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37 files changed, 4682 insertions, 9 deletions
diff --git a/Documentation/hid/hid-bpf.rst b/Documentation/hid/hid-bpf.rst new file mode 100644 index 000000000000..a55f191d49a3 --- /dev/null +++ b/Documentation/hid/hid-bpf.rst @@ -0,0 +1,512 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======= +HID-BPF +======= + +HID is a standard protocol for input devices but some devices may require +custom tweaks, traditionally done with a kernel driver fix. Using the eBPF +capabilities instead speeds up development and adds new capabilities to the +existing HID interfaces. + +.. contents:: + :local: + :depth: 2 + + +When (and why) to use HID-BPF +============================= + +There are several use cases when using HID-BPF is better +than standard kernel driver fix: + +Dead zone of a joystick +----------------------- + +Assuming you have a joystick that is getting older, it is common to see it +wobbling around its neutral point. This is usually filtered at the application +level by adding a *dead zone* for this specific axis. + +With HID-BPF, we can apply this filtering in the kernel directly so userspace +does not get woken up when nothing else is happening on the input controller. + +Of course, given that this dead zone is specific to an individual device, we +can not create a generic fix for all of the same joysticks. Adding a custom +kernel API for this (e.g. by adding a sysfs entry) does not guarantee this new +kernel API will be broadly adopted and maintained. + +HID-BPF allows the userspace program to load the program itself, ensuring we +only load the custom API when we have a user. + +Simple fixup of report descriptor +--------------------------------- + +In the HID tree, half of the drivers only fix one key or one byte +in the report descriptor. These fixes all require a kernel patch and the +subsequent shepherding into a release, a long and painful process for users. + +We can reduce this burden by providing an eBPF program instead. Once such a +program has been verified by the user, we can embed the source code into the +kernel tree and ship the eBPF program and load it directly instead of loading +a specific kernel module for it. + +Note: distribution of eBPF programs and their inclusion in the kernel is not +yet fully implemented + +Add a new feature that requires a new kernel API +------------------------------------------------ + +An example for such a feature are the Universal Stylus Interface (USI) pens. +Basically, USI pens require a new kernel API because there are new +channels of communication that our HID and input stack do not support. +Instead of using hidraw or creating new sysfs entries or ioctls, we can rely +on eBPF to have the kernel API controlled by the consumer and to not +impact the performances by waking up userspace every time there is an +event. + +Morph a device into something else and control that from userspace +------------------------------------------------------------------ + +The kernel has a relatively static mapping of HID items to evdev bits. +It cannot decide to dynamically transform a given device into something else +as it does not have the required context and any such transformation cannot be +undone (or even discovered) by userspace. + +However, some devices are useless with that static way of defining devices. For +example, the Microsoft Surface Dial is a pushbutton with haptic feedback that +is barely usable as of today. + +With eBPF, userspace can morph that device into a mouse, and convert the dial +events into wheel events. Also, the userspace program can set/unset the haptic +feedback depending on the context. For example, if a menu is visible on the +screen we likely need to have a haptic click every 15 degrees. But when +scrolling in a web page the user experience is better when the device emits +events at the highest resolution. + +Firewall +-------- + +What if we want to prevent other users to access a specific feature of a +device? (think a possibly broken firmware update entry point) + +With eBPF, we can intercept any HID command emitted to the device and +validate it or not. + +This also allows to sync the state between the userspace and the +kernel/bpf program because we can intercept any incoming command. + +Tracing +------- + +The last usage is tracing events and all the fun we can do we BPF to summarize +and analyze events. + +Right now, tracing relies on hidraw. It works well except for a couple +of issues: + +1. if the driver doesn't export a hidraw node, we can't trace anything + (eBPF will be a "god-mode" there, so this may raise some eyebrows) +2. hidraw doesn't catch other processes' requests to the device, which + means that we have cases where we need to add printks to the kernel + to understand what is happening. + +High-level view of HID-BPF +========================== + +The main idea behind HID-BPF is that it works at an array of bytes level. +Thus, all of the parsing of the HID report and the HID report descriptor +must be implemented in the userspace component that loads the eBPF +program. + +For example, in the dead zone joystick from above, knowing which fields +in the data stream needs to be set to ``0`` needs to be computed by userspace. + +A corollary of this is that HID-BPF doesn't know about the other subsystems +available in the kernel. *You can not directly emit input event through the +input API from eBPF*. + +When a BPF program needs to emit input events, it needs to talk with the HID +protocol, and rely on the HID kernel processing to translate the HID data into +input events. + +Available types of programs +=========================== + +HID-BPF is built "on top" of BPF, meaning that we use tracing method to +declare our programs. + +HID-BPF has the following attachment types available: + +1. event processing/filtering with ``SEC("fmod_ret/hid_bpf_device_event")`` in libbpf +2. actions coming from userspace with ``SEC("syscall")`` in libbpf +3. change of the report descriptor with ``SEC("fmod_ret/hid_bpf_rdesc_fixup")`` in libbpf + +A ``hid_bpf_device_event`` is calling a BPF program when an event is received from +the device. Thus we are in IRQ context and can act on the data or notify userspace. +And given that we are in IRQ context, we can not talk back to the device. + +A ``syscall`` means that userspace called the syscall ``BPF_PROG_RUN`` facility. +This time, we can do any operations allowed by HID-BPF, and talking to the device is +allowed. + +Last, ``hid_bpf_rdesc_fixup`` is different from the others as there can be only one +BPF program of this type. This is called on ``probe`` from the driver and allows to +change the report descriptor from the BPF program. Once a ``hid_bpf_rdesc_fixup`` +program has been loaded, it is not possible to overwrite it unless the program which +inserted it allows us by pinning the program and closing all of its fds pointing to it. + +Developer API: +============== + +User API data structures available in programs: +----------------------------------------------- + +.. kernel-doc:: include/linux/hid_bpf.h + +Available tracing functions to attach a HID-BPF program: +-------------------------------------------------------- + +.. kernel-doc:: drivers/hid/bpf/hid_bpf_dispatch.c + :functions: hid_bpf_device_event hid_bpf_rdesc_fixup + +Available API that can be used in all HID-BPF programs: +------------------------------------------------------- + +.. kernel-doc:: drivers/hid/bpf/hid_bpf_dispatch.c + :functions: hid_bpf_get_data + +Available API that can be used in syscall HID-BPF programs: +----------------------------------------------------------- + +.. kernel-doc:: drivers/hid/bpf/hid_bpf_dispatch.c + :functions: hid_bpf_attach_prog hid_bpf_hw_request hid_bpf_allocate_context hid_bpf_release_context + +General overview of a HID-BPF program +===================================== + +Accessing the data attached to the context +------------------------------------------ + +The ``struct hid_bpf_ctx`` doesn't export the ``data`` fields directly and to access +it, a bpf program needs to first call :c:func:`hid_bpf_get_data`. + +``offset`` can be any integer, but ``size`` needs to be constant, known at compile +time. + +This allows the following: + +1. for a given device, if we know that the report length will always be of a certain value, + we can request the ``data`` pointer to point at the full report length. + + The kernel will ensure we are using a correct size and offset and eBPF will ensure + the code will not attempt to read or write outside of the boundaries:: + + __u8 *data = hid_bpf_get_data(ctx, 0 /* offset */, 256 /* size */); + + if (!data) + return 0; /* ensure data is correct, now the verifier knows we + * have 256 bytes available */ + + bpf_printk("hello world: %02x %02x %02x", data[0], data[128], data[255]); + +2. if the report length is variable, but we know the value of ``X`` is always a 16-bit + integer, we can then have a pointer to that value only:: + + __u16 *x = hid_bpf_get_data(ctx, offset, sizeof(*x)); + + if (!x) + return 0; /* something went wrong */ + + *x += 1; /* increment X by one */ + +Effect of a HID-BPF program +--------------------------- + +For all HID-BPF attachment types except for :c:func:`hid_bpf_rdesc_fixup`, several eBPF +programs can be attached to the same device. + +Unless ``HID_BPF_FLAG_INSERT_HEAD`` is added to the flags while attaching the +program, the new program is appended at the end of the list. +``HID_BPF_FLAG_INSERT_HEAD`` will insert the new program at the beginning of the +list which is useful for e.g. tracing where we need to get the unprocessed events +from the device. + +Note that if there are multiple programs using the ``HID_BPF_FLAG_INSERT_HEAD`` flag, +only the most recently loaded one is actually the first in the list. + +``SEC("fmod_ret/hid_bpf_device_event")`` +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Whenever a matching event is raised, the eBPF programs are called one after the other +and are working on the same data buffer. + +If a program changes the data associated with the context, the next one will see +the modified data but it will have *no* idea of what the original data was. + +Once all the programs are run and return ``0`` or a positive value, the rest of the +HID stack will work on the modified data, with the ``size`` field of the last hid_bpf_ctx +being the new size of the input stream of data. + +A BPF program returning a negative error discards the event, i.e. this event will not be +processed by the HID stack. Clients (hidraw, input, LEDs) will **not** see this event. + +``SEC("syscall")`` +~~~~~~~~~~~~~~~~~~ + +``syscall`` are not attached to a given device. To tell which device we are working +with, userspace needs to refer to the device by its unique system id (the last 4 numbers +in the sysfs path: ``/sys/bus/hid/devices/xxxx:yyyy:zzzz:0000``). + +To retrieve a context associated with the device, the program must call +:c:func:`hid_bpf_allocate_context` and must release it with :c:func:`hid_bpf_release_context` +before returning. +Once the context is retrieved, one can also request a pointer to kernel memory with +:c:func:`hid_bpf_get_data`. This memory is big enough to support all input/output/feature +reports of the given device. + +``SEC("fmod_ret/hid_bpf_rdesc_fixup")`` +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The ``hid_bpf_rdesc_fixup`` program works in a similar manner to +``.report_fixup`` of ``struct hid_driver``. + +When the device is probed, the kernel sets the data buffer of the context with the +content of the report descriptor. The memory associated with that buffer is +``HID_MAX_DESCRIPTOR_SIZE`` (currently 4kB). + +The eBPF program can modify the data buffer at-will and the kernel uses the +modified content and size as the report descriptor. + +Whenever a ``SEC("fmod_ret/hid_bpf_rdesc_fixup")`` program is attached (if no +program was attached before), the kernel immediately disconnects the HID device +and does a reprobe. + +In the same way, when the ``SEC("fmod_ret/hid_bpf_rdesc_fixup")`` program is +detached, the kernel issues a disconnect on the device. + +There is no ``detach`` facility in HID-BPF. Detaching a program happens when +all the user space file descriptors pointing at a program are closed. +Thus, if we need to replace a report descriptor fixup, some cooperation is +required from the owner of the original report descriptor fixup. +The previous owner will likely pin the program in the bpffs, and we can then +replace it through normal bpf operations. + +Attaching a bpf program to a device +=================================== + +``libbpf`` does not export any helper to attach a HID-BPF program. +Users need to use a dedicated ``syscall`` program which will call +``hid_bpf_attach_prog(hid_id, program_fd, flags)``. + +``hid_id`` is the unique system ID of the HID device (the last 4 numbers in the +sysfs path: ``/sys/bus/hid/devices/xxxx:yyyy:zzzz:0000``) + +``progam_fd`` is the opened file descriptor of the program to attach. + +``flags`` is of type ``enum hid_bpf_attach_flags``. + +We can not rely on hidraw to bind a BPF program to a HID device. hidraw is an +artefact of the processing of the HID device, and is not stable. Some drivers +even disable it, so that removes the tracing capabilies on those devices +(where it is interesting to get the non-hidraw traces). + +On the other hand, the ``hid_id`` is stable for the entire life of the HID device, +even if we change its report descriptor. + +Given that hidraw is not stable when the device disconnects/reconnects, we recommend +accessing the current report descriptor of the device through the sysfs. +This is available at ``/sys/bus/hid/devices/BUS:VID:PID.000N/report_descriptor`` as a +binary stream. + +Parsing the report descriptor is the responsibility of the BPF programmer or the userspace +component that loads the eBPF program. + +An (almost) complete example of a BPF enhanced HID device +========================================================= + +*Foreword: for most parts, this could be implemented as a kernel driver* + +Let's imagine we have a new tablet device that has some haptic capabilities +to simulate the surface the user is scratching on. This device would also have +a specific 3 positions switch to toggle between *pencil on paper*, *cray on a wall* +and *brush on a painting canvas*. To make things even better, we can control the +physical position of the switch through a feature report. + +And of course, the switch is relying on some userspace component to control the +haptic feature of the device itself. + +Filtering events +---------------- + +The first step consists in filtering events from the device. Given that the switch +position is actually reported in the flow of the pen events, using hidraw to implement +that filtering would mean that we wake up userspace for every single event. + +This is OK for libinput, but having an external library that is just interested in +one byte in the report is less than ideal. + +For that, we can create a basic skeleton for our BPF program:: + + #include "vmlinux.h" + #include <bpf/bpf_helpers.h> + #include <bpf/bpf_tracing.h> + + /* HID programs need to be GPL */ + char _license[] SEC("license") = "GPL"; + + /* HID-BPF kfunc API definitions */ + 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; + + struct { + __uint(type, BPF_MAP_TYPE_RINGBUF); + __uint(max_entries, 4096 * 64); + } ringbuf SEC(".maps"); + + struct attach_prog_args { + int prog_fd; + unsigned int hid; + unsigned int flags; + int retval; + }; + + SEC("syscall") + int attach_prog(struct attach_prog_args *ctx) + { + ctx->retval = hid_bpf_attach_prog(ctx->hid, + ctx->prog_fd, + ctx->flags); + return 0; + } + + __u8 current_value = 0; + + SEC("?fmod_ret/hid_bpf_device_event") + int BPF_PROG(filter_switch, struct hid_bpf_ctx *hid_ctx) + { + __u8 *data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 192 /* size */); + __u8 *buf; + + if (!data) + return 0; /* EPERM check */ + + if (current_value != data[152]) { + buf = bpf_ringbuf_reserve(&ringbuf, 1, 0); + if (!buf) + return 0; + + *buf = data[152]; + + bpf_ringbuf_commit(buf, 0); + + current_value = data[152]; + } + + return 0; + } + +To attach ``filter_switch``, userspace needs to call the ``attach_prog`` syscall +program first:: + + static int attach_filter(struct hid *hid_skel, int hid_id) + { + int err, prog_fd; + int ret = -1; + struct attach_prog_args args = { + .hid = hid_id, + }; + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattrs, + .ctx_in = &args, + .ctx_size_in = sizeof(args), + ); + + args.prog_fd = bpf_program__fd(hid_skel->progs.filter_switch); + + prog_fd = bpf_program__fd(hid_skel->progs.attach_prog); + + err = bpf_prog_test_run_opts(prog_fd, &tattrs); + return err; + } + +Our userspace program can now listen to notifications on the ring buffer, and +is awaken only when the value changes. + +Controlling the device +---------------------- + +To be able to change the haptic feedback from the tablet, the userspace program +needs to emit a feature report on the device itself. + +Instead of using hidraw for that, we can create a ``SEC("syscall")`` program +that talks to the device:: + + /* some more HID-BPF kfunc API definitions */ + extern struct hid_bpf_ctx *hid_bpf_allocate_context(unsigned int hid_id) __ksym; + extern void hid_bpf_release_context(struct hid_bpf_ctx *ctx) __ksym; + extern int hid_bpf_hw_request(struct hid_bpf_ctx *ctx, + __u8* data, + size_t len, + enum hid_report_type type, + enum hid_class_request reqtype) __ksym; + + + struct hid_send_haptics_args { + /* data needs to come at offset 0 so we can do a memcpy into it */ + __u8 data[10]; + unsigned int hid; + }; + + SEC("syscall") + int send_haptic(struct hid_send_haptics_args *args) + { + struct hid_bpf_ctx *ctx; + int ret = 0; + + ctx = hid_bpf_allocate_context(args->hid); + if (!ctx) + return 0; /* EPERM check */ + + ret = hid_bpf_hw_request(ctx, + args->data, + 10, + HID_FEATURE_REPORT, + HID_REQ_SET_REPORT); + + hid_bpf_release_context(ctx); + + return ret; + } + +And then userspace needs to call that program directly:: + + static int set_haptic(struct hid *hid_skel, int hid_id, __u8 haptic_value) + { + int err, prog_fd; + int ret = -1; + struct hid_send_haptics_args args = { + .hid = hid_id, + }; + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattrs, + .ctx_in = &args, + .ctx_size_in = sizeof(args), + ); + + args.data[0] = 0x02; /* report ID of the feature on our device */ + args.data[1] = haptic_value; + + prog_fd = bpf_program__fd(hid_skel->progs.set_haptic); + + err = bpf_prog_test_run_opts(prog_fd, &tattrs); + return err; + } + +Now our userspace program is aware of the haptic state and can control it. The +program could make this state further available to other userspace programs +(e.g. via a DBus API). + +The interesting bit here is that we did not created a new kernel API for this. +Which means that if there is a bug in our implementation, we can change the +interface with the kernel at-will, because the userspace application is +responsible for its own usage. diff --git a/Documentation/hid/index.rst b/Documentation/hid/index.rst index e50f513c579c..b2028f382f11 100644 --- a/Documentation/hid/index.rst +++ b/Documentation/hid/index.rst @@ -11,6 +11,7 @@ Human Interface Devices (HID) hidraw hid-sensor hid-transport + hid-bpf uhid diff --git a/MAINTAINERS b/MAINTAINERS index 1b391ca7cf91..752126fba795 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9097,9 +9097,12 @@ M: Benjamin Tissoires <[email protected]> S: Maintained T: git git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git +F: Documentation/hid/ F: drivers/hid/ F: include/linux/hid* F: include/uapi/linux/hid* +F: samples/hid/ +F: tools/testing/selftests/hid/ HID LOGITECH DRIVERS R: Filipe Laíns <[email protected]> diff --git a/drivers/Makefile b/drivers/Makefile index bdf1c66141c9..cf5d8b86da8f 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -137,7 +137,7 @@ obj-$(CONFIG_CRYPTO) += crypto/ obj-$(CONFIG_SUPERH) += sh/ obj-y += clocksource/ obj-$(CONFIG_DCA) += dca/ -obj-$(CONFIG_HID) += hid/ +obj-$(CONFIG_HID_SUPPORT) += hid/ obj-$(CONFIG_PPC_PS3) += ps3/ obj-$(CONFIG_OF) += of/ obj-$(CONFIG_SSB) += ssb/ diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig index 185a077d59cd..b345bbfb57bf 100644 --- a/drivers/hid/Kconfig +++ b/drivers/hid/Kconfig @@ -2,13 +2,20 @@ # # HID driver configuration # -menu "HID support" - depends on INPUT +menuconfig HID_SUPPORT + bool "HID bus support" + default y + depends on INPUT + help + This option adds core support for human interface device (HID). + You will also need drivers from the following menu to make use of it. + +if HID_SUPPORT config HID - tristate "HID bus support" - depends on INPUT + tristate "HID bus core support" default y + depends on INPUT help A human interface device (HID) is a type of computer device that interacts directly with and takes input from humans. The term "HID" @@ -1278,6 +1285,8 @@ config HID_KUNIT_TEST endmenu +source "drivers/hid/bpf/Kconfig" + endif # HID source "drivers/hid/usbhid/Kconfig" @@ -1290,4 +1299,4 @@ source "drivers/hid/amd-sfh-hid/Kconfig" source "drivers/hid/surface-hid/Kconfig" -endmenu +endif # HID_SUPPORT diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile index e8014c1a2f8b..c45b516eb767 100644 --- a/drivers/hid/Makefile +++ b/drivers/hid/Makefile @@ -5,6 +5,8 @@ hid-y := hid-core.o hid-input.o hid-quirks.o hid-$(CONFIG_DEBUG_FS) += hid-debug.o +obj-$(CONFIG_HID_BPF) += bpf/ + obj-$(CONFIG_HID) += hid.o obj-$(CONFIG_UHID) += uhid.o diff --git a/drivers/hid/amd-sfh-hid/Kconfig b/drivers/hid/amd-sfh-hid/Kconfig index db069a83e9a2..56e473fc3c93 100644 --- a/drivers/hid/amd-sfh-hid/Kconfig +++ b/drivers/hid/amd-sfh-hid/Kconfig @@ -2,10 +2,10 @@ menu "AMD SFH HID Support" depends on X86_64 || COMPILE_TEST depends on PCI - depends on HID config AMD_SFH_HID tristate "AMD Sensor Fusion Hub" + select HID help If you say yes to this option, support will be included for the AMD Sensor Fusion Hub. diff --git a/drivers/hid/bpf/Kconfig b/drivers/hid/bpf/Kconfig new file mode 100644 index 000000000000..298634fc3335 --- /dev/null +++ b/drivers/hid/bpf/Kconfig @@ -0,0 +1,17 @@ +# SPDX-License-Identifier: GPL-2.0-only +menu "HID-BPF support" + +config HID_BPF + bool "HID-BPF support" + default HID_SUPPORT + depends on BPF && BPF_SYSCALL + help + This option allows to support eBPF programs on the HID subsystem. + eBPF programs can fix HID devices in a lighter way than a full + kernel patch and allow a lot more flexibility. + + For documentation, see Documentation/hid/hid-bpf.rst + + If unsure, say Y. + +endmenu diff --git a/drivers/hid/bpf/Makefile b/drivers/hid/bpf/Makefile new file mode 100644 index 000000000000..cf55120cf7d6 --- /dev/null +++ b/drivers/hid/bpf/Makefile @@ -0,0 +1,11 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for HID-BPF +# + +LIBBPF_INCLUDE = $(srctree)/tools/lib + +obj-$(CONFIG_HID_BPF) += hid_bpf.o +CFLAGS_hid_bpf_dispatch.o += -I$(LIBBPF_INCLUDE) +CFLAGS_hid_bpf_jmp_table.o += -I$(LIBBPF_INCLUDE) +hid_bpf-objs += hid_bpf_dispatch.o hid_bpf_jmp_table.o diff --git a/drivers/hid/bpf/entrypoints/Makefile b/drivers/hid/bpf/entrypoints/Makefile new file mode 100644 index 000000000000..a12edcfa4fe3 --- /dev/null +++ b/drivers/hid/bpf/entrypoints/Makefile @@ -0,0 +1,93 @@ +# SPDX-License-Identifier: GPL-2.0 +OUTPUT := .output +abs_out := $(abspath $(OUTPUT)) + +CLANG ?= clang +LLC ?= llc +LLVM_STRIP ?= llvm-strip + +TOOLS_PATH := $(abspath ../../../../tools) +BPFTOOL_SRC := $(TOOLS_PATH)/bpf/bpftool +BPFTOOL_OUTPUT := $(abs_out)/bpftool +DEFAULT_BPFTOOL := $(BPFTOOL_OUTPUT)/bootstrap/bpftool +BPFTOOL ?= $(DEFAULT_BPFTOOL) + +LIBBPF_SRC := $(TOOLS_PATH)/lib/bpf +LIBBPF_OUTPUT := $(abs_out)/libbpf +LIBBPF_DESTDIR := $(LIBBPF_OUTPUT) +LIBBPF_INCLUDE := $(LIBBPF_DESTDIR)/include +BPFOBJ := $(LIBBPF_OUTPUT)/libbpf.a + +INCLUDES := -I$(OUTPUT) -I$(LIBBPF_INCLUDE) -I$(TOOLS_PATH)/include/uapi +CFLAGS := -g -Wall + +VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \ + $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux) \ + ../../../../vmlinux \ + /sys/kernel/btf/vmlinux \ + /boot/vmlinux-$(shell uname -r) +VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS)))) +ifeq ($(VMLINUX_BTF),) +$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)") +endif + +ifeq ($(V),1) +Q = +msg = +else +Q = @ +msg = @printf ' %-8s %s%s\n' "$(1)" "$(notdir $(2))" "$(if $(3), $(3))"; +MAKEFLAGS += --no-print-directory +submake_extras := feature_display=0 +endif + +.DELETE_ON_ERROR: + +.PHONY: all clean + +all: entrypoints.lskel.h + +clean: + $(call msg,CLEAN) + $(Q)rm -rf $(OUTPUT) entrypoints + +entrypoints.lskel.h: $(OUTPUT)/entrypoints.bpf.o | $(BPFTOOL) + $(call msg,GEN-SKEL,$@) + $(Q)$(BPFTOOL) gen skeleton -L $< > $@ + + +$(OUTPUT)/entrypoints.bpf.o: entrypoints.bpf.c $(OUTPUT)/vmlinux.h $(BPFOBJ) | $(OUTPUT) + $(call msg,BPF,$@) + $(Q)$(CLANG) -g -O2 -target bpf $(INCLUDES) \ + -c $(filter %.c,$^) -o $@ && \ + $(LLVM_STRIP) -g $@ + +$(OUTPUT)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) | $(INCLUDE_DIR) +ifeq ($(VMLINUX_H),) + $(call msg,GEN,,$@) + $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@ +else + $(call msg,CP,,$@) + $(Q)cp "$(VMLINUX_H)" $@ +endif + +$(OUTPUT) $(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT): + $(call msg,MKDIR,$@) + $(Q)mkdir -p $@ + +$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUTPUT) + $(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) \ + OUTPUT=$(abspath $(dir $@))/ prefix= \ + DESTDIR=$(LIBBPF_DESTDIR) $(abspath $@) install_headers + +ifeq ($(CROSS_COMPILE),) +$(DEFAULT_BPFTOOL): $(BPFOBJ) | $(BPFTOOL_OUTPUT) + $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOL_SRC) \ + OUTPUT=$(BPFTOOL_OUTPUT)/ \ + LIBBPF_BOOTSTRAP_OUTPUT=$(LIBBPF_OUTPUT)/ \ + LIBBPF_BOOTSTRAP_DESTDIR=$(LIBBPF_DESTDIR)/ bootstrap +else +$(DEFAULT_BPFTOOL): | $(BPFTOOL_OUTPUT) + $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOL_SRC) \ + OUTPUT=$(BPFTOOL_OUTPUT)/ bootstrap +endif diff --git a/drivers/hid/bpf/entrypoints/README b/drivers/hid/bpf/entrypoints/README new file mode 100644 index 000000000000..147e0d41509f --- /dev/null +++ b/drivers/hid/bpf/entrypoints/README @@ -0,0 +1,4 @@ +WARNING: +If you change "entrypoints.bpf.c" do "make -j" in this directory to rebuild "entrypoints.skel.h". +Make sure to have clang 10 installed. +See Documentation/bpf/bpf_devel_QA.rst diff --git a/drivers/hid/bpf/entrypoints/entrypoints.bpf.c b/drivers/hid/bpf/entrypoints/entrypoints.bpf.c new file mode 100644 index 000000000000..7c1895d9e5c0 --- /dev/null +++ b/drivers/hid/bpf/entrypoints/entrypoints.bpf.c @@ -0,0 +1,34 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Benjamin Tissoires */ + +#include ".output/vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +#define HID_BPF_MAX_PROGS 1024 + +extern void call_hid_bpf_prog_put_deferred(struct work_struct *work) __ksym; + +struct { + __uint(type, BPF_MAP_TYPE_PROG_ARRAY); + __uint(max_entries, HID_BPF_MAX_PROGS); + __uint(key_size, sizeof(__u32)); + __uint(value_size, sizeof(__u32)); +} hid_jmp_table SEC(".maps"); + +SEC("fmod_ret/__hid_bpf_tail_call") +int BPF_PROG(hid_tail_call, struct hid_bpf_ctx *hctx) +{ + bpf_tail_call(ctx, &hid_jmp_table, hctx->index); + + return 0; +} + +SEC("fentry/bpf_prog_put_deferred") +int BPF_PROG(hid_bpf_prog_put_deferred, struct work_struct *work) +{ + call_hid_bpf_prog_put_deferred(work); + return 0; +} + +char LICENSE[] SEC("license") = "GPL"; diff --git a/drivers/hid/bpf/entrypoints/entrypoints.lskel.h b/drivers/hid/bpf/entrypoints/entrypoints.lskel.h new file mode 100644 index 000000000000..9ffb991b3e6f --- /dev/null +++ b/drivers/hid/bpf/entrypoints/entrypoints.lskel.h @@ -0,0 +1,330 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +/* THIS FILE IS AUTOGENERATED BY BPFTOOL! */ +#ifndef __ENTRYPOINTS_BPF_SKEL_H__ +#define __ENTRYPOINTS_BPF_SKEL_H__ + +#include <bpf/skel_internal.h> + +struct entrypoints_bpf { + struct bpf_loader_ctx ctx; + struct { + struct bpf_map_desc hid_jmp_table; + } maps; + struct { + struct bpf_prog_desc hid_tail_call; + struct bpf_prog_desc hid_bpf_prog_put_deferred; + } progs; + struct { + int hid_tail_call_fd; + int hid_bpf_prog_put_deferred_fd; + } links; +}; + +static inline int +entrypoints_bpf__hid_tail_call__attach(struct entrypoints_bpf *skel) +{ + int prog_fd = skel->progs.hid_tail_call.prog_fd; + int fd = skel_raw_tracepoint_open(NULL, prog_fd); + + if (fd > 0) + skel->links.hid_tail_call_fd = fd; + return fd; +} + +static inline int +entrypoints_bpf__hid_bpf_prog_put_deferred__attach(struct entrypoints_bpf *skel) +{ + int prog_fd = skel->progs.hid_bpf_prog_put_deferred.prog_fd; + int fd = skel_raw_tracepoint_open(NULL, prog_fd); + + if (fd > 0) + skel->links.hid_bpf_prog_put_deferred_fd = fd; + return fd; +} + +static inline int +entrypoints_bpf__attach(struct entrypoints_bpf *skel) +{ + int ret = 0; + + ret = ret < 0 ? ret : entrypoints_bpf__hid_tail_call__attach(skel); + ret = ret < 0 ? ret : entrypoints_bpf__hid_bpf_prog_put_deferred__attach(skel); + return ret < 0 ? ret : 0; +} + +static inline void +entrypoints_bpf__detach(struct entrypoints_bpf *skel) +{ + skel_closenz(skel->links.hid_tail_call_fd); + skel_closenz(skel->links.hid_bpf_prog_put_deferred_fd); +} +static void +entrypoints_bpf__destroy(struct entrypoints_bpf *skel) +{ + if (!skel) + return; + entrypoints_bpf__detach(skel); + skel_closenz(skel->progs.hid_tail_call.prog_fd); + skel_closenz(skel->progs.hid_bpf_prog_put_deferred.prog_fd); + skel_closenz(skel->maps.hid_jmp_table.map_fd); + skel_free(skel); +} +static inline struct entrypoints_bpf * +entrypoints_bpf__open(void) +{ + struct entrypoints_bpf *skel; + + skel = skel_alloc(sizeof(*skel)); + if (!skel) + goto cleanup; + skel->ctx.sz = (void *)&skel->links - (void *)skel; + return skel; +cleanup: + entrypoints_bpf__destroy(skel); + return NULL; +} + +static inline int +entrypoints_bpf__load(struct entrypoints_bpf *skel) +{ + struct bpf_load_and_run_opts opts = {}; + int err; + + opts.ctx = (struct bpf_loader_ctx *)skel; + opts.data_sz = 3792; + opts.data = (void *)"\ +\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ +\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ +\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ +\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ +\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ +\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ +\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ +\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ 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inline struct entrypoints_bpf * +entrypoints_bpf__open_and_load(void) +{ + struct entrypoints_bpf *skel; + + skel = entrypoints_bpf__open(); + if (!skel) + return NULL; + if (entrypoints_bpf__load(skel)) { + entrypoints_bpf__destroy(skel); + return NULL; + } + return skel; +} + +__attribute__((unused)) static void +entrypoints_bpf__assert(struct entrypoints_bpf *s __attribute__((unused))) +{ +#ifdef __cplusplus +#define _Static_assert static_assert +#endif +#ifdef __cplusplus +#undef _Static_assert +#endif +} + +#endif /* __ENTRYPOINTS_BPF_SKEL_H__ */ diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c new file mode 100644 index 000000000000..c3920c7964dc --- /dev/null +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -0,0 +1,531 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * HID-BPF support for Linux + * + * Copyright (c) 2022 Benjamin Tissoires + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/bitops.h> +#include <linux/btf.h> +#include <linux/btf_ids.h> +#include <linux/filter.h> +#include <linux/hid.h> +#include <linux/hid_bpf.h> +#include <linux/init.h> +#include <linux/kfifo.h> +#include <linux/minmax.h> +#include <linux/module.h> +#include <linux/workqueue.h> +#include "hid_bpf_dispatch.h" +#include "entrypoints/entrypoints.lskel.h" + +struct hid_bpf_ops *hid_bpf_ops; +EXPORT_SYMBOL(hid_bpf_ops); + +/** + * hid_bpf_device_event - Called whenever an event is coming in from the device + * + * @ctx: The HID-BPF context + * + * @return %0 on success and keep processing; a positive value to change the + * incoming size buffer; a negative error code to interrupt the processing + * of this event + * + * Declare an %fmod_ret tracing bpf program to this function and attach this + * program through hid_bpf_attach_prog() to have this helper called for + * any incoming event from the device itself. + * + * The function is called while on IRQ context, so we can not sleep. + */ +/* never used by the kernel but declared so we can load and attach a tracepoint */ +__weak noinline int hid_bpf_device_event(struct hid_bpf_ctx *ctx) +{ + return 0; +} +ALLOW_ERROR_INJECTION(hid_bpf_device_event, ERRNO); + +u8 * +dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type, u8 *data, + u32 *size, int interrupt) +{ + struct hid_bpf_ctx_kern ctx_kern = { + .ctx = { + .hid = hdev, + .report_type = type, + .allocated_size = hdev->bpf.allocated_data, + .size = *size, + }, + .data = hdev->bpf.device_data, + }; + int ret; + + if (type >= HID_REPORT_TYPES) + return ERR_PTR(-EINVAL); + + /* no program has been attached yet */ + if (!hdev->bpf.device_data) + return data; + + memset(ctx_kern.data, 0, hdev->bpf.allocated_data); + memcpy(ctx_kern.data, data, *size); + + ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_DEVICE_EVENT, &ctx_kern); + if (ret < 0) + return ERR_PTR(ret); + + if (ret) { + if (ret > ctx_kern.ctx.allocated_size) + return ERR_PTR(-EINVAL); + + *size = ret; + } + + return ctx_kern.data; +} +EXPORT_SYMBOL_GPL(dispatch_hid_bpf_device_event); + +/** + * hid_bpf_rdesc_fixup - Called when the probe function parses the report + * descriptor of the HID device + * + * @ctx: The HID-BPF context + * + * @return 0 on success and keep processing; a positive value to change the + * incoming size buffer; a negative error code to interrupt the processing + * of this event + * + * Declare an %fmod_ret tracing bpf program to this function and attach this + * program through hid_bpf_attach_prog() to have this helper called before any + * parsing of the report descriptor by HID. + */ +/* never used by the kernel but declared so we can load and attach a tracepoint */ +__weak noinline int hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx) +{ + return 0; +} +ALLOW_ERROR_INJECTION(hid_bpf_rdesc_fixup, ERRNO); + +u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size) +{ + int ret; + struct hid_bpf_ctx_kern ctx_kern = { + .ctx = { + .hid = hdev, + .size = *size, + .allocated_size = HID_MAX_DESCRIPTOR_SIZE, + }, + }; + + ctx_kern.data = kzalloc(ctx_kern.ctx.allocated_size, GFP_KERNEL); + if (!ctx_kern.data) + goto ignore_bpf; + + memcpy(ctx_kern.data, rdesc, min_t(unsigned int, *size, HID_MAX_DESCRIPTOR_SIZE)); + + ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern); + if (ret < 0) + goto ignore_bpf; + + if (ret) { + if (ret > ctx_kern.ctx.allocated_size) + goto ignore_bpf; + + *size = ret; + } + + rdesc = krealloc(ctx_kern.data, *size, GFP_KERNEL); + + return rdesc; + + ignore_bpf: + kfree(ctx_kern.data); + return kmemdup(rdesc, *size, GFP_KERNEL); +} +EXPORT_SYMBOL_GPL(call_hid_bpf_rdesc_fixup); + +/** + * hid_bpf_get_data - Get the kernel memory pointer associated with the context @ctx + * + * @ctx: The HID-BPF context + * @offset: The offset within the memory + * @rdwr_buf_size: the const size of the buffer + * + * @returns %NULL on error, an %__u8 memory pointer on success + */ +noinline __u8 * +hid_bpf_get_data(struct hid_bpf_ctx *ctx, unsigned int offset, const size_t rdwr_buf_size) +{ + struct hid_bpf_ctx_kern *ctx_kern; + + if (!ctx) + return NULL; + + ctx_kern = container_of(ctx, struct hid_bpf_ctx_kern, ctx); + + if (rdwr_buf_size + offset > ctx->allocated_size) + return NULL; + + return ctx_kern->data + offset; +} + +/* + * The following set contains all functions we agree BPF programs + * can use. + */ +BTF_SET8_START(hid_bpf_kfunc_ids) +BTF_ID_FLAGS(func, call_hid_bpf_prog_put_deferred) +BTF_ID_FLAGS(func, hid_bpf_get_data, KF_RET_NULL) +BTF_SET8_END(hid_bpf_kfunc_ids) + +static const struct btf_kfunc_id_set hid_bpf_kfunc_set = { + .owner = THIS_MODULE, + .set = &hid_bpf_kfunc_ids, +}; + +static int device_match_id(struct device *dev, const void *id) +{ + struct hid_device *hdev = to_hid_device(dev); + + return hdev->id == *(int *)id; +} + +static int __hid_bpf_allocate_data(struct hid_device *hdev, u8 **data, u32 *size) +{ + u8 *alloc_data; + unsigned int i, j, max_report_len = 0; + size_t alloc_size = 0; + + /* compute the maximum report length for this device */ + for (i = 0; i < HID_REPORT_TYPES; i++) { + struct hid_report_enum *report_enum = hdev->report_enum + i; + + for (j = 0; j < HID_MAX_IDS; j++) { + struct hid_report *report = report_enum->report_id_hash[j]; + + if (report) + max_report_len = max(max_report_len, hid_report_len(report)); + } + } + + /* + * Give us a little bit of extra space and some predictability in the + * buffer length we create. This way, we can tell users that they can + * work on chunks of 64 bytes of memory without having the bpf verifier + * scream at them. + */ + alloc_size = DIV_ROUND_UP(max_report_len, 64) * 64; + + alloc_data = kzalloc(alloc_size, GFP_KERNEL); + if (!alloc_data) + return -ENOMEM; + + *data = alloc_data; + *size = alloc_size; + + return 0; +} + +static int hid_bpf_allocate_event_data(struct hid_device *hdev) +{ + /* hdev->bpf.device_data is already allocated, abort */ + if (hdev->bpf.device_data) + return 0; + + return __hid_bpf_allocate_data(hdev, &hdev->bpf.device_data, &hdev->bpf.allocated_data); +} + +int hid_bpf_reconnect(struct hid_device *hdev) +{ + if (!test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status)) + return device_reprobe(&hdev->dev); + + return 0; +} + +/** + * hid_bpf_attach_prog - Attach the given @prog_fd to the given HID device + * + * @hid_id: the system unique identifier of the HID device + * @prog_fd: an fd in the user process representing the program to attach + * @flags: any logical OR combination of &enum hid_bpf_attach_flags + * + * @returns %0 on success, an error code otherwise. + */ +/* called from syscall */ +noinline int +hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, __u32 flags) +{ + struct hid_device *hdev; + struct device *dev; + int err, prog_type = hid_bpf_get_prog_attach_type(prog_fd); + + if (!hid_bpf_ops) + return -EINVAL; + + if (prog_type < 0) + return prog_type; + + if (prog_type >= HID_BPF_PROG_TYPE_MAX) + return -EINVAL; + + if ((flags & ~HID_BPF_FLAG_MASK)) + return -EINVAL; + + dev = bus_find_device(hid_bpf_ops->bus_type, NULL, &hid_id, device_match_id); + if (!dev) + return -EINVAL; + + hdev = to_hid_device(dev); + + if (prog_type == HID_BPF_PROG_TYPE_DEVICE_EVENT) { + err = hid_bpf_allocate_event_data(hdev); + if (err) + return err; + } + + err = __hid_bpf_attach_prog(hdev, prog_type, prog_fd, flags); + if (err) + return err; + + if (prog_type == HID_BPF_PROG_TYPE_RDESC_FIXUP) { + err = hid_bpf_reconnect(hdev); + if (err) + return err; + } + + return 0; +} + +/** + * hid_bpf_allocate_context - Allocate a context to the given HID device + * + * @hid_id: the system unique identifier of the HID device + * + * @returns A pointer to &struct hid_bpf_ctx on success, %NULL on error. + */ +noinline struct hid_bpf_ctx * +hid_bpf_allocate_context(unsigned int hid_id) +{ + struct hid_device *hdev; + struct hid_bpf_ctx_kern *ctx_kern = NULL; + struct device *dev; + + if (!hid_bpf_ops) + return NULL; + + dev = bus_find_device(hid_bpf_ops->bus_type, NULL, &hid_id, device_match_id); + if (!dev) + return NULL; + + hdev = to_hid_device(dev); + + ctx_kern = kzalloc(sizeof(*ctx_kern), GFP_KERNEL); + if (!ctx_kern) + return NULL; + + ctx_kern->ctx.hid = hdev; + + return &ctx_kern->ctx; +} + +/** + * hid_bpf_release_context - Release the previously allocated context @ctx + * + * @ctx: the HID-BPF context to release + * + */ +noinline void +hid_bpf_release_context(struct hid_bpf_ctx *ctx) +{ + struct hid_bpf_ctx_kern *ctx_kern; + + if (!ctx) + return; + + ctx_kern = container_of(ctx, struct hid_bpf_ctx_kern, ctx); + + kfree(ctx_kern); +} + +/** + * hid_bpf_hw_request - Communicate with a HID device + * + * @ctx: the HID-BPF context previously allocated in hid_bpf_allocate_context() + * @buf: a %PTR_TO_MEM buffer + * @buf__sz: the size of the data to transfer + * @rtype: the type of the report (%HID_INPUT_REPORT, %HID_FEATURE_REPORT, %HID_OUTPUT_REPORT) + * @reqtype: the type of the request (%HID_REQ_GET_REPORT, %HID_REQ_SET_REPORT, ...) + * + * @returns %0 on success, a negative error code otherwise. + */ +noinline int +hid_bpf_hw_request(struct hid_bpf_ctx *ctx, __u8 *buf, size_t buf__sz, + enum hid_report_type rtype, enum hid_class_request reqtype) +{ + struct hid_device *hdev; + struct hid_report *report; + struct hid_report_enum *report_enum; + u8 *dma_data; + u32 report_len; + int ret; + + /* check arguments */ + if (!ctx || !hid_bpf_ops || !buf) + return -EINVAL; + + switch (rtype) { + case HID_INPUT_REPORT: + case HID_OUTPUT_REPORT: + case HID_FEATURE_REPORT: + break; + default: + return -EINVAL; + } + + switch (reqtype) { + case HID_REQ_GET_REPORT: + case HID_REQ_GET_IDLE: + case HID_REQ_GET_PROTOCOL: + case HID_REQ_SET_REPORT: + case HID_REQ_SET_IDLE: + case HID_REQ_SET_PROTOCOL: + break; + default: + return -EINVAL; + } + + if (buf__sz < 1) + return -EINVAL; + + hdev = (struct hid_device *)ctx->hid; /* discard const */ + + report_enum = hdev->report_enum + rtype; + report = hid_bpf_ops->hid_get_report(report_enum, buf); + if (!report) + return -EINVAL; + + report_len = hid_report_len(report); + + if (buf__sz > report_len) + buf__sz = report_len; + + dma_data = kmemdup(buf, buf__sz, GFP_KERNEL); + if (!dma_data) + return -ENOMEM; + + ret = hid_bpf_ops->hid_hw_raw_request(hdev, + dma_data[0], + dma_data, + buf__sz, + rtype, + reqtype); + + if (ret > 0) + memcpy(buf, dma_data, ret); + + kfree(dma_data); + return ret; +} + +/* for syscall HID-BPF */ +BTF_SET8_START(hid_bpf_syscall_kfunc_ids) +BTF_ID_FLAGS(func, hid_bpf_attach_prog) +BTF_ID_FLAGS(func, hid_bpf_allocate_context, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, hid_bpf_release_context, KF_RELEASE) +BTF_ID_FLAGS(func, hid_bpf_hw_request) +BTF_SET8_END(hid_bpf_syscall_kfunc_ids) + +static const struct btf_kfunc_id_set hid_bpf_syscall_kfunc_set = { + .owner = THIS_MODULE, + .set = &hid_bpf_syscall_kfunc_ids, +}; + +int hid_bpf_connect_device(struct hid_device *hdev) +{ + struct hid_bpf_prog_list *prog_list; + + rcu_read_lock(); + prog_list = rcu_dereference(hdev->bpf.progs[HID_BPF_PROG_TYPE_DEVICE_EVENT]); + rcu_read_unlock(); + + /* only allocate BPF data if there are programs attached */ + if (!prog_list) + return 0; + + return hid_bpf_allocate_event_data(hdev); +} +EXPORT_SYMBOL_GPL(hid_bpf_connect_device); + +void hid_bpf_disconnect_device(struct hid_device *hdev) +{ + kfree(hdev->bpf.device_data); + hdev->bpf.device_data = NULL; + hdev->bpf.allocated_data = 0; +} +EXPORT_SYMBOL_GPL(hid_bpf_disconnect_device); + +void hid_bpf_destroy_device(struct hid_device *hdev) +{ + if (!hdev) + return; + + /* mark the device as destroyed in bpf so we don't reattach it */ + hdev->bpf.destroyed = true; + + __hid_bpf_destroy_device(hdev); +} +EXPORT_SYMBOL_GPL(hid_bpf_destroy_device); + +void hid_bpf_device_init(struct hid_device *hdev) +{ + spin_lock_init(&hdev->bpf.progs_lock); +} +EXPORT_SYMBOL_GPL(hid_bpf_device_init); + +static int __init hid_bpf_init(void) +{ + int err; + + /* Note: if we exit with an error any time here, we would entirely break HID, which + * is probably not something we want. So we log an error and return success. + * + * This is not a big deal: the syscall allowing to attach a BPF program to a HID device + * will not be available, so nobody will be able to use the functionality. + */ + + err = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &hid_bpf_kfunc_set); + if (err) { + pr_warn("error while setting HID BPF tracing kfuncs: %d", err); + return 0; + } + + err = hid_bpf_preload_skel(); + if (err) { + pr_warn("error while preloading HID BPF dispatcher: %d", err); + return 0; + } + + /* register syscalls after we are sure we can load our preloaded bpf program */ + err = register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &hid_bpf_syscall_kfunc_set); + if (err) { + pr_warn("error while setting HID BPF syscall kfuncs: %d", err); + return 0; + } + + return 0; +} + +static void __exit hid_bpf_exit(void) +{ + /* HID depends on us, so if we hit that code, we are guaranteed that hid + * has been removed and thus we do not need to clear the HID devices + */ + hid_bpf_free_links_and_skel(); +} + +late_initcall(hid_bpf_init); +module_exit(hid_bpf_exit); +MODULE_AUTHOR("Benjamin Tissoires"); +MODULE_LICENSE("GPL"); diff --git a/drivers/hid/bpf/hid_bpf_dispatch.h b/drivers/hid/bpf/hid_bpf_dispatch.h new file mode 100644 index 000000000000..2eeab1f746dd --- /dev/null +++ b/drivers/hid/bpf/hid_bpf_dispatch.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef _BPF_HID_BPF_DISPATCH_H +#define _BPF_HID_BPF_DISPATCH_H + +#include <linux/hid.h> + +struct hid_bpf_ctx_kern { + struct hid_bpf_ctx ctx; + u8 *data; +}; + +int hid_bpf_preload_skel(void); +void hid_bpf_free_links_and_skel(void); +int hid_bpf_get_prog_attach_type(int prog_fd); +int __hid_bpf_attach_prog(struct hid_device *hdev, enum hid_bpf_prog_type prog_type, int prog_fd, + __u32 flags); +void __hid_bpf_destroy_device(struct hid_device *hdev); +int hid_bpf_prog_run(struct hid_device *hdev, enum hid_bpf_prog_type type, + struct hid_bpf_ctx_kern *ctx_kern); +int hid_bpf_reconnect(struct hid_device *hdev); + +struct bpf_prog; + +/* HID-BPF internal kfuncs API */ +void call_hid_bpf_prog_put_deferred(struct work_struct *work); + +#endif diff --git a/drivers/hid/bpf/hid_bpf_jmp_table.c b/drivers/hid/bpf/hid_bpf_jmp_table.c new file mode 100644 index 000000000000..579a6c06906e --- /dev/null +++ b/drivers/hid/bpf/hid_bpf_jmp_table.c @@ -0,0 +1,565 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * HID-BPF support for Linux + * + * Copyright (c) 2022 Benjamin Tissoires + */ + +#include <linux/bitops.h> +#include <linux/btf.h> +#include <linux/btf_ids.h> +#include <linux/circ_buf.h> +#include <linux/filter.h> +#include <linux/hid.h> +#include <linux/hid_bpf.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/workqueue.h> +#include "hid_bpf_dispatch.h" +#include "entrypoints/entrypoints.lskel.h" + +#define HID_BPF_MAX_PROGS 1024 /* keep this in sync with preloaded bpf, + * needs to be a power of 2 as we use it as + * a circular buffer + */ + +#define NEXT(idx) (((idx) + 1) & (HID_BPF_MAX_PROGS - 1)) +#define PREV(idx) (((idx) - 1) & (HID_BPF_MAX_PROGS - 1)) + +/* + * represents one attached program stored in the hid jump table + */ +struct hid_bpf_prog_entry { + struct bpf_prog *prog; + struct hid_device *hdev; + enum hid_bpf_prog_type type; + u16 idx; +}; + +struct hid_bpf_jmp_table { + struct bpf_map *map; + struct hid_bpf_prog_entry entries[HID_BPF_MAX_PROGS]; /* compacted list, circular buffer */ + int tail, head; + struct bpf_prog *progs[HID_BPF_MAX_PROGS]; /* idx -> progs mapping */ + unsigned long enabled[BITS_TO_LONGS(HID_BPF_MAX_PROGS)]; +}; + +#define FOR_ENTRIES(__i, __start, __end) \ + for (__i = __start; CIRC_CNT(__end, __i, HID_BPF_MAX_PROGS); __i = NEXT(__i)) + +static struct hid_bpf_jmp_table jmp_table; + +static DEFINE_MUTEX(hid_bpf_attach_lock); /* held when attaching/detaching programs */ + +static void hid_bpf_release_progs(struct work_struct *work); + +static DECLARE_WORK(release_work, hid_bpf_release_progs); + +BTF_ID_LIST(hid_bpf_btf_ids) +BTF_ID(func, hid_bpf_device_event) /* HID_BPF_PROG_TYPE_DEVICE_EVENT */ +BTF_ID(func, hid_bpf_rdesc_fixup) /* HID_BPF_PROG_TYPE_RDESC_FIXUP */ + +static int hid_bpf_max_programs(enum hid_bpf_prog_type type) +{ + switch (type) { + case HID_BPF_PROG_TYPE_DEVICE_EVENT: + return HID_BPF_MAX_PROGS_PER_DEV; + case HID_BPF_PROG_TYPE_RDESC_FIXUP: + return 1; + default: + return -EINVAL; + } +} + +static int hid_bpf_program_count(struct hid_device *hdev, + struct bpf_prog *prog, + enum hid_bpf_prog_type type) +{ + int i, n = 0; + + if (type >= HID_BPF_PROG_TYPE_MAX) + return -EINVAL; + + FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { + struct hid_bpf_prog_entry *entry = &jmp_table.entries[i]; + + if (type != HID_BPF_PROG_TYPE_UNDEF && entry->type != type) + continue; + + if (hdev && entry->hdev != hdev) + continue; + + if (prog && entry->prog != prog) + continue; + + n++; + } + + return n; +} + +__weak noinline int __hid_bpf_tail_call(struct hid_bpf_ctx *ctx) +{ + return 0; +} +ALLOW_ERROR_INJECTION(__hid_bpf_tail_call, ERRNO); + +int hid_bpf_prog_run(struct hid_device *hdev, enum hid_bpf_prog_type type, + struct hid_bpf_ctx_kern *ctx_kern) +{ + struct hid_bpf_prog_list *prog_list; + int i, idx, err = 0; + + rcu_read_lock(); + prog_list = rcu_dereference(hdev->bpf.progs[type]); + + if (!prog_list) + goto out_unlock; + + for (i = 0; i < prog_list->prog_cnt; i++) { + idx = prog_list->prog_idx[i]; + + if (!test_bit(idx, jmp_table.enabled)) + continue; + + ctx_kern->ctx.index = idx; + err = __hid_bpf_tail_call(&ctx_kern->ctx); + if (err < 0) + break; + if (err) + ctx_kern->ctx.retval = err; + } + + out_unlock: + rcu_read_unlock(); + + return err; +} + +/* + * assign the list of programs attached to a given hid device. + */ +static void __hid_bpf_set_hdev_progs(struct hid_device *hdev, struct hid_bpf_prog_list *new_list, + enum hid_bpf_prog_type type) +{ + struct hid_bpf_prog_list *old_list; + + spin_lock(&hdev->bpf.progs_lock); + old_list = rcu_dereference_protected(hdev->bpf.progs[type], + lockdep_is_held(&hdev->bpf.progs_lock)); + rcu_assign_pointer(hdev->bpf.progs[type], new_list); + spin_unlock(&hdev->bpf.progs_lock); + synchronize_rcu(); + + kfree(old_list); +} + +/* + * allocate and populate the list of programs attached to a given hid device. + * + * Must be called under lock. + */ +static int hid_bpf_populate_hdev(struct hid_device *hdev, enum hid_bpf_prog_type type) +{ + struct hid_bpf_prog_list *new_list; + int i; + + if (type >= HID_BPF_PROG_TYPE_MAX || !hdev) + return -EINVAL; + + if (hdev->bpf.destroyed) + return 0; + + new_list = kzalloc(sizeof(*new_list), GFP_KERNEL); + if (!new_list) + return -ENOMEM; + + FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { + struct hid_bpf_prog_entry *entry = &jmp_table.entries[i]; + + if (entry->type == type && entry->hdev == hdev && + test_bit(entry->idx, jmp_table.enabled)) + new_list->prog_idx[new_list->prog_cnt++] = entry->idx; + } + + __hid_bpf_set_hdev_progs(hdev, new_list, type); + + return 0; +} + +static void __hid_bpf_do_release_prog(int map_fd, unsigned int idx) +{ + skel_map_delete_elem(map_fd, &idx); + jmp_table.progs[idx] = NULL; +} + +static void hid_bpf_release_progs(struct work_struct *work) +{ + int i, j, n, map_fd = -1; + + if (!jmp_table.map) + return; + + /* retrieve a fd of our prog_array map in BPF */ + map_fd = skel_map_get_fd_by_id(jmp_table.map->id); + if (map_fd < 0) + return; + + mutex_lock(&hid_bpf_attach_lock); /* protects against attaching new programs */ + + /* detach unused progs from HID devices */ + FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { + struct hid_bpf_prog_entry *entry = &jmp_table.entries[i]; + enum hid_bpf_prog_type type; + struct hid_device *hdev; + + if (test_bit(entry->idx, jmp_table.enabled)) + continue; + + /* we have an attached prog */ + if (entry->hdev) { + hdev = entry->hdev; + type = entry->type; + + hid_bpf_populate_hdev(hdev, type); + + /* mark all other disabled progs from hdev of the given type as detached */ + FOR_ENTRIES(j, i, jmp_table.head) { + struct hid_bpf_prog_entry *next; + + next = &jmp_table.entries[j]; + + if (test_bit(next->idx, jmp_table.enabled)) + continue; + + if (next->hdev == hdev && next->type == type) + next->hdev = NULL; + } + + /* if type was rdesc fixup, reconnect device */ + if (type == HID_BPF_PROG_TYPE_RDESC_FIXUP) + hid_bpf_reconnect(hdev); + } + } + + /* remove all unused progs from the jump table */ + FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { + struct hid_bpf_prog_entry *entry = &jmp_table.entries[i]; + + if (test_bit(entry->idx, jmp_table.enabled)) + continue; + + if (entry->prog) + __hid_bpf_do_release_prog(map_fd, entry->idx); + } + + /* compact the entry list */ + n = jmp_table.tail; + FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { + struct hid_bpf_prog_entry *entry = &jmp_table.entries[i]; + + if (!test_bit(entry->idx, jmp_table.enabled)) + continue; + + jmp_table.entries[n] = jmp_table.entries[i]; + n = NEXT(n); + } + + jmp_table.head = n; + + mutex_unlock(&hid_bpf_attach_lock); + + if (map_fd >= 0) + close_fd(map_fd); +} + +static void hid_bpf_release_prog_at(int idx) +{ + int map_fd = -1; + + /* retrieve a fd of our prog_array map in BPF */ + map_fd = skel_map_get_fd_by_id(jmp_table.map->id); + if (map_fd < 0) + return; + + __hid_bpf_do_release_prog(map_fd, idx); + + close(map_fd); +} + +/* + * Insert the given BPF program represented by its fd in the jmp table. + * Returns the index in the jump table or a negative error. + */ +static int hid_bpf_insert_prog(int prog_fd, struct bpf_prog *prog) +{ + int i, index = -1, map_fd = -1, err = -EINVAL; + + /* retrieve a fd of our prog_array map in BPF */ + map_fd = skel_map_get_fd_by_id(jmp_table.map->id); + + if (map_fd < 0) { + err = -EINVAL; + goto out; + } + + /* find the first available index in the jmp_table */ + for (i = 0; i < HID_BPF_MAX_PROGS; i++) { + if (!jmp_table.progs[i] && index < 0) { + /* mark the index as used */ + jmp_table.progs[i] = prog; + index = i; + __set_bit(i, jmp_table.enabled); + } + } + if (index < 0) { + err = -ENOMEM; + goto out; + } + + /* insert the program in the jump table */ + err = skel_map_update_elem(map_fd, &index, &prog_fd, 0); + if (err) + goto out; + + /* + * The program has been safely inserted, decrement the reference count + * so it doesn't interfere with the number of actual user handles. + * This is safe to do because: + * - we overrite the put_ptr in the prog fd map + * - we also have a cleanup function that monitors when a program gets + * released and we manually do the cleanup in the prog fd map + */ + bpf_prog_sub(prog, 1); + + /* return the index */ + err = index; + + out: + if (err < 0) + __hid_bpf_do_release_prog(map_fd, index); + if (map_fd >= 0) + close_fd(map_fd); + return err; +} + +int hid_bpf_get_prog_attach_type(int prog_fd) +{ + struct bpf_prog *prog = NULL; + int i; + int prog_type = HID_BPF_PROG_TYPE_UNDEF; + + prog = bpf_prog_get(prog_fd); + if (IS_ERR(prog)) + return PTR_ERR(prog); + + for (i = 0; i < HID_BPF_PROG_TYPE_MAX; i++) { + if (hid_bpf_btf_ids[i] == prog->aux->attach_btf_id) { + prog_type = i; + break; + } + } + + bpf_prog_put(prog); + + return prog_type; +} + +/* called from syscall */ +noinline int +__hid_bpf_attach_prog(struct hid_device *hdev, enum hid_bpf_prog_type prog_type, + int prog_fd, __u32 flags) +{ + struct bpf_prog *prog = NULL; + struct hid_bpf_prog_entry *prog_entry; + int cnt, err = -EINVAL, prog_idx = -1; + + /* take a ref on the prog itself */ + prog = bpf_prog_get(prog_fd); + if (IS_ERR(prog)) + return PTR_ERR(prog); + + mutex_lock(&hid_bpf_attach_lock); + + /* do not attach too many programs to a given HID device */ + cnt = hid_bpf_program_count(hdev, NULL, prog_type); + if (cnt < 0) { + err = cnt; + goto out_unlock; + } + + if (cnt >= hid_bpf_max_programs(prog_type)) { + err = -E2BIG; + goto out_unlock; + } + + prog_idx = hid_bpf_insert_prog(prog_fd, prog); + /* if the jmp table is full, abort */ + if (prog_idx < 0) { + err = prog_idx; + goto out_unlock; + } + + if (flags & HID_BPF_FLAG_INSERT_HEAD) { + /* take the previous prog_entry slot */ + jmp_table.tail = PREV(jmp_table.tail); + prog_entry = &jmp_table.entries[jmp_table.tail]; + } else { + /* take the next prog_entry slot */ + prog_entry = &jmp_table.entries[jmp_table.head]; + jmp_table.head = NEXT(jmp_table.head); + } + + /* we steal the ref here */ + prog_entry->prog = prog; + prog_entry->idx = prog_idx; + prog_entry->hdev = hdev; + prog_entry->type = prog_type; + + /* finally store the index in the device list */ + err = hid_bpf_populate_hdev(hdev, prog_type); + if (err) + hid_bpf_release_prog_at(prog_idx); + + out_unlock: + mutex_unlock(&hid_bpf_attach_lock); + + /* we only use prog as a key in the various tables, so we don't need to actually + * increment the ref count. + */ + bpf_prog_put(prog); + + return err; +} + +void __hid_bpf_destroy_device(struct hid_device *hdev) +{ + int type, i; + struct hid_bpf_prog_list *prog_list; + + rcu_read_lock(); + + for (type = 0; type < HID_BPF_PROG_TYPE_MAX; type++) { + prog_list = rcu_dereference(hdev->bpf.progs[type]); + + if (!prog_list) + continue; + + for (i = 0; i < prog_list->prog_cnt; i++) + __clear_bit(prog_list->prog_idx[i], jmp_table.enabled); + } + + rcu_read_unlock(); + + for (type = 0; type < HID_BPF_PROG_TYPE_MAX; type++) + __hid_bpf_set_hdev_progs(hdev, NULL, type); + + /* schedule release of all detached progs */ + schedule_work(&release_work); +} + +void call_hid_bpf_prog_put_deferred(struct work_struct *work) +{ + struct bpf_prog_aux *aux; + struct bpf_prog *prog; + bool found = false; + int i; + + aux = container_of(work, struct bpf_prog_aux, work); + prog = aux->prog; + + /* we don't need locking here because the entries in the progs table + * are stable: + * if there are other users (and the progs entries might change), we + * would simply not have been called. + */ + for (i = 0; i < HID_BPF_MAX_PROGS; i++) { + if (jmp_table.progs[i] == prog) { + __clear_bit(i, jmp_table.enabled); + found = true; + } + } + + if (found) + /* schedule release of all detached progs */ + schedule_work(&release_work); +} + +static void hid_bpf_prog_fd_array_put_ptr(void *ptr) +{ +} + +#define HID_BPF_PROGS_COUNT 2 + +static struct bpf_link *links[HID_BPF_PROGS_COUNT]; +static struct entrypoints_bpf *skel; + +void hid_bpf_free_links_and_skel(void) +{ + int i; + + /* the following is enough to release all programs attached to hid */ + if (jmp_table.map) + bpf_map_put_with_uref(jmp_table.map); + + for (i = 0; i < ARRAY_SIZE(links); i++) { + if (!IS_ERR_OR_NULL(links[i])) + bpf_link_put(links[i]); + } + entrypoints_bpf__destroy(skel); +} + +#define ATTACH_AND_STORE_LINK(__name) do { \ + err = entrypoints_bpf__##__name##__attach(skel); \ + if (err) \ + goto out; \ + \ + links[idx] = bpf_link_get_from_fd(skel->links.__name##_fd); \ + if (IS_ERR(links[idx])) { \ + err = PTR_ERR(links[idx]); \ + goto out; \ + } \ + \ + /* Avoid taking over stdin/stdout/stderr of init process. Zeroing out \ + * makes skel_closenz() a no-op later in iterators_bpf__destroy(). \ + */ \ + close_fd(skel->links.__name##_fd); \ + skel->links.__name##_fd = 0; \ + idx++; \ +} while (0) + +static struct bpf_map_ops hid_bpf_prog_fd_maps_ops; + +int hid_bpf_preload_skel(void) +{ + int err, idx = 0; + + skel = entrypoints_bpf__open(); + if (!skel) + return -ENOMEM; + + err = entrypoints_bpf__load(skel); + if (err) + goto out; + + jmp_table.map = bpf_map_get_with_uref(skel->maps.hid_jmp_table.map_fd); + if (IS_ERR(jmp_table.map)) { + err = PTR_ERR(jmp_table.map); + goto out; + } + + /* our jump table is stealing refs, so we should not decrement on removal of elements */ + hid_bpf_prog_fd_maps_ops = *jmp_table.map->ops; + hid_bpf_prog_fd_maps_ops.map_fd_put_ptr = hid_bpf_prog_fd_array_put_ptr; + + jmp_table.map->ops = &hid_bpf_prog_fd_maps_ops; + + ATTACH_AND_STORE_LINK(hid_tail_call); + ATTACH_AND_STORE_LINK(hid_bpf_prog_put_deferred); + + return 0; +out: + hid_bpf_free_links_and_skel(); + return err; +} diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 9c1d31f63f85..fa4436b8101e 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1218,7 +1218,8 @@ int hid_open_report(struct hid_device *device) return -ENODEV; size = device->dev_rsize; - buf = kmemdup(start, size, GFP_KERNEL); + /* call_hid_bpf_rdesc_fixup() ensures we work on a copy of rdesc */ + buf = call_hid_bpf_rdesc_fixup(device, start, &size); if (buf == NULL) return -ENOMEM; @@ -2040,6 +2041,12 @@ int hid_input_report(struct hid_device *hid, enum hid_report_type type, u8 *data report_enum = hid->report_enum + type; hdrv = hid->driver; + data = dispatch_hid_bpf_device_event(hid, type, data, &size, interrupt); + if (IS_ERR(data)) { + ret = PTR_ERR(data); + goto unlock; + } + if (!size) { dbg_hid("empty report\n"); ret = -1; @@ -2154,6 +2161,10 @@ int hid_connect(struct hid_device *hdev, unsigned int connect_mask) int len; int ret; + ret = hid_bpf_connect_device(hdev); + if (ret) + return ret; + if (hdev->quirks & HID_QUIRK_HIDDEV_FORCE) connect_mask |= (HID_CONNECT_HIDDEV_FORCE | HID_CONNECT_HIDDEV); if (hdev->quirks & HID_QUIRK_HIDINPUT_FORCE) @@ -2255,6 +2266,8 @@ void hid_disconnect(struct hid_device *hdev) if (hdev->claimed & HID_CLAIMED_HIDRAW) hidraw_disconnect(hdev); hdev->claimed = 0; + + hid_bpf_disconnect_device(hdev); } EXPORT_SYMBOL_GPL(hid_disconnect); @@ -2790,6 +2803,8 @@ struct hid_device *hid_allocate_device(void) sema_init(&hdev->driver_input_lock, 1); mutex_init(&hdev->ll_open_lock); + hid_bpf_device_init(hdev); + return hdev; } EXPORT_SYMBOL_GPL(hid_allocate_device); @@ -2816,6 +2831,7 @@ static void hid_remove_device(struct hid_device *hdev) */ void hid_destroy_device(struct hid_device *hdev) { + hid_bpf_destroy_device(hdev); hid_remove_device(hdev); put_device(&hdev->dev); } @@ -2902,6 +2918,15 @@ int hid_check_keys_pressed(struct hid_device *hid) } EXPORT_SYMBOL_GPL(hid_check_keys_pressed); +#ifdef CONFIG_HID_BPF +static struct hid_bpf_ops hid_ops = { + .hid_get_report = hid_get_report, + .hid_hw_raw_request = hid_hw_raw_request, + .owner = THIS_MODULE, + .bus_type = &hid_bus_type, +}; +#endif + static int __init hid_init(void) { int ret; @@ -2916,6 +2941,10 @@ static int __init hid_init(void) goto err; } +#ifdef CONFIG_HID_BPF + hid_bpf_ops = &hid_ops; +#endif + ret = hidraw_init(); if (ret) goto err_bus; @@ -2931,6 +2960,9 @@ err: static void __exit hid_exit(void) { +#ifdef CONFIG_HID_BPF + hid_bpf_ops = NULL; +#endif hid_debug_exit(); hidraw_exit(); bus_unregister(&hid_bus_type); diff --git a/include/linux/hid.h b/include/linux/hid.h index 8677ae38599e..cd3c52fae7b1 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -26,6 +26,7 @@ #include <linux/mutex.h> #include <linux/power_supply.h> #include <uapi/linux/hid.h> +#include <linux/hid_bpf.h> /* * We parse each description item into this structure. Short items data @@ -651,6 +652,10 @@ struct hid_device { /* device report descriptor */ wait_queue_head_t debug_wait; unsigned int id; /* system unique id */ + +#ifdef CONFIG_BPF + struct hid_bpf bpf; /* hid-bpf data */ +#endif /* CONFIG_BPF */ }; #define to_hid_device(pdev) \ diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h new file mode 100644 index 000000000000..3ca85ab91325 --- /dev/null +++ b/include/linux/hid_bpf.h @@ -0,0 +1,163 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ + +#ifndef __HID_BPF_H +#define __HID_BPF_H + +#include <linux/spinlock.h> +#include <uapi/linux/hid.h> + +struct hid_device; + +/* + * The following is the user facing HID BPF API. + * + * Extra care should be taken when editing this part, as + * it might break existing out of the tree bpf programs. + */ + +/** + * struct hid_bpf_ctx - User accessible data for all HID programs + * + * ``data`` is not directly accessible from the context. We need to issue + * a call to ``hid_bpf_get_data()`` in order to get a pointer to that field. + * + * All of these fields are currently read-only. + * + * @index: program index in the jump table. No special meaning (a smaller index + * doesn't mean the program will be executed before another program with + * a bigger index). + * @hid: the ``struct hid_device`` representing the device itself + * @report_type: used for ``hid_bpf_device_event()`` + * @allocated_size: Allocated size of data. + * + * This is how much memory is available and can be requested + * by the HID program. + * Note that for ``HID_BPF_RDESC_FIXUP``, that memory is set to + * ``4096`` (4 KB) + * @size: Valid data in the data field. + * + * Programs can get the available valid size in data by fetching this field. + * Programs can also change this value by returning a positive number in the + * program. + * To discard the event, return a negative error code. + * + * ``size`` must always be less or equal than ``allocated_size`` (it is enforced + * once all BPF programs have been run). + * @retval: Return value of the previous program. + */ +struct hid_bpf_ctx { + __u32 index; + const struct hid_device *hid; + __u32 allocated_size; + enum hid_report_type report_type; + union { + __s32 retval; + __s32 size; + }; +}; + +/** + * enum hid_bpf_attach_flags - flags used when attaching a HIF-BPF program + * + * @HID_BPF_FLAG_NONE: no specific flag is used, the kernel choses where to + * insert the program + * @HID_BPF_FLAG_INSERT_HEAD: insert the given program before any other program + * currently attached to the device. This doesn't + * guarantee that this program will always be first + * @HID_BPF_FLAG_MAX: sentinel value, not to be used by the callers + */ +enum hid_bpf_attach_flags { + HID_BPF_FLAG_NONE = 0, + HID_BPF_FLAG_INSERT_HEAD = _BITUL(0), + HID_BPF_FLAG_MAX, +}; + +/* Following functions are tracepoints that BPF programs can attach to */ +int hid_bpf_device_event(struct hid_bpf_ctx *ctx); +int hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx); + +/* Following functions are kfunc that we export to BPF programs */ +/* available everywhere in HID-BPF */ +__u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx, unsigned int offset, const size_t __sz); + +/* only available in syscall */ +int hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, __u32 flags); +int hid_bpf_hw_request(struct hid_bpf_ctx *ctx, __u8 *buf, size_t buf__sz, + enum hid_report_type rtype, enum hid_class_request reqtype); +struct hid_bpf_ctx *hid_bpf_allocate_context(unsigned int hid_id); +void hid_bpf_release_context(struct hid_bpf_ctx *ctx); + +/* + * Below is HID internal + */ + +/* internal function to call eBPF programs, not to be used by anybody */ +int __hid_bpf_tail_call(struct hid_bpf_ctx *ctx); + +#define HID_BPF_MAX_PROGS_PER_DEV 64 +#define HID_BPF_FLAG_MASK (((HID_BPF_FLAG_MAX - 1) << 1) - 1) + +/* types of HID programs to attach to */ +enum hid_bpf_prog_type { + HID_BPF_PROG_TYPE_UNDEF = -1, + HID_BPF_PROG_TYPE_DEVICE_EVENT, /* an event is emitted from the device */ + HID_BPF_PROG_TYPE_RDESC_FIXUP, + HID_BPF_PROG_TYPE_MAX, +}; + +struct hid_report_enum; + +struct hid_bpf_ops { + struct hid_report *(*hid_get_report)(struct hid_report_enum *report_enum, const u8 *data); + int (*hid_hw_raw_request)(struct hid_device *hdev, + unsigned char reportnum, __u8 *buf, + size_t len, enum hid_report_type rtype, + enum hid_class_request reqtype); + struct module *owner; + struct bus_type *bus_type; +}; + +extern struct hid_bpf_ops *hid_bpf_ops; + +struct hid_bpf_prog_list { + u16 prog_idx[HID_BPF_MAX_PROGS_PER_DEV]; + u8 prog_cnt; +}; + +/* stored in each device */ +struct hid_bpf { + u8 *device_data; /* allocated when a bpf program of type + * SEC(f.../hid_bpf_device_event) has been attached + * to this HID device + */ + u32 allocated_data; + + struct hid_bpf_prog_list __rcu *progs[HID_BPF_PROG_TYPE_MAX]; /* attached BPF progs */ + bool destroyed; /* prevents the assignment of any progs */ + + spinlock_t progs_lock; /* protects RCU update of progs */ +}; + +#ifdef CONFIG_HID_BPF +u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type, u8 *data, + u32 *size, int interrupt); +int hid_bpf_connect_device(struct hid_device *hdev); +void hid_bpf_disconnect_device(struct hid_device *hdev); +void hid_bpf_destroy_device(struct hid_device *hid); +void hid_bpf_device_init(struct hid_device *hid); +u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size); +#else /* CONFIG_HID_BPF */ +static inline u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type, + u8 *data, u32 *size, int interrupt) { return data; } +static inline int hid_bpf_connect_device(struct hid_device *hdev) { return 0; } +static inline void hid_bpf_disconnect_device(struct hid_device *hdev) {} +static inline void hid_bpf_destroy_device(struct hid_device *hid) {} +static inline void hid_bpf_device_init(struct hid_device *hid) {} +static inline u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size) +{ + return kmemdup(rdesc, *size, GFP_KERNEL); +} + +#endif /* CONFIG_HID_BPF */ + +#endif /* __HID_BPF_H */ diff --git a/net/bluetooth/hidp/Kconfig b/net/bluetooth/hidp/Kconfig index 14100f341f33..6746be07e222 100644 --- a/net/bluetooth/hidp/Kconfig +++ b/net/bluetooth/hidp/Kconfig @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0-only config BT_HIDP tristate "HIDP protocol support" - depends on BT_BREDR && INPUT + depends on BT_BREDR && INPUT && HID_SUPPORT select HID help HIDP (Human Interface Device Protocol) is a transport layer diff --git a/samples/hid/.gitignore b/samples/hid/.gitignore new file mode 100644 index 000000000000..3ea0fed3bbad --- /dev/null +++ b/samples/hid/.gitignore @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0-only +hid_mouse +hid_surface_dial +*.out +*.skel.h +/vmlinux.h +/bpftool/ +/libbpf/ diff --git a/samples/hid/Makefile b/samples/hid/Makefile new file mode 100644 index 000000000000..026288280a03 --- /dev/null +++ b/samples/hid/Makefile @@ -0,0 +1,250 @@ +# 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 +tprogs-y += hid_surface_dial + +# 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 +hid_surface_dial-objs := hid_surface_dial.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: $(obj)/hid_mouse.skel.h +$(obj)/hid_surface_dial.o: $(obj)/hid_surface_dial.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 hid_surface_dial.skel.h +clean-files += $(LINKED_SKELS) + +hid_mouse.skel.h-deps := hid_mouse.bpf.o hid_bpf_attach.bpf.o +hid_surface_dial.skel.h-deps := hid_surface_dial.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..4fff31dbe0e7 --- /dev/null +++ b/samples/hid/hid_bpf_helpers.h @@ -0,0 +1,21 @@ +/* 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 struct hid_bpf_ctx *hid_bpf_allocate_context(unsigned int hid_id) __ksym; +extern void hid_bpf_release_context(struct hid_bpf_ctx *ctx) __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; +} diff --git a/samples/hid/hid_surface_dial.bpf.c b/samples/hid/hid_surface_dial.bpf.c new file mode 100644 index 000000000000..1f80478c0918 --- /dev/null +++ b/samples/hid/hid_surface_dial.bpf.c @@ -0,0 +1,134 @@ +// 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_helpers.h" + +#define HID_UP_BUTTON 0x0009 +#define HID_GD_WHEEL 0x0038 + +SEC("fmod_ret/hid_bpf_device_event") +int BPF_PROG(hid_event, struct hid_bpf_ctx *hctx) +{ + __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */); + + if (!data) + return 0; /* EPERM check */ + + /* Touch */ + data[1] &= 0xfd; + + /* X */ + data[4] = 0; + data[5] = 0; + + /* Y */ + data[6] = 0; + data[7] = 0; + + return 0; +} + +/* 72 == 360 / 5 -> 1 report every 5 degrees */ +int resolution = 72; +int physical = 5; + +struct haptic_syscall_args { + unsigned int hid; + int retval; +}; + +static __u8 haptic_data[8]; + +SEC("syscall") +int set_haptic(struct haptic_syscall_args *args) +{ + struct hid_bpf_ctx *ctx; + const size_t size = sizeof(haptic_data); + u16 *res; + int ret; + + if (size > sizeof(haptic_data)) + return -7; /* -E2BIG */ + + ctx = hid_bpf_allocate_context(args->hid); + if (!ctx) + return -1; /* EPERM check */ + + haptic_data[0] = 1; /* report ID */ + + ret = hid_bpf_hw_request(ctx, haptic_data, size, HID_FEATURE_REPORT, HID_REQ_GET_REPORT); + + bpf_printk("probed/remove event ret value: %d", ret); + bpf_printk("buf: %02x %02x %02x", + haptic_data[0], + haptic_data[1], + haptic_data[2]); + bpf_printk(" %02x %02x %02x", + haptic_data[3], + haptic_data[4], + haptic_data[5]); + bpf_printk(" %02x %02x", + haptic_data[6], + haptic_data[7]); + + /* whenever resolution multiplier is not 3600, we have the fixed report descriptor */ + res = (u16 *)&haptic_data[1]; + if (*res != 3600) { +// haptic_data[1] = 72; /* resolution multiplier */ +// haptic_data[2] = 0; /* resolution multiplier */ +// haptic_data[3] = 0; /* Repeat Count */ + haptic_data[4] = 3; /* haptic Auto Trigger */ +// haptic_data[5] = 5; /* Waveform Cutoff Time */ +// haptic_data[6] = 80; /* Retrigger Period */ +// haptic_data[7] = 0; /* Retrigger Period */ + } else { + haptic_data[4] = 0; + } + + ret = hid_bpf_hw_request(ctx, haptic_data, size, HID_FEATURE_REPORT, HID_REQ_SET_REPORT); + + bpf_printk("set haptic ret value: %d -> %d", ret, haptic_data[4]); + + args->retval = ret; + + hid_bpf_release_context(ctx); + + return 0; +} + +/* Convert REL_DIAL into REL_WHEEL */ +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 */); + __u16 *res, *phys; + + if (!data) + return 0; /* EPERM check */ + + /* Convert TOUCH into a button */ + data[31] = HID_UP_BUTTON; + data[33] = 2; + + /* Convert REL_DIAL into REL_WHEEL */ + data[45] = HID_GD_WHEEL; + + /* Change Resolution Multiplier */ + phys = (__u16 *)&data[61]; + *phys = physical; + res = (__u16 *)&data[66]; + *res = resolution; + + /* Convert X,Y from Abs to Rel */ + data[88] = 0x06; + data[98] = 0x06; + + return 0; +} + +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = 1; diff --git a/samples/hid/hid_surface_dial.c b/samples/hid/hid_surface_dial.c new file mode 100644 index 000000000000..4bc97373a708 --- /dev/null +++ b/samples/hid/hid_surface_dial.c @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2022 Benjamin Tissoires + * + * This program will morph the Microsoft Surface Dial into a mouse, + * and depending on the chosen resolution enable or not the haptic feedback: + * - a resolution (-r) of 3600 will report 3600 "ticks" in one full rotation + * without haptic feedback + * - any other resolution will report N "ticks" in a full rotation with haptic + * feedback + * + * A good default for low resolution haptic scrolling is 72 (1 "tick" every 5 + * degrees), and set to 3600 for smooth scrolling. + */ + +#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_surface_dial.skel.h" +#include "hid_bpf_attach.h" + +static bool running = true; + +struct haptic_syscall_args { + unsigned int hid; + int retval; +}; + +static void int_exit(int sig) +{ + running = false; + exit(0); +} + +static void usage(const char *prog) +{ + fprintf(stderr, + "%s: %s [OPTIONS] /sys/bus/hid/devices/0BUS:0VID:0PID:00ID\n\n" + " OPTIONS:\n" + " -r N\t set the given resolution to the device (number of ticks per 360°)\n\n", + __func__, prog); + fprintf(stderr, + "This program will morph the Microsoft Surface Dial into a mouse,\n" + "and depending on the chosen resolution enable or not the haptic feedback:\n" + "- a resolution (-r) of 3600 will report 3600 'ticks' in one full rotation\n" + " without haptic feedback\n" + "- any other resolution will report N 'ticks' in a full rotation with haptic\n" + " feedback\n" + "\n" + "A good default for low resolution haptic scrolling is 72 (1 'tick' every 5\n" + "degrees), and set to 3600 for smooth scrolling.\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); +} + +static int attach_prog(struct hid_surface_dial *skel, struct bpf_program *prog, int hid_id) +{ + struct attach_prog_args args = { + .hid = hid_id, + .retval = -1, + }; + int attach_fd, err; + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr, + .ctx_in = &args, + .ctx_size_in = sizeof(args), + ); + + attach_fd = bpf_program__fd(skel->progs.attach_prog); + if (attach_fd < 0) { + fprintf(stderr, "can't locate attach prog: %m\n"); + return 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; + } + return 0; +} + +static int set_haptic(struct hid_surface_dial *skel, int hid_id) +{ + struct haptic_syscall_args args = { + .hid = hid_id, + .retval = -1, + }; + int haptic_fd, err; + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr, + .ctx_in = &args, + .ctx_size_in = sizeof(args), + ); + + haptic_fd = bpf_program__fd(skel->progs.set_haptic); + if (haptic_fd < 0) { + fprintf(stderr, "can't locate haptic prog: %m\n"); + return 1; + } + + err = bpf_prog_test_run_opts(haptic_fd, &tattr); + if (err) { + fprintf(stderr, "can't set haptic configuration to hid device %d: %m (err: %d)\n", + hid_id, err); + return 1; + } + return 0; +} + +int main(int argc, char **argv) +{ + struct hid_surface_dial *skel; + struct bpf_program *prog; + const char *optstr = "r:"; + const char *sysfs_path; + int opt, hid_id, resolution = 72; + + while ((opt = getopt(argc, argv, optstr)) != -1) { + switch (opt) { + case 'r': + { + char *endp = NULL; + long l = -1; + + if (optarg) { + l = strtol(optarg, &endp, 10); + if (endp && *endp) + l = -1; + } + + if (l < 0) { + fprintf(stderr, + "invalid r option %s - expecting a number\n", + optarg ? optarg : ""); + exit(EXIT_FAILURE); + }; + + resolution = (int) l; + break; + } + 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_surface_dial__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; + } + + skel->data->resolution = resolution; + skel->data->physical = (int)(resolution / 72); + + bpf_object__for_each_program(prog, *skel->skeleton->obj) { + /* ignore syscalls */ + if (bpf_program__get_type(prog) != BPF_PROG_TYPE_TRACING) + continue; + + attach_prog(skel, prog, hid_id); + } + + signal(SIGINT, int_exit); + signal(SIGTERM, int_exit); + + set_haptic(skel, hid_id); + + while (running) + sleep(1); + + hid_surface_dial__destroy(skel); + + return 0; +} diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index f07aef7c592c..479127efddf9 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -26,6 +26,7 @@ TARGETS += fpu TARGETS += ftrace TARGETS += futex TARGETS += gpio +TARGETS += hid TARGETS += intel_pstate TARGETS += ipc TARGETS += ir diff --git a/tools/testing/selftests/hid/.gitignore b/tools/testing/selftests/hid/.gitignore new file mode 100644 index 000000000000..a462ca6ab2c0 --- /dev/null +++ b/tools/testing/selftests/hid/.gitignore @@ -0,0 +1,4 @@ +bpftool +*.skel.h +/tools +hid_bpf diff --git a/tools/testing/selftests/hid/Makefile b/tools/testing/selftests/hid/Makefile new file mode 100644 index 000000000000..693f1cb6e47a --- /dev/null +++ b/tools/testing/selftests/hid/Makefile @@ -0,0 +1,233 @@ +# SPDX-License-Identifier: GPL-2.0 + +# based on tools/testing/selftest/bpf/Makefile +include ../../../build/Build.include +include ../../../scripts/Makefile.arch +include ../../../scripts/Makefile.include + +CXX ?= $(CROSS_COMPILE)g++ + +CURDIR := $(abspath .) +TOOLSDIR := $(abspath ../../..) +TOP_SRCDIR = $(CURDIR)/../../../.. +KHDR_INCLUDES := $(TOP_SRCDIR)/usr/include +LIBDIR := $(TOOLSDIR)/lib +BPFDIR := $(LIBDIR)/bpf +TOOLSINCDIR := $(TOOLSDIR)/include +BPFTOOLDIR := $(TOOLSDIR)/bpf/bpftool +HOSTPKG_CONFIG := pkg-config + +CFLAGS += -g -O0 -rdynamic -Wall -Werror -I$(KHDR_INCLUDES) +LDLIBS += -lelf -lz -lrt -lpthread + +# Silence some warnings when compiled with clang +ifneq ($(LLVM),) +CFLAGS += -Wno-unused-command-line-argument +endif + +# Order correspond to 'make run_tests' order +TEST_GEN_PROGS = hid_bpf + +# Emit succinct information message describing current building step +# $1 - generic step name (e.g., CC, LINK, etc); +# $2 - optional "flavor" specifier; if provided, will be emitted as [flavor]; +# $3 - target (assumed to be file); only file name will be emitted; +# $4 - optional extra arg, emitted as-is, if provided. +ifeq ($(V),1) +Q = +msg = +else +Q = @ +msg = @printf ' %-8s%s %s%s\n' "$(1)" "$(if $(2), [$(2)])" "$(notdir $(3))" "$(if $(4), $(4))"; +MAKEFLAGS += --no-print-directory +submake_extras := feature_display=0 +endif + +# override lib.mk's default rules +OVERRIDE_TARGETS := 1 +override define CLEAN + $(call msg,CLEAN) + $(Q)$(RM) -r $(TEST_GEN_PROGS) + $(Q)$(RM) -r $(EXTRA_CLEAN) +endef + +include ../lib.mk + +SCRATCH_DIR := $(OUTPUT)/tools +BUILD_DIR := $(SCRATCH_DIR)/build +INCLUDE_DIR := $(SCRATCH_DIR)/include +BPFOBJ := $(BUILD_DIR)/libbpf/libbpf.a +ifneq ($(CROSS_COMPILE),) +HOST_BUILD_DIR := $(BUILD_DIR)/host +HOST_SCRATCH_DIR := $(OUTPUT)/host-tools +HOST_INCLUDE_DIR := $(HOST_SCRATCH_DIR)/include +else +HOST_BUILD_DIR := $(BUILD_DIR) +HOST_SCRATCH_DIR := $(SCRATCH_DIR) +HOST_INCLUDE_DIR := $(INCLUDE_DIR) +endif +HOST_BPFOBJ := $(HOST_BUILD_DIR)/libbpf/libbpf.a +RESOLVE_BTFIDS := $(HOST_BUILD_DIR)/resolve_btfids/resolve_btfids + +VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \ + $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux) \ + ../../../../vmlinux \ + /sys/kernel/btf/vmlinux \ + /boot/vmlinux-$(shell uname -r) +VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS)))) +ifeq ($(VMLINUX_BTF),) +$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)") +endif + +# Define simple and short `make test_progs`, `make test_sysctl`, etc targets +# to build individual tests. +# NOTE: Semicolon at the end is critical to override lib.mk's default static +# rule for binaries. +$(notdir $(TEST_GEN_PROGS)): %: $(OUTPUT)/% ; + +# sort removes libbpf duplicates when not cross-building +MAKE_DIRS := $(sort $(BUILD_DIR)/libbpf $(HOST_BUILD_DIR)/libbpf \ + $(HOST_BUILD_DIR)/bpftool $(HOST_BUILD_DIR)/resolve_btfids \ + $(INCLUDE_DIR)) +$(MAKE_DIRS): + $(call msg,MKDIR,,$@) + $(Q)mkdir -p $@ + +$(OUTPUT)/%.o: %.c + $(call msg,CC,,$@) + $(Q)$(CC) $(CFLAGS) -c $(filter %.c,$^) $(LDLIBS) -o $@ + +# LLVM's ld.lld doesn't support all the architectures, so use it only on x86 +ifeq ($(SRCARCH),x86) +LLD := lld +else +LLD := ld +endif + +DEFAULT_BPFTOOL := $(HOST_SCRATCH_DIR)/sbin/bpftool + +TEST_GEN_PROGS_EXTENDED += $(DEFAULT_BPFTOOL) + +$(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED): $(BPFOBJ) + +BPFTOOL ?= $(DEFAULT_BPFTOOL) +$(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \ + $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/bpftool + $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \ + ARCH= CROSS_COMPILE= CC=$(HOSTCC) LD=$(HOSTLD) \ + EXTRA_CFLAGS='-g -O0' \ + OUTPUT=$(HOST_BUILD_DIR)/bpftool/ \ + LIBBPF_OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \ + LIBBPF_DESTDIR=$(HOST_SCRATCH_DIR)/ \ + prefix= DESTDIR=$(HOST_SCRATCH_DIR)/ install-bin + +$(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \ + $(KHDR_INCLUDES)/linux/bpf.h \ + | $(BUILD_DIR)/libbpf + $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(BUILD_DIR)/libbpf/ \ + EXTRA_CFLAGS='-g -O0' \ + DESTDIR=$(SCRATCH_DIR) prefix= all install_headers + +ifneq ($(BPFOBJ),$(HOST_BPFOBJ)) +$(HOST_BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \ + $(KHDR_INCLUDES)/linux/bpf.h \ + | $(HOST_BUILD_DIR)/libbpf + $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) \ + EXTRA_CFLAGS='-g -O0' ARCH= CROSS_COMPILE= \ + OUTPUT=$(HOST_BUILD_DIR)/libbpf/ CC=$(HOSTCC) LD=$(HOSTLD) \ + DESTDIR=$(HOST_SCRATCH_DIR)/ prefix= all install_headers +endif + +$(INCLUDE_DIR)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) | $(INCLUDE_DIR) +ifeq ($(VMLINUX_H),) + $(call msg,GEN,,$@) + $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@ +else + $(call msg,CP,,$@) + $(Q)cp "$(VMLINUX_H)" $@ +endif + +$(RESOLVE_BTFIDS): $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/resolve_btfids \ + $(TOOLSDIR)/bpf/resolve_btfids/main.c \ + $(TOOLSDIR)/lib/rbtree.c \ + $(TOOLSDIR)/lib/zalloc.c \ + $(TOOLSDIR)/lib/string.c \ + $(TOOLSDIR)/lib/ctype.c \ + $(TOOLSDIR)/lib/str_error_r.c + $(Q)$(MAKE) $(submake_extras) -C $(TOOLSDIR)/bpf/resolve_btfids \ + CC=$(HOSTCC) LD=$(HOSTLD) AR=$(HOSTAR) \ + LIBBPF_INCLUDE=$(HOST_INCLUDE_DIR) \ + OUTPUT=$(HOST_BUILD_DIR)/resolve_btfids/ BPFOBJ=$(HOST_BPFOBJ) + +# Get Clang's default includes on this system, as opposed to those seen by +# '-target bpf'. This fixes "missing" files on some architectures/distros, +# such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc. +# +# Use '-idirafter': Don't interfere with include mechanics except where the +# build would have failed anyways. +define get_sys_includes +$(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 '__riscv_xlen ' | awk '{printf("-D__riscv_xlen=%d -D__BITS_PER_LONG=%d", $$3, $$3)}') +endef + +# Determine target endianness. +IS_LITTLE_ENDIAN = $(shell $(CC) -dM -E - </dev/null | \ + grep 'define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__') +MENDIAN=$(if $(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian) + +CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG)) +BPF_CFLAGS = -g -Werror -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN) \ + -I$(INCLUDE_DIR) -I$(CURDIR) -I$(KHDR_INCLUDES) \ + -I$(abspath $(OUTPUT)/../usr/include) + +CLANG_CFLAGS = $(CLANG_SYS_INCLUDES) \ + -Wno-compare-distinct-pointer-types + +# Build BPF object using Clang +# $1 - input .c file +# $2 - output .o file +# $3 - CFLAGS +define CLANG_BPF_BUILD_RULE + $(call msg,CLNG-BPF,$(TRUNNER_BINARY),$2) + $(Q)$(CLANG) $3 -O2 -target bpf -c $1 -mcpu=v3 -o $2 +endef +# Similar to CLANG_BPF_BUILD_RULE, but with disabled alu32 +define CLANG_NOALU32_BPF_BUILD_RULE + $(call msg,CLNG-BPF,$(TRUNNER_BINARY),$2) + $(Q)$(CLANG) $3 -O2 -target bpf -c $1 -mcpu=v2 -o $2 +endef +# Build BPF object using GCC +define GCC_BPF_BUILD_RULE + $(call msg,GCC-BPF,$(TRUNNER_BINARY),$2) + $(Q)$(BPF_GCC) $3 -O2 -c $1 -o $2 +endef + +BPF_PROGS_DIR := progs +BPF_BUILD_RULE := CLANG_BPF_BUILD_RULE +BPF_SRCS := $(notdir $(wildcard $(BPF_PROGS_DIR)/*.c)) +BPF_OBJS := $(patsubst %.c,$(OUTPUT)/%.bpf.o, $(BPF_SRCS)) +BPF_SKELS := $(patsubst %.c,$(OUTPUT)/%.skel.h, $(BPF_SRCS)) +TEST_GEN_FILES += $(BPF_OBJS) + +$(BPF_PROGS_DIR)-bpfobjs := y +$(BPF_OBJS): $(OUTPUT)/%.bpf.o: \ + $(BPF_PROGS_DIR)/%.c \ + $(wildcard $(BPF_PROGS_DIR)/*.h) \ + $(INCLUDE_DIR)/vmlinux.h \ + $(wildcard $(BPFDIR)/hid_bpf_*.h) \ + $(wildcard $(BPFDIR)/*.bpf.h) \ + | $(OUTPUT) $(BPFOBJ) + $(call $(BPF_BUILD_RULE),$<,$@, $(BPF_CFLAGS)) + +$(BPF_SKELS): %.skel.h: %.bpf.o $(BPFTOOL) | $(OUTPUT) + $(call msg,GEN-SKEL,$(BINARY),$@) + $(Q)$(BPFTOOL) gen object $(<:.o=.linked1.o) $< + $(Q)$(BPFTOOL) gen skeleton $(<:.o=.linked1.o) name $(notdir $(<:.bpf.o=)) > $@ + +$(OUTPUT)/%:%.c $(BPF_SKELS) + $(call msg,BINARY,,$@) + $(Q)$(LINK.c) $^ $(LDLIBS) -o $@ + +EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR) feature bpftool \ + $(addprefix $(OUTPUT)/,*.o *.skel.h no_alu32) diff --git a/tools/testing/selftests/hid/config b/tools/testing/selftests/hid/config new file mode 100644 index 000000000000..d4130489c1b1 --- /dev/null +++ b/tools/testing/selftests/hid/config @@ -0,0 +1,20 @@ +CONFIG_BPF_EVENTS=y +CONFIG_BPFILTER=y +CONFIG_BPF_JIT_ALWAYS_ON=y +CONFIG_BPF_JIT=y +CONFIG_BPF_KPROBE_OVERRIDE=y +CONFIG_BPF_LSM=y +CONFIG_BPF_PRELOAD_UMD=y +CONFIG_BPF_PRELOAD=y +CONFIG_BPF_STREAM_PARSER=y +CONFIG_BPF_SYSCALL=y +CONFIG_BPF=y +CONFIG_CGROUP_BPF=y +CONFIG_DEBUG_INFO_BTF=y +CONFIG_FPROBE=y +CONFIG_FTRACE_SYSCALLS=y +CONFIG_FUNCTION_TRACER=y +CONFIG_HIDRAW=y +CONFIG_HID=y +CONFIG_INPUT_EVDEV=y +CONFIG_UHID=y diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c new file mode 100644 index 000000000000..6615c26fb5dd --- /dev/null +++ b/tools/testing/selftests/hid/hid_bpf.c @@ -0,0 +1,845 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Red Hat */ +#include "hid.skel.h" + +#include "../kselftest_harness.h" + +#include <bpf/bpf.h> +#include <fcntl.h> +#include <fnmatch.h> +#include <dirent.h> +#include <poll.h> +#include <pthread.h> +#include <stdbool.h> +#include <linux/hidraw.h> +#include <linux/uhid.h> + +#define SHOW_UHID_DEBUG 0 + +static unsigned char rdesc[] = { + 0x06, 0x00, 0xff, /* Usage Page (Vendor Defined Page 1) */ + 0x09, 0x21, /* Usage (Vendor Usage 0x21) */ + 0xa1, 0x01, /* COLLECTION (Application) */ + 0x09, 0x01, /* Usage (Vendor Usage 0x01) */ + 0xa1, 0x00, /* COLLECTION (Physical) */ + 0x85, 0x02, /* REPORT_ID (2) */ + 0x19, 0x01, /* USAGE_MINIMUM (1) */ + 0x29, 0x08, /* USAGE_MAXIMUM (3) */ + 0x15, 0x00, /* LOGICAL_MINIMUM (0) */ + 0x25, 0xff, /* LOGICAL_MAXIMUM (255) */ + 0x95, 0x08, /* REPORT_COUNT (8) */ + 0x75, 0x08, /* REPORT_SIZE (8) */ + 0x81, 0x02, /* INPUT (Data,Var,Abs) */ + 0xc0, /* END_COLLECTION */ + 0x09, 0x01, /* Usage (Vendor Usage 0x01) */ + 0xa1, 0x00, /* COLLECTION (Physical) */ + 0x85, 0x01, /* REPORT_ID (1) */ + 0x06, 0x00, 0xff, /* Usage Page (Vendor Defined Page 1) */ + 0x19, 0x01, /* USAGE_MINIMUM (1) */ + 0x29, 0x03, /* USAGE_MAXIMUM (3) */ + 0x15, 0x00, /* LOGICAL_MINIMUM (0) */ + 0x25, 0x01, /* LOGICAL_MAXIMUM (1) */ + 0x95, 0x03, /* REPORT_COUNT (3) */ + 0x75, 0x01, /* REPORT_SIZE (1) */ + 0x81, 0x02, /* INPUT (Data,Var,Abs) */ + 0x95, 0x01, /* REPORT_COUNT (1) */ + 0x75, 0x05, /* REPORT_SIZE (5) */ + 0x81, 0x01, /* INPUT (Cnst,Var,Abs) */ + 0x05, 0x01, /* USAGE_PAGE (Generic Desktop) */ + 0x09, 0x30, /* USAGE (X) */ + 0x09, 0x31, /* USAGE (Y) */ + 0x15, 0x81, /* LOGICAL_MINIMUM (-127) */ + 0x25, 0x7f, /* LOGICAL_MAXIMUM (127) */ + 0x75, 0x10, /* REPORT_SIZE (16) */ + 0x95, 0x02, /* REPORT_COUNT (2) */ + 0x81, 0x06, /* INPUT (Data,Var,Rel) */ + + 0x06, 0x00, 0xff, /* Usage Page (Vendor Defined Page 1) */ + 0x19, 0x01, /* USAGE_MINIMUM (1) */ + 0x29, 0x03, /* USAGE_MAXIMUM (3) */ + 0x15, 0x00, /* LOGICAL_MINIMUM (0) */ + 0x25, 0x01, /* LOGICAL_MAXIMUM (1) */ + 0x95, 0x03, /* REPORT_COUNT (3) */ + 0x75, 0x01, /* REPORT_SIZE (1) */ + 0x91, 0x02, /* Output (Data,Var,Abs) */ + 0x95, 0x01, /* REPORT_COUNT (1) */ + 0x75, 0x05, /* REPORT_SIZE (5) */ + 0x91, 0x01, /* Output (Cnst,Var,Abs) */ + + 0x06, 0x00, 0xff, /* Usage Page (Vendor Defined Page 1) */ + 0x19, 0x06, /* USAGE_MINIMUM (6) */ + 0x29, 0x08, /* USAGE_MAXIMUM (8) */ + 0x15, 0x00, /* LOGICAL_MINIMUM (0) */ + 0x25, 0x01, /* LOGICAL_MAXIMUM (1) */ + 0x95, 0x03, /* REPORT_COUNT (3) */ + 0x75, 0x01, /* REPORT_SIZE (1) */ + 0xb1, 0x02, /* Feature (Data,Var,Abs) */ + 0x95, 0x01, /* REPORT_COUNT (1) */ + 0x75, 0x05, /* REPORT_SIZE (5) */ + 0x91, 0x01, /* Output (Cnst,Var,Abs) */ + + 0xc0, /* END_COLLECTION */ + 0xc0, /* END_COLLECTION */ +}; + +static __u8 feature_data[] = { 1, 2 }; + +struct attach_prog_args { + int prog_fd; + unsigned int hid; + int retval; + int insert_head; +}; + +struct hid_hw_request_syscall_args { + __u8 data[10]; + unsigned int hid; + int retval; + size_t size; + enum hid_report_type type; + __u8 request_type; +}; + +#define ASSERT_OK(data) ASSERT_FALSE(data) +#define ASSERT_OK_PTR(ptr) ASSERT_NE(NULL, ptr) + +#define UHID_LOG(fmt, ...) do { \ + if (SHOW_UHID_DEBUG) \ + TH_LOG(fmt, ##__VA_ARGS__); \ +} while (0) + +static pthread_mutex_t uhid_started_mtx = PTHREAD_MUTEX_INITIALIZER; +static pthread_cond_t uhid_started = PTHREAD_COND_INITIALIZER; + +/* no need to protect uhid_stopped, only one thread accesses it */ +static bool uhid_stopped; + +static int uhid_write(struct __test_metadata *_metadata, int fd, const struct uhid_event *ev) +{ + ssize_t ret; + + ret = write(fd, ev, sizeof(*ev)); + if (ret < 0) { + TH_LOG("Cannot write to uhid: %m"); + return -errno; + } else if (ret != sizeof(*ev)) { + TH_LOG("Wrong size written to uhid: %zd != %zu", + ret, sizeof(ev)); + return -EFAULT; + } else { + return 0; + } +} + +static int uhid_create(struct __test_metadata *_metadata, int fd, int rand_nb) +{ + struct uhid_event ev; + char buf[25]; + + sprintf(buf, "test-uhid-device-%d", rand_nb); + + memset(&ev, 0, sizeof(ev)); + ev.type = UHID_CREATE; + strcpy((char *)ev.u.create.name, buf); + ev.u.create.rd_data = rdesc; + ev.u.create.rd_size = sizeof(rdesc); + ev.u.create.bus = BUS_USB; + ev.u.create.vendor = 0x0001; + ev.u.create.product = 0x0a37; + ev.u.create.version = 0; + ev.u.create.country = 0; + + sprintf(buf, "%d", rand_nb); + strcpy((char *)ev.u.create.phys, buf); + + return uhid_write(_metadata, fd, &ev); +} + +static void uhid_destroy(struct __test_metadata *_metadata, int fd) +{ + struct uhid_event ev; + + memset(&ev, 0, sizeof(ev)); + ev.type = UHID_DESTROY; + + uhid_write(_metadata, fd, &ev); +} + +static int uhid_event(struct __test_metadata *_metadata, int fd) +{ + struct uhid_event ev, answer; + ssize_t ret; + + memset(&ev, 0, sizeof(ev)); + ret = read(fd, &ev, sizeof(ev)); + if (ret == 0) { + UHID_LOG("Read HUP on uhid-cdev"); + return -EFAULT; + } else if (ret < 0) { + UHID_LOG("Cannot read uhid-cdev: %m"); + return -errno; + } else if (ret != sizeof(ev)) { + UHID_LOG("Invalid size read from uhid-dev: %zd != %zu", + ret, sizeof(ev)); + return -EFAULT; + } + + switch (ev.type) { + case UHID_START: + pthread_mutex_lock(&uhid_started_mtx); + pthread_cond_signal(&uhid_started); + pthread_mutex_unlock(&uhid_started_mtx); + + UHID_LOG("UHID_START from uhid-dev"); + break; + case UHID_STOP: + uhid_stopped = true; + + UHID_LOG("UHID_STOP from uhid-dev"); + break; + case UHID_OPEN: + UHID_LOG("UHID_OPEN from uhid-dev"); + break; + case UHID_CLOSE: + UHID_LOG("UHID_CLOSE from uhid-dev"); + break; + case UHID_OUTPUT: + UHID_LOG("UHID_OUTPUT from uhid-dev"); + break; + case UHID_GET_REPORT: + UHID_LOG("UHID_GET_REPORT from uhid-dev"); + + answer.type = UHID_GET_REPORT_REPLY; + answer.u.get_report_reply.id = ev.u.get_report.id; + answer.u.get_report_reply.err = ev.u.get_report.rnum == 1 ? 0 : -EIO; + answer.u.get_report_reply.size = sizeof(feature_data); + memcpy(answer.u.get_report_reply.data, feature_data, sizeof(feature_data)); + + uhid_write(_metadata, fd, &answer); + + break; + case UHID_SET_REPORT: + UHID_LOG("UHID_SET_REPORT from uhid-dev"); + break; + default: + TH_LOG("Invalid event from uhid-dev: %u", ev.type); + } + + return 0; +} + +struct uhid_thread_args { + int fd; + struct __test_metadata *_metadata; +}; +static void *uhid_read_events_thread(void *arg) +{ + struct uhid_thread_args *args = (struct uhid_thread_args *)arg; + struct __test_metadata *_metadata = args->_metadata; + struct pollfd pfds[1]; + int fd = args->fd; + int ret = 0; + + pfds[0].fd = fd; + pfds[0].events = POLLIN; + + uhid_stopped = false; + + while (!uhid_stopped) { + ret = poll(pfds, 1, 100); + if (ret < 0) { + TH_LOG("Cannot poll for fds: %m"); + break; + } + if (pfds[0].revents & POLLIN) { + ret = uhid_event(_metadata, fd); + if (ret) + break; + } + } + + return (void *)(long)ret; +} + +static int uhid_start_listener(struct __test_metadata *_metadata, pthread_t *tid, int uhid_fd) +{ + struct uhid_thread_args args = { + .fd = uhid_fd, + ._metadata = _metadata, + }; + int err; + + pthread_mutex_lock(&uhid_started_mtx); + err = pthread_create(tid, NULL, uhid_read_events_thread, (void *)&args); + ASSERT_EQ(0, err) { + TH_LOG("Could not start the uhid thread: %d", err); + pthread_mutex_unlock(&uhid_started_mtx); + close(uhid_fd); + return -EIO; + } + pthread_cond_wait(&uhid_started, &uhid_started_mtx); + pthread_mutex_unlock(&uhid_started_mtx); + + return 0; +} + +static int uhid_send_event(struct __test_metadata *_metadata, int fd, __u8 *buf, size_t size) +{ + struct uhid_event ev; + + if (size > sizeof(ev.u.input.data)) + return -E2BIG; + + memset(&ev, 0, sizeof(ev)); + ev.type = UHID_INPUT2; + ev.u.input2.size = size; + + memcpy(ev.u.input2.data, buf, size); + + return uhid_write(_metadata, fd, &ev); +} + +static int setup_uhid(struct __test_metadata *_metadata, int rand_nb) +{ + int fd; + const char *path = "/dev/uhid"; + int ret; + + fd = open(path, O_RDWR | O_CLOEXEC); + ASSERT_GE(fd, 0) TH_LOG("open uhid-cdev failed; %d", fd); + + ret = uhid_create(_metadata, fd, rand_nb); + ASSERT_EQ(0, ret) { + TH_LOG("create uhid device failed: %d", ret); + close(fd); + } + + return fd; +} + +static bool match_sysfs_device(int dev_id, const char *workdir, struct dirent *dir) +{ + const char *target = "0003:0001:0A37.*"; + char phys[512]; + char uevent[1024]; + char temp[512]; + int fd, nread; + bool found = false; + + if (fnmatch(target, dir->d_name, 0)) + return false; + + /* we found the correct VID/PID, now check for phys */ + sprintf(uevent, "%s/%s/uevent", workdir, dir->d_name); + + fd = open(uevent, O_RDONLY | O_NONBLOCK); + if (fd < 0) + return false; + + sprintf(phys, "PHYS=%d", dev_id); + + nread = read(fd, temp, ARRAY_SIZE(temp)); + if (nread > 0 && (strstr(temp, phys)) != NULL) + found = true; + + close(fd); + + return found; +} + +static int get_hid_id(int dev_id) +{ + const char *workdir = "/sys/devices/virtual/misc/uhid"; + const char *str_id; + DIR *d; + struct dirent *dir; + int found = -1, attempts = 3; + + /* it would be nice to be able to use nftw, but the no_alu32 target doesn't support it */ + + while (found < 0 && attempts > 0) { + attempts--; + d = opendir(workdir); + if (d) { + while ((dir = readdir(d)) != NULL) { + if (!match_sysfs_device(dev_id, workdir, dir)) + continue; + + str_id = dir->d_name + sizeof("0003:0001:0A37."); + found = (int)strtol(str_id, NULL, 16); + + break; + } + closedir(d); + } + if (found < 0) + usleep(100000); + } + + return found; +} + +static int get_hidraw(int dev_id) +{ + const char *workdir = "/sys/devices/virtual/misc/uhid"; + char sysfs[1024]; + DIR *d, *subd; + struct dirent *dir, *subdir; + int i, found = -1; + + /* retry 5 times in case the system is loaded */ + for (i = 5; i > 0; i--) { + usleep(10); + d = opendir(workdir); + + if (!d) + continue; + + while ((dir = readdir(d)) != NULL) { + if (!match_sysfs_device(dev_id, workdir, dir)) + continue; + + sprintf(sysfs, "%s/%s/hidraw", workdir, dir->d_name); + + subd = opendir(sysfs); + if (!subd) + continue; + + while ((subdir = readdir(subd)) != NULL) { + if (fnmatch("hidraw*", subdir->d_name, 0)) + continue; + + found = atoi(subdir->d_name + strlen("hidraw")); + } + + closedir(subd); + + if (found > 0) + break; + } + closedir(d); + } + + return found; +} + +static int open_hidraw(int dev_id) +{ + int hidraw_number; + char hidraw_path[64] = { 0 }; + + hidraw_number = get_hidraw(dev_id); + if (hidraw_number < 0) + return hidraw_number; + + /* open hidraw node to check the other side of the pipe */ + sprintf(hidraw_path, "/dev/hidraw%d", hidraw_number); + return open(hidraw_path, O_RDWR | O_NONBLOCK); +} + +FIXTURE(hid_bpf) { + int dev_id; + int uhid_fd; + int hidraw_fd; + int hid_id; + pthread_t tid; + struct hid *skel; +}; +static void detach_bpf(FIXTURE_DATA(hid_bpf) * self) +{ + if (self->hidraw_fd) + close(self->hidraw_fd); + self->hidraw_fd = 0; + + hid__destroy(self->skel); + self->skel = NULL; +} + +FIXTURE_TEARDOWN(hid_bpf) { + void *uhid_err; + + uhid_destroy(_metadata, self->uhid_fd); + + detach_bpf(self); + pthread_join(self->tid, &uhid_err); +} +#define TEARDOWN_LOG(fmt, ...) do { \ + TH_LOG(fmt, ##__VA_ARGS__); \ + hid_bpf_teardown(_metadata, self, variant); \ +} while (0) + +FIXTURE_SETUP(hid_bpf) +{ + time_t t; + int err; + + /* initialize random number generator */ + srand((unsigned int)time(&t)); + + self->dev_id = rand() % 1024; + + self->uhid_fd = setup_uhid(_metadata, self->dev_id); + + /* locate the uev, self, variant);ent file of the created device */ + self->hid_id = get_hid_id(self->dev_id); + ASSERT_GT(self->hid_id, 0) + TEARDOWN_LOG("Could not locate uhid device id: %d", self->hid_id); + + err = uhid_start_listener(_metadata, &self->tid, self->uhid_fd); + ASSERT_EQ(0, err) TEARDOWN_LOG("could not start udev listener: %d", err); +} + +struct test_program { + const char *name; + int insert_head; +}; +#define LOAD_PROGRAMS(progs) \ + load_programs(progs, ARRAY_SIZE(progs), _metadata, self, variant) +#define LOAD_BPF \ + load_programs(NULL, 0, _metadata, self, variant) +static void load_programs(const struct test_program programs[], + const size_t progs_count, + struct __test_metadata *_metadata, + FIXTURE_DATA(hid_bpf) * self, + const FIXTURE_VARIANT(hid_bpf) * variant) +{ + int attach_fd, err = -EINVAL; + struct attach_prog_args args = { + .retval = -1, + }; + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr, + .ctx_in = &args, + .ctx_size_in = sizeof(args), + ); + + /* open the bpf file */ + self->skel = hid__open(); + ASSERT_OK_PTR(self->skel) TEARDOWN_LOG("Error while calling hid__open"); + + for (int i = 0; i < progs_count; i++) { + struct bpf_program *prog; + + prog = bpf_object__find_program_by_name(*self->skel->skeleton->obj, + programs[i].name); + ASSERT_OK_PTR(prog) TH_LOG("can not find program by name '%s'", programs[i].name); + + bpf_program__set_autoload(prog, true); + } + + err = hid__load(self->skel); + ASSERT_OK(err) TH_LOG("hid_skel_load failed: %d", err); + + attach_fd = bpf_program__fd(self->skel->progs.attach_prog); + ASSERT_GE(attach_fd, 0) TH_LOG("locate attach_prog: %d", attach_fd); + + for (int i = 0; i < progs_count; i++) { + struct bpf_program *prog; + + prog = bpf_object__find_program_by_name(*self->skel->skeleton->obj, + programs[i].name); + ASSERT_OK_PTR(prog) TH_LOG("can not find program by name '%s'", programs[i].name); + + args.prog_fd = bpf_program__fd(prog); + args.hid = self->hid_id; + args.insert_head = programs[i].insert_head; + err = bpf_prog_test_run_opts(attach_fd, &tattr); + ASSERT_OK(args.retval) TH_LOG("attach_hid(%s): %d", programs[i].name, args.retval); + } + + self->hidraw_fd = open_hidraw(self->dev_id); + ASSERT_GE(self->hidraw_fd, 0) TH_LOG("open_hidraw"); +} + +/* + * A simple test to see if the fixture is working fine. + * If this fails, none of the other tests will pass. + */ +TEST_F(hid_bpf, test_create_uhid) +{ +} + +/* + * Attach hid_first_event to the given uhid device, + * retrieve and open the matching hidraw node, + * inject one event in the uhid device, + * check that the program sees it and can change the data + */ +TEST_F(hid_bpf, raw_event) +{ + const struct test_program progs[] = { + { .name = "hid_first_event" }, + }; + __u8 buf[10] = {0}; + int err; + + LOAD_PROGRAMS(progs); + + /* check that the program is correctly loaded */ + ASSERT_EQ(self->skel->data->callback_check, 52) TH_LOG("callback_check1"); + ASSERT_EQ(self->skel->data->callback2_check, 52) TH_LOG("callback2_check1"); + + /* inject one event */ + buf[0] = 1; + buf[1] = 42; + uhid_send_event(_metadata, self->uhid_fd, buf, 6); + + /* check that hid_first_event() was executed */ + ASSERT_EQ(self->skel->data->callback_check, 42) TH_LOG("callback_check1"); + + /* read the data from hidraw */ + memset(buf, 0, sizeof(buf)); + err = read(self->hidraw_fd, buf, sizeof(buf)); + ASSERT_EQ(err, 6) TH_LOG("read_hidraw"); + ASSERT_EQ(buf[0], 1); + ASSERT_EQ(buf[2], 47); + + /* inject another event */ + memset(buf, 0, sizeof(buf)); + buf[0] = 1; + buf[1] = 47; + uhid_send_event(_metadata, self->uhid_fd, buf, 6); + + /* check that hid_first_event() was executed */ + ASSERT_EQ(self->skel->data->callback_check, 47) TH_LOG("callback_check1"); + + /* read the data from hidraw */ + memset(buf, 0, sizeof(buf)); + err = read(self->hidraw_fd, buf, sizeof(buf)); + ASSERT_EQ(err, 6) TH_LOG("read_hidraw"); + ASSERT_EQ(buf[2], 52); +} + +/* + * Ensures that we can attach/detach programs + */ +TEST_F(hid_bpf, test_attach_detach) +{ + const struct test_program progs[] = { + { .name = "hid_first_event" }, + }; + __u8 buf[10] = {0}; + int err; + + LOAD_PROGRAMS(progs); + + /* inject one event */ + buf[0] = 1; + buf[1] = 42; + uhid_send_event(_metadata, self->uhid_fd, buf, 6); + + /* read the data from hidraw */ + memset(buf, 0, sizeof(buf)); + err = read(self->hidraw_fd, buf, sizeof(buf)); + ASSERT_EQ(err, 6) TH_LOG("read_hidraw"); + ASSERT_EQ(buf[0], 1); + ASSERT_EQ(buf[2], 47); + + /* pin the program and immediately unpin it */ +#define PIN_PATH "/sys/fs/bpf/hid_first_event" + bpf_program__pin(self->skel->progs.hid_first_event, PIN_PATH); + remove(PIN_PATH); +#undef PIN_PATH + usleep(100000); + + /* detach the program */ + detach_bpf(self); + + self->hidraw_fd = open_hidraw(self->dev_id); + ASSERT_GE(self->hidraw_fd, 0) TH_LOG("open_hidraw"); + + /* inject another event */ + memset(buf, 0, sizeof(buf)); + buf[0] = 1; + buf[1] = 47; + uhid_send_event(_metadata, self->uhid_fd, buf, 6); + + /* read the data from hidraw */ + memset(buf, 0, sizeof(buf)); + err = read(self->hidraw_fd, buf, sizeof(buf)); + ASSERT_EQ(err, 6) TH_LOG("read_hidraw_no_bpf"); + ASSERT_EQ(buf[0], 1); + ASSERT_EQ(buf[1], 47); + ASSERT_EQ(buf[2], 0); + + /* re-attach our program */ + + LOAD_PROGRAMS(progs); + + /* inject one event */ + memset(buf, 0, sizeof(buf)); + buf[0] = 1; + buf[1] = 42; + uhid_send_event(_metadata, self->uhid_fd, buf, 6); + + /* read the data from hidraw */ + memset(buf, 0, sizeof(buf)); + err = read(self->hidraw_fd, buf, sizeof(buf)); + ASSERT_EQ(err, 6) TH_LOG("read_hidraw"); + ASSERT_EQ(buf[0], 1); + ASSERT_EQ(buf[2], 47); +} + +/* + * Attach hid_change_report_id to the given uhid device, + * retrieve and open the matching hidraw node, + * inject one event in the uhid device, + * check that the program sees it and can change the data + */ +TEST_F(hid_bpf, test_hid_change_report) +{ + const struct test_program progs[] = { + { .name = "hid_change_report_id" }, + }; + __u8 buf[10] = {0}; + int err; + + LOAD_PROGRAMS(progs); + + /* inject one event */ + buf[0] = 1; + buf[1] = 42; + uhid_send_event(_metadata, self->uhid_fd, buf, 6); + + /* read the data from hidraw */ + memset(buf, 0, sizeof(buf)); + err = read(self->hidraw_fd, buf, sizeof(buf)); + ASSERT_EQ(err, 9) TH_LOG("read_hidraw"); + ASSERT_EQ(buf[0], 2); + ASSERT_EQ(buf[1], 42); + ASSERT_EQ(buf[2], 0) TH_LOG("leftovers_from_previous_test"); +} + +/* + * Attach hid_user_raw_request to the given uhid device, + * call the bpf program from userspace + * check that the program is called and does the expected. + */ +TEST_F(hid_bpf, test_hid_user_raw_request_call) +{ + struct hid_hw_request_syscall_args args = { + .retval = -1, + .type = HID_FEATURE_REPORT, + .request_type = HID_REQ_GET_REPORT, + .size = 10, + }; + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattrs, + .ctx_in = &args, + .ctx_size_in = sizeof(args), + ); + int err, prog_fd; + + LOAD_BPF; + + args.hid = self->hid_id; + args.data[0] = 1; /* report ID */ + + prog_fd = bpf_program__fd(self->skel->progs.hid_user_raw_request); + + err = bpf_prog_test_run_opts(prog_fd, &tattrs); + ASSERT_OK(err) TH_LOG("error while calling bpf_prog_test_run_opts"); + + ASSERT_EQ(args.retval, 2); + + ASSERT_EQ(args.data[1], 2); +} + +/* + * Attach hid_insert{0,1,2} to the given uhid device, + * retrieve and open the matching hidraw node, + * inject one event in the uhid device, + * check that the programs have been inserted in the correct order. + */ +TEST_F(hid_bpf, test_hid_attach_flags) +{ + const struct test_program progs[] = { + { + .name = "hid_test_insert2", + .insert_head = 0, + }, + { + .name = "hid_test_insert1", + .insert_head = 1, + }, + { + .name = "hid_test_insert3", + .insert_head = 0, + }, + }; + __u8 buf[10] = {0}; + int err; + + LOAD_PROGRAMS(progs); + + /* inject one event */ + buf[0] = 1; + uhid_send_event(_metadata, self->uhid_fd, buf, 6); + + /* read the data from hidraw */ + memset(buf, 0, sizeof(buf)); + err = read(self->hidraw_fd, buf, sizeof(buf)); + ASSERT_EQ(err, 6) TH_LOG("read_hidraw"); + ASSERT_EQ(buf[1], 1); + ASSERT_EQ(buf[2], 2); + ASSERT_EQ(buf[3], 3); +} + +/* + * Attach hid_rdesc_fixup to the given uhid device, + * retrieve and open the matching hidraw node, + * check that the hidraw report descriptor has been updated. + */ +TEST_F(hid_bpf, test_rdesc_fixup) +{ + struct hidraw_report_descriptor rpt_desc = {0}; + const struct test_program progs[] = { + { .name = "hid_rdesc_fixup" }, + }; + int err, desc_size; + + LOAD_PROGRAMS(progs); + + /* check that hid_rdesc_fixup() was executed */ + ASSERT_EQ(self->skel->data->callback2_check, 0x21); + + /* read the exposed report descriptor from hidraw */ + err = ioctl(self->hidraw_fd, HIDIOCGRDESCSIZE, &desc_size); + ASSERT_GE(err, 0) TH_LOG("error while reading HIDIOCGRDESCSIZE: %d", err); + + /* ensure the new size of the rdesc is bigger than the old one */ + ASSERT_GT(desc_size, sizeof(rdesc)); + + rpt_desc.size = desc_size; + err = ioctl(self->hidraw_fd, HIDIOCGRDESC, &rpt_desc); + ASSERT_GE(err, 0) TH_LOG("error while reading HIDIOCGRDESC: %d", err); + + ASSERT_EQ(rpt_desc.value[4], 0x42); +} + +static int libbpf_print_fn(enum libbpf_print_level level, + const char *format, va_list args) +{ + char buf[1024]; + + if (level == LIBBPF_DEBUG) + return 0; + + snprintf(buf, sizeof(buf), "# %s", format); + + vfprintf(stdout, buf, args); + return 0; +} + +static void __attribute__((constructor)) __constructor_order_last(void) +{ + if (!__constructor_order) + __constructor_order = _CONSTRUCTOR_ORDER_BACKWARD; +} + +int main(int argc, char **argv) +{ + /* Use libbpf 1.0 API mode */ + libbpf_set_strict_mode(LIBBPF_STRICT_ALL); + libbpf_set_print(libbpf_print_fn); + + return test_harness_run(argc, argv); +} diff --git a/tools/testing/selftests/hid/progs/hid.c b/tools/testing/selftests/hid/progs/hid.c new file mode 100644 index 000000000000..6a86af0aa545 --- /dev/null +++ b/tools/testing/selftests/hid/progs/hid.c @@ -0,0 +1,196 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Red hat */ +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> +#include "hid_bpf_helpers.h" + +char _license[] SEC("license") = "GPL"; + +struct attach_prog_args { + int prog_fd; + unsigned int hid; + int retval; + int insert_head; +}; + +__u64 callback_check = 52; +__u64 callback2_check = 52; + +SEC("?fmod_ret/hid_bpf_device_event") +int BPF_PROG(hid_first_event, struct hid_bpf_ctx *hid_ctx) +{ + __u8 *rw_data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 3 /* size */); + + if (!rw_data) + return 0; /* EPERM check */ + + callback_check = rw_data[1]; + + rw_data[2] = rw_data[1] + 5; + + return hid_ctx->size; +} + +SEC("?fmod_ret/hid_bpf_device_event") +int BPF_PROG(hid_change_report_id, struct hid_bpf_ctx *hid_ctx) +{ + __u8 *rw_data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 3 /* size */); + + if (!rw_data) + return 0; /* EPERM check */ + + rw_data[0] = 2; + + return 9; +} + +SEC("syscall") +int attach_prog(struct attach_prog_args *ctx) +{ + ctx->retval = hid_bpf_attach_prog(ctx->hid, + ctx->prog_fd, + ctx->insert_head ? HID_BPF_FLAG_INSERT_HEAD : + HID_BPF_FLAG_NONE); + return 0; +} + +struct hid_hw_request_syscall_args { + /* data needs to come at offset 0 so we can use it in calls */ + __u8 data[10]; + unsigned int hid; + int retval; + size_t size; + enum hid_report_type type; + __u8 request_type; +}; + +SEC("syscall") +int hid_user_raw_request(struct hid_hw_request_syscall_args *args) +{ + struct hid_bpf_ctx *ctx; + const size_t size = args->size; + int i, ret = 0; + + if (size > sizeof(args->data)) + return -7; /* -E2BIG */ + + ctx = hid_bpf_allocate_context(args->hid); + if (!ctx) + return -1; /* EPERM check */ + + ret = hid_bpf_hw_request(ctx, + args->data, + size, + args->type, + args->request_type); + args->retval = ret; + + hid_bpf_release_context(ctx); + + return 0; +} + +static const __u8 rdesc[] = { + 0x05, 0x01, /* USAGE_PAGE (Generic Desktop) */ + 0x09, 0x32, /* USAGE (Z) */ + 0x95, 0x01, /* REPORT_COUNT (1) */ + 0x81, 0x06, /* INPUT (Data,Var,Rel) */ + + 0x06, 0x00, 0xff, /* Usage Page (Vendor Defined Page 1) */ + 0x19, 0x01, /* USAGE_MINIMUM (1) */ + 0x29, 0x03, /* USAGE_MAXIMUM (3) */ + 0x15, 0x00, /* LOGICAL_MINIMUM (0) */ + 0x25, 0x01, /* LOGICAL_MAXIMUM (1) */ + 0x95, 0x03, /* REPORT_COUNT (3) */ + 0x75, 0x01, /* REPORT_SIZE (1) */ + 0x91, 0x02, /* Output (Data,Var,Abs) */ + 0x95, 0x01, /* REPORT_COUNT (1) */ + 0x75, 0x05, /* REPORT_SIZE (5) */ + 0x91, 0x01, /* Output (Cnst,Var,Abs) */ + + 0x06, 0x00, 0xff, /* Usage Page (Vendor Defined Page 1) */ + 0x19, 0x06, /* USAGE_MINIMUM (6) */ + 0x29, 0x08, /* USAGE_MAXIMUM (8) */ + 0x15, 0x00, /* LOGICAL_MINIMUM (0) */ + 0x25, 0x01, /* LOGICAL_MAXIMUM (1) */ + 0x95, 0x03, /* REPORT_COUNT (3) */ + 0x75, 0x01, /* REPORT_SIZE (1) */ + 0xb1, 0x02, /* Feature (Data,Var,Abs) */ + 0x95, 0x01, /* REPORT_COUNT (1) */ + 0x75, 0x05, /* REPORT_SIZE (5) */ + 0x91, 0x01, /* Output (Cnst,Var,Abs) */ + + 0xc0, /* END_COLLECTION */ + 0xc0, /* END_COLLECTION */ +}; + +SEC("?fmod_ret/hid_bpf_rdesc_fixup") +int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hid_ctx) +{ + __u8 *data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 4096 /* size */); + + if (!data) + return 0; /* EPERM check */ + + callback2_check = data[4]; + + /* insert rdesc at offset 73 */ + __builtin_memcpy(&data[73], rdesc, sizeof(rdesc)); + + /* Change Usage Vendor globally */ + data[4] = 0x42; + + return sizeof(rdesc) + 73; +} + +SEC("?fmod_ret/hid_bpf_device_event") +int BPF_PROG(hid_test_insert1, struct hid_bpf_ctx *hid_ctx) +{ + __u8 *data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 4 /* size */); + + if (!data) + return 0; /* EPERM check */ + + /* we need to be run first */ + if (data[2] || data[3]) + return -1; + + data[1] = 1; + + return 0; +} + +SEC("?fmod_ret/hid_bpf_device_event") +int BPF_PROG(hid_test_insert2, struct hid_bpf_ctx *hid_ctx) +{ + __u8 *data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 4 /* size */); + + if (!data) + return 0; /* EPERM check */ + + /* after insert0 and before insert2 */ + if (!data[1] || data[3]) + return -1; + + data[2] = 2; + + return 0; +} + +SEC("?fmod_ret/hid_bpf_device_event") +int BPF_PROG(hid_test_insert3, struct hid_bpf_ctx *hid_ctx) +{ + __u8 *data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 4 /* size */); + + if (!data) + return 0; /* EPERM check */ + + /* at the end */ + if (!data[1] || !data[2]) + return -1; + + data[3] = 3; + + return 0; +} diff --git a/tools/testing/selftests/hid/progs/hid_bpf_helpers.h b/tools/testing/selftests/hid/progs/hid_bpf_helpers.h new file mode 100644 index 000000000000..4fff31dbe0e7 --- /dev/null +++ b/tools/testing/selftests/hid/progs/hid_bpf_helpers.h @@ -0,0 +1,21 @@ +/* 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 struct hid_bpf_ctx *hid_bpf_allocate_context(unsigned int hid_id) __ksym; +extern void hid_bpf_release_context(struct hid_bpf_ctx *ctx) __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 */ |