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// 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,
};
/*
* Currently rc-core does not support 64-bit scancodes, but there are many
* known protocols with more than 32 bits. So, define the interface as u64
* as a future-proof.
*/
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_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 (capable(CAP_SYS_ADMIN))
return bpf_get_trace_printk_proto();
/* fall through */
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, &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, &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)
BPF_PROG_RUN_ARRAY(raw->progs, &raw->bpf_sample, BPF_PROG_RUN);
}
/*
* 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);
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);
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);
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;
}