[RFC][PATCH] GCOV: profile by modules

[gengcixi@gmail.com]

From: Cixi Geng <cixi.geng1@unisoc.com>

The CONFIG_GCOV_PROFILE_ALL will compile kernel by profiling entire
kernel which will lead to kernel run slower.Use GCOV_PROFILE_MODULES
to control part of the kernel modules to open gcov.

Only add SERIAL_GCOV for an example.

Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
---
 drivers/tty/serial/Kconfig  |  6 ++++++
 drivers/tty/serial/Makefile |  1 +
 kernel/gcov/Kconfig         | 15 +++++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index adf9e80e7dc9..0b4c070f6c74 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1566,3 +1566,9 @@ endmenu
 
 config SERIAL_MCTRL_GPIO
 	tristate
+
+config SERIAL_GCOV
+       bool "open gcov for serial"
+       depends on GCOV_PROFILE_MODULES
+       help
+         Say Y here to enable gcov in serial.
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index d056ee6cca33..7be1202286d2 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -2,6 +2,7 @@
 #
 # Makefile for the kernel serial device drivers.
 #
+GCOV_PROFILE := $(CONFIG_SERIAL_GCOV)
 
 obj-$(CONFIG_SERIAL_CORE) += serial_core.o
 
diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
index 3941a9c48f83..7f9c1d2476c9 100644
--- a/kernel/gcov/Kconfig
+++ b/kernel/gcov/Kconfig
@@ -51,6 +51,21 @@ config GCOV_PROFILE_ALL
 	larger and run slower. Also be sure to exclude files from profiling
 	which are not linked to the kernel image to prevent linker errors.
 
+config GCOV_PROFILE_MODULES
+	bool "Profile Kernel subsytem"
+	depends on !COMPILE_TEST
+	depends on GCOV_KERNEL
+	depends on ARCH_HAS_GCOV_PROFILE_ALL
+	default n
+	help
+	This options activates profiling for the specified kernel modules.
+
+	If unsure, say N.
+
+	When some modules need Gcov data, enable this config, then configure
+	with gcov on the corresponding modules configs.The directories or files
+	of these modules will be added profiling flags after kernel compile.
+
 choice
 	prompt "Specify GCOV format"
 	depends on GCOV_KERNEL
-- 
2.17.1