kbuild: Add -Wa,--fatal-warnings to as-instr invocation

commit 0ee695a471 upstream.

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 <ebiggers@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Eric Biggers <ebiggers@google.com>
Tested-by: Andy Chiu <andybnac@gmail.com>
Reviewed-by: Andy Chiu <andybnac@gmail.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20240125-fix-riscv-option-arch-llvm-18-v1-1-390ac9cc3cd0@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nathan Chancellor 2024-01-25 10:32:11 -07:00 committed by Greg Kroah-Hartman
parent 3c6cefdc24
commit d9071321f4
2 changed files with 2 additions and 2 deletions

View File

@ -33,7 +33,7 @@ ld-option = $(success,$(LD) -v $(1))
# $(as-instr,<instr>)
# Return y if the assembler supports <instr>, 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)

View File

@ -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)