2018-05-29 03:49:11

by Luc Van Oostenryck

[permalink] [raw]
Subject: [PATCH v2] kbuild: add endianness flag to CHEKCFLAGS

The kernel depends on macros like __BYTE_ORDER__,
__BIG_ENDIAN__ or __LITTLE_ENDIAN__.

OTOH, sparse doesn't know about the endianness of the kernel and
by default uses the same as the machine on which sparse was built.

Ensure that sparse can predefine the macros corresponding to
how the kernel was configured by adding -m{big,little}-endian
to CHECKFLAGS in the main Makefile (and so for all archs).
Also, remove the equivalent done in arch specific Makefiles.

Signed-off-by: Luc Van Oostenryck <[email protected]>
---
Makefile | 3 +++
arch/openrisc/Makefile | 1 -
arch/parisc/Makefile | 2 +-
arch/s390/Makefile | 2 +-
4 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 56ba070df..6c6610913 100644
--- a/Makefile
+++ b/Makefile
@@ -878,6 +878,9 @@ ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
LDFLAGS_vmlinux += $(call ld-option, -X,)
endif

+# insure the checker run with the right endianness
+CHECKFLAGS += $(if $(CONFIG_CPU_BIG_ENDIAN),-mbig-endian,-mlittle-endian)
+
# Default kernel image to build when no specific target is given.
# KBUILD_IMAGE may be overruled on the command line or
# set in the environment
diff --git a/arch/openrisc/Makefile b/arch/openrisc/Makefile
index cf8802962..89076a66e 100644
--- a/arch/openrisc/Makefile
+++ b/arch/openrisc/Makefile
@@ -25,7 +25,6 @@ LDFLAGS_vmlinux :=
LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)

KBUILD_CFLAGS += -pipe -ffixed-r10 -D__linux__
-CHECKFLAGS += -mbig-endian

ifeq ($(CONFIG_OPENRISC_HAVE_INST_MUL),y)
KBUILD_CFLAGS += $(call cc-option,-mhard-mul)
diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
index 34ac503e2..348ae4779 100644
--- a/arch/parisc/Makefile
+++ b/arch/parisc/Makefile
@@ -22,7 +22,7 @@ KBUILD_IMAGE := vmlinuz
KBUILD_DEFCONFIG := default_defconfig

NM = sh $(srctree)/arch/parisc/nm
-CHECKFLAGS += -D__hppa__=1 -mbig-endian
+CHECKFLAGS += -D__hppa__=1
LIBGCC = $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
export LIBGCC

diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index c79936d02..68a690442 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -18,7 +18,7 @@ KBUILD_CFLAGS += -m64
KBUILD_AFLAGS += -m64
UTS_MACHINE := s390x
STACK_SIZE := 16384
-CHECKFLAGS += -D__s390__ -D__s390x__ -mbig-endian
+CHECKFLAGS += -D__s390__ -D__s390x__

export LD_BFD

--
2.17.0



2018-05-29 13:11:28

by Masahiro Yamada

[permalink] [raw]
Subject: Re: [PATCH v2] kbuild: add endianness flag to CHEKCFLAGS

2018-05-29 3:27 GMT+09:00 Luc Van Oostenryck <[email protected]>:
> The kernel depends on macros like __BYTE_ORDER__,
> __BIG_ENDIAN__ or __LITTLE_ENDIAN__.
>
> OTOH, sparse doesn't know about the endianness of the kernel and
> by default uses the same as the machine on which sparse was built.
>
> Ensure that sparse can predefine the macros corresponding to
> how the kernel was configured by adding -m{big,little}-endian
> to CHECKFLAGS in the main Makefile (and so for all archs).
> Also, remove the equivalent done in arch specific Makefiles.
>
> Signed-off-by: Luc Van Oostenryck <[email protected]>
> ---


Applied to linux-kbuild. Thanks.


> Makefile | 3 +++
> arch/openrisc/Makefile | 1 -
> arch/parisc/Makefile | 2 +-
> arch/s390/Makefile | 2 +-
> 4 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 56ba070df..6c6610913 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -878,6 +878,9 @@ ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
> LDFLAGS_vmlinux += $(call ld-option, -X,)
> endif
>
> +# insure the checker run with the right endianness
> +CHECKFLAGS += $(if $(CONFIG_CPU_BIG_ENDIAN),-mbig-endian,-mlittle-endian)
> +
> # Default kernel image to build when no specific target is given.
> # KBUILD_IMAGE may be overruled on the command line or
> # set in the environment
> diff --git a/arch/openrisc/Makefile b/arch/openrisc/Makefile
> index cf8802962..89076a66e 100644
> --- a/arch/openrisc/Makefile
> +++ b/arch/openrisc/Makefile
> @@ -25,7 +25,6 @@ LDFLAGS_vmlinux :=
> LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
>
> KBUILD_CFLAGS += -pipe -ffixed-r10 -D__linux__
> -CHECKFLAGS += -mbig-endian
>
> ifeq ($(CONFIG_OPENRISC_HAVE_INST_MUL),y)
> KBUILD_CFLAGS += $(call cc-option,-mhard-mul)
> diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
> index 34ac503e2..348ae4779 100644
> --- a/arch/parisc/Makefile
> +++ b/arch/parisc/Makefile
> @@ -22,7 +22,7 @@ KBUILD_IMAGE := vmlinuz
> KBUILD_DEFCONFIG := default_defconfig
>
> NM = sh $(srctree)/arch/parisc/nm
> -CHECKFLAGS += -D__hppa__=1 -mbig-endian
> +CHECKFLAGS += -D__hppa__=1
> LIBGCC = $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
> export LIBGCC
>
> diff --git a/arch/s390/Makefile b/arch/s390/Makefile
> index c79936d02..68a690442 100644
> --- a/arch/s390/Makefile
> +++ b/arch/s390/Makefile
> @@ -18,7 +18,7 @@ KBUILD_CFLAGS += -m64
> KBUILD_AFLAGS += -m64
> UTS_MACHINE := s390x
> STACK_SIZE := 16384
> -CHECKFLAGS += -D__s390__ -D__s390x__ -mbig-endian
> +CHECKFLAGS += -D__s390__ -D__s390x__
>
> export LD_BFD
>
> --
> 2.17.0
>
> --
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--
Best Regards
Masahiro Yamada