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1// SPDX-License-Identifier: GPL-2.02// bpf-lirc.c - handles bpf3//4// Copyright (C) 2018 Sean Young <sean@mess.org>5 6#include <linux/bpf.h>7#include <linux/filter.h>8#include <linux/bpf_lirc.h>9#include "rc-core-priv.h"10 11#define lirc_rcu_dereference(p) \12 rcu_dereference_protected(p, lockdep_is_held(&ir_raw_handler_lock))13 14/*15 * BPF interface for raw IR16 */17const struct bpf_prog_ops lirc_mode2_prog_ops = {18};19 20BPF_CALL_1(bpf_rc_repeat, u32*, sample)21{22 struct ir_raw_event_ctrl *ctrl;23 24 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample);25 26 rc_repeat(ctrl->dev);27 28 return 0;29}30 31static const struct bpf_func_proto rc_repeat_proto = {32 .func = bpf_rc_repeat,33 .gpl_only = true, /* rc_repeat is EXPORT_SYMBOL_GPL */34 .ret_type = RET_INTEGER,35 .arg1_type = ARG_PTR_TO_CTX,36};37 38BPF_CALL_4(bpf_rc_keydown, u32*, sample, u32, protocol, u64, scancode,39 u32, toggle)40{41 struct ir_raw_event_ctrl *ctrl;42 43 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample);44 45 rc_keydown(ctrl->dev, protocol, scancode, toggle != 0);46 47 return 0;48}49 50static const struct bpf_func_proto rc_keydown_proto = {51 .func = bpf_rc_keydown,52 .gpl_only = true, /* rc_keydown is EXPORT_SYMBOL_GPL */53 .ret_type = RET_INTEGER,54 .arg1_type = ARG_PTR_TO_CTX,55 .arg2_type = ARG_ANYTHING,56 .arg3_type = ARG_ANYTHING,57 .arg4_type = ARG_ANYTHING,58};59 60BPF_CALL_3(bpf_rc_pointer_rel, u32*, sample, s32, rel_x, s32, rel_y)61{62 struct ir_raw_event_ctrl *ctrl;63 64 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample);65 66 input_report_rel(ctrl->dev->input_dev, REL_X, rel_x);67 input_report_rel(ctrl->dev->input_dev, REL_Y, rel_y);68 input_sync(ctrl->dev->input_dev);69 70 return 0;71}72 73static const struct bpf_func_proto rc_pointer_rel_proto = {74 .func = bpf_rc_pointer_rel,75 .gpl_only = true,76 .ret_type = RET_INTEGER,77 .arg1_type = ARG_PTR_TO_CTX,78 .arg2_type = ARG_ANYTHING,79 .arg3_type = ARG_ANYTHING,80};81 82static const struct bpf_func_proto *83lirc_mode2_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)84{85 switch (func_id) {86 case BPF_FUNC_rc_repeat:87 return &rc_repeat_proto;88 case BPF_FUNC_rc_keydown:89 return &rc_keydown_proto;90 case BPF_FUNC_rc_pointer_rel:91 return &rc_pointer_rel_proto;92 case BPF_FUNC_map_lookup_elem:93 return &bpf_map_lookup_elem_proto;94 case BPF_FUNC_map_update_elem:95 return &bpf_map_update_elem_proto;96 case BPF_FUNC_map_delete_elem:97 return &bpf_map_delete_elem_proto;98 case BPF_FUNC_map_push_elem:99 return &bpf_map_push_elem_proto;100 case BPF_FUNC_map_pop_elem:101 return &bpf_map_pop_elem_proto;102 case BPF_FUNC_map_peek_elem:103 return &bpf_map_peek_elem_proto;104 case BPF_FUNC_ktime_get_ns:105 return &bpf_ktime_get_ns_proto;106 case BPF_FUNC_ktime_get_boot_ns:107 return &bpf_ktime_get_boot_ns_proto;108 case BPF_FUNC_tail_call:109 return &bpf_tail_call_proto;110 case BPF_FUNC_get_prandom_u32:111 return &bpf_get_prandom_u32_proto;112 case BPF_FUNC_trace_printk:113 if (bpf_token_capable(prog->aux->token, CAP_PERFMON))114 return bpf_get_trace_printk_proto();115 fallthrough;116 default:117 return NULL;118 }119}120 121static bool lirc_mode2_is_valid_access(int off, int size,122 enum bpf_access_type type,123 const struct bpf_prog *prog,124 struct bpf_insn_access_aux *info)125{126 /* We have one field of u32 */127 return type == BPF_READ && off == 0 && size == sizeof(u32);128}129 130const struct bpf_verifier_ops lirc_mode2_verifier_ops = {131 .get_func_proto = lirc_mode2_func_proto,132 .is_valid_access = lirc_mode2_is_valid_access133};134 135#define BPF_MAX_PROGS 64136 137static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog)138{139 struct bpf_prog_array *old_array;140 struct bpf_prog_array *new_array;141 struct ir_raw_event_ctrl *raw;142 int ret;143 144 if (rcdev->driver_type != RC_DRIVER_IR_RAW)145 return -EINVAL;146 147 ret = mutex_lock_interruptible(&ir_raw_handler_lock);148 if (ret)149 return ret;150 151 raw = rcdev->raw;152 if (!raw) {153 ret = -ENODEV;154 goto unlock;155 }156 157 old_array = lirc_rcu_dereference(raw->progs);158 if (old_array && bpf_prog_array_length(old_array) >= BPF_MAX_PROGS) {159 ret = -E2BIG;160 goto unlock;161 }162 163 ret = bpf_prog_array_copy(old_array, NULL, prog, 0, &new_array);164 if (ret < 0)165 goto unlock;166 167 rcu_assign_pointer(raw->progs, new_array);168 bpf_prog_array_free(old_array);169 170unlock:171 mutex_unlock(&ir_raw_handler_lock);172 return ret;173}174 175static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog)176{177 struct bpf_prog_array *old_array;178 struct bpf_prog_array *new_array;179 struct ir_raw_event_ctrl *raw;180 int ret;181 182 if (rcdev->driver_type != RC_DRIVER_IR_RAW)183 return -EINVAL;184 185 ret = mutex_lock_interruptible(&ir_raw_handler_lock);186 if (ret)187 return ret;188 189 raw = rcdev->raw;190 if (!raw) {191 ret = -ENODEV;192 goto unlock;193 }194 195 old_array = lirc_rcu_dereference(raw->progs);196 ret = bpf_prog_array_copy(old_array, prog, NULL, 0, &new_array);197 /*198 * Do not use bpf_prog_array_delete_safe() as we would end up199 * with a dummy entry in the array, and the we would free the200 * dummy in lirc_bpf_free()201 */202 if (ret)203 goto unlock;204 205 rcu_assign_pointer(raw->progs, new_array);206 bpf_prog_array_free(old_array);207 bpf_prog_put(prog);208unlock:209 mutex_unlock(&ir_raw_handler_lock);210 return ret;211}212 213void lirc_bpf_run(struct rc_dev *rcdev, u32 sample)214{215 struct ir_raw_event_ctrl *raw = rcdev->raw;216 217 raw->bpf_sample = sample;218 219 if (raw->progs) {220 rcu_read_lock();221 bpf_prog_run_array(rcu_dereference(raw->progs),222 &raw->bpf_sample, bpf_prog_run);223 rcu_read_unlock();224 }225}226 227/*228 * This should be called once the rc thread has been stopped, so there can be229 * no concurrent bpf execution.230 *231 * Should be called with the ir_raw_handler_lock held.232 */233void lirc_bpf_free(struct rc_dev *rcdev)234{235 struct bpf_prog_array_item *item;236 struct bpf_prog_array *array;237 238 array = lirc_rcu_dereference(rcdev->raw->progs);239 if (!array)240 return;241 242 for (item = array->items; item->prog; item++)243 bpf_prog_put(item->prog);244 245 bpf_prog_array_free(array);246}247 248int lirc_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)249{250 struct rc_dev *rcdev;251 int ret;252 253 if (attr->attach_flags)254 return -EINVAL;255 256 rcdev = rc_dev_get_from_fd(attr->target_fd, true);257 if (IS_ERR(rcdev))258 return PTR_ERR(rcdev);259 260 ret = lirc_bpf_attach(rcdev, prog);261 262 put_device(&rcdev->dev);263 264 return ret;265}266 267int lirc_prog_detach(const union bpf_attr *attr)268{269 struct bpf_prog *prog;270 struct rc_dev *rcdev;271 int ret;272 273 if (attr->attach_flags)274 return -EINVAL;275 276 prog = bpf_prog_get_type(attr->attach_bpf_fd,277 BPF_PROG_TYPE_LIRC_MODE2);278 if (IS_ERR(prog))279 return PTR_ERR(prog);280 281 rcdev = rc_dev_get_from_fd(attr->target_fd, true);282 if (IS_ERR(rcdev)) {283 bpf_prog_put(prog);284 return PTR_ERR(rcdev);285 }286 287 ret = lirc_bpf_detach(rcdev, prog);288 289 bpf_prog_put(prog);290 put_device(&rcdev->dev);291 292 return ret;293}294 295int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr)296{297 __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);298 struct bpf_prog_array *progs;299 struct rc_dev *rcdev;300 u32 cnt, flags = 0;301 int ret;302 303 if (attr->query.query_flags)304 return -EINVAL;305 306 rcdev = rc_dev_get_from_fd(attr->query.target_fd, false);307 if (IS_ERR(rcdev))308 return PTR_ERR(rcdev);309 310 if (rcdev->driver_type != RC_DRIVER_IR_RAW) {311 ret = -EINVAL;312 goto put;313 }314 315 ret = mutex_lock_interruptible(&ir_raw_handler_lock);316 if (ret)317 goto put;318 319 progs = lirc_rcu_dereference(rcdev->raw->progs);320 cnt = progs ? bpf_prog_array_length(progs) : 0;321 322 if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) {323 ret = -EFAULT;324 goto unlock;325 }326 327 if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) {328 ret = -EFAULT;329 goto unlock;330 }331 332 if (attr->query.prog_cnt != 0 && prog_ids && cnt)333 ret = bpf_prog_array_copy_to_user(progs, prog_ids,334 attr->query.prog_cnt);335 336unlock:337 mutex_unlock(&ir_raw_handler_lock);338put:339 put_device(&rcdev->dev);340 341 return ret;342}343