From 5cc1247204616528b427e276c97c5bc4c9612347 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Fri, 5 Mar 2021 10:27:07 +0100 Subject: kbuild: add CONFIG_VMLINUX_MAP expert option It can be quite useful to have ld emit a link map file, in order to debug or verify that special sections end up where they are supposed to, and to see what LD_DEAD_CODE_DATA_ELIMINATION manages to get rid of. The only reason I'm not just adding this unconditionally is that the .map file can be rather large (several MB), and that's a waste of space when one isn't interested in these things. Also make it depend on CONFIG_EXPERT. Signed-off-by: Rasmus Villemoes Signed-off-by: Masahiro Yamada --- lib/Kconfig.debug | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 2779c29d9981..b479ae609a31 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -449,6 +449,16 @@ config VMLINUX_VALIDATION depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT default y +config VMLINUX_MAP + bool "Generate vmlinux.map file when linking" + depends on EXPERT + help + Selecting this option will pass "-Map=vmlinux.map" to ld + when linking vmlinux. That file can be useful for verifying + and debugging magic section games, and for seeing which + pieces of code get eliminated with + CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. + config DEBUG_FORCE_WEAK_PER_CPU bool "Force weak per-cpu definitions" depends on DEBUG_KERNEL -- cgit From 2e98815794fb51250da4528f67fc2f699d5e3c37 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 16 Mar 2021 01:12:57 +0900 Subject: kbuild: dwarf: use AS_VERSION instead of test_dwarf5_support.sh The test code in scripts/test_dwarf5_support.sh is somewhat difficult to understand, but after all, we want to check binutils >= 2.35.2 From the former discussion, the requirement for generating DWARF v5 from C code is as follows: - gcc + gnu as -> requires gcc 5.0+ (but 7.0+ for full support) - clang + gnu as -> requires binutils 2.35.2+ - clang + integrated as -> OK Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor Reviewed-by: Nick Desaulniers --- lib/Kconfig.debug | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index b479ae609a31..c85d5f7a1aeb 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -284,8 +284,7 @@ config DEBUG_INFO_DWARF4 config DEBUG_INFO_DWARF5 bool "Generate DWARF Version 5 debuginfo" - depends on GCC_VERSION >= 50000 || CC_IS_CLANG - depends on CC_IS_GCC || $(success,$(srctree)/scripts/test_dwarf5_support.sh $(CC) $(CLANG_FLAGS)) + depends on GCC_VERSION >= 50000 || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) depends on !DEBUG_INFO_BTF help Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc -- cgit