GCC changed the default C standard dialect from gnu17 to gnu23, which should not have impacted the kernel because it explicitly requests the gnu11 standard in the main Makefile. However, there are certain places in the s390 code that use their own CFLAGS without a '-std=' value, which break with this dialect change because of the kernel's own definitions of bool, false, and true conflicting with the C23 reserved keywords.
include/linux/stddef.h:11:9: error: cannot use keyword 'false' as enumeration constant 11 | false = 0, | ^~~~~ include/linux/stddef.h:11:9: note: 'false' is a keyword with '-std=c23' onwards include/linux/types.h:35:33: error: 'bool' cannot be defined via 'typedef' 35 | typedef _Bool bool; | ^~~~ include/linux/types.h:35:33: note: 'bool' is a keyword with '-std=c23' onwards
Add '-std=gnu11' to the decompressor and purgatory CFLAGS to eliminate these errors and make the C standard version of these areas match the rest of the kernel.
Cc: stable@vger.kernel.org Signed-off-by: Nathan Chancellor nathan@kernel.org --- I only see one other error in various files with a recent GCC 15.0.1 snapshot, which I can eliminate by dropping the version part of the condition for CONFIG_GCC_ASM_FLAG_OUTPUT_BROKEN. Is this a regression of the fix for the problem of GCC 14.2.0 or is something else doing on here?
arch/s390/include/asm/bitops.h: Assembler messages: arch/s390/include/asm/bitops.h:60: Error: operand 1: syntax error; missing ')' after base register arch/s390/include/asm/bitops.h:60: Error: operand 2: syntax error; ')' not allowed here arch/s390/include/asm/bitops.h:60: Error: junk at end of line: `,4' arch/s390/include/asm/bitops.h:60: Error: operand 1: syntax error; missing ')' after base register arch/s390/include/asm/bitops.h:60: Error: operand 2: syntax error; ')' not allowed here arch/s390/include/asm/bitops.h:60: Error: junk at end of line: `,64' arch/s390/include/asm/bitops.h:60: Error: operand 1: syntax error; missing ')' after base register arch/s390/include/asm/bitops.h:60: Error: operand 2: syntax error; ')' not allowed here arch/s390/include/asm/bitops.h:60: Error: junk at end of line: `,4' make[6]: *** [scripts/Makefile.build:194: fs/gfs2/glock.o] Error 1 --- arch/s390/Makefile | 2 +- arch/s390/purgatory/Makefile | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/s390/Makefile b/arch/s390/Makefile index 3f25498dac65..5fae311203c2 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -22,7 +22,7 @@ KBUILD_AFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -D__ASSEMBLY__ ifndef CONFIG_AS_IS_LLVM KBUILD_AFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),$(aflags_dwarf)) endif -KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -mpacked-stack +KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -mpacked-stack -std=gnu11 KBUILD_CFLAGS_DECOMPRESSOR += -DDISABLE_BRANCH_PROFILING -D__NO_FORTIFY KBUILD_CFLAGS_DECOMPRESSOR += -D__DECOMPRESSOR KBUILD_CFLAGS_DECOMPRESSOR += -fno-delete-null-pointer-checks -msoft-float -mbackchain diff --git a/arch/s390/purgatory/Makefile b/arch/s390/purgatory/Makefile index 24eccaa29337..bdcf2a3b6c41 100644 --- a/arch/s390/purgatory/Makefile +++ b/arch/s390/purgatory/Makefile @@ -13,7 +13,7 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS -D__NO_FORTIFY $(obj)/mem.o: $(srctree)/arch/s390/lib/mem.S FORCE $(call if_changed_rule,as_o_S)
-KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes +KBUILD_CFLAGS := -std=gnu11 -fno-strict-aliasing -Wall -Wstrict-prototypes KBUILD_CFLAGS += -Wno-pointer-sign -Wno-sign-compare KBUILD_CFLAGS += -fno-zero-initialized-in-bss -fno-builtin -ffreestanding KBUILD_CFLAGS += -Os -m64 -msoft-float -fno-common
--- base-commit: b2832409e00b6330781458d7db0080508a35a9a8 change-id: 20250122-s390-fix-std-for-gcc-15-0abfa4caf757
Best regards,
On Wed, Jan 22, 2025 at 07:54:27PM -0700, Nathan Chancellor wrote:
GCC changed the default C standard dialect from gnu17 to gnu23, which should not have impacted the kernel because it explicitly requests the gnu11 standard in the main Makefile. However, there are certain places in the s390 code that use their own CFLAGS without a '-std=' value, which break with this dialect change because of the kernel's own definitions of bool, false, and true conflicting with the C23 reserved keywords.
include/linux/stddef.h:11:9: error: cannot use keyword 'false' as enumeration constant 11 | false = 0, | ^~~~~ include/linux/stddef.h:11:9: note: 'false' is a keyword with '-std=c23' onwards include/linux/types.h:35:33: error: 'bool' cannot be defined via 'typedef' 35 | typedef _Bool bool; | ^~~~ include/linux/types.h:35:33: note: 'bool' is a keyword with '-std=c23' onwards
Add '-std=gnu11' to the decompressor and purgatory CFLAGS to eliminate these errors and make the C standard version of these areas match the rest of the kernel.
Cc: stable@vger.kernel.org Signed-off-by: Nathan Chancellor nathan@kernel.org
Thanks! Tested-by: Heiko Carstens hca@linux.ibm.com
Alexander, can you pick this up, please?
I only see one other error in various files with a recent GCC 15.0.1 snapshot, which I can eliminate by dropping the version part of the condition for CONFIG_GCC_ASM_FLAG_OUTPUT_BROKEN. Is this a regression of the fix for the problem of GCC 14.2.0 or is something else doing on here?
arch/s390/include/asm/bitops.h: Assembler messages: arch/s390/include/asm/bitops.h:60: Error: operand 1: syntax error; missing ')' after base register arch/s390/include/asm/bitops.h:60: Error: operand 2: syntax error; ')' not allowed here arch/s390/include/asm/bitops.h:60: Error: junk at end of line: `,4'
That is I bug I recently introduced. The patch below fixes that. Thanks for reporting!
From 2f58027ec1302714bb4d728b08dc5c88498d18b1 Mon Sep 17 00:00:00 2001 From: Heiko Carstens hca@linux.ibm.com Date: Thu, 23 Jan 2025 09:14:15 +0100 Subject: [PATCH] s390/bitops: Use correct constraint for arch_test_bit() inline assembly
Use the "Q" instead of "R" constraint to correctly reflect the instruction format of the tm instruction: the first operand is a memory reference without index register and short displacement. The "R" constraint indicates a memory reference with index register instead.
This may lead to compile errors like:
arch/s390/include/asm/bitops.h: Assembler messages: arch/s390/include/asm/bitops.h:60: Error: operand 1: syntax error; missing ')' after base register arch/s390/include/asm/bitops.h:60: Error: operand 2: syntax error; ')' not allowed here arch/s390/include/asm/bitops.h:60: Error: junk at end of line: `,4'
Reported-by: Nathan Chancellor nathan@kernel.org Closes: https://lore.kernel.org/r/20250122-s390-fix-std-for-gcc-15-v1-1-8b00cadee083... Fixes: b2bc1b1a77c0 ("s390/bitops: Provide optimized arch_test_bit()") Signed-off-by: Heiko Carstens hca@linux.ibm.com --- arch/s390/include/asm/bitops.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h index 15aa64e3020e..d5125296ade2 100644 --- a/arch/s390/include/asm/bitops.h +++ b/arch/s390/include/asm/bitops.h @@ -60,7 +60,7 @@ static __always_inline bool arch_test_bit(unsigned long nr, const volatile unsig asm volatile( " tm %[addr],%[mask]\n" : "=@cc" (cc) - : [addr] "R" (*addr), [mask] "I" (mask) + : [addr] "Q" (*addr), [mask] "I" (mask) ); return cc == 3; }
On Wed, Jan 22, 2025 at 07:54:27PM -0700, Nathan Chancellor wrote:
GCC changed the default C standard dialect from gnu17 to gnu23, which should not have impacted the kernel because it explicitly requests the gnu11 standard in the main Makefile. However, there are certain places in the s390 code that use their own CFLAGS without a '-std=' value, which break with this dialect change because of the kernel's own definitions of bool, false, and true conflicting with the C23 reserved keywords.
include/linux/stddef.h:11:9: error: cannot use keyword 'false' as enumeration constant 11 | false = 0, | ^~~~~ include/linux/stddef.h:11:9: note: 'false' is a keyword with '-std=c23' onwards include/linux/types.h:35:33: error: 'bool' cannot be defined via 'typedef' 35 | typedef _Bool bool; | ^~~~ include/linux/types.h:35:33: note: 'bool' is a keyword with '-std=c23' onwards
Add '-std=gnu11' to the decompressor and purgatory CFLAGS to eliminate these errors and make the C standard version of these areas match the rest of the kernel.
Cc: stable@vger.kernel.org Signed-off-by: Nathan Chancellor nathan@kernel.org
...
arch/s390/Makefile | 2 +- arch/s390/purgatory/Makefile | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
Applied, thanks!
linux-stable-mirror@lists.linaro.org
-
Alexander Gordeev -
Heiko Carstens -
Nathan Chancellor