[linux-block.git] / drivers / media / rc / bpf-lirc.c

// SPDX-License-Identifier: GPL-2.0
// bpf-lirc.c - handles bpf
//
// Copyright (C) 2018 Sean Young <sean@mess.org>

#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/bpf_lirc.h>
#include "rc-core-priv.h"

#define lirc_rcu_dereference(p)						\
	rcu_dereference_protected(p, lockdep_is_held(&ir_raw_handler_lock))

/*
 * BPF interface for raw IR
 */
const struct bpf_prog_ops lirc_mode2_prog_ops = {
};

BPF_CALL_1(bpf_rc_repeat, u32*, sample)
{
	struct ir_raw_event_ctrl *ctrl;

	ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample);

	rc_repeat(ctrl->dev);

	return 0;
}

static const struct bpf_func_proto rc_repeat_proto = {
	.func	   = bpf_rc_repeat,
	.gpl_only  = true, /* rc_repeat is EXPORT_SYMBOL_GPL */
	.ret_type  = RET_INTEGER,
	.arg1_type = ARG_PTR_TO_CTX,
};

BPF_CALL_4(bpf_rc_keydown, u32*, sample, u32, protocol, u64, scancode,
	   u32, toggle)
{
	struct ir_raw_event_ctrl *ctrl;

	ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample);

	rc_keydown(ctrl->dev, protocol, scancode, toggle != 0);

	return 0;
}

static const struct bpf_func_proto rc_keydown_proto = {
	.func	   = bpf_rc_keydown,
	.gpl_only  = true, /* rc_keydown is EXPORT_SYMBOL_GPL */
	.ret_type  = RET_INTEGER,
	.arg1_type = ARG_PTR_TO_CTX,
	.arg2_type = ARG_ANYTHING,
	.arg3_type = ARG_ANYTHING,
	.arg4_type = ARG_ANYTHING,
};

BPF_CALL_3(bpf_rc_pointer_rel, u32*, sample, s32, rel_x, s32, rel_y)
{
	struct ir_raw_event_ctrl *ctrl;

	ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample);

	input_report_rel(ctrl->dev->input_dev, REL_X, rel_x);
	input_report_rel(ctrl->dev->input_dev, REL_Y, rel_y);
	input_sync(ctrl->dev->input_dev);

	return 0;
}

static const struct bpf_func_proto rc_pointer_rel_proto = {
	.func	   = bpf_rc_pointer_rel,
	.gpl_only  = true,
	.ret_type  = RET_INTEGER,
	.arg1_type = ARG_PTR_TO_CTX,
	.arg2_type = ARG_ANYTHING,
	.arg3_type = ARG_ANYTHING,
};

static const struct bpf_func_proto *
lirc_mode2_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
	switch (func_id) {
	case BPF_FUNC_rc_repeat:
		return &rc_repeat_proto;
	case BPF_FUNC_rc_keydown:
		return &rc_keydown_proto;
	case BPF_FUNC_rc_pointer_rel:
		return &rc_pointer_rel_proto;
	case BPF_FUNC_map_lookup_elem:
		return &bpf_map_lookup_elem_proto;
	case BPF_FUNC_map_update_elem:
		return &bpf_map_update_elem_proto;
	case BPF_FUNC_map_delete_elem:
		return &bpf_map_delete_elem_proto;
	case BPF_FUNC_map_push_elem:
		return &bpf_map_push_elem_proto;
	case BPF_FUNC_map_pop_elem:
		return &bpf_map_pop_elem_proto;
	case BPF_FUNC_map_peek_elem:
		return &bpf_map_peek_elem_proto;
	case BPF_FUNC_ktime_get_ns:
		return &bpf_ktime_get_ns_proto;
	case BPF_FUNC_ktime_get_boot_ns:
		return &bpf_ktime_get_boot_ns_proto;
	case BPF_FUNC_tail_call:
		return &bpf_tail_call_proto;
	case BPF_FUNC_get_prandom_u32:
		return &bpf_get_prandom_u32_proto;
	case BPF_FUNC_trace_printk:
		if (perfmon_capable())
			return bpf_get_trace_printk_proto();
		fallthrough;
	default:
		return NULL;
	}
}

static bool lirc_mode2_is_valid_access(int off, int size,
				       enum bpf_access_type type,
				       const struct bpf_prog *prog,
				       struct bpf_insn_access_aux *info)
{
	/* We have one field of u32 */
	return type == BPF_READ && off == 0 && size == sizeof(u32);
}

const struct bpf_verifier_ops lirc_mode2_verifier_ops = {
	.get_func_proto  = lirc_mode2_func_proto,
	.is_valid_access = lirc_mode2_is_valid_access
};

#define BPF_MAX_PROGS 64

static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog)
{
	struct bpf_prog_array *old_array;
	struct bpf_prog_array *new_array;
	struct ir_raw_event_ctrl *raw;
	int ret;

	if (rcdev->driver_type != RC_DRIVER_IR_RAW)
		return -EINVAL;

	ret = mutex_lock_interruptible(&ir_raw_handler_lock);
	if (ret)
		return ret;

	raw = rcdev->raw;
	if (!raw) {
		ret = -ENODEV;
		goto unlock;
	}

	old_array = lirc_rcu_dereference(raw->progs);
	if (old_array && bpf_prog_array_length(old_array) >= BPF_MAX_PROGS) {
		ret = -E2BIG;
		goto unlock;
	}

	ret = bpf_prog_array_copy(old_array, NULL, prog, 0, &new_array);
	if (ret < 0)
		goto unlock;

	rcu_assign_pointer(raw->progs, new_array);
	bpf_prog_array_free(old_array);

unlock:
	mutex_unlock(&ir_raw_handler_lock);
	return ret;
}

static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog)
{
	struct bpf_prog_array *old_array;
	struct bpf_prog_array *new_array;
	struct ir_raw_event_ctrl *raw;
	int ret;

	if (rcdev->driver_type != RC_DRIVER_IR_RAW)
		return -EINVAL;

	ret = mutex_lock_interruptible(&ir_raw_handler_lock);
	if (ret)
		return ret;

	raw = rcdev->raw;
	if (!raw) {
		ret = -ENODEV;
		goto unlock;
	}

	old_array = lirc_rcu_dereference(raw->progs);
	ret = bpf_prog_array_copy(old_array, prog, NULL, 0, &new_array);
	/*
	 * Do not use bpf_prog_array_delete_safe() as we would end up
	 * with a dummy entry in the array, and the we would free the
	 * dummy in lirc_bpf_free()
	 */
	if (ret)
		goto unlock;

	rcu_assign_pointer(raw->progs, new_array);
	bpf_prog_array_free(old_array);
	bpf_prog_put(prog);
unlock:
	mutex_unlock(&ir_raw_handler_lock);
	return ret;
}

void lirc_bpf_run(struct rc_dev *rcdev, u32 sample)
{
	struct ir_raw_event_ctrl *raw = rcdev->raw;

	raw->bpf_sample = sample;

	if (raw->progs) {
		rcu_read_lock();
		bpf_prog_run_array(rcu_dereference(raw->progs),
				   &raw->bpf_sample, bpf_prog_run);
		rcu_read_unlock();
	}
}

/*
 * This should be called once the rc thread has been stopped, so there can be
 * no concurrent bpf execution.
 *
 * Should be called with the ir_raw_handler_lock held.
 */
void lirc_bpf_free(struct rc_dev *rcdev)
{
	struct bpf_prog_array_item *item;
	struct bpf_prog_array *array;

	array = lirc_rcu_dereference(rcdev->raw->progs);
	if (!array)
		return;

	for (item = array->items; item->prog; item++)
		bpf_prog_put(item->prog);

	bpf_prog_array_free(array);
}

int lirc_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
{
	struct rc_dev *rcdev;
	int ret;

	if (attr->attach_flags)
		return -EINVAL;

	rcdev = rc_dev_get_from_fd(attr->target_fd, true);
	if (IS_ERR(rcdev))
		return PTR_ERR(rcdev);

	ret = lirc_bpf_attach(rcdev, prog);

	put_device(&rcdev->dev);

	return ret;
}

int lirc_prog_detach(const union bpf_attr *attr)
{
	struct bpf_prog *prog;
	struct rc_dev *rcdev;
	int ret;

	if (attr->attach_flags)
		return -EINVAL;

	prog = bpf_prog_get_type(attr->attach_bpf_fd,
				 BPF_PROG_TYPE_LIRC_MODE2);
	if (IS_ERR(prog))
		return PTR_ERR(prog);

	rcdev = rc_dev_get_from_fd(attr->target_fd, true);
	if (IS_ERR(rcdev)) {
		bpf_prog_put(prog);
		return PTR_ERR(rcdev);
	}

	ret = lirc_bpf_detach(rcdev, prog);

	bpf_prog_put(prog);
	put_device(&rcdev->dev);

	return ret;
}

int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr)
{
	__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
	struct bpf_prog_array *progs;
	struct rc_dev *rcdev;
	u32 cnt, flags = 0;
	int ret;

	if (attr->query.query_flags)
		return -EINVAL;

	rcdev = rc_dev_get_from_fd(attr->query.target_fd, false);
	if (IS_ERR(rcdev))
		return PTR_ERR(rcdev);

	if (rcdev->driver_type != RC_DRIVER_IR_RAW) {
		ret = -EINVAL;
		goto put;
	}

	ret = mutex_lock_interruptible(&ir_raw_handler_lock);
	if (ret)
		goto put;

	progs = lirc_rcu_dereference(rcdev->raw->progs);
	cnt = progs ? bpf_prog_array_length(progs) : 0;

	if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) {
		ret = -EFAULT;
		goto unlock;
	}

	if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) {
		ret = -EFAULT;
		goto unlock;
	}

	if (attr->query.prog_cnt != 0 && prog_ids && cnt)
		ret = bpf_prog_array_copy_to_user(progs, prog_ids,
						  attr->query.prog_cnt);

unlock:
	mutex_unlock(&ir_raw_handler_lock);
put:
	put_device(&rcdev->dev);

	return ret;
}
Commit	Line	Data
f4364dcf SY	1	// SPDX-License-Identifier: GPL-2.0
	2	// bpf-lirc.c - handles bpf
	3	//
	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
02205d2e SF	11	#define lirc_rcu_dereference(p) \
	12	rcu_dereference_protected(p, lockdep_is_held(&ir_raw_handler_lock))
	13
f4364dcf SY	14	/*
	15	* BPF interface for raw IR
	16	*/
	17	const struct bpf_prog_ops lirc_mode2_prog_ops = {
	18	};
	19
	20	BPF_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
	31	static 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
f4364dcf SY	38	BPF_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
	50	static 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
01d3240a SY	60	BPF_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
	73	static 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
f4364dcf SY	82	static const struct bpf_func_proto *
	83	lirc_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;
01d3240a SY	90	case BPF_FUNC_rc_pointer_rel:
01d3240a SY	91	return &rc_pointer_rel_proto;
f4364dcf SY	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;
02a8c817 AC	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;
f4364dcf SY	104	case BPF_FUNC_ktime_get_ns:
f4364dcf SY	105	return &bpf_ktime_get_ns_proto;
71d19214 MŻ	106	case BPF_FUNC_ktime_get_boot_ns:
71d19214 MŻ	107	return &bpf_ktime_get_boot_ns_proto;
f4364dcf SY	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:
2c78ee89	113	if (perfmon_capable())
f4364dcf	114	return bpf_get_trace_printk_proto();
df561f66	115	fallthrough;
f4364dcf SY	116	default:
	117	return NULL;
	118	}
	119	}
	120
	121	static 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
	130	const struct bpf_verifier_ops lirc_mode2_verifier_ops = {
	131	.get_func_proto = lirc_mode2_func_proto,
	132	.is_valid_access = lirc_mode2_is_valid_access
	133	};
	134
	135	#define BPF_MAX_PROGS 64
	136
	137	static int lirc_bpf_attach(struct rc_dev rcdev, struct bpf_prog prog)
	138	{
02205d2e	139	struct bpf_prog_array *old_array;
f4364dcf SY	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
02205d2e SF	157	old_array = lirc_rcu_dereference(raw->progs);
02205d2e SF	158	if (old_array && bpf_prog_array_length(old_array) >= BPF_MAX_PROGS) {
f4364dcf SY	159	ret = -E2BIG;
	160	goto unlock;
	161	}
	162
82e6b1ee	163	ret = bpf_prog_array_copy(old_array, NULL, prog, 0, &new_array);
f4364dcf SY	164	if (ret < 0)
	165	goto unlock;
	166
	167	rcu_assign_pointer(raw->progs, new_array);
	168	bpf_prog_array_free(old_array);
	169
	170	unlock:
	171	mutex_unlock(&ir_raw_handler_lock);
	172	return ret;
	173	}
	174
	175	static int lirc_bpf_detach(struct rc_dev rcdev, struct bpf_prog prog)
	176	{
02205d2e	177	struct bpf_prog_array *old_array;
f4364dcf SY	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
02205d2e	195	old_array = lirc_rcu_dereference(raw->progs);
82e6b1ee	196	ret = bpf_prog_array_copy(old_array, prog, NULL, 0, &new_array);
f4364dcf SY	197	/*
	198	* Do not use bpf_prog_array_delete_safe() as we would end up
	199	* with a dummy entry in the array, and the we would free the
	200	* 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);
92cab799	207	bpf_prog_put(prog);
f4364dcf SY	208	unlock:
	209	mutex_unlock(&ir_raw_handler_lock);
	210	return ret;
	211	}
	212
	213	void 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
055eb955 SF	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	}
f4364dcf SY	225	}
	226
	227	/*
	228	* This should be called once the rc thread has been stopped, so there can be
	229	* no concurrent bpf execution.
02205d2e SF	230	*
02205d2e SF	231	* Should be called with the ir_raw_handler_lock held.
f4364dcf SY	232	*/
	233	void lirc_bpf_free(struct rc_dev *rcdev)
	234	{
394e40a2	235	struct bpf_prog_array_item *item;
02205d2e	236	struct bpf_prog_array *array;
f4364dcf	237
02205d2e SF	238	array = lirc_rcu_dereference(rcdev->raw->progs);
02205d2e SF	239	if (!array)
f4364dcf SY	240	return;
f4364dcf SY	241
02205d2e	242	for (item = array->items; item->prog; item++)
394e40a2	243	bpf_prog_put(item->prog);
f4364dcf	244
02205d2e	245	bpf_prog_array_free(array);
f4364dcf SY	246	}
f4364dcf SY	247
fdb5c453	248	int lirc_prog_attach(const union bpf_attr attr, struct bpf_prog prog)
f4364dcf	249	{
f4364dcf SY	250	struct rc_dev *rcdev;
	251	int ret;
	252
	253	if (attr->attach_flags)
	254	return -EINVAL;
	255
6a9d5524	256	rcdev = rc_dev_get_from_fd(attr->target_fd, true);
fdb5c453	257	if (IS_ERR(rcdev))
f4364dcf	258	return PTR_ERR(rcdev);
f4364dcf SY	259
f4364dcf SY	260	ret = lirc_bpf_attach(rcdev, prog);
f4364dcf SY	261
	262	put_device(&rcdev->dev);
	263
	264	return ret;
	265	}
	266
	267	int 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
6a9d5524	281	rcdev = rc_dev_get_from_fd(attr->target_fd, true);
f4364dcf SY	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
	295	int 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);
02205d2e	298	struct bpf_prog_array *progs;
f4364dcf SY	299	struct rc_dev *rcdev;
	300	u32 cnt, flags = 0;
	301	int ret;
	302
	303	if (attr->query.query_flags)
	304	return -EINVAL;
	305
6a9d5524	306	rcdev = rc_dev_get_from_fd(attr->query.target_fd, false);
f4364dcf SY	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
02205d2e	319	progs = lirc_rcu_dereference(rcdev->raw->progs);
f4364dcf SY	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)
647d446d SY	333	ret = bpf_prog_array_copy_to_user(progs, prog_ids,
647d446d SY	334	attr->query.prog_cnt);
f4364dcf SY	335
	336	unlock:
	337	mutex_unlock(&ir_raw_handler_lock);
	338	put:
	339	put_device(&rcdev->dev);
	340
	341	return ret;
	342	}