From 0ee695a471a750cad4fff22286d91e038b1ef62f Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Thu, 25 Jan 2024 10:32:11 -0700 Subject: kbuild: Add -Wa,--fatal-warnings to as-instr invocation Certain assembler instruction tests may only induce warnings from the assembler on an unsupported instruction or option, which causes as-instr to succeed when it was expected to fail. Some tests workaround this limitation by additionally testing that invalid input fails as expected. However, this is fragile if the assembler is changed to accept the invalid input, as it will cause the instruction/option to be unavailable like it was unsupported even when it is. Use '-Wa,--fatal-warnings' in the as-instr macro to turn these warnings into hard errors, which avoids this fragility and makes tests more robust and well formed. Cc: stable@vger.kernel.org Suggested-by: Eric Biggers Signed-off-by: Nathan Chancellor Tested-by: Eric Biggers Tested-by: Andy Chiu Reviewed-by: Andy Chiu Tested-by: Conor Dooley Reviewed-by: Conor Dooley Acked-by: Masahiro Yamada Link: https://lore.kernel.org/r/20240125-fix-riscv-option-arch-llvm-18-v1-1-390ac9cc3cd0@kernel.org Signed-off-by: Palmer Dabbelt --- scripts/Kconfig.include | 2 +- scripts/Makefile.compiler | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include index 5a84b6443875..3ee8ecfb8c04 100644 --- a/scripts/Kconfig.include +++ b/scripts/Kconfig.include @@ -33,7 +33,7 @@ ld-option = $(success,$(LD) -v $(1)) # $(as-instr,) # Return y if the assembler supports , n otherwise -as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -c -x assembler-with-cpp -o /dev/null -) +as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -Wa$(comma)--fatal-warnings -c -x assembler-with-cpp -o /dev/null -) # check if $(CC) and $(LD) exist $(error-if,$(failure,command -v $(CC)),C compiler '$(CC)' not found) diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler index 8fcb427405a6..92be0c9a13ee 100644 --- a/scripts/Makefile.compiler +++ b/scripts/Makefile.compiler @@ -38,7 +38,7 @@ as-option = $(call try-run,\ # Usage: aflags-y += $(call as-instr,instr,option1,option2) as-instr = $(call try-run,\ - printf "%b\n" "$(1)" | $(CC) -Werror $(CLANG_FLAGS) $(KBUILD_AFLAGS) -c -x assembler-with-cpp -o "$$TMP" -,$(2),$(3)) + printf "%b\n" "$(1)" | $(CC) -Werror $(CLANG_FLAGS) $(KBUILD_AFLAGS) -Wa$(comma)--fatal-warnings -c -x assembler-with-cpp -o "$$TMP" -,$(2),$(3)) # __cc-option # Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586) -- cgit From 3aff0c459e77ac0fb1c4d6884433467f797f7357 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Thu, 25 Jan 2024 10:32:12 -0700 Subject: RISC-V: Drop invalid test from CONFIG_AS_HAS_OPTION_ARCH Commit e4bb020f3dbb ("riscv: detect assembler support for .option arch") added two tests, one for a valid value to '.option arch' that should succeed and one for an invalid value that is expected to fail to make sure that support for '.option arch' is properly detected because Clang does not error when '.option arch' is not supported: $ clang --target=riscv64-linux-gnu -Werror -x assembler -c -o /dev/null <(echo '.option arch, +m') /dev/fd/63:1:9: warning: unknown option, expected 'push', 'pop', 'rvc', 'norvc', 'relax' or 'norelax' .option arch, +m ^ $ echo $? 0 Unfortunately, the invalid test started being accepted by Clang after the linked llvm-project change, which causes CONFIG_AS_HAS_OPTION_ARCH and configurations that depend on it to be silently disabled, even though those versions do support '.option arch'. The invalid test can be avoided altogether by using '-Wa,--fatal-warnings', which will turn all assembler warnings into errors, like '-Werror' does for the compiler: $ clang --target=riscv64-linux-gnu -Werror -Wa,--fatal-warnings -x assembler -c -o /dev/null <(echo '.option arch, +m') /dev/fd/63:1:9: error: unknown option, expected 'push', 'pop', 'rvc', 'norvc', 'relax' or 'norelax' .option arch, +m ^ $ echo $? 1 The as-instr macros have been updated to make use of this flag, so remove the invalid test, which allows CONFIG_AS_HAS_OPTION_ARCH to work for all compiler versions. Cc: stable@vger.kernel.org Fixes: e4bb020f3dbb ("riscv: detect assembler support for .option arch") Link: https://github.com/llvm/llvm-project/commit/3ac9fe69f70a2b3541266daedbaaa7dc9c007a2a Reported-by: Eric Biggers Closes: https://lore.kernel.org/r/20240121011341.GA97368@sol.localdomain/ Signed-off-by: Nathan Chancellor Tested-by: Eric Biggers Tested-by: Andy Chiu Reviewed-by: Andy Chiu Tested-by: Conor Dooley Reviewed-by: Conor Dooley Acked-by: Masahiro Yamada Link: https://lore.kernel.org/r/20240125-fix-riscv-option-arch-llvm-18-v1-2-390ac9cc3cd0@kernel.org Signed-off-by: Palmer Dabbelt --- arch/riscv/Kconfig | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index bffbd869a068..e3142ce531a0 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -315,7 +315,6 @@ config AS_HAS_OPTION_ARCH # https://reviews.llvm.org/D123515 def_bool y depends on $(as-instr, .option arch$(comma) +m) - depends on !$(as-instr, .option arch$(comma) -i) source "arch/riscv/Kconfig.socs" source "arch/riscv/Kconfig.errata" -- cgit