diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig index eb2c3b6eca7f..d5b35a6ba899 100644 --- a/drivers/media/rc/Kconfig +++ b/drivers/media/rc/Kconfig @@ -25,6 +25,19 @@ config LIRC passes raw IR to and from userspace, which is needed for IR transmitting (aka "blasting") and for the lirc daemon. +config BPF_LIRC_MODE2 + bool "Support for eBPF programs attached to lirc devices" + depends on BPF_SYSCALL + depends on RC_CORE=y + depends on LIRC + help + Allow attaching eBPF programs to a lirc device using the bpf(2) + syscall command BPF_PROG_ATTACH. This is supported for raw IR + receivers. + + These eBPF programs can be used to decode IR into scancodes, for + IR protocols not supported by the kernel decoders. + menuconfig RC_DECODERS bool "Remote controller decoders" depends on RC_CORE diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile index 2e1c87066f6c..e0340d043fe8 100644 --- a/drivers/media/rc/Makefile +++ b/drivers/media/rc/Makefile @@ -5,6 +5,7 @@ obj-y += keymaps/ obj-$(CONFIG_RC_CORE) += rc-core.o rc-core-y := rc-main.o rc-ir-raw.o rc-core-$(CONFIG_LIRC) += lirc_dev.o +rc-core-$(CONFIG_BPF_LIRC_MODE2) += bpf-lirc.o obj-$(CONFIG_IR_NEC_DECODER) += ir-nec-decoder.o obj-$(CONFIG_IR_RC5_DECODER) += ir-rc5-decoder.o obj-$(CONFIG_IR_RC6_DECODER) += ir-rc6-decoder.o diff --git a/drivers/media/rc/bpf-lirc.c b/drivers/media/rc/bpf-lirc.c new file mode 100644 index 000000000000..40826bba06b6 --- /dev/null +++ b/drivers/media/rc/bpf-lirc.c @@ -0,0 +1,313 @@ +// SPDX-License-Identifier: GPL-2.0 +// bpf-lirc.c - handles bpf +// +// Copyright (C) 2018 Sean Young + +#include +#include +#include +#include "rc-core-priv.h" + +/* + * 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, +}; + +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_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_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 __rcu *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; + } + + if (raw->progs && bpf_prog_array_length(raw->progs) >= BPF_MAX_PROGS) { + ret = -E2BIG; + goto unlock; + } + + old_array = raw->progs; + 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 __rcu *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 = 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); +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. + */ +void lirc_bpf_free(struct rc_dev *rcdev) +{ + struct bpf_prog **progs; + + if (!rcdev->raw->progs) + return; + + progs = rcu_dereference(rcdev->raw->progs)->progs; + while (*progs) + bpf_prog_put(*progs++); + + bpf_prog_array_free(rcdev->raw->progs); +} + +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; + + 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_attach(rcdev, prog); + if (ret) + bpf_prog_put(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 __rcu *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 = 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, cnt); + +unlock: + mutex_unlock(&ir_raw_handler_lock); +put: + put_device(&rcdev->dev); + + return ret; +} diff --git a/drivers/media/rc/lirc_dev.c b/drivers/media/rc/lirc_dev.c index 24e9fbb80e81..da7013a12a58 100644 --- a/drivers/media/rc/lirc_dev.c +++ b/drivers/media/rc/lirc_dev.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -104,6 +105,12 @@ void ir_lirc_raw_event(struct rc_dev *dev, struct ir_raw_event ev) TO_US(ev.duration), TO_STR(ev.pulse)); } + /* + * bpf does not care about the gap generated above; that exists + * for backwards compatibility + */ + lirc_bpf_run(dev, sample); + spin_lock_irqsave(&dev->lirc_fh_lock, flags); list_for_each_entry(fh, &dev->lirc_fh, list) { if (LIRC_IS_TIMEOUT(sample) && !fh->send_timeout_reports) @@ -816,4 +823,27 @@ void __exit lirc_dev_exit(void) unregister_chrdev_region(lirc_base_dev, RC_DEV_MAX); } +struct rc_dev *rc_dev_get_from_fd(int fd) +{ + struct fd f = fdget(fd); + struct lirc_fh *fh; + struct rc_dev *dev; + + if (!f.file) + return ERR_PTR(-EBADF); + + if (f.file->f_op != &lirc_fops) { + fdput(f); + return ERR_PTR(-EINVAL); + } + + fh = f.file->private_data; + dev = fh->rc; + + get_device(&dev->dev); + fdput(f); + + return dev; +} + MODULE_ALIAS("lirc_dev"); diff --git a/drivers/media/rc/rc-core-priv.h b/drivers/media/rc/rc-core-priv.h index e0e6a17460f6..eb004757038b 100644 --- a/drivers/media/rc/rc-core-priv.h +++ b/drivers/media/rc/rc-core-priv.h @@ -13,6 +13,7 @@ #define MAX_IR_EVENT_SIZE 512 #include +#include #include /** @@ -57,6 +58,11 @@ struct ir_raw_event_ctrl { /* raw decoder state follows */ struct ir_raw_event prev_ev; struct ir_raw_event this_ev; + +#ifdef CONFIG_BPF_LIRC_MODE2 + u32 bpf_sample; + struct bpf_prog_array __rcu *progs; +#endif struct nec_dec { int state; unsigned count; @@ -126,6 +132,9 @@ struct ir_raw_event_ctrl { } imon; }; +/* Mutex for locking raw IR processing and handler change */ +extern struct mutex ir_raw_handler_lock; + /* macros for IR decoders */ static inline bool geq_margin(unsigned d1, unsigned d2, unsigned margin) { @@ -288,6 +297,7 @@ void ir_lirc_raw_event(struct rc_dev *dev, struct ir_raw_event ev); void ir_lirc_scancode_event(struct rc_dev *dev, struct lirc_scancode *lsc); int ir_lirc_register(struct rc_dev *dev); void ir_lirc_unregister(struct rc_dev *dev); +struct rc_dev *rc_dev_get_from_fd(int fd); #else static inline int lirc_dev_init(void) { return 0; } static inline void lirc_dev_exit(void) {} @@ -299,4 +309,15 @@ static inline int ir_lirc_register(struct rc_dev *dev) { return 0; } static inline void ir_lirc_unregister(struct rc_dev *dev) { } #endif +/* + * bpf interface + */ +#ifdef CONFIG_BPF_LIRC_MODE2 +void lirc_bpf_free(struct rc_dev *dev); +void lirc_bpf_run(struct rc_dev *dev, u32 sample); +#else +static inline void lirc_bpf_free(struct rc_dev *dev) { } +static inline void lirc_bpf_run(struct rc_dev *dev, u32 sample) { } +#endif + #endif /* _RC_CORE_PRIV */ diff --git a/drivers/media/rc/rc-ir-raw.c b/drivers/media/rc/rc-ir-raw.c index 374f83105a23..7675b7ee5bc7 100644 --- a/drivers/media/rc/rc-ir-raw.c +++ b/drivers/media/rc/rc-ir-raw.c @@ -14,7 +14,7 @@ static LIST_HEAD(ir_raw_client_list); /* Used to handle IR raw handler extensions */ -static DEFINE_MUTEX(ir_raw_handler_lock); +DEFINE_MUTEX(ir_raw_handler_lock); static LIST_HEAD(ir_raw_handler_list); static atomic64_t available_protocols = ATOMIC64_INIT(0); @@ -621,9 +621,17 @@ void ir_raw_event_unregister(struct rc_dev *dev) list_for_each_entry(handler, &ir_raw_handler_list, list) if (handler->raw_unregister) handler->raw_unregister(dev); - mutex_unlock(&ir_raw_handler_lock); + + lirc_bpf_free(dev); ir_raw_event_free(dev); + + /* + * A user can be calling bpf(BPF_PROG_{QUERY|ATTACH|DETACH}), so + * ensure that the raw member is null on unlock; this is how + * "device gone" is checked. + */ + mutex_unlock(&ir_raw_handler_lock); } /* diff --git a/include/linux/bpf_lirc.h b/include/linux/bpf_lirc.h new file mode 100644 index 000000000000..5f8a4283092d --- /dev/null +++ b/include/linux/bpf_lirc.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _BPF_LIRC_H +#define _BPF_LIRC_H + +#include + +#ifdef CONFIG_BPF_LIRC_MODE2 +int lirc_prog_attach(const union bpf_attr *attr); +int lirc_prog_detach(const union bpf_attr *attr); +int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr); +#else +static inline int lirc_prog_attach(const union bpf_attr *attr) +{ + return -EINVAL; +} + +static inline int lirc_prog_detach(const union bpf_attr *attr) +{ + return -EINVAL; +} + +static inline int lirc_prog_query(const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return -EINVAL; +} +#endif + +#endif /* _BPF_LIRC_H */ diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index b161e506dcfc..c5700c2d5549 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -26,6 +26,9 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT, raw_tracepoint) #ifdef CONFIG_CGROUP_BPF BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_DEVICE, cg_dev) #endif +#ifdef CONFIG_BPF_LIRC_MODE2 +BPF_PROG_TYPE(BPF_PROG_TYPE_LIRC_MODE2, lirc_mode2) +#endif BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 33f37eb0b6bf..64ac0f7a689e 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -143,6 +143,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_RAW_TRACEPOINT, BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_PROG_TYPE_LWT_SEG6LOCAL, + BPF_PROG_TYPE_LIRC_MODE2, }; enum bpf_attach_type { @@ -162,6 +163,7 @@ enum bpf_attach_type { BPF_CGROUP_INET6_POST_BIND, BPF_CGROUP_UDP4_SENDMSG, BPF_CGROUP_UDP6_SENDMSG, + BPF_LIRC_MODE2, __MAX_BPF_ATTACH_TYPE }; @@ -2005,6 +2007,53 @@ union bpf_attr { * direct packet access. * Return * 0 on success, or a negative error in case of failure. + * + * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle) + * Description + * This helper is used in programs implementing IR decoding, to + * report a successfully decoded key press with *scancode*, + * *toggle* value in the given *protocol*. The scancode will be + * translated to a keycode using the rc keymap, and reported as + * an input key down event. After a period a key up event is + * generated. This period can be extended by calling either + * **bpf_rc_keydown** () again with the same values, or calling + * **bpf_rc_repeat** (). + * + * Some protocols include a toggle bit, in case the button was + * released and pressed again between consecutive scancodes. + * + * The *ctx* should point to the lirc sample as passed into + * the program. + * + * The *protocol* is the decoded protocol number (see + * **enum rc_proto** for some predefined values). + * + * This helper is only available is the kernel was compiled with + * the **CONFIG_BPF_LIRC_MODE2** configuration option set to + * "**y**". + * + * Return + * 0 + * + * int bpf_rc_repeat(void *ctx) + * Description + * This helper is used in programs implementing IR decoding, to + * report a successfully decoded repeat key message. This delays + * the generation of a key up event for previously generated + * key down event. + * + * Some IR protocols like NEC have a special IR message for + * repeating last button, for when a button is held down. + * + * The *ctx* should point to the lirc sample as passed into + * the program. + * + * This helper is only available is the kernel was compiled with + * the **CONFIG_BPF_LIRC_MODE2** configuration option set to + * "**y**". + * + * Return + * 0 */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -2083,7 +2132,9 @@ union bpf_attr { FN(lwt_push_encap), \ FN(lwt_seg6_store_bytes), \ FN(lwt_seg6_adjust_srh), \ - FN(lwt_seg6_action), + FN(lwt_seg6_action), \ + FN(rc_repeat), \ + FN(rc_keydown), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index e254526d6744..7365d79ae00d 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -11,6 +11,7 @@ */ #include #include +#include #include #include #include @@ -1582,6 +1583,8 @@ static int bpf_prog_attach(const union bpf_attr *attr) case BPF_SK_SKB_STREAM_PARSER: case BPF_SK_SKB_STREAM_VERDICT: return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_SKB, true); + case BPF_LIRC_MODE2: + return lirc_prog_attach(attr); default: return -EINVAL; } @@ -1654,6 +1657,8 @@ static int bpf_prog_detach(const union bpf_attr *attr) case BPF_SK_SKB_STREAM_PARSER: case BPF_SK_SKB_STREAM_VERDICT: return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_SKB, false); + case BPF_LIRC_MODE2: + return lirc_prog_detach(attr); default: return -EINVAL; } @@ -1703,6 +1708,8 @@ static int bpf_prog_query(const union bpf_attr *attr, case BPF_CGROUP_SOCK_OPS: case BPF_CGROUP_DEVICE: break; + case BPF_LIRC_MODE2: + return lirc_prog_query(attr, uattr); default: return -EINVAL; }