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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /lib/ts_fsm.c | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'lib/ts_fsm.c')
| -rw-r--r-- | lib/ts_fsm.c | 338 |
1 files changed, 338 insertions, 0 deletions
diff --git a/lib/ts_fsm.c b/lib/ts_fsm.c new file mode 100644 index 000000000..053615f4f --- /dev/null +++ b/lib/ts_fsm.c @@ -0,0 +1,338 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * lib/ts_fsm.c A naive finite state machine text search approach + * + * Authors: Thomas Graf <tgraf@suug.ch> + * + * ========================================================================== + * + * A finite state machine consists of n states (struct ts_fsm_token) + * representing the pattern as a finite automaton. The data is read + * sequentially on an octet basis. Every state token specifies the number + * of recurrences and the type of value accepted which can be either a + * specific character or ctype based set of characters. The available + * type of recurrences include 1, (0|1), [0 n], and [1 n]. + * + * The algorithm differs between strict/non-strict mode specifying + * whether the pattern has to start at the first octet. Strict mode + * is enabled by default and can be disabled by inserting + * TS_FSM_HEAD_IGNORE as the first token in the chain. + * + * The runtime performance of the algorithm should be around O(n), + * however while in strict mode the average runtime can be better. + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/string.h> +#include <linux/ctype.h> +#include <linux/textsearch.h> +#include <linux/textsearch_fsm.h> + +struct ts_fsm +{ + unsigned int ntokens; + struct ts_fsm_token tokens[]; +}; + +/* other values derived from ctype.h */ +#define _A 0x100 /* ascii */ +#define _W 0x200 /* wildcard */ + +/* Map to _ctype flags and some magic numbers */ +static const u16 token_map[TS_FSM_TYPE_MAX+1] = { + [TS_FSM_SPECIFIC] = 0, + [TS_FSM_WILDCARD] = _W, + [TS_FSM_CNTRL] = _C, + [TS_FSM_LOWER] = _L, + [TS_FSM_UPPER] = _U, + [TS_FSM_PUNCT] = _P, + [TS_FSM_SPACE] = _S, + [TS_FSM_DIGIT] = _D, + [TS_FSM_XDIGIT] = _D | _X, + [TS_FSM_ALPHA] = _U | _L, + [TS_FSM_ALNUM] = _U | _L | _D, + [TS_FSM_PRINT] = _P | _U | _L | _D | _SP, + [TS_FSM_GRAPH] = _P | _U | _L | _D, + [TS_FSM_ASCII] = _A, +}; + +static const u16 token_lookup_tbl[256] = { +_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 0- 3 */ +_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 4- 7 */ +_W|_A|_C, _W|_A|_C|_S, _W|_A|_C|_S, _W|_A|_C|_S, /* 8- 11 */ +_W|_A|_C|_S, _W|_A|_C|_S, _W|_A|_C, _W|_A|_C, /* 12- 15 */ +_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 16- 19 */ +_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 20- 23 */ +_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 24- 27 */ +_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 28- 31 */ +_W|_A|_S|_SP, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 32- 35 */ +_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 36- 39 */ +_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 40- 43 */ +_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 44- 47 */ +_W|_A|_D, _W|_A|_D, _W|_A|_D, _W|_A|_D, /* 48- 51 */ +_W|_A|_D, _W|_A|_D, _W|_A|_D, _W|_A|_D, /* 52- 55 */ +_W|_A|_D, _W|_A|_D, _W|_A|_P, _W|_A|_P, /* 56- 59 */ +_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 60- 63 */ +_W|_A|_P, _W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U|_X, /* 64- 67 */ +_W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U, /* 68- 71 */ +_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 72- 75 */ +_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 76- 79 */ +_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 80- 83 */ +_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 84- 87 */ +_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_P, /* 88- 91 */ +_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 92- 95 */ +_W|_A|_P, _W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L|_X, /* 96- 99 */ +_W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L, /* 100-103 */ +_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 104-107 */ +_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 108-111 */ +_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 112-115 */ +_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 116-119 */ +_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_P, /* 120-123 */ +_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_C, /* 124-127 */ +_W, _W, _W, _W, /* 128-131 */ +_W, _W, _W, _W, /* 132-135 */ +_W, _W, _W, _W, /* 136-139 */ +_W, _W, _W, _W, /* 140-143 */ +_W, _W, _W, _W, /* 144-147 */ +_W, _W, _W, _W, /* 148-151 */ +_W, _W, _W, _W, /* 152-155 */ +_W, _W, _W, _W, /* 156-159 */ +_W|_S|_SP, _W|_P, _W|_P, _W|_P, /* 160-163 */ +_W|_P, _W|_P, _W|_P, _W|_P, /* 164-167 */ +_W|_P, _W|_P, _W|_P, _W|_P, /* 168-171 */ +_W|_P, _W|_P, _W|_P, _W|_P, /* 172-175 */ +_W|_P, _W|_P, _W|_P, _W|_P, /* 176-179 */ +_W|_P, _W|_P, _W|_P, _W|_P, /* 180-183 */ +_W|_P, _W|_P, _W|_P, _W|_P, /* 184-187 */ +_W|_P, _W|_P, _W|_P, _W|_P, /* 188-191 */ +_W|_U, _W|_U, _W|_U, _W|_U, /* 192-195 */ +_W|_U, _W|_U, _W|_U, _W|_U, /* 196-199 */ +_W|_U, _W|_U, _W|_U, _W|_U, /* 200-203 */ +_W|_U, _W|_U, _W|_U, _W|_U, /* 204-207 */ +_W|_U, _W|_U, _W|_U, _W|_U, /* 208-211 */ +_W|_U, _W|_U, _W|_U, _W|_P, /* 212-215 */ +_W|_U, _W|_U, _W|_U, _W|_U, /* 216-219 */ +_W|_U, _W|_U, _W|_U, _W|_L, /* 220-223 */ +_W|_L, _W|_L, _W|_L, _W|_L, /* 224-227 */ +_W|_L, _W|_L, _W|_L, _W|_L, /* 228-231 */ +_W|_L, _W|_L, _W|_L, _W|_L, /* 232-235 */ +_W|_L, _W|_L, _W|_L, _W|_L, /* 236-239 */ +_W|_L, _W|_L, _W|_L, _W|_L, /* 240-243 */ +_W|_L, _W|_L, _W|_L, _W|_P, /* 244-247 */ +_W|_L, _W|_L, _W|_L, _W|_L, /* 248-251 */ +_W|_L, _W|_L, _W|_L, _W|_L}; /* 252-255 */ + +static inline int match_token(struct ts_fsm_token *t, u8 d) +{ + if (t->type) + return (token_lookup_tbl[d] & t->type) != 0; + else + return t->value == d; +} + +static unsigned int fsm_find(struct ts_config *conf, struct ts_state *state) +{ + struct ts_fsm *fsm = ts_config_priv(conf); + struct ts_fsm_token *cur = NULL, *next; + unsigned int match_start, block_idx = 0, tok_idx; + unsigned block_len = 0, strict, consumed = state->offset; + const u8 *data; + +#define GET_NEXT_BLOCK() \ +({ consumed += block_idx; \ + block_idx = 0; \ + block_len = conf->get_next_block(consumed, &data, conf, state); }) + +#define TOKEN_MISMATCH() \ + do { \ + if (strict) \ + goto no_match; \ + block_idx++; \ + goto startover; \ + } while(0) + +#define end_of_data() unlikely(block_idx >= block_len && !GET_NEXT_BLOCK()) + + if (end_of_data()) + goto no_match; + + strict = fsm->tokens[0].recur != TS_FSM_HEAD_IGNORE; + +startover: + match_start = consumed + block_idx; + + for (tok_idx = 0; tok_idx < fsm->ntokens; tok_idx++) { + cur = &fsm->tokens[tok_idx]; + + if (likely(tok_idx < (fsm->ntokens - 1))) + next = &fsm->tokens[tok_idx + 1]; + else + next = NULL; + + switch (cur->recur) { + case TS_FSM_SINGLE: + if (end_of_data()) + goto no_match; + + if (!match_token(cur, data[block_idx])) + TOKEN_MISMATCH(); + break; + + case TS_FSM_PERHAPS: + if (end_of_data() || + !match_token(cur, data[block_idx])) + continue; + break; + + case TS_FSM_MULTI: + if (end_of_data()) + goto no_match; + + if (!match_token(cur, data[block_idx])) + TOKEN_MISMATCH(); + + block_idx++; + fallthrough; + + case TS_FSM_ANY: + if (next == NULL) + goto found_match; + + if (end_of_data()) + continue; + + while (!match_token(next, data[block_idx])) { + if (!match_token(cur, data[block_idx])) + TOKEN_MISMATCH(); + block_idx++; + if (end_of_data()) + goto no_match; + } + continue; + + /* + * Optimization: Prefer small local loop over jumping + * back and forth until garbage at head is munched. + */ + case TS_FSM_HEAD_IGNORE: + if (end_of_data()) + continue; + + while (!match_token(next, data[block_idx])) { + /* + * Special case, don't start over upon + * a mismatch, give the user the + * chance to specify the type of data + * allowed to be ignored. + */ + if (!match_token(cur, data[block_idx])) + goto no_match; + + block_idx++; + if (end_of_data()) + goto no_match; + } + + match_start = consumed + block_idx; + continue; + } + + block_idx++; + } + + if (end_of_data()) + goto found_match; + +no_match: + return UINT_MAX; + +found_match: + state->offset = consumed + block_idx; + return match_start; +} + +static struct ts_config *fsm_init(const void *pattern, unsigned int len, + gfp_t gfp_mask, int flags) +{ + int i, err = -EINVAL; + struct ts_config *conf; + struct ts_fsm *fsm; + struct ts_fsm_token *tokens = (struct ts_fsm_token *) pattern; + unsigned int ntokens = len / sizeof(*tokens); + size_t priv_size = sizeof(*fsm) + len; + + if (len % sizeof(struct ts_fsm_token) || ntokens < 1) + goto errout; + + if (flags & TS_IGNORECASE) + goto errout; + + for (i = 0; i < ntokens; i++) { + struct ts_fsm_token *t = &tokens[i]; + + if (t->type > TS_FSM_TYPE_MAX || t->recur > TS_FSM_RECUR_MAX) + goto errout; + + if (t->recur == TS_FSM_HEAD_IGNORE && + (i != 0 || i == (ntokens - 1))) + goto errout; + } + + conf = alloc_ts_config(priv_size, gfp_mask); + if (IS_ERR(conf)) + return conf; + + conf->flags = flags; + fsm = ts_config_priv(conf); + fsm->ntokens = ntokens; + memcpy(fsm->tokens, pattern, len); + + for (i = 0; i < fsm->ntokens; i++) { + struct ts_fsm_token *t = &fsm->tokens[i]; + t->type = token_map[t->type]; + } + + return conf; + +errout: + return ERR_PTR(err); +} + +static void *fsm_get_pattern(struct ts_config *conf) +{ + struct ts_fsm *fsm = ts_config_priv(conf); + return fsm->tokens; +} + +static unsigned int fsm_get_pattern_len(struct ts_config *conf) +{ + struct ts_fsm *fsm = ts_config_priv(conf); + return fsm->ntokens * sizeof(struct ts_fsm_token); +} + +static struct ts_ops fsm_ops = { + .name = "fsm", + .find = fsm_find, + .init = fsm_init, + .get_pattern = fsm_get_pattern, + .get_pattern_len = fsm_get_pattern_len, + .owner = THIS_MODULE, + .list = LIST_HEAD_INIT(fsm_ops.list) +}; + +static int __init init_fsm(void) +{ + return textsearch_register(&fsm_ops); +} + +static void __exit exit_fsm(void) +{ + textsearch_unregister(&fsm_ops); +} + +MODULE_DESCRIPTION("naive finite state machine text search"); +MODULE_LICENSE("GPL"); + +module_init(init_fsm); +module_exit(exit_fsm); |
