@ static bool stack_trace_consume_entry(void *cookie, unsigned long addr)
 		c->skip--;
 		return true;
 	}
-	c->store[c->len++] = addr;
+	c->store[c->len++] = fi->pc;
 	return c->len < c->size;
 }
 
-static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr)
+static bool stack_trace_consume_entry_nosched(void *cookie, struct frame_info *fi)
 {
-	if (in_sched_functions(addr))
+	if (in_sched_functions(fi->pc))
 		return true;
-	return stack_trace_consume_entry(cookie, addr);
+	return stack_trace_consume_entry(cookie, fi);
 }
 
 /**
-- 
2.25.1