From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux 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 ... --- lib/seq_buf.c | 439 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 439 insertions(+) create mode 100644 lib/seq_buf.c (limited to 'lib/seq_buf.c') diff --git a/lib/seq_buf.c b/lib/seq_buf.c new file mode 100644 index 000000000..a92093f34 --- /dev/null +++ b/lib/seq_buf.c @@ -0,0 +1,439 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * seq_buf.c + * + * Copyright (C) 2014 Red Hat Inc, Steven Rostedt + * + * The seq_buf is a handy tool that allows you to pass a descriptor around + * to a buffer that other functions can write to. It is similar to the + * seq_file functionality but has some differences. + * + * To use it, the seq_buf must be initialized with seq_buf_init(). + * This will set up the counters within the descriptor. You can call + * seq_buf_init() more than once to reset the seq_buf to start + * from scratch. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/** + * seq_buf_can_fit - can the new data fit in the current buffer? + * @s: the seq_buf descriptor + * @len: The length to see if it can fit in the current buffer + * + * Returns: true if there's enough unused space in the seq_buf buffer + * to fit the amount of new data according to @len. + */ +static bool seq_buf_can_fit(struct seq_buf *s, size_t len) +{ + return s->len + len <= s->size; +} + +/** + * seq_buf_print_seq - move the contents of seq_buf into a seq_file + * @m: the seq_file descriptor that is the destination + * @s: the seq_buf descriptor that is the source. + * + * Returns: zero on success, non-zero otherwise. + */ +int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s) +{ + unsigned int len = seq_buf_used(s); + + return seq_write(m, s->buffer, len); +} + +/** + * seq_buf_vprintf - sequence printing of information. + * @s: seq_buf descriptor + * @fmt: printf format string + * @args: va_list of arguments from a printf() type function + * + * Writes a vnprintf() format into the sequence buffer. + * + * Returns: zero on success, -1 on overflow. + */ +int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args) +{ + int len; + + WARN_ON(s->size == 0); + + if (s->len < s->size) { + len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args); + if (s->len + len < s->size) { + s->len += len; + return 0; + } + } + seq_buf_set_overflow(s); + return -1; +} + +/** + * seq_buf_printf - sequence printing of information + * @s: seq_buf descriptor + * @fmt: printf format string + * + * Writes a printf() format into the sequence buffer. + * + * Returns: zero on success, -1 on overflow. + */ +int seq_buf_printf(struct seq_buf *s, const char *fmt, ...) +{ + va_list ap; + int ret; + + va_start(ap, fmt); + ret = seq_buf_vprintf(s, fmt, ap); + va_end(ap); + + return ret; +} +EXPORT_SYMBOL_GPL(seq_buf_printf); + +/** + * seq_buf_do_printk - printk() seq_buf line by line + * @s: seq_buf descriptor + * @lvl: printk level + * + * printk()-s a multi-line sequential buffer line by line. The function + * makes sure that the buffer in @s is NUL-terminated and safe to read + * as a string. + */ +void seq_buf_do_printk(struct seq_buf *s, const char *lvl) +{ + const char *start, *lf; + + if (s->size == 0 || s->len == 0) + return; + + start = seq_buf_str(s); + while ((lf = strchr(start, '\n'))) { + int len = lf - start + 1; + + printk("%s%.*s", lvl, len, start); + start = ++lf; + } + + /* No trailing LF */ + if (start < s->buffer + s->len) + printk("%s%s\n", lvl, start); +} +EXPORT_SYMBOL_GPL(seq_buf_do_printk); + +#ifdef CONFIG_BINARY_PRINTF +/** + * seq_buf_bprintf - Write the printf string from binary arguments + * @s: seq_buf descriptor + * @fmt: The format string for the @binary arguments + * @binary: The binary arguments for @fmt. + * + * When recording in a fast path, a printf may be recorded with just + * saving the format and the arguments as they were passed to the + * function, instead of wasting cycles converting the arguments into + * ASCII characters. Instead, the arguments are saved in a 32 bit + * word array that is defined by the format string constraints. + * + * This function will take the format and the binary array and finish + * the conversion into the ASCII string within the buffer. + * + * Returns: zero on success, -1 on overflow. + */ +int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary) +{ + unsigned int len = seq_buf_buffer_left(s); + int ret; + + WARN_ON(s->size == 0); + + if (s->len < s->size) { + ret = bstr_printf(s->buffer + s->len, len, fmt, binary); + if (s->len + ret < s->size) { + s->len += ret; + return 0; + } + } + seq_buf_set_overflow(s); + return -1; +} +#endif /* CONFIG_BINARY_PRINTF */ + +/** + * seq_buf_puts - sequence printing of simple string + * @s: seq_buf descriptor + * @str: simple string to record + * + * Copy a simple string into the sequence buffer. + * + * Returns: zero on success, -1 on overflow. + */ +int seq_buf_puts(struct seq_buf *s, const char *str) +{ + size_t len = strlen(str); + + WARN_ON(s->size == 0); + + /* Add 1 to len for the trailing null byte which must be there */ + len += 1; + + if (seq_buf_can_fit(s, len)) { + memcpy(s->buffer + s->len, str, len); + /* Don't count the trailing null byte against the capacity */ + s->len += len - 1; + return 0; + } + seq_buf_set_overflow(s); + return -1; +} +EXPORT_SYMBOL_GPL(seq_buf_puts); + +/** + * seq_buf_putc - sequence printing of simple character + * @s: seq_buf descriptor + * @c: simple character to record + * + * Copy a single character into the sequence buffer. + * + * Returns: zero on success, -1 on overflow. + */ +int seq_buf_putc(struct seq_buf *s, unsigned char c) +{ + WARN_ON(s->size == 0); + + if (seq_buf_can_fit(s, 1)) { + s->buffer[s->len++] = c; + return 0; + } + seq_buf_set_overflow(s); + return -1; +} +EXPORT_SYMBOL_GPL(seq_buf_putc); + +/** + * seq_buf_putmem - write raw data into the sequence buffer + * @s: seq_buf descriptor + * @mem: The raw memory to copy into the buffer + * @len: The length of the raw memory to copy (in bytes) + * + * There may be cases where raw memory needs to be written into the + * buffer and a strcpy() would not work. Using this function allows + * for such cases. + * + * Returns: zero on success, -1 on overflow. + */ +int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len) +{ + WARN_ON(s->size == 0); + + if (seq_buf_can_fit(s, len)) { + memcpy(s->buffer + s->len, mem, len); + s->len += len; + return 0; + } + seq_buf_set_overflow(s); + return -1; +} + +#define MAX_MEMHEX_BYTES 8U +#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) + +/** + * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex + * @s: seq_buf descriptor + * @mem: The raw memory to write its hex ASCII representation of + * @len: The length of the raw memory to copy (in bytes) + * + * This is similar to seq_buf_putmem() except instead of just copying the + * raw memory into the buffer it writes its ASCII representation of it + * in hex characters. + * + * Returns: zero on success, -1 on overflow. + */ +int seq_buf_putmem_hex(struct seq_buf *s, const void *mem, + unsigned int len) +{ + unsigned char hex[HEX_CHARS]; + const unsigned char *data = mem; + unsigned int start_len; + int i, j; + + WARN_ON(s->size == 0); + + BUILD_BUG_ON(MAX_MEMHEX_BYTES * 2 >= HEX_CHARS); + + while (len) { + start_len = min(len, MAX_MEMHEX_BYTES); +#ifdef __BIG_ENDIAN + for (i = 0, j = 0; i < start_len; i++) { +#else + for (i = start_len-1, j = 0; i >= 0; i--) { +#endif + hex[j++] = hex_asc_hi(data[i]); + hex[j++] = hex_asc_lo(data[i]); + } + if (WARN_ON_ONCE(j == 0 || j/2 > len)) + break; + + /* j increments twice per loop */ + hex[j++] = ' '; + + seq_buf_putmem(s, hex, j); + if (seq_buf_has_overflowed(s)) + return -1; + + len -= start_len; + data += start_len; + } + return 0; +} +EXPORT_SYMBOL_GPL(seq_buf_putmem_hex); + +/** + * seq_buf_path - copy a path into the sequence buffer + * @s: seq_buf descriptor + * @path: path to write into the sequence buffer. + * @esc: set of characters to escape in the output + * + * Write a path name into the sequence buffer. + * + * Returns: the number of written bytes on success, -1 on overflow. + */ +int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc) +{ + char *buf; + size_t size = seq_buf_get_buf(s, &buf); + int res = -1; + + WARN_ON(s->size == 0); + + if (size) { + char *p = d_path(path, buf, size); + if (!IS_ERR(p)) { + char *end = seq_mangle_path(buf, p, esc); + if (end) + res = end - buf; + } + } + seq_buf_commit(s, res); + + return res; +} + +/** + * seq_buf_to_user - copy the sequence buffer to user space + * @s: seq_buf descriptor + * @ubuf: The userspace memory location to copy to + * @start: The first byte in the buffer to copy + * @cnt: The amount to copy + * + * Copies the sequence buffer into the userspace memory pointed to + * by @ubuf. It starts from @start and writes up to @cnt characters + * or until it reaches the end of the content in the buffer (@s->len), + * whichever comes first. + * + * Returns: + * On success, it returns a positive number of the number of bytes + * it copied. + * + * On failure it returns -EBUSY if all of the content in the + * sequence has been already read, which includes nothing in the + * sequence (@s->len == @start). + * + * Returns -EFAULT if the copy to userspace fails. + */ +int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, size_t start, int cnt) +{ + int len; + int ret; + + if (!cnt) + return 0; + + len = seq_buf_used(s); + + if (len <= start) + return -EBUSY; + + len -= start; + if (cnt > len) + cnt = len; + ret = copy_to_user(ubuf, s->buffer + start, cnt); + if (ret == cnt) + return -EFAULT; + + return cnt - ret; +} + +/** + * seq_buf_hex_dump - print formatted hex dump into the sequence buffer + * @s: seq_buf descriptor + * @prefix_str: string to prefix each line with; + * caller supplies trailing spaces for alignment if desired + * @prefix_type: controls whether prefix of an offset, address, or none + * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE) + * @rowsize: number of bytes to print per line; must be 16 or 32 + * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1) + * @buf: data blob to dump + * @len: number of bytes in the @buf + * @ascii: include ASCII after the hex output + * + * Function is an analogue of print_hex_dump() and thus has similar interface. + * + * linebuf size is maximal length for one line. + * 32 * 3 - maximum bytes per line, each printed into 2 chars + 1 for + * separating space + * 2 - spaces separating hex dump and ASCII representation + * 32 - ASCII representation + * 1 - terminating '\0' + * + * Returns: zero on success, -1 on overflow. + */ +int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str, int prefix_type, + int rowsize, int groupsize, + const void *buf, size_t len, bool ascii) +{ + const u8 *ptr = buf; + int i, linelen, remaining = len; + unsigned char linebuf[32 * 3 + 2 + 32 + 1]; + int ret; + + if (rowsize != 16 && rowsize != 32) + rowsize = 16; + + for (i = 0; i < len; i += rowsize) { + linelen = min(remaining, rowsize); + remaining -= rowsize; + + hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize, + linebuf, sizeof(linebuf), ascii); + + switch (prefix_type) { + case DUMP_PREFIX_ADDRESS: + ret = seq_buf_printf(s, "%s%p: %s\n", + prefix_str, ptr + i, linebuf); + break; + case DUMP_PREFIX_OFFSET: + ret = seq_buf_printf(s, "%s%.8x: %s\n", + prefix_str, i, linebuf); + break; + default: + ret = seq_buf_printf(s, "%s%s\n", prefix_str, linebuf); + break; + } + if (ret) + return ret; + } + return 0; +} -- cgit v1.3.1