1 // SPDX-License-Identifier: GPL-2.0
2 // bpf-lirc.c - handles bpf
4 // Copyright (C) 2018 Sean Young <sean@mess.org>
7 #include <linux/filter.h>
8 #include <linux/bpf_lirc.h>
9 #include "rc-core-priv.h"
12 * BPF interface for raw IR
14 const struct bpf_prog_ops lirc_mode2_prog_ops = {
17 BPF_CALL_1(bpf_rc_repeat, u32*, sample)
19 struct ir_raw_event_ctrl *ctrl;
21 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample);
28 static const struct bpf_func_proto rc_repeat_proto = {
29 .func = bpf_rc_repeat,
30 .gpl_only = true, /* rc_repeat is EXPORT_SYMBOL_GPL */
31 .ret_type = RET_INTEGER,
32 .arg1_type = ARG_PTR_TO_CTX,
36 * Currently rc-core does not support 64-bit scancodes, but there are many
37 * known protocols with more than 32 bits. So, define the interface as u64
40 BPF_CALL_4(bpf_rc_keydown, u32*, sample, u32, protocol, u64, scancode,
43 struct ir_raw_event_ctrl *ctrl;
45 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample);
47 rc_keydown(ctrl->dev, protocol, scancode, toggle != 0);
52 static const struct bpf_func_proto rc_keydown_proto = {
53 .func = bpf_rc_keydown,
54 .gpl_only = true, /* rc_keydown is EXPORT_SYMBOL_GPL */
55 .ret_type = RET_INTEGER,
56 .arg1_type = ARG_PTR_TO_CTX,
57 .arg2_type = ARG_ANYTHING,
58 .arg3_type = ARG_ANYTHING,
59 .arg4_type = ARG_ANYTHING,
62 static const struct bpf_func_proto *
63 lirc_mode2_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
66 case BPF_FUNC_rc_repeat:
67 return &rc_repeat_proto;
68 case BPF_FUNC_rc_keydown:
69 return &rc_keydown_proto;
70 case BPF_FUNC_map_lookup_elem:
71 return &bpf_map_lookup_elem_proto;
72 case BPF_FUNC_map_update_elem:
73 return &bpf_map_update_elem_proto;
74 case BPF_FUNC_map_delete_elem:
75 return &bpf_map_delete_elem_proto;
76 case BPF_FUNC_ktime_get_ns:
77 return &bpf_ktime_get_ns_proto;
78 case BPF_FUNC_tail_call:
79 return &bpf_tail_call_proto;
80 case BPF_FUNC_get_prandom_u32:
81 return &bpf_get_prandom_u32_proto;
82 case BPF_FUNC_trace_printk:
83 if (capable(CAP_SYS_ADMIN))
84 return bpf_get_trace_printk_proto();
91 static bool lirc_mode2_is_valid_access(int off, int size,
92 enum bpf_access_type type,
93 const struct bpf_prog *prog,
94 struct bpf_insn_access_aux *info)
96 /* We have one field of u32 */
97 return type == BPF_READ && off == 0 && size == sizeof(u32);
100 const struct bpf_verifier_ops lirc_mode2_verifier_ops = {
101 .get_func_proto = lirc_mode2_func_proto,
102 .is_valid_access = lirc_mode2_is_valid_access
105 #define BPF_MAX_PROGS 64
107 static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog)
109 struct bpf_prog_array __rcu *old_array;
110 struct bpf_prog_array *new_array;
111 struct ir_raw_event_ctrl *raw;
114 if (rcdev->driver_type != RC_DRIVER_IR_RAW)
117 ret = mutex_lock_interruptible(&ir_raw_handler_lock);
127 if (raw->progs && bpf_prog_array_length(raw->progs) >= BPF_MAX_PROGS) {
132 old_array = raw->progs;
133 ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array);
137 rcu_assign_pointer(raw->progs, new_array);
138 bpf_prog_array_free(old_array);
141 mutex_unlock(&ir_raw_handler_lock);
145 static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog)
147 struct bpf_prog_array __rcu *old_array;
148 struct bpf_prog_array *new_array;
149 struct ir_raw_event_ctrl *raw;
152 if (rcdev->driver_type != RC_DRIVER_IR_RAW)
155 ret = mutex_lock_interruptible(&ir_raw_handler_lock);
165 old_array = raw->progs;
166 ret = bpf_prog_array_copy(old_array, prog, NULL, &new_array);
168 * Do not use bpf_prog_array_delete_safe() as we would end up
169 * with a dummy entry in the array, and the we would free the
170 * dummy in lirc_bpf_free()
175 rcu_assign_pointer(raw->progs, new_array);
176 bpf_prog_array_free(old_array);
178 mutex_unlock(&ir_raw_handler_lock);
182 void lirc_bpf_run(struct rc_dev *rcdev, u32 sample)
184 struct ir_raw_event_ctrl *raw = rcdev->raw;
186 raw->bpf_sample = sample;
189 BPF_PROG_RUN_ARRAY(raw->progs, &raw->bpf_sample, BPF_PROG_RUN);
193 * This should be called once the rc thread has been stopped, so there can be
194 * no concurrent bpf execution.
196 void lirc_bpf_free(struct rc_dev *rcdev)
198 struct bpf_prog_array_item *item;
200 if (!rcdev->raw->progs)
203 item = rcu_dereference(rcdev->raw->progs)->items;
205 bpf_prog_put(item->prog);
209 bpf_prog_array_free(rcdev->raw->progs);
212 int lirc_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
214 struct rc_dev *rcdev;
217 if (attr->attach_flags)
220 rcdev = rc_dev_get_from_fd(attr->target_fd);
222 return PTR_ERR(rcdev);
224 ret = lirc_bpf_attach(rcdev, prog);
226 put_device(&rcdev->dev);
231 int lirc_prog_detach(const union bpf_attr *attr)
233 struct bpf_prog *prog;
234 struct rc_dev *rcdev;
237 if (attr->attach_flags)
240 prog = bpf_prog_get_type(attr->attach_bpf_fd,
241 BPF_PROG_TYPE_LIRC_MODE2);
243 return PTR_ERR(prog);
245 rcdev = rc_dev_get_from_fd(attr->target_fd);
248 return PTR_ERR(rcdev);
251 ret = lirc_bpf_detach(rcdev, prog);
254 put_device(&rcdev->dev);
259 int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr)
261 __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
262 struct bpf_prog_array __rcu *progs;
263 struct rc_dev *rcdev;
267 if (attr->query.query_flags)
270 rcdev = rc_dev_get_from_fd(attr->query.target_fd);
272 return PTR_ERR(rcdev);
274 if (rcdev->driver_type != RC_DRIVER_IR_RAW) {
279 ret = mutex_lock_interruptible(&ir_raw_handler_lock);
283 progs = rcdev->raw->progs;
284 cnt = progs ? bpf_prog_array_length(progs) : 0;
286 if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) {
291 if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) {
296 if (attr->query.prog_cnt != 0 && prog_ids && cnt)
297 ret = bpf_prog_array_copy_to_user(progs, prog_ids, cnt);
300 mutex_unlock(&ir_raw_handler_lock);
302 put_device(&rcdev->dev);