From 89775a27ff6d0396b44de0d6f44dcbc25221fdda Mon Sep 17 00:00:00 2001 From: Nathan Chancellor <nathan@kernel.org> Date: Wed, 16 Aug 2023 10:35:43 -0700 Subject: [PATCH] lib/Kconfig.debug: Restrict DEBUG_INFO_SPLIT for RISC-V When building for ARCH=riscv using LLVM < 14, there is an error with CONFIG_DEBUG_INFO_SPLIT=y: error: A dwo section may not contain relocations This was worked around in LLVM 15 by disallowing '-gsplit-dwarf' with '-mrelax' (the default), so CONFIG_DEBUG_INFO_SPLIT is not selectable with newer versions of LLVM: $ clang --target=riscv64-linux-gnu -gsplit-dwarf -c -o /dev/null -x c /dev/null clang: error: -gsplit-dwarf is unsupported with RISC-V linker relaxation (-mrelax) GCC silently had a similar issue that was resolved with GCC 12.x. Restrict CONFIG_DEBUG_INFO_SPLIT for RISC-V when using LLVM or GCC < 12.x to avoid these known issues. Link: https://github.com/ClangBuiltLinux/linux/issues/1914 Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090 Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/all/202308090204.9yZffBWo-lkp@intel.com/ Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20230816-riscv-debug_info_split-v1-1-d1019d6ccc11@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> --- lib/Kconfig.debug | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 39ffd218e960b..7bad297b48fbe 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -355,6 +355,11 @@ endchoice # "Compressed Debug information" config DEBUG_INFO_SPLIT bool "Produce split debuginfo in .dwo files" depends on $(cc-option,-gsplit-dwarf) + # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC + # prior to 12.x: + # https://github.com/llvm/llvm-project/issues/56642 + # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090 + depends on !RISCV || GCC_VERSION >= 120000 help Generate debug info into separate .dwo files. This significantly reduces the build directory size for builds with DEBUG_INFO, -- 2.30.2