Several Makefiles use 'hostprogs' to build programs for the host architecture where it is not appropriate to do so. This is just because Kbuild lacks the support for building programs for the target architecture. This series introduce 'userprogs' syntax and use it from sample and bpf Makefiles. Sam worked on this in 2014. https://lkml.org/lkml/2014/7/13/154 He used 'uapiprogs-y' but I just thought the meaning of "UAPI programs" is unclear. Naming the syntax is one of the most difficult parts. I chose 'userprogs'. Anothor choice I had in my mind was 'targetprogs'. You can test this series quickly by 'make allmodconfig samples/' When building objects for userspace, [U] is displayed. masahiro@oscar:~/workspace/linux$ make allmodconfig samples/ [snip] AR samples/vfio-mdev/built-in.a CC [M] samples/vfio-mdev/mtty.o CC [M] samples/vfio-mdev/mdpy.o CC [M] samples/vfio-mdev/mdpy-fb.o CC [M] samples/vfio-mdev/mbochs.o AR samples/mei/built-in.a CC [U] samples/mei/mei-amt-version CC [U] samples/auxdisplay/cfag12864b-example CC [M] samples/configfs/configfs_sample.o CC [M] samples/connector/cn_test.o CC [U] samples/connector/ucon CC [M] samples/ftrace/ftrace-direct.o CC [M] samples/ftrace/ftrace-direct-too.o CC [M] samples/ftrace/ftrace-direct-modify.o CC [M] samples/ftrace/sample-trace-array.o CC [U] samples/hidraw/hid-example CC [M] samples/hw_breakpoint/data_breakpoint.o CC [M] samples/kdb/kdb_hello.o CC [M] samples/kfifo/bytestream-example.o CC [M] samples/kfifo/dma-example.o CC [M] samples/kfifo/inttype-example.o CC [M] samples/kfifo/record-example.o CC [M] samples/kobject/kobject-example.o CC [M] samples/kobject/kset-example.o CC [M] samples/kprobes/kprobe_example.o CC [M] samples/kprobes/kretprobe_example.o CC [M] samples/livepatch/livepatch-sample.o CC [M] samples/livepatch/livepatch-shadow-mod.o CC [M] samples/livepatch/livepatch-shadow-fix1.o CC [M] samples/livepatch/livepatch-shadow-fix2.o CC [M] samples/livepatch/livepatch-callbacks-demo.o CC [M] samples/livepatch/livepatch-callbacks-mod.o CC [M] samples/livepatch/livepatch-callbacks-busymod.o CC [M] samples/rpmsg/rpmsg_client_sample.o CC [U] samples/seccomp/bpf-fancy.o CC [U] samples/seccomp/bpf-helper.o LD [U] samples/seccomp/bpf-fancy CC [U] samples/seccomp/dropper CC [U] samples/seccomp/bpf-direct CC [U] samples/seccomp/user-trap CC [U] samples/timers/hpet_example CC [M] samples/trace_events/trace-events-sample.o CC [M] samples/trace_printk/trace-printk.o CC [U] samples/uhid/uhid-example CC [M] samples/v4l/v4l2-pci-skeleton.o CC [U] samples/vfs/test-fsmount CC [U] samples/vfs/test-statx samples/vfs/test-statx.c:24:15: warning: ‘struct foo’ declared inside parameter list will not be visible outside of this definition or declaration 24 | #define statx foo | ^~~ CC [U] samples/watchdog/watchdog-simple AR samples/built-in.a Changes for v2: - Fix ARCH=i386 build error for bpfilter_umh - Rename 'user-ccflags' to 'userccflags' because 'user-ccflags' would conflict if an object called 'user.o' exists in the directory. - Support 'userldflags' Masahiro Yamada (14): bpfilter: match bit size of bpfilter_umh to that of the kernel kbuild: add infrastructure to build userspace programs bpfilter: use 'userprogs' syntax to build bpfilter_umh samples: seccomp: build sample programs for target architecture kbuild: doc: document the new syntax 'userprogs' samples: uhid: build sample program for target architecture samples: hidraw: build sample program for target architecture samples: connector: build sample program for target architecture samples: vfs: build sample programs for target architecture samples: pidfd: build sample program for target architecture samples: mei: build sample program for target architecture samples: auxdisplay: use 'userprogs' syntax samples: timers: use 'userprogs' syntax samples: watchdog: use 'userprogs' syntax Sam Ravnborg (1): samples: uhid: fix warnings in uhid-example Documentation/kbuild/makefiles.rst | 183 +++++++++++++++++++++-------- Makefile | 13 +- init/Kconfig | 4 +- net/bpfilter/Makefile | 11 +- samples/Kconfig | 26 +++- samples/Makefile | 4 + samples/auxdisplay/Makefile | 11 +- samples/connector/Makefile | 12 +- samples/hidraw/Makefile | 9 +- samples/mei/Makefile | 9 +- samples/pidfd/Makefile | 8 +- samples/seccomp/Makefile | 42 +------ samples/timers/Makefile | 17 +-- samples/uhid/.gitignore | 2 + samples/uhid/Makefile | 9 +- samples/uhid/uhid-example.c | 4 +- samples/vfs/Makefile | 11 +- samples/watchdog/Makefile | 10 +- scripts/Makefile.build | 6 + scripts/Makefile.clean | 2 +- scripts/Makefile.userprogs | 45 +++++++ usr/include/Makefile | 4 + 22 files changed, 267 insertions(+), 175 deletions(-) create mode 100644 samples/uhid/.gitignore create mode 100644 scripts/Makefile.userprogs -- 2.25.1