linux kernel 添加版本信息

1. 平常做法

内核中配置上 CONFIG_LOCALVERSION_AUTO 就能自动带 git 或 svn 的版本号；
带来问题：厂商提供的 ko 文件使用报警告；

2. 使用 profs

2.1 修改 Makefile 文件

diff --git a/Makefile b/Makefile
index 059a6718..91f12d38 100755
--- a/Makefile
+++ b/Makefile
@@ -1122,8 +1122,15 @@ archprepare: archheaders archscripts prepare1 scripts_basicprepare0: archprepare gcc-plugins$(Q)$(MAKE) $(build)=.+GIT_HASH       := $(shell git rev-parse --short HEAD 2>/dev/null)
+BUILD_DATE     := $(shell date +%Y-%m-%d)
+
+vendor_version.h:
+	echo "#define VENDOR_GIT_HASH \"$(GIT_HASH)\"" > include/generated/vendor_version.h
+	echo "#define VENDOR_BUILD_TIME \"$(BUILD_DATE)\"" >> include/generated/vendor_version.h
+# All the preparing..
-prepare: prepare0 prepare-objtool
+prepare: prepare0 prepare-objtool vendor_version.h

2.2 编写 vendor_version.c 文件，并直接编译进 Makefile

diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index d4ba7e9c..45526df9 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
+obj-y				+= vender_version.olkdtm-$(CONFIG_LKDTM)		+= lkdtm_core.o
diff --git a/drivers/misc/vender_version.c b/drivers/misc/vender_version.c
index e69de29b..a289be8f 100644
--- a/drivers/misc/vender_version.c
+++ b/drivers/misc/vender_version.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+#include <generated/vendor_version.h> // 自动生成的头文件
+
+static int vendor_version_show(struct seq_file *m, void *v)
+{
+	seq_printf(m,
+			   "build:   %s\n"
+			   "git:     %s\n",
+			   VENDOR_BUILD_TIME,
+			   VENDOR_GIT_HASH);
+	return 0;
+}
+
+static int vendor_version_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, vendor_version_show, NULL);
+}
+
+static const struct file_operations vendor_version_fops = {
+	.owner = THIS_MODULE,
+	.open = vendor_version_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static int __init vendor_version_init(void)
+{
+	proc_create("vendor_version", 0444, NULL, &vendor_version_fops);
+	return 0;
+}
+
+static void __exit vendor_version_exit(void)
+{
+	remove_proc_entry("vendor_version", NULL);
+}
+
+module_init(vendor_version_init);
+module_exit(vendor_version_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Vendor Version Info");