On 2025-09-24 16:20:55+0200, Benjamin Berg wrote: > From: Benjamin Berg <[email protected]> > > Add NOLIBC_CFLAGS and NOLIBC_OBJS to build files against nolibc rather > than libc. With this it is possible to move to nolibc in smaller steps. > > Set NOLIBC_IGNORE_ERRNO, as the nolibc errno implementation is overly > simple and cannot handle threading. nolibc provides sys_* functions that > do not emulate the libc errno behaviour and can be used instead. > > Leave the syscall definition for kernel code for now, but guard it as it > is a macro in nolibc. > > Signed-off-by: Benjamin Berg <[email protected]> > > --- > v3: > - Change the syscall guard to use __KERNEL__ > > v2: > - Do not include nolibc.h via CFLAGS > - Make syscall guard more explicit > - Remove __UM_NOLIBC__ define, it is not needed > - Fix out-of-tree building > --- > arch/um/Makefile | 20 +++++++++++++++++++- > arch/um/include/shared/os.h | 2 ++ > arch/um/include/shared/user.h | 1 - > arch/um/scripts/Makefile.rules | 8 +++++++- > 4 files changed, 28 insertions(+), 3 deletions(-) > > diff --git a/arch/um/Makefile b/arch/um/Makefile > index f7c509262568..c3a81df50911 100644 > --- a/arch/um/Makefile > +++ b/arch/um/Makefile > @@ -78,6 +78,24 @@ USER_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst > -I%,,$(KBUILD_CFLAGS))) \ > -include $(srctree)/include/linux/kern_levels.h \ > -include $(srctree)/$(ARCH_DIR)/include/shared/user.h > > +NOLIBC_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst > -I%,,$(KBUILD_CFLAGS))) \ > + $(ARCH_INCLUDE) $(MODE_INCLUDE) $(filter -I%,$(CFLAGS)) \ > + -I $(srctree)/tools/include \ > + -D__EXPORTED_HEADERS__ \ > + -D__UM_HOST__ \ > + -DNOLIBC_NO_RUNTIME \ > + -DNOLIBC_IGNORE_ERRNO \ > + -nostdlib -nostdinc -static \ > + -I$(srctree)/include/uapi \ > + -I$(srctree)/$(HOST_DIR)/include/uapi \ > + -I$(objtree)/$(HOST_DIR)/include/generated/uapi \ > + -I $(srctree)/tools/include/nolibc \ > + -I $(srctree)/usr/include \
This looks incorrect. The UAPI headers would be installed to $(objtree). But UML does not even use CONFIG_HEADERS_INSTALL. Also the whitespace is inconsistent between different lines. > + -include $(objtree)/include/generated/autoconf.h \ > + -include $(srctree)/tools/include/linux/kconfig.h \ > + -include $(srctree)/include/linux/kern_levels.h \ > + -include $(srctree)/$(ARCH_DIR)/include/shared/user.h > + > #This will adjust *FLAGS accordingly to the platform. > include $(srctree)/$(ARCH_DIR)/Makefile-os-Linux > > @@ -160,4 +178,4 @@ archclean: > -o -name '*.gcov' \) -type f -print | xargs rm -f > $(Q)$(MAKE) -f $(srctree)/Makefile ARCH=$(HEADER_ARCH) clean > > -export HEADER_ARCH SUBARCH USER_CFLAGS CFLAGS_NO_HARDENING DEV_NULL_PATH > +export HEADER_ARCH SUBARCH USER_CFLAGS NOLIBC_CFLAGS CFLAGS_NO_HARDENING > DEV_NULL_PATH (...)
