samples/hid: fix broken vmlinux path for VMLINUX_BTF

Commit 13b25489b6f8 ("kbuild: change working directory to external
module directory with M=") changed kbuild working directory of hid-bpf
sample

samples/hid: fix broken vmlinux path for VMLINUX_BTF

Commit 13b25489b6f8 ("kbuild: change working directory to external
module directory with M=") changed kbuild working directory of hid-bpf
sample programs to samples/hid, which broke the vmlinux path for
VMLINUX_BTF, as the Makefiles assume the current work directory to be
the kernel output directory and use a relative path (i.e., ./vmlinux):

Makefile:173: *** Cannot find a vmlinux for VMLINUX_BTF at any of " /path/to/linux/samples/hid/vmlinux", build the kernel or set VMLINUX_BTF or VMLINUX_H variable. Stop.

Correctly refer to the kernel output directory using $(objtree).

Fixes: 13b25489b6f8 ("kbuild: change working directory to external module directory with M=")
Tested-by: Ruowen Qin <[email protected]>
Suggested-by: Daniel Borkmann <[email protected]>
Suggested-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Jinghao Jia <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Benjamin Tissoires <[email protected]>

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samples/hid: remove unnecessary -I flags from libbpf EXTRA_CFLAGS

Commit 5a6ea7022ff4 ("samples/bpf: Remove unnecessary -I flags from
libbpf EXTRA_CFLAGS") fixed the build error caused by redundant

samples/hid: remove unnecessary -I flags from libbpf EXTRA_CFLAGS

Commit 5a6ea7022ff4 ("samples/bpf: Remove unnecessary -I flags from
libbpf EXTRA_CFLAGS") fixed the build error caused by redundant include
path for samples/bpf, but not samples/hid.

Apply the same fix on samples/hid as well.

Fixes: 13b25489b6f8 ("kbuild: change working directory to external module directory with M=")
Tested-by: Ruowen Qin <[email protected]>
Signed-off-by: Jinghao Jia <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Benjamin Tissoires <[email protected]>

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HID: samples: convert the 2 HID-BPF samples into struct_ops

This is mostly mechanical: attach_prog is dropped, and
the SEC are converted into struct_ops.

Link: https://lore.kernel.org/r/20240608-hi

HID: samples: convert the 2 HID-BPF samples into struct_ops

This is mostly mechanical: attach_prog is dropped, and
the SEC are converted into struct_ops.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Benjamin Tissoires <[email protected]>

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kbuild: use $(src) instead of $(srctree)/$(src) for source directory

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention withou

kbuild: use $(src) instead of $(srctree)/$(src) for source directory

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:

src := $(obj)

When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.

This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.

To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.

Going forward, the variables used in Makefiles will have the following
meanings:

$(obj) - directory in the object tree
$(src) - directory in the source tree (changed by this commit)
$(objtree) - the top of the kernel object tree
$(srctree) - the top of the kernel source tree

Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nicolas Schier <[email protected]>

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bpf: Replace deprecated -target with --target= for Clang

The -target option has been deprecated since clang 3.4 in 2013. Therefore, use
the preferred --target=bpf form instead. This also matches how

bpf: Replace deprecated -target with --target= for Clang

The -target option has been deprecated since clang 3.4 in 2013. Therefore, use
the preferred --target=bpf form instead. This also matches how we use --target=
in scripts/Makefile.clang.

Signed-off-by: Fangrui Song <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Yonghong Song <[email protected]>
Acked-by: Quentin Monnet <[email protected]>
Link: https://github.com/llvm/llvm-project/commit/274b6f0c87a6a1798de0a68135afc7f95def6277
Link: https://lore.kernel.org/bpf/[email protected]

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samples/hid: add Surface Dial example

Add a more complete HID-BPF example.

Signed-off-by: Benjamin Tissoires <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

samples/hid: add new hid BPF example

Everything should be available in the selftest part of the tree, but
providing an example without uhid and hidraw will be more easy to
follow for users.

This ex

samples/hid: add new hid BPF example

Everything should be available in the selftest part of the tree, but
providing an example without uhid and hidraw will be more easy to
follow for users.

This example will probably ever only work on the Etekcity Scroll 6E
because we need to adapt the various raw values to the actual device.

On that device, the X and Y axis will be swapped and inverted, and on
any other device, chances are high that the device will not work until
Ctrl-C is hit.

The Makefiles are taken from samples/bpf to not reinvent the wheel and
to force using in-kernel libbpf and bpftool.

Signed-off-by: Benjamin Tissoires <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

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