* [PATCH v2 1/2] kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang
@ 2020-06-30 15:06 Masahiro Yamada
2020-06-30 15:06 ` [PATCH v2 2/2] kbuild: make Clang build userprogs for target architecture Masahiro Yamada
2020-06-30 21:14 ` [PATCH v2 1/2] kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang Nathan Chancellor
0 siblings, 2 replies; 4+ messages in thread
From: Masahiro Yamada @ 2020-06-30 15:06 UTC (permalink / raw)
To: linux-kbuild; +Cc: linux-kernel, Masahiro Yamada, clang-built-linux
scripts/cc-can-link.sh tests if the compiler can link userspace
programs.
When $(CC) is GCC, it is checked against the target architecture
because the toolchain prefix is specified as a part of $(CC).
When $(CC) is Clang, it is checked against the host architecture
because --target option is missing.
Pass $(CLANG_FLAGS) to scripts/cc-can-link.sh to evaluate the link
capability for the target architecture.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
Changes in v2:
- New patch
init/Kconfig | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index a46aa8f3174d..d0313e7725fa 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -49,13 +49,13 @@ config CLANG_VERSION
config CC_CAN_LINK
bool
- default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(m64-flag)) if 64BIT
- default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(m32-flag))
+ default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag)) if 64BIT
+ default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag))
config CC_CAN_LINK_STATIC
bool
- default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) -static $(m64-flag)) if 64BIT
- default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) -static $(m32-flag))
+ default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) -static $(m64-flag)) if 64BIT
+ default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) -static $(m32-flag))
config CC_HAS_ASM_GOTO
def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 2/2] kbuild: make Clang build userprogs for target architecture
2020-06-30 15:06 [PATCH v2 1/2] kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang Masahiro Yamada
@ 2020-06-30 15:06 ` Masahiro Yamada
2020-06-30 21:14 ` Nathan Chancellor
2020-06-30 21:14 ` [PATCH v2 1/2] kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang Nathan Chancellor
1 sibling, 1 reply; 4+ messages in thread
From: Masahiro Yamada @ 2020-06-30 15:06 UTC (permalink / raw)
To: linux-kbuild
Cc: linux-kernel, Masahiro Yamada, Nick Desaulniers, Michal Marek,
Sam Ravnborg, clang-built-linux
Programs added 'userprogs' should be compiled for the target
architecture i.e. the same architecture as the kernel.
GCC does this correctly since the target architecture is implied
by the toolchain prefix.
Clang builds userspace programs always for the host architecture
because the target triple is currently missing.
Fix this.
Fixes: 7f3a59db274c ("kbuild: add infrastructure to build userspace programs")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
---
(no changes since v1)
Makefile | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/Makefile b/Makefile
index ac2c61c37a73..bc48810d1655 100644
--- a/Makefile
+++ b/Makefile
@@ -970,8 +970,8 @@ LDFLAGS_vmlinux += --pack-dyn-relocs=relr
endif
# Align the bit size of userspace programs with the kernel
-KBUILD_USERCFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS))
-KBUILD_USERLDFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS))
+KBUILD_USERCFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
+KBUILD_USERLDFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
# make the checker run with the right architecture
CHECKFLAGS += --arch=$(ARCH)
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2 2/2] kbuild: make Clang build userprogs for target architecture
2020-06-30 15:06 ` [PATCH v2 2/2] kbuild: make Clang build userprogs for target architecture Masahiro Yamada
@ 2020-06-30 21:14 ` Nathan Chancellor
0 siblings, 0 replies; 4+ messages in thread
From: Nathan Chancellor @ 2020-06-30 21:14 UTC (permalink / raw)
To: Masahiro Yamada
Cc: linux-kbuild, linux-kernel, Nick Desaulniers, Michal Marek,
Sam Ravnborg, clang-built-linux
On Wed, Jul 01, 2020 at 12:06:25AM +0900, Masahiro Yamada wrote:
> Programs added 'userprogs' should be compiled for the target
> architecture i.e. the same architecture as the kernel.
>
> GCC does this correctly since the target architecture is implied
> by the toolchain prefix.
>
> Clang builds userspace programs always for the host architecture
> because the target triple is currently missing.
>
> Fix this.
>
> Fixes: 7f3a59db274c ("kbuild: add infrastructure to build userspace programs")
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>
> (no changes since v1)
>
> Makefile | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index ac2c61c37a73..bc48810d1655 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -970,8 +970,8 @@ LDFLAGS_vmlinux += --pack-dyn-relocs=relr
> endif
>
> # Align the bit size of userspace programs with the kernel
> -KBUILD_USERCFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS))
> -KBUILD_USERLDFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS))
> +KBUILD_USERCFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
> +KBUILD_USERLDFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
>
> # make the checker run with the right architecture
> CHECKFLAGS += --arch=$(ARCH)
> --
> 2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2 1/2] kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang
2020-06-30 15:06 [PATCH v2 1/2] kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang Masahiro Yamada
2020-06-30 15:06 ` [PATCH v2 2/2] kbuild: make Clang build userprogs for target architecture Masahiro Yamada
@ 2020-06-30 21:14 ` Nathan Chancellor
1 sibling, 0 replies; 4+ messages in thread
From: Nathan Chancellor @ 2020-06-30 21:14 UTC (permalink / raw)
To: Masahiro Yamada; +Cc: linux-kbuild, linux-kernel, clang-built-linux
On Wed, Jul 01, 2020 at 12:06:24AM +0900, Masahiro Yamada wrote:
> scripts/cc-can-link.sh tests if the compiler can link userspace
> programs.
>
> When $(CC) is GCC, it is checked against the target architecture
> because the toolchain prefix is specified as a part of $(CC).
>
> When $(CC) is Clang, it is checked against the host architecture
> because --target option is missing.
>
> Pass $(CLANG_FLAGS) to scripts/cc-can-link.sh to evaluate the link
> capability for the target architecture.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>
> Changes in v2:
> - New patch
>
> init/Kconfig | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/init/Kconfig b/init/Kconfig
> index a46aa8f3174d..d0313e7725fa 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -49,13 +49,13 @@ config CLANG_VERSION
>
> config CC_CAN_LINK
> bool
> - default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(m64-flag)) if 64BIT
> - default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(m32-flag))
> + default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag)) if 64BIT
> + default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag))
>
> config CC_CAN_LINK_STATIC
> bool
> - default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) -static $(m64-flag)) if 64BIT
> - default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) -static $(m32-flag))
> + default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) -static $(m64-flag)) if 64BIT
> + default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) -static $(m32-flag))
>
> config CC_HAS_ASM_GOTO
> def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-06-30 15:06 [PATCH v2 1/2] kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang Masahiro Yamada
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2020-06-30 21:14 ` [PATCH v2 1/2] kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang Nathan Chancellor
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