From 34fde61f723b3387e12116390fa38540b18ced2e Mon Sep 17 00:00:00 2001
From: Mukesh Ojha <mojha@codeaurora.org>
Date: Tue, 13 Apr 2021 09:32:41 +0530
Subject: [PATCH] ANDROID: logbuf: vendor hook for logbuf dump on oops

Initial kernel bootup logs get overwritten after running
for a long time, and there can be debugging scenario where
we need initial ~100s bootup logs for debugging.
'android_vh_initial_logbuf' vendor hook is helping in
achieving this purpose.

Bug: 185182649
Change-Id: I706824aeb566c09ecaf4b5900973d6cee8a2f35b
Signed-off-by: Mukesh Ojha <mojha@codeaurora.org>
---
 drivers/android/vendor_hooks.c |  2 ++
 include/trace/hooks/logbuf.h   | 26 ++++++++++++++++++++++++++
 kernel/printk/printk.c         |  3 +++
 3 files changed, 31 insertions(+)
 create mode 100644 include/trace/hooks/logbuf.h

diff --git a/drivers/android/vendor_hooks.c b/drivers/android/vendor_hooks.c
index f65cb834abcf..e3dd3745d47e 100644
--- a/drivers/android/vendor_hooks.c
+++ b/drivers/android/vendor_hooks.c
@@ -50,6 +50,7 @@
 #include <trace/hooks/typec.h>
 #include <trace/hooks/gpiolib.h>
 #include <trace/hooks/signal.h>
+#include <trace/hooks/logbuf.h>
 
 /*
  * Export tracepoints that act as a bare tracehook (ie: have no trace event
@@ -238,3 +239,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_binder_preset);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_post_init_entity_util_avg);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_typec_tcpm_get_timer);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_typec_tcpm_adj_current_limit);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_logbuf);
diff --git a/include/trace/hooks/logbuf.h b/include/trace/hooks/logbuf.h
new file mode 100644
index 000000000000..a599bf8c2cbf
--- /dev/null
+++ b/include/trace/hooks/logbuf.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM logbuf
+
+#define TRACE_INCLUDE_PATH trace/hooks
+
+#if !defined(_TRACE_HOOK_LOGBUF_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HOOK_LOGBUF_H
+
+#include <linux/tracepoint.h>
+#include <trace/hooks/vendor_hooks.h>
+
+#if defined(CONFIG_TRACEPOINTS) && defined(CONFIG_ANDROID_VENDOR_HOOKS)
+struct printk_ringbuffer;
+struct printk_record;
+
+DECLARE_HOOK(android_vh_logbuf,
+	TP_PROTO(struct printk_ringbuffer *rb, struct printk_record *r),
+	TP_ARGS(rb, r))
+#else
+#define trace_android_vh_logbuf(rb, r)
+#endif
+
+#endif /* _TRACE_HOOK_LOGBUF_H */
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index b56d7d561e7e..09b63b9aea9c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -56,6 +56,7 @@
 #include <trace/events/printk.h>
 #undef CREATE_TRACE_POINTS
 #include <trace/hooks/printk.h>
+#include <trace/hooks/logbuf.h>
 
 #include "printk_ringbuffer.h"
 #include "console_cmdline.h"
@@ -538,6 +539,8 @@ static int log_store(u32 caller_id, int facility, int level,
 	else
 		prb_final_commit(&e);
 
+	trace_android_vh_logbuf(prb, &r);
+
 	return (text_len + trunc_msg_len);
 }