Commit aea447141c7e ("powerpc: Disable -Wbuiltin-requires-header when setjmp is used") disabled -Wbuiltin-requires-header because of a warning about the setjmp and longjmp declarations.

r367387 in clang added another diagnostic around this, complaining that there is no jmp_buf declaration.

In file included from ../arch/powerpc/xmon/xmon.c:47: ../arch/powerpc/include/asm/setjmp.h:10:13: error: declaration of built-in function 'setjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>. [-Werror,-Wincomplete-setjmp-declaration] extern long setjmp(long *); ^ ../arch/powerpc/include/asm/setjmp.h:11:13: error: declaration of built-in function 'longjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>. [-Werror,-Wincomplete-setjmp-declaration] extern void longjmp(long *, long); ^ 2 errors generated.

We are not using the standard library's longjmp/setjmp implementations for obvious reasons; make this clear to clang by using -ffreestanding on these files.

Cc: stable@vger.kernel.org # 4.14+ Link: https://github.com/ClangBuiltLinux/linux/issues/625 Link: https://github.com/llvm/llvm-project/commit/3be25e79477db2d31ac46493d97eca8c... Link: https://godbolt.org/z/B2oQnl Suggested-by: Segher Boessenkool segher@kernel.crashing.org Reviewed-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Nathan Chancellor natechancellor@gmail.com ---

v1 -> v3 (I skipped v2 because the first patch in the series already had a v2):

* Use -ffreestanding instead of outright disabling the warning because it is legitimate.

v3 -> v4:

* Rebase on v5.4-rc3

* Add Nick's reviewed-by and Compiler Explorer link.

arch/powerpc/kernel/Makefile | 4 ++-- arch/powerpc/xmon/Makefile | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index a7ca8fe62368..f1f362146135 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -5,8 +5,8 @@

CFLAGS_ptrace.o += -DUTS_MACHINE='"$(UTS_MACHINE)"'

-# Disable clang warning for using setjmp without setjmp.h header -CFLAGS_crash.o += $(call cc-disable-warning, builtin-requires-header) +# Avoid clang warnings around longjmp/setjmp declarations +CFLAGS_crash.o += -ffreestanding

ifdef CONFIG_PPC64 CFLAGS_prom_init.o += $(NO_MINIMAL_TOC) diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile index f142570ad860..c3842dbeb1b7 100644 --- a/arch/powerpc/xmon/Makefile +++ b/arch/powerpc/xmon/Makefile @@ -1,8 +1,8 @@ # SPDX-License-Identifier: GPL-2.0 # Makefile for xmon

-# Disable clang warning for using setjmp without setjmp.h header -subdir-ccflags-y := $(call cc-disable-warning, builtin-requires-header) +# Avoid clang warnings around longjmp/setjmp declarations +subdir-ccflags-y := -ffreestanding

GCOV_PROFILE := n KCOV_INSTRUMENT := n