Building userspace applications through the kbuild "userprogs" framework requires a libc. Kernel toolchains often do not contain a libc. In this case it is useful to use the nolibc library from the kernel tree. Nolibc does not support all architectures and requires compiler flags.
Add a kconfig option, so users can know where it is available and provide a variable for common options. Signed-off-by: Thomas Weißschuh <[email protected]> Reviewed-by: Nicolas Schier <[email protected]> --- MAINTAINERS | 2 ++ init/Kconfig | 2 ++ init/Kconfig.nolibc | 16 ++++++++++++++++ init/Makefile.nolibc | 13 +++++++++++++ 4 files changed, 33 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index 2fb1c75afd16..be4f6242b3fc 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18960,6 +18960,8 @@ M: Willy Tarreau <[email protected]> M: Thomas Weißschuh <[email protected]> S: Maintained T: git git://git.kernel.org/pub/scm/linux/kernel/git/nolibc/linux-nolibc.git +F: init/Kconfig.nolibc +F: init/Makefile.nolibc F: tools/include/nolibc/ F: tools/testing/selftests/nolibc/ diff --git a/init/Kconfig b/init/Kconfig index 3bb92a3f6cc1..c37d9227ba72 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -106,6 +106,8 @@ config CC_CAN_LINK default $(cc_can_link_user,$(m64-flag)) if 64BIT default $(cc_can_link_user,$(m32-flag)) +source "init/Kconfig.nolibc" + # Fixed in GCC 14, 13.3, 12.4 and 11.5 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921 config GCC_ASM_GOTO_OUTPUT_BROKEN diff --git a/init/Kconfig.nolibc b/init/Kconfig.nolibc new file mode 100644 index 000000000000..07488ef18f4f --- /dev/null +++ b/init/Kconfig.nolibc @@ -0,0 +1,16 @@ +# SPDX-License-Identifier: GPL-2.0 + +config ARCH_HAS_NOLIBC + bool + default y if ARM + default y if ARM64 + default y if LOONGARCH + default y if M68K + default y if MIPS + default y if PPC + default y if RISCV + default y if S390 + default y if SPARC + default y if SUPERH + default y if UML_X86 + default y if X86 diff --git a/init/Makefile.nolibc b/init/Makefile.nolibc new file mode 100644 index 000000000000..dacc78ab4c81 --- /dev/null +++ b/init/Makefile.nolibc @@ -0,0 +1,13 @@ +# SPDX-License-Identifier: GPL-2.0 +# Compiler flags, which are necessary to build userspace applications with the +# in-kernel libc "nolibc". + +ifeq ($(and $(CONFIG_ARCH_HAS_NOLIBC),$(CONFIG_HEADERS_INSTALL)),y) + +NOLIBC_USERCFLAGS := -nostdlib -nostdinc -static -ffreestanding \ + -fno-asynchronous-unwind-tables -fno-stack-protector \ + -I$(objtree)/usr/include -I$(srctree)/tools/include/nolibc/ + +NOLIBC_USERLDFLAGS := -nostdlib -nostdinc -static + +endif # CONFIG_ARCH_HAS_NOLIBC && CONFIG_HEADERS_INSTALL -- 2.53.0
