[PATCH v2] kbuild: add configurable debug info level

[Dmitrii Bundin <dmitrii.bundin.a@gmail.com>]

Provides a way to configure debug info level (-glevel).
Debug level 3 includes extra information such as macro definitions. With
level 3 enabled it's possible to expand macros right from the debugging
session in gdb simplifying debugging when complicated macros involved.
The default level is set to 2 to not change the default build behavior.

Signed-off-by: Dmitrii Bundin <dmitrii.bundin.a@gmail.com>
---

Changes in v2: https://lore.kernel.org/all/20220804223504.4739-1-dmitrii.bundin.a@gmail.com/
  - Replace hardcoded -g3 with a configurable debug info level

 lib/Kconfig.debug      | 11 +++++++++++
 scripts/Makefile.debug |  2 +-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 2e24db4bff19..a17c12c20290 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -304,6 +304,17 @@ config DEBUG_INFO_REDUCED
 	  DEBUG_INFO build and compile times are reduced too.
 	  Only works with newer gcc versions.
 
+config DEBUG_INFO_LEVEL
+	int "Debug info level"
+	range 0 3
+	default "2"
+	help
+	  Sets the level of how much debug information to generate (-glevel).
+	  Level 1 produces minimal debug information without including information
+	  about local variables. Level 3 includes extra information like macro
+	  definitions. Setting up level 3 will require significantly more disk
+	  space and increase built time. Level 0 produces no debug information.
+
 config DEBUG_INFO_COMPRESSED
 	bool "Compressed debugging information"
 	depends on $(cc-option,-gz=zlib)
diff --git a/scripts/Makefile.debug b/scripts/Makefile.debug
index 9f39b0130551..28beffc42e71 100644
--- a/scripts/Makefile.debug
+++ b/scripts/Makefile.debug
@@ -3,7 +3,7 @@ DEBUG_CFLAGS	:=
 ifdef CONFIG_DEBUG_INFO_SPLIT
 DEBUG_CFLAGS	+= -gsplit-dwarf
 else
-DEBUG_CFLAGS	+= -g
+DEBUG_CFLAGS	+= -g$(CONFIG_DEBUG_INFO_LEVEL)
 endif
 
 ifndef CONFIG_AS_IS_LLVM
-- 
2.17.1