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338 lines
7.5 KiB
338 lines
7.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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// bpf-lirc.c - handles bpf |
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// |
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// Copyright (C) 2018 Sean Young <[email protected]> |
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#include <linux/bpf.h> |
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#include <linux/filter.h> |
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#include <linux/bpf_lirc.h> |
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#include "rc-core-priv.h" |
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#define lirc_rcu_dereference(p) \ |
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rcu_dereference_protected(p, lockdep_is_held(&ir_raw_handler_lock)) |
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/* |
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* BPF interface for raw IR |
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*/ |
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const struct bpf_prog_ops lirc_mode2_prog_ops = { |
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}; |
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BPF_CALL_1(bpf_rc_repeat, u32*, sample) |
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{ |
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struct ir_raw_event_ctrl *ctrl; |
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ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); |
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rc_repeat(ctrl->dev); |
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return 0; |
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} |
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static const struct bpf_func_proto rc_repeat_proto = { |
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.func = bpf_rc_repeat, |
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.gpl_only = true, /* rc_repeat is EXPORT_SYMBOL_GPL */ |
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.ret_type = RET_INTEGER, |
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.arg1_type = ARG_PTR_TO_CTX, |
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}; |
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BPF_CALL_4(bpf_rc_keydown, u32*, sample, u32, protocol, u64, scancode, |
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u32, toggle) |
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{ |
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struct ir_raw_event_ctrl *ctrl; |
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ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); |
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rc_keydown(ctrl->dev, protocol, scancode, toggle != 0); |
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return 0; |
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} |
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static const struct bpf_func_proto rc_keydown_proto = { |
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.func = bpf_rc_keydown, |
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.gpl_only = true, /* rc_keydown is EXPORT_SYMBOL_GPL */ |
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.ret_type = RET_INTEGER, |
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.arg1_type = ARG_PTR_TO_CTX, |
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.arg2_type = ARG_ANYTHING, |
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.arg3_type = ARG_ANYTHING, |
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.arg4_type = ARG_ANYTHING, |
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}; |
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BPF_CALL_3(bpf_rc_pointer_rel, u32*, sample, s32, rel_x, s32, rel_y) |
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{ |
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struct ir_raw_event_ctrl *ctrl; |
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ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); |
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input_report_rel(ctrl->dev->input_dev, REL_X, rel_x); |
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input_report_rel(ctrl->dev->input_dev, REL_Y, rel_y); |
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input_sync(ctrl->dev->input_dev); |
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return 0; |
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} |
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static const struct bpf_func_proto rc_pointer_rel_proto = { |
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.func = bpf_rc_pointer_rel, |
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.gpl_only = true, |
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.ret_type = RET_INTEGER, |
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.arg1_type = ARG_PTR_TO_CTX, |
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.arg2_type = ARG_ANYTHING, |
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.arg3_type = ARG_ANYTHING, |
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}; |
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static const struct bpf_func_proto * |
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lirc_mode2_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) |
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{ |
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switch (func_id) { |
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case BPF_FUNC_rc_repeat: |
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return &rc_repeat_proto; |
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case BPF_FUNC_rc_keydown: |
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return &rc_keydown_proto; |
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case BPF_FUNC_rc_pointer_rel: |
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return &rc_pointer_rel_proto; |
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case BPF_FUNC_map_lookup_elem: |
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return &bpf_map_lookup_elem_proto; |
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case BPF_FUNC_map_update_elem: |
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return &bpf_map_update_elem_proto; |
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case BPF_FUNC_map_delete_elem: |
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return &bpf_map_delete_elem_proto; |
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case BPF_FUNC_map_push_elem: |
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return &bpf_map_push_elem_proto; |
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case BPF_FUNC_map_pop_elem: |
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return &bpf_map_pop_elem_proto; |
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case BPF_FUNC_map_peek_elem: |
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return &bpf_map_peek_elem_proto; |
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case BPF_FUNC_ktime_get_ns: |
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return &bpf_ktime_get_ns_proto; |
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case BPF_FUNC_ktime_get_boot_ns: |
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return &bpf_ktime_get_boot_ns_proto; |
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case BPF_FUNC_tail_call: |
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return &bpf_tail_call_proto; |
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case BPF_FUNC_get_prandom_u32: |
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return &bpf_get_prandom_u32_proto; |
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case BPF_FUNC_trace_printk: |
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if (perfmon_capable()) |
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return bpf_get_trace_printk_proto(); |
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fallthrough; |
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default: |
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return NULL; |
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} |
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} |
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static bool lirc_mode2_is_valid_access(int off, int size, |
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enum bpf_access_type type, |
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const struct bpf_prog *prog, |
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struct bpf_insn_access_aux *info) |
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{ |
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/* We have one field of u32 */ |
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return type == BPF_READ && off == 0 && size == sizeof(u32); |
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} |
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const struct bpf_verifier_ops lirc_mode2_verifier_ops = { |
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.get_func_proto = lirc_mode2_func_proto, |
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.is_valid_access = lirc_mode2_is_valid_access |
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}; |
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#define BPF_MAX_PROGS 64 |
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static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog) |
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{ |
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struct bpf_prog_array *old_array; |
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struct bpf_prog_array *new_array; |
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struct ir_raw_event_ctrl *raw; |
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int ret; |
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if (rcdev->driver_type != RC_DRIVER_IR_RAW) |
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return -EINVAL; |
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ret = mutex_lock_interruptible(&ir_raw_handler_lock); |
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if (ret) |
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return ret; |
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raw = rcdev->raw; |
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if (!raw) { |
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ret = -ENODEV; |
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goto unlock; |
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} |
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old_array = lirc_rcu_dereference(raw->progs); |
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if (old_array && bpf_prog_array_length(old_array) >= BPF_MAX_PROGS) { |
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ret = -E2BIG; |
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goto unlock; |
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} |
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ret = bpf_prog_array_copy(old_array, NULL, prog, 0, &new_array); |
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if (ret < 0) |
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goto unlock; |
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rcu_assign_pointer(raw->progs, new_array); |
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bpf_prog_array_free(old_array); |
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unlock: |
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mutex_unlock(&ir_raw_handler_lock); |
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return ret; |
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} |
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static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog) |
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{ |
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struct bpf_prog_array *old_array; |
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struct bpf_prog_array *new_array; |
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struct ir_raw_event_ctrl *raw; |
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int ret; |
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if (rcdev->driver_type != RC_DRIVER_IR_RAW) |
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return -EINVAL; |
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ret = mutex_lock_interruptible(&ir_raw_handler_lock); |
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if (ret) |
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return ret; |
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raw = rcdev->raw; |
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if (!raw) { |
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ret = -ENODEV; |
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goto unlock; |
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} |
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old_array = lirc_rcu_dereference(raw->progs); |
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ret = bpf_prog_array_copy(old_array, prog, NULL, 0, &new_array); |
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/* |
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* Do not use bpf_prog_array_delete_safe() as we would end up |
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* with a dummy entry in the array, and the we would free the |
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* dummy in lirc_bpf_free() |
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*/ |
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if (ret) |
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goto unlock; |
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rcu_assign_pointer(raw->progs, new_array); |
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bpf_prog_array_free(old_array); |
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bpf_prog_put(prog); |
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unlock: |
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mutex_unlock(&ir_raw_handler_lock); |
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return ret; |
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} |
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void lirc_bpf_run(struct rc_dev *rcdev, u32 sample) |
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{ |
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struct ir_raw_event_ctrl *raw = rcdev->raw; |
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raw->bpf_sample = sample; |
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if (raw->progs) |
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BPF_PROG_RUN_ARRAY(raw->progs, &raw->bpf_sample, bpf_prog_run); |
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} |
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/* |
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* This should be called once the rc thread has been stopped, so there can be |
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* no concurrent bpf execution. |
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* |
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* Should be called with the ir_raw_handler_lock held. |
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*/ |
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void lirc_bpf_free(struct rc_dev *rcdev) |
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{ |
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struct bpf_prog_array_item *item; |
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struct bpf_prog_array *array; |
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array = lirc_rcu_dereference(rcdev->raw->progs); |
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if (!array) |
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return; |
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for (item = array->items; item->prog; item++) |
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bpf_prog_put(item->prog); |
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bpf_prog_array_free(array); |
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} |
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int lirc_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) |
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{ |
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struct rc_dev *rcdev; |
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int ret; |
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if (attr->attach_flags) |
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return -EINVAL; |
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rcdev = rc_dev_get_from_fd(attr->target_fd); |
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if (IS_ERR(rcdev)) |
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return PTR_ERR(rcdev); |
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ret = lirc_bpf_attach(rcdev, prog); |
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put_device(&rcdev->dev); |
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return ret; |
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} |
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int lirc_prog_detach(const union bpf_attr *attr) |
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{ |
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struct bpf_prog *prog; |
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struct rc_dev *rcdev; |
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int ret; |
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if (attr->attach_flags) |
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return -EINVAL; |
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prog = bpf_prog_get_type(attr->attach_bpf_fd, |
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BPF_PROG_TYPE_LIRC_MODE2); |
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if (IS_ERR(prog)) |
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return PTR_ERR(prog); |
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rcdev = rc_dev_get_from_fd(attr->target_fd); |
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if (IS_ERR(rcdev)) { |
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bpf_prog_put(prog); |
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return PTR_ERR(rcdev); |
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} |
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ret = lirc_bpf_detach(rcdev, prog); |
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bpf_prog_put(prog); |
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put_device(&rcdev->dev); |
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return ret; |
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} |
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int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) |
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{ |
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__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids); |
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struct bpf_prog_array *progs; |
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struct rc_dev *rcdev; |
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u32 cnt, flags = 0; |
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int ret; |
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if (attr->query.query_flags) |
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return -EINVAL; |
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rcdev = rc_dev_get_from_fd(attr->query.target_fd); |
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if (IS_ERR(rcdev)) |
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return PTR_ERR(rcdev); |
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if (rcdev->driver_type != RC_DRIVER_IR_RAW) { |
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ret = -EINVAL; |
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goto put; |
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} |
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ret = mutex_lock_interruptible(&ir_raw_handler_lock); |
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if (ret) |
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goto put; |
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progs = lirc_rcu_dereference(rcdev->raw->progs); |
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cnt = progs ? bpf_prog_array_length(progs) : 0; |
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if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) { |
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ret = -EFAULT; |
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goto unlock; |
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} |
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if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) { |
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ret = -EFAULT; |
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goto unlock; |
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} |
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if (attr->query.prog_cnt != 0 && prog_ids && cnt) |
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ret = bpf_prog_array_copy_to_user(progs, prog_ids, |
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attr->query.prog_cnt); |
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unlock: |
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mutex_unlock(&ir_raw_handler_lock); |
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put: |
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put_device(&rcdev->dev); |
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return ret; |
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}
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