forked from luck/tmp_suning_uos_patched
fca5e94921
Even after commitc624adc9cb("samples: fix binderfs sample"), this sample is never compiled. 'hostprogs' teaches Kbuild that this is a host program, but not enough to order to compile it. You must add it to 'always-y' to really compile it. Since this sample has never been compiled in upstream, various issues are left unnoticed. [1] compilers without <linux/android/binderfs.h> are still widely used <linux/android/binderfs.h> is only available since commitc13295ad21("binderfs: rename header to binderfs.h"), i.e., Linux 5.0 If your compiler is based on UAPI headers older than Linux 5.0, you will see the following error: samples/binderfs/binderfs_example.c:16:10: fatal error: linux/android/binderfs.h: No such file or directory #include <linux/android/binderfs.h> ^~~~~~~~~~~~~~~~~~~~~~~~~~ compilation terminated. You cannot rely on compilers having such a new header. The common approach is to install UAPI headers of this kernel into usr/include, and then add it to the header search path. I added 'depends on HEADERS_INSTALL' in Kconfig, and '-I usr/include' compiler flag in Makefile. [2] compile the sample for target architecture Because headers_install works for the target architecture, only the native compiler was able to build sample code that requires '-I usr/include'. Commit7f3a59db27("kbuild: add infrastructure to build userspace programs") added the new syntax 'userprogs' to compile user-space programs for the target architecture. Use it, and then 'ifndef CROSS_COMPILE' will go away. I added 'depends on CC_CAN_LINK' because $(CC) is not necessarily capable of linking user-space programs. [3] use subdir-y to descend into samples/binderfs Since this directory does not contain any kernel-space code, it has no point in generating built-in.a or modules.order. Replace obj-$(CONFIG_...) with subdir-$(CONFIG_...). [4] -Wunused-variable warning If I compile this, I see the following warning. samples/binderfs/binderfs_example.c: In function 'main': samples/binderfs/binderfs_example.c:21:9: warning: unused variable 'len' [-Wunused-variable] 21 | size_t len; | ^~~ I removed the unused 'len'. [5] CONFIG_ANDROID_BINDERFS is not required Since this is a user-space standalone program, it is independent of the kernel configuration. Remove 'depends on ANDROID_BINDERFS'. Fixes:9762dc1432("samples: add binderfs sample program") Fixes:c624adc9cb("samples: fix binderfs sample") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
30 lines
1.2 KiB
Makefile
30 lines
1.2 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# Makefile for Linux samples code
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subdir-$(CONFIG_SAMPLE_AUXDISPLAY) += auxdisplay
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subdir-$(CONFIG_SAMPLE_ANDROID_BINDERFS) += binderfs
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obj-$(CONFIG_SAMPLE_CONFIGFS) += configfs/
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obj-$(CONFIG_SAMPLE_CONNECTOR) += connector/
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subdir-$(CONFIG_SAMPLE_HIDRAW) += hidraw
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obj-$(CONFIG_SAMPLE_HW_BREAKPOINT) += hw_breakpoint/
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obj-$(CONFIG_SAMPLE_KDB) += kdb/
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obj-$(CONFIG_SAMPLE_KFIFO) += kfifo/
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obj-$(CONFIG_SAMPLE_KOBJECT) += kobject/
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obj-$(CONFIG_SAMPLE_KPROBES) += kprobes/
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obj-$(CONFIG_SAMPLE_LIVEPATCH) += livepatch/
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subdir-$(CONFIG_SAMPLE_PIDFD) += pidfd
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obj-$(CONFIG_SAMPLE_QMI_CLIENT) += qmi/
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obj-$(CONFIG_SAMPLE_RPMSG_CLIENT) += rpmsg/
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subdir-$(CONFIG_SAMPLE_SECCOMP) += seccomp
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subdir-$(CONFIG_SAMPLE_TIMER) += timers
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obj-$(CONFIG_SAMPLE_TRACE_EVENTS) += trace_events/
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obj-$(CONFIG_SAMPLE_TRACE_PRINTK) += trace_printk/
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obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace/
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obj-$(CONFIG_SAMPLE_TRACE_ARRAY) += ftrace/
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subdir-$(CONFIG_SAMPLE_UHID) += uhid
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obj-$(CONFIG_VIDEO_PCI_SKELETON) += v4l/
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obj-y += vfio-mdev/
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subdir-$(CONFIG_SAMPLE_VFS) += vfs
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obj-$(CONFIG_SAMPLE_INTEL_MEI) += mei/
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subdir-$(CONFIG_SAMPLE_WATCHDOG) += watchdog
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