From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- drivers/media/rc/ir-nec-decoder.c | 278 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 278 insertions(+) create mode 100644 drivers/media/rc/ir-nec-decoder.c (limited to 'drivers/media/rc/ir-nec-decoder.c') diff --git a/drivers/media/rc/ir-nec-decoder.c b/drivers/media/rc/ir-nec-decoder.c new file mode 100644 index 000000000..37b99432a --- /dev/null +++ b/drivers/media/rc/ir-nec-decoder.c @@ -0,0 +1,278 @@ +// SPDX-License-Identifier: GPL-2.0 +// ir-nec-decoder.c - handle NEC IR Pulse/Space protocol +// +// Copyright (C) 2010 by Mauro Carvalho Chehab + +#include +#include +#include "rc-core-priv.h" + +#define NEC_NBITS 32 +#define NEC_UNIT 563 /* us */ +#define NEC_HEADER_PULSE (16 * NEC_UNIT) +#define NECX_HEADER_PULSE (8 * NEC_UNIT) /* Less common NEC variant */ +#define NEC_HEADER_SPACE (8 * NEC_UNIT) +#define NEC_REPEAT_SPACE (4 * NEC_UNIT) +#define NEC_BIT_PULSE (1 * NEC_UNIT) +#define NEC_BIT_0_SPACE (1 * NEC_UNIT) +#define NEC_BIT_1_SPACE (3 * NEC_UNIT) +#define NEC_TRAILER_PULSE (1 * NEC_UNIT) +#define NEC_TRAILER_SPACE (10 * NEC_UNIT) /* even longer in reality */ +#define NECX_REPEAT_BITS 1 + +enum nec_state { + STATE_INACTIVE, + STATE_HEADER_SPACE, + STATE_BIT_PULSE, + STATE_BIT_SPACE, + STATE_TRAILER_PULSE, + STATE_TRAILER_SPACE, +}; + +/** + * ir_nec_decode() - Decode one NEC pulse or space + * @dev: the struct rc_dev descriptor of the device + * @ev: the struct ir_raw_event descriptor of the pulse/space + * + * This function returns -EINVAL if the pulse violates the state machine + */ +static int ir_nec_decode(struct rc_dev *dev, struct ir_raw_event ev) +{ + struct nec_dec *data = &dev->raw->nec; + u32 scancode; + enum rc_proto rc_proto; + u8 address, not_address, command, not_command; + + if (!is_timing_event(ev)) { + if (ev.overflow) + data->state = STATE_INACTIVE; + return 0; + } + + dev_dbg(&dev->dev, "NEC decode started at state %d (%uus %s)\n", + data->state, ev.duration, TO_STR(ev.pulse)); + + switch (data->state) { + + case STATE_INACTIVE: + if (!ev.pulse) + break; + + if (eq_margin(ev.duration, NEC_HEADER_PULSE, NEC_UNIT * 2)) { + data->is_nec_x = false; + data->necx_repeat = false; + } else if (eq_margin(ev.duration, NECX_HEADER_PULSE, NEC_UNIT / 2)) + data->is_nec_x = true; + else + break; + + data->count = 0; + data->state = STATE_HEADER_SPACE; + return 0; + + case STATE_HEADER_SPACE: + if (ev.pulse) + break; + + if (eq_margin(ev.duration, NEC_HEADER_SPACE, NEC_UNIT)) { + data->state = STATE_BIT_PULSE; + return 0; + } else if (eq_margin(ev.duration, NEC_REPEAT_SPACE, NEC_UNIT / 2)) { + data->state = STATE_TRAILER_PULSE; + return 0; + } + + break; + + case STATE_BIT_PULSE: + if (!ev.pulse) + break; + + if (!eq_margin(ev.duration, NEC_BIT_PULSE, NEC_UNIT / 2)) + break; + + data->state = STATE_BIT_SPACE; + return 0; + + case STATE_BIT_SPACE: + if (ev.pulse) + break; + + if (data->necx_repeat && data->count == NECX_REPEAT_BITS && + geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2)) { + dev_dbg(&dev->dev, "Repeat last key\n"); + rc_repeat(dev); + data->state = STATE_INACTIVE; + return 0; + } else if (data->count > NECX_REPEAT_BITS) + data->necx_repeat = false; + + data->bits <<= 1; + if (eq_margin(ev.duration, NEC_BIT_1_SPACE, NEC_UNIT / 2)) + data->bits |= 1; + else if (!eq_margin(ev.duration, NEC_BIT_0_SPACE, NEC_UNIT / 2)) + break; + data->count++; + + if (data->count == NEC_NBITS) + data->state = STATE_TRAILER_PULSE; + else + data->state = STATE_BIT_PULSE; + + return 0; + + case STATE_TRAILER_PULSE: + if (!ev.pulse) + break; + + if (!eq_margin(ev.duration, NEC_TRAILER_PULSE, NEC_UNIT / 2)) + break; + + data->state = STATE_TRAILER_SPACE; + return 0; + + case STATE_TRAILER_SPACE: + if (ev.pulse) + break; + + if (!geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2)) + break; + + if (data->count == NEC_NBITS) { + address = bitrev8((data->bits >> 24) & 0xff); + not_address = bitrev8((data->bits >> 16) & 0xff); + command = bitrev8((data->bits >> 8) & 0xff); + not_command = bitrev8((data->bits >> 0) & 0xff); + + scancode = ir_nec_bytes_to_scancode(address, + not_address, + command, + not_command, + &rc_proto); + + if (data->is_nec_x) + data->necx_repeat = true; + + rc_keydown(dev, rc_proto, scancode, 0); + } else { + rc_repeat(dev); + } + + data->state = STATE_INACTIVE; + return 0; + } + + dev_dbg(&dev->dev, "NEC decode failed at count %d state %d (%uus %s)\n", + data->count, data->state, ev.duration, TO_STR(ev.pulse)); + data->state = STATE_INACTIVE; + return -EINVAL; +} + +/** + * ir_nec_scancode_to_raw() - encode an NEC scancode ready for modulation. + * @protocol: specific protocol to use + * @scancode: a single NEC scancode. + */ +static u32 ir_nec_scancode_to_raw(enum rc_proto protocol, u32 scancode) +{ + unsigned int addr, addr_inv, data, data_inv; + + data = scancode & 0xff; + + if (protocol == RC_PROTO_NEC32) { + /* 32-bit NEC (used by Apple and TiVo remotes) */ + /* scan encoding: aaAAddDD */ + addr_inv = (scancode >> 24) & 0xff; + addr = (scancode >> 16) & 0xff; + data_inv = (scancode >> 8) & 0xff; + } else if (protocol == RC_PROTO_NECX) { + /* Extended NEC */ + /* scan encoding AAaaDD */ + addr = (scancode >> 16) & 0xff; + addr_inv = (scancode >> 8) & 0xff; + data_inv = data ^ 0xff; + } else { + /* Normal NEC */ + /* scan encoding: AADD */ + addr = (scancode >> 8) & 0xff; + addr_inv = addr ^ 0xff; + data_inv = data ^ 0xff; + } + + /* raw encoding: ddDDaaAA */ + return data_inv << 24 | + data << 16 | + addr_inv << 8 | + addr; +} + +static const struct ir_raw_timings_pd ir_nec_timings = { + .header_pulse = NEC_HEADER_PULSE, + .header_space = NEC_HEADER_SPACE, + .bit_pulse = NEC_BIT_PULSE, + .bit_space[0] = NEC_BIT_0_SPACE, + .bit_space[1] = NEC_BIT_1_SPACE, + .trailer_pulse = NEC_TRAILER_PULSE, + .trailer_space = NEC_TRAILER_SPACE, + .msb_first = 0, +}; + +/** + * ir_nec_encode() - Encode a scancode as a stream of raw events + * + * @protocol: protocol to encode + * @scancode: scancode to encode + * @events: array of raw ir events to write into + * @max: maximum size of @events + * + * Returns: The number of events written. + * -ENOBUFS if there isn't enough space in the array to fit the + * encoding. In this case all @max events will have been written. + */ +static int ir_nec_encode(enum rc_proto protocol, u32 scancode, + struct ir_raw_event *events, unsigned int max) +{ + struct ir_raw_event *e = events; + int ret; + u32 raw; + + /* Convert a NEC scancode to raw NEC data */ + raw = ir_nec_scancode_to_raw(protocol, scancode); + + /* Modulate the raw data using a pulse distance modulation */ + ret = ir_raw_gen_pd(&e, max, &ir_nec_timings, NEC_NBITS, raw); + if (ret < 0) + return ret; + + return e - events; +} + +static struct ir_raw_handler nec_handler = { + .protocols = RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | + RC_PROTO_BIT_NEC32, + .decode = ir_nec_decode, + .encode = ir_nec_encode, + .carrier = 38000, + .min_timeout = NEC_TRAILER_SPACE, +}; + +static int __init ir_nec_decode_init(void) +{ + ir_raw_handler_register(&nec_handler); + + printk(KERN_INFO "IR NEC protocol handler initialized\n"); + return 0; +} + +static void __exit ir_nec_decode_exit(void) +{ + ir_raw_handler_unregister(&nec_handler); +} + +module_init(ir_nec_decode_init); +module_exit(ir_nec_decode_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Mauro Carvalho Chehab"); +MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); +MODULE_DESCRIPTION("NEC IR protocol decoder"); -- cgit v1.3.1