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-rw-r--r--MAINTAINERS1
-rw-r--r--samples/hid/.gitignore7
-rw-r--r--samples/hid/Makefile246
-rw-r--r--samples/hid/Makefile.target75
-rw-r--r--samples/hid/hid_bpf_attach.bpf.c18
-rw-r--r--samples/hid/hid_bpf_attach.h14
-rw-r--r--samples/hid/hid_bpf_helpers.h19
-rw-r--r--samples/hid/hid_mouse.bpf.c112
-rw-r--r--samples/hid/hid_mouse.c155
9 files changed, 647 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS
index 81eb9abbc17a..76d8185c408e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9100,6 +9100,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git
F: drivers/hid/
F: include/linux/hid*
F: include/uapi/linux/hid*
+F: samples/hid/
F: tools/testing/selftests/hid/
HID LOGITECH DRIVERS
diff --git a/samples/hid/.gitignore b/samples/hid/.gitignore
new file mode 100644
index 000000000000..8cb45592e29a
--- /dev/null
+++ b/samples/hid/.gitignore
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+hid_mouse
+*.out
+*.skel.h
+/vmlinux.h
+/bpftool/
+/libbpf/
diff --git a/samples/hid/Makefile b/samples/hid/Makefile
new file mode 100644
index 000000000000..8fe6ccfc5f29
--- /dev/null
+++ b/samples/hid/Makefile
@@ -0,0 +1,246 @@
+# SPDX-License-Identifier: GPL-2.0
+
+HID_SAMPLES_PATH ?= $(abspath $(srctree)/$(src))
+TOOLS_PATH := $(HID_SAMPLES_PATH)/../../tools
+
+pound := \#
+
+# List of programs to build
+tprogs-y += hid_mouse
+
+# Libbpf dependencies
+LIBBPF_SRC = $(TOOLS_PATH)/lib/bpf
+LIBBPF_OUTPUT = $(abspath $(HID_SAMPLES_PATH))/libbpf
+LIBBPF_DESTDIR = $(LIBBPF_OUTPUT)
+LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include
+LIBBPF = $(LIBBPF_OUTPUT)/libbpf.a
+
+EXTRA_HEADERS := hid_bpf_attach.h
+EXTRA_BPF_HEADERS := hid_bpf_helpers.h
+
+hid_mouse-objs := hid_mouse.o
+
+# Tell kbuild to always build the programs
+always-y := $(tprogs-y)
+
+ifeq ($(ARCH), arm)
+# Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux
+# headers when arm instruction set identification is requested.
+ARM_ARCH_SELECTOR := $(filter -D__LINUX_ARM_ARCH__%, $(KBUILD_CFLAGS))
+BPF_EXTRA_CFLAGS := $(ARM_ARCH_SELECTOR)
+TPROGS_CFLAGS += $(ARM_ARCH_SELECTOR)
+endif
+
+ifeq ($(ARCH), mips)
+TPROGS_CFLAGS += -D__SANE_USERSPACE_TYPES__
+ifdef CONFIG_MACH_LOONGSON64
+BPF_EXTRA_CFLAGS += -I$(srctree)/arch/mips/include/asm/mach-loongson64
+BPF_EXTRA_CFLAGS += -I$(srctree)/arch/mips/include/asm/mach-generic
+endif
+endif
+
+TPROGS_CFLAGS += -Wall -O2
+TPROGS_CFLAGS += -Wmissing-prototypes
+TPROGS_CFLAGS += -Wstrict-prototypes
+
+TPROGS_CFLAGS += -I$(objtree)/usr/include
+TPROGS_CFLAGS += -I$(LIBBPF_INCLUDE)
+TPROGS_CFLAGS += -I$(srctree)/tools/include
+
+ifdef SYSROOT
+TPROGS_CFLAGS += --sysroot=$(SYSROOT)
+TPROGS_LDFLAGS := -L$(SYSROOT)/usr/lib
+endif
+
+TPROGS_LDLIBS += $(LIBBPF) -lelf -lz
+
+# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
+# make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang
+LLC ?= llc
+CLANG ?= clang
+OPT ?= opt
+LLVM_DIS ?= llvm-dis
+LLVM_OBJCOPY ?= llvm-objcopy
+LLVM_READELF ?= llvm-readelf
+BTF_PAHOLE ?= pahole
+
+# Detect that we're cross compiling and use the cross compiler
+ifdef CROSS_COMPILE
+CLANG_ARCH_ARGS = --target=$(notdir $(CROSS_COMPILE:%-=%))
+endif
+
+# Don't evaluate probes and warnings if we need to run make recursively
+ifneq ($(src),)
+HDR_PROBE := $(shell printf "$(pound)include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" | \
+ $(CC) $(TPROGS_CFLAGS) $(TPROGS_LDFLAGS) -x c - \
+ -o /dev/null 2>/dev/null && echo okay)
+
+ifeq ($(HDR_PROBE),)
+$(warning WARNING: Detected possible issues with include path.)
+$(warning WARNING: Please install kernel headers locally (make headers_install).)
+endif
+
+BTF_LLC_PROBE := $(shell $(LLC) -march=bpf -mattr=help 2>&1 | grep dwarfris)
+BTF_PAHOLE_PROBE := $(shell $(BTF_PAHOLE) --help 2>&1 | grep BTF)
+BTF_OBJCOPY_PROBE := $(shell $(LLVM_OBJCOPY) --help 2>&1 | grep -i 'usage.*llvm')
+BTF_LLVM_PROBE := $(shell echo "int main() { return 0; }" | \
+ $(CLANG) -target bpf -O2 -g -c -x c - -o ./llvm_btf_verify.o; \
+ $(LLVM_READELF) -S ./llvm_btf_verify.o | grep BTF; \
+ /bin/rm -f ./llvm_btf_verify.o)
+
+BPF_EXTRA_CFLAGS += -fno-stack-protector
+ifneq ($(BTF_LLVM_PROBE),)
+ BPF_EXTRA_CFLAGS += -g
+else
+ifneq ($(and $(BTF_LLC_PROBE),$(BTF_PAHOLE_PROBE),$(BTF_OBJCOPY_PROBE)),)
+ BPF_EXTRA_CFLAGS += -g
+ LLC_FLAGS += -mattr=dwarfris
+ DWARF2BTF = y
+endif
+endif
+endif
+
+# Trick to allow make to be run from this directory
+all:
+ $(MAKE) -C ../../ M=$(CURDIR) HID_SAMPLES_PATH=$(CURDIR)
+
+clean:
+ $(MAKE) -C ../../ M=$(CURDIR) clean
+ @find $(CURDIR) -type f -name '*~' -delete
+ @$(RM) -r $(CURDIR)/libbpf $(CURDIR)/bpftool
+
+$(LIBBPF): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUTPUT)
+# Fix up variables inherited from Kbuild that tools/ build system won't like
+ $(MAKE) -C $(LIBBPF_SRC) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \
+ LDFLAGS=$(TPROGS_LDFLAGS) srctree=$(HID_SAMPLES_PATH)/../../ \
+ O= OUTPUT=$(LIBBPF_OUTPUT)/ DESTDIR=$(LIBBPF_DESTDIR) prefix= \
+ $@ install_headers
+
+BPFTOOLDIR := $(TOOLS_PATH)/bpf/bpftool
+BPFTOOL_OUTPUT := $(abspath $(HID_SAMPLES_PATH))/bpftool
+BPFTOOL := $(BPFTOOL_OUTPUT)/bootstrap/bpftool
+$(BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) | $(BPFTOOL_OUTPUT)
+ $(MAKE) -C $(BPFTOOLDIR) srctree=$(HID_SAMPLES_PATH)/../../ \
+ OUTPUT=$(BPFTOOL_OUTPUT)/ bootstrap
+
+$(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT):
+ $(call msg,MKDIR,$@)
+ $(Q)mkdir -p $@
+
+FORCE:
+
+
+# Verify LLVM compiler tools are available and bpf target is supported by llc
+.PHONY: verify_cmds verify_target_bpf $(CLANG) $(LLC)
+
+verify_cmds: $(CLANG) $(LLC)
+ @for TOOL in $^ ; do \
+ if ! (which -- "$${TOOL}" > /dev/null 2>&1); then \
+ echo "*** ERROR: Cannot find LLVM tool $${TOOL}" ;\
+ exit 1; \
+ else true; fi; \
+ done
+
+verify_target_bpf: verify_cmds
+ @if ! (${LLC} -march=bpf -mattr=help > /dev/null 2>&1); then \
+ echo "*** ERROR: LLVM (${LLC}) does not support 'bpf' target" ;\
+ echo " NOTICE: LLVM version >= 3.7.1 required" ;\
+ exit 2; \
+ else true; fi
+
+$(HID_SAMPLES_PATH)/*.c: verify_target_bpf $(LIBBPF)
+$(src)/*.c: verify_target_bpf $(LIBBPF)
+
+libbpf_hdrs: $(LIBBPF)
+
+.PHONY: libbpf_hdrs
+
+$(obj)/hid_mouse.o: $(obj)/hid_mouse.skel.h
+
+-include $(HID_SAMPLES_PATH)/Makefile.target
+
+VMLINUX_BTF_PATHS ?= $(abspath $(if $(O),$(O)/vmlinux)) \
+ $(abspath $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)) \
+ $(abspath ./vmlinux)
+VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
+
+$(obj)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL)
+ifeq ($(VMLINUX_H),)
+ifeq ($(VMLINUX_BTF),)
+ $(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)",\
+ build the kernel or set VMLINUX_BTF or VMLINUX_H variable)
+endif
+ $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
+else
+ $(Q)cp "$(VMLINUX_H)" $@
+endif
+
+clean-files += vmlinux.h
+
+# Get Clang's default includes on this system, as opposed to those seen by
+# '-target bpf'. This fixes "missing" files on some architectures/distros,
+# such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc.
+#
+# Use '-idirafter': Don't interfere with include mechanics except where the
+# build would have failed anyways.
+define get_sys_includes
+$(shell $(1) -v -E - </dev/null 2>&1 \
+ | sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }') \
+$(shell $(1) -dM -E - </dev/null | grep '#define __riscv_xlen ' | sed 's/#define /-D/' | sed 's/ /=/')
+endef
+
+CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))
+
+EXTRA_BPF_HEADERS_SRC := $(addprefix $(src)/,$(EXTRA_BPF_HEADERS))
+
+$(obj)/%.bpf.o: $(src)/%.bpf.c $(EXTRA_BPF_HEADERS_SRC) $(obj)/vmlinux.h
+ @echo " CLANG-BPF " $@
+ $(Q)$(CLANG) -g -O2 -target bpf -D__TARGET_ARCH_$(SRCARCH) \
+ -Wno-compare-distinct-pointer-types -I$(srctree)/include \
+ -I$(srctree)/samples/bpf -I$(srctree)/tools/include \
+ -I$(LIBBPF_INCLUDE) $(CLANG_SYS_INCLUDES) \
+ -c $(filter %.bpf.c,$^) -o $@
+
+LINKED_SKELS := hid_mouse.skel.h
+clean-files += $(LINKED_SKELS)
+
+hid_mouse.skel.h-deps := hid_mouse.bpf.o hid_bpf_attach.bpf.o
+
+LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.bpf.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps)))
+
+BPF_SRCS_LINKED := $(notdir $(wildcard $(src)/*.bpf.c))
+BPF_OBJS_LINKED := $(patsubst %.bpf.c,$(obj)/%.bpf.o, $(BPF_SRCS_LINKED))
+BPF_SKELS_LINKED := $(addprefix $(obj)/,$(LINKED_SKELS))
+
+$(BPF_SKELS_LINKED): $(BPF_OBJS_LINKED) $(BPFTOOL)
+ @echo " BPF GEN-OBJ " $(@:.skel.h=)
+ $(Q)$(BPFTOOL) gen object $(@:.skel.h=.lbpf.o) $(addprefix $(obj)/,$($(@F)-deps))
+ @echo " BPF GEN-SKEL" $(@:.skel.h=)
+ $(Q)$(BPFTOOL) gen skeleton $(@:.skel.h=.lbpf.o) name $(notdir $(@:.skel.h=)) > $@
+
+# asm/sysreg.h - inline assembly used by it is incompatible with llvm.
+# But, there is no easy way to fix it, so just exclude it since it is
+# useless for BPF samples.
+# below we use long chain of commands, clang | opt | llvm-dis | llc,
+# to generate final object file. 'clang' compiles the source into IR
+# with native target, e.g., x64, arm64, etc. 'opt' does bpf CORE IR builtin
+# processing (llvm12) and IR optimizations. 'llvm-dis' converts
+# 'opt' output to IR, and finally 'llc' generates bpf byte code.
+$(obj)/%.o: $(src)/%.c
+ @echo " CLANG-bpf " $@
+ $(Q)$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(BPF_EXTRA_CFLAGS) \
+ -I$(obj) -I$(srctree)/tools/testing/selftests/bpf/ \
+ -I$(LIBBPF_INCLUDE) \
+ -D__KERNEL__ -D__BPF_TRACING__ -Wno-unused-value -Wno-pointer-sign \
+ -D__TARGET_ARCH_$(SRCARCH) -Wno-compare-distinct-pointer-types \
+ -Wno-gnu-variable-sized-type-not-at-end \
+ -Wno-address-of-packed-member -Wno-tautological-compare \
+ -Wno-unknown-warning-option $(CLANG_ARCH_ARGS) \
+ -fno-asynchronous-unwind-tables \
+ -I$(srctree)/samples/hid/ \
+ -O2 -emit-llvm -Xclang -disable-llvm-passes -c $< -o - | \
+ $(OPT) -O2 -mtriple=bpf-pc-linux | $(LLVM_DIS) | \
+ $(LLC) -march=bpf $(LLC_FLAGS) -filetype=obj -o $@
+ifeq ($(DWARF2BTF),y)
+ $(BTF_PAHOLE) -J $@
+endif
diff --git a/samples/hid/Makefile.target b/samples/hid/Makefile.target
new file mode 100644
index 000000000000..7621f55e2947
--- /dev/null
+++ b/samples/hid/Makefile.target
@@ -0,0 +1,75 @@
+# SPDX-License-Identifier: GPL-2.0
+# ==========================================================================
+# Building binaries on the host system
+# Binaries are not used during the compilation of the kernel, and intended
+# to be build for target board, target board can be host of course. Added to
+# build binaries to run not on host system.
+#
+# Sample syntax
+# tprogs-y := xsk_example
+# Will compile xsk_example.c and create an executable named xsk_example
+#
+# tprogs-y := xdpsock
+# xdpsock-objs := xdpsock_1.o xdpsock_2.o
+# Will compile xdpsock_1.c and xdpsock_2.c, and then link the executable
+# xdpsock, based on xdpsock_1.o and xdpsock_2.o
+#
+# Derived from scripts/Makefile.host
+#
+__tprogs := $(sort $(tprogs-y))
+
+# C code
+# Executables compiled from a single .c file
+tprog-csingle := $(foreach m,$(__tprogs), \
+ $(if $($(m)-objs),,$(m)))
+
+# C executables linked based on several .o files
+tprog-cmulti := $(foreach m,$(__tprogs),\
+ $(if $($(m)-objs),$(m)))
+
+# Object (.o) files compiled from .c files
+tprog-cobjs := $(sort $(foreach m,$(__tprogs),$($(m)-objs)))
+
+tprog-csingle := $(addprefix $(obj)/,$(tprog-csingle))
+tprog-cmulti := $(addprefix $(obj)/,$(tprog-cmulti))
+tprog-cobjs := $(addprefix $(obj)/,$(tprog-cobjs))
+
+#####
+# Handle options to gcc. Support building with separate output directory
+
+_tprogc_flags = $(TPROGS_CFLAGS) \
+ $(TPROGCFLAGS_$(basetarget).o)
+
+# $(objtree)/$(obj) for including generated headers from checkin source files
+ifeq ($(KBUILD_EXTMOD),)
+ifdef building_out_of_srctree
+_tprogc_flags += -I $(objtree)/$(obj)
+endif
+endif
+
+tprogc_flags = -Wp,-MD,$(depfile) $(_tprogc_flags)
+
+# Create executable from a single .c file
+# tprog-csingle -> Executable
+quiet_cmd_tprog-csingle = CC $@
+ cmd_tprog-csingle = $(CC) $(tprogc_flags) $(TPROGS_LDFLAGS) -o $@ $< \
+ $(TPROGS_LDLIBS) $(TPROGLDLIBS_$(@F))
+$(tprog-csingle): $(obj)/%: $(src)/%.c FORCE
+ $(call if_changed_dep,tprog-csingle)
+
+# Link an executable based on list of .o files, all plain c
+# tprog-cmulti -> executable
+quiet_cmd_tprog-cmulti = LD $@
+ cmd_tprog-cmulti = $(CC) $(tprogc_flags) $(TPROGS_LDFLAGS) -o $@ \
+ $(addprefix $(obj)/,$($(@F)-objs)) \
+ $(TPROGS_LDLIBS) $(TPROGLDLIBS_$(@F))
+$(tprog-cmulti): $(tprog-cobjs) FORCE
+ $(call if_changed,tprog-cmulti)
+$(call multi_depend, $(tprog-cmulti), , -objs)
+
+# Create .o file from a single .c file
+# tprog-cobjs -> .o
+quiet_cmd_tprog-cobjs = CC $@
+ cmd_tprog-cobjs = $(CC) $(tprogc_flags) -c -o $@ $<
+$(tprog-cobjs): $(obj)/%.o: $(src)/%.c FORCE
+ $(call if_changed_dep,tprog-cobjs)
diff --git a/samples/hid/hid_bpf_attach.bpf.c b/samples/hid/hid_bpf_attach.bpf.c
new file mode 100644
index 000000000000..d4dce4ea7c6e
--- /dev/null
+++ b/samples/hid/hid_bpf_attach.bpf.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2022 Benjamin Tissoires
+ */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "hid_bpf_attach.h"
+#include "hid_bpf_helpers.h"
+
+SEC("syscall")
+int attach_prog(struct attach_prog_args *ctx)
+{
+ ctx->retval = hid_bpf_attach_prog(ctx->hid,
+ ctx->prog_fd,
+ 0);
+ return 0;
+}
diff --git a/samples/hid/hid_bpf_attach.h b/samples/hid/hid_bpf_attach.h
new file mode 100644
index 000000000000..35bb28b49264
--- /dev/null
+++ b/samples/hid/hid_bpf_attach.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (c) 2022 Benjamin Tissoires
+ */
+
+#ifndef __HID_BPF_ATTACH_H
+#define __HID_BPF_ATTACH_H
+
+struct attach_prog_args {
+ int prog_fd;
+ unsigned int hid;
+ int retval;
+};
+
+#endif /* __HID_BPF_ATTACH_H */
diff --git a/samples/hid/hid_bpf_helpers.h b/samples/hid/hid_bpf_helpers.h
new file mode 100644
index 000000000000..c555aeef5e37
--- /dev/null
+++ b/samples/hid/hid_bpf_helpers.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (c) 2022 Benjamin Tissoires
+ */
+
+#ifndef __HID_BPF_HELPERS_H
+#define __HID_BPF_HELPERS_H
+
+/* following are kfuncs exported by HID for HID-BPF */
+extern __u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx,
+ unsigned int offset,
+ const size_t __sz) __ksym;
+extern int hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, u32 flags) __ksym;
+extern int hid_bpf_hw_request(struct hid_bpf_ctx *ctx,
+ __u8 *data,
+ size_t buf__sz,
+ enum hid_report_type type,
+ enum hid_class_request reqtype) __ksym;
+
+#endif /* __HID_BPF_HELPERS_H */
diff --git a/samples/hid/hid_mouse.bpf.c b/samples/hid/hid_mouse.bpf.c
new file mode 100644
index 000000000000..7c8b453ccb16
--- /dev/null
+++ b/samples/hid/hid_mouse.bpf.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "hid_bpf_helpers.h"
+
+SEC("fmod_ret/hid_bpf_device_event")
+int BPF_PROG(hid_y_event, struct hid_bpf_ctx *hctx)
+{
+ s16 y;
+ __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */);
+
+ if (!data)
+ return 0; /* EPERM check */
+
+ bpf_printk("event: size: %d", hctx->size);
+ bpf_printk("incoming event: %02x %02x %02x",
+ data[0],
+ data[1],
+ data[2]);
+ bpf_printk(" %02x %02x %02x",
+ data[3],
+ data[4],
+ data[5]);
+ bpf_printk(" %02x %02x %02x",
+ data[6],
+ data[7],
+ data[8]);
+
+ y = data[3] | (data[4] << 8);
+
+ y = -y;
+
+ data[3] = y & 0xFF;
+ data[4] = (y >> 8) & 0xFF;
+
+ bpf_printk("modified event: %02x %02x %02x",
+ data[0],
+ data[1],
+ data[2]);
+ bpf_printk(" %02x %02x %02x",
+ data[3],
+ data[4],
+ data[5]);
+ bpf_printk(" %02x %02x %02x",
+ data[6],
+ data[7],
+ data[8]);
+
+ return 0;
+}
+
+SEC("fmod_ret/hid_bpf_device_event")
+int BPF_PROG(hid_x_event, struct hid_bpf_ctx *hctx)
+{
+ s16 x;
+ __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */);
+
+ if (!data)
+ return 0; /* EPERM check */
+
+ x = data[1] | (data[2] << 8);
+
+ x = -x;
+
+ data[1] = x & 0xFF;
+ data[2] = (x >> 8) & 0xFF;
+ return 0;
+}
+
+SEC("fmod_ret/hid_bpf_rdesc_fixup")
+int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hctx)
+{
+ __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */);
+
+ if (!data)
+ return 0; /* EPERM check */
+
+ bpf_printk("rdesc: %02x %02x %02x",
+ data[0],
+ data[1],
+ data[2]);
+ bpf_printk(" %02x %02x %02x",
+ data[3],
+ data[4],
+ data[5]);
+ bpf_printk(" %02x %02x %02x ...",
+ data[6],
+ data[7],
+ data[8]);
+
+ /*
+ * The original report descriptor contains:
+ *
+ * 0x05, 0x01, // Usage Page (Generic Desktop) 30
+ * 0x16, 0x01, 0x80, // Logical Minimum (-32767) 32
+ * 0x26, 0xff, 0x7f, // Logical Maximum (32767) 35
+ * 0x09, 0x30, // Usage (X) 38
+ * 0x09, 0x31, // Usage (Y) 40
+ *
+ * So byte 39 contains Usage X and byte 41 Usage Y.
+ *
+ * We simply swap the axes here.
+ */
+ data[39] = 0x31;
+ data[41] = 0x30;
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/samples/hid/hid_mouse.c b/samples/hid/hid_mouse.c
new file mode 100644
index 000000000000..018f1185f203
--- /dev/null
+++ b/samples/hid/hid_mouse.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2022 Benjamin Tissoires
+ *
+ * This is a pure HID-BPF example, and should be considered as such:
+ * on the Etekcity Scroll 6E, the X and Y axes will be swapped and
+ * inverted. On any other device... Not sure what this will do.
+ *
+ * This C main file is generic though. To adapt the code and test, users
+ * must amend only the .bpf.c file, which this program will load any
+ * eBPF program it finds.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <libgen.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <unistd.h>
+
+#include <linux/bpf.h>
+#include <linux/errno.h>
+
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "hid_mouse.skel.h"
+#include "hid_bpf_attach.h"
+
+static bool running = true;
+
+static void int_exit(int sig)
+{
+ running = false;
+ exit(0);
+}
+
+static void usage(const char *prog)
+{
+ fprintf(stderr,
+ "%s: %s /sys/bus/hid/devices/0BUS:0VID:0PID:00ID\n\n",
+ __func__, prog);
+ fprintf(stderr,
+ "This program will upload and attach a HID-BPF program to the given device.\n"
+ "On the Etekcity Scroll 6E, the X and Y axis will be inverted, but on any other\n"
+ "device, chances are high that the device will not be working anymore\n\n"
+ "consider this as a demo and adapt the eBPF program to your needs\n"
+ "Hit Ctrl-C to unbind the program and reset the device\n");
+}
+
+static int get_hid_id(const char *path)
+{
+ const char *str_id, *dir;
+ char uevent[1024];
+ int fd;
+
+ memset(uevent, 0, sizeof(uevent));
+ snprintf(uevent, sizeof(uevent) - 1, "%s/uevent", path);
+
+ fd = open(uevent, O_RDONLY | O_NONBLOCK);
+ if (fd < 0)
+ return -ENOENT;
+
+ close(fd);
+
+ dir = basename((char *)path);
+
+ str_id = dir + sizeof("0003:0001:0A37.");
+ return (int)strtol(str_id, NULL, 16);
+}
+
+int main(int argc, char **argv)
+{
+ struct hid_mouse *skel;
+ struct bpf_program *prog;
+ int err;
+ const char *optstr = "";
+ const char *sysfs_path;
+ int opt, hid_id, attach_fd;
+ struct attach_prog_args args = {
+ .retval = -1,
+ };
+ DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr,
+ .ctx_in = &args,
+ .ctx_size_in = sizeof(args),
+ );
+
+ while ((opt = getopt(argc, argv, optstr)) != -1) {
+ switch (opt) {
+ default:
+ usage(basename(argv[0]));
+ return 1;
+ }
+ }
+
+ if (optind == argc) {
+ usage(basename(argv[0]));
+ return 1;
+ }
+
+ sysfs_path = argv[optind];
+ if (!sysfs_path) {
+ perror("sysfs");
+ return 1;
+ }
+
+ skel = hid_mouse__open_and_load();
+ if (!skel) {
+ fprintf(stderr, "%s %s:%d", __func__, __FILE__, __LINE__);
+ return -1;
+ }
+
+ hid_id = get_hid_id(sysfs_path);
+
+ if (hid_id < 0) {
+ fprintf(stderr, "can not open HID device: %m\n");
+ return 1;
+ }
+ args.hid = hid_id;
+
+ attach_fd = bpf_program__fd(skel->progs.attach_prog);
+ if (attach_fd < 0) {
+ fprintf(stderr, "can't locate attach prog: %m\n");
+ return 1;
+ }
+
+ bpf_object__for_each_program(prog, *skel->skeleton->obj) {
+ /* ignore syscalls */
+ if (bpf_program__get_type(prog) != BPF_PROG_TYPE_TRACING)
+ continue;
+
+ args.retval = -1;
+ args.prog_fd = bpf_program__fd(prog);
+ err = bpf_prog_test_run_opts(attach_fd, &tattr);
+ if (err) {
+ fprintf(stderr, "can't attach prog to hid device %d: %m (err: %d)\n",
+ hid_id, err);
+ return 1;
+ }
+ }
+
+ signal(SIGINT, int_exit);
+ signal(SIGTERM, int_exit);
+
+ while (running)
+ sleep(1);
+
+ hid_mouse__destroy(skel);
+
+ return 0;
+}
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