#define CREATE_TRACE_POINTS
#include <trace/events/printk.h>
+#include "printk_ringbuffer.h"
#include "console_cmdline.h"
#include "braille.h"
#include "internal.h"
static int console_msg_format = MSG_FORMAT_DEFAULT;
/*
- * The printk log buffer consists of a chain of concatenated variable
- * length records. Every record starts with a record header, containing
- * the overall length of the record.
+ * The printk log buffer consists of a sequenced collection of records, each
+ * containing variable length message and dictionary text. Every record
+ * also contains its own meta-data (@info).
*
- * The heads to the first and last entry in the buffer, as well as the
- * sequence numbers of these entries are maintained when messages are
- * stored.
+ * Every record meta-data carries the timestamp in microseconds, as well as
+ * the standard userspace syslog level and syslog facility. The usual kernel
+ * messages use LOG_KERN; userspace-injected messages always carry a matching
+ * syslog facility, by default LOG_USER. The origin of every message can be
+ * reliably determined that way.
*
- * If the heads indicate available messages, the length in the header
- * tells the start next message. A length == 0 for the next message
- * indicates a wrap-around to the beginning of the buffer.
+ * The human readable log message of a record is available in @text, the
+ * length of the message text in @text_len. The stored message is not
+ * terminated.
*
- * Every record carries the monotonic timestamp in microseconds, as well as
- * the standard userspace syslog level and syslog facility. The usual
- * kernel messages use LOG_KERN; userspace-injected messages always carry
- * a matching syslog facility, by default LOG_USER. The origin of every
- * message can be reliably determined that way.
- *
- * The human readable log message directly follows the message header. The
- * length of the message text is stored in the header, the stored message
- * is not terminated.
- *
- * Optionally, a message can carry a dictionary of properties (key/value pairs),
- * to provide userspace with a machine-readable message context.
+ * Optionally, a record can carry a dictionary of properties (key/value
+ * pairs), to provide userspace with a machine-readable message context. The
+ * length of the dictionary is available in @dict_len. The dictionary is not
+ * terminated.
*
* Examples for well-defined, commonly used property names are:
* DEVICE=b12:8 device identifier
* follows directly after a '=' character. Every property is terminated by
* a '\0' character. The last property is not terminated.
*
- * Example of a message structure:
- * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec
- * 0008 34 00 record is 52 bytes long
- * 000a 0b 00 text is 11 bytes long
- * 000c 1f 00 dictionary is 23 bytes long
- * 000e 03 00 LOG_KERN (facility) LOG_ERR (level)
- * 0010 69 74 27 73 20 61 20 6c "it's a l"
- * 69 6e 65 "ine"
- * 001b 44 45 56 49 43 "DEVIC"
- * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D"
- * 52 49 56 45 52 3d 62 75 "RIVER=bu"
- * 67 "g"
- * 0032 00 00 00 padding to next message header
- *
- * The 'struct printk_log' buffer header must never be directly exported to
+ * Example of record values:
+ * record.text_buf = "it's a line" (unterminated)
+ * record.dict_buf = "DEVICE=b8:2\0DRIVER=bug" (unterminated)
+ * record.info.seq = 56
+ * record.info.ts_nsec = 36863
+ * record.info.text_len = 11
+ * record.info.dict_len = 22
+ * record.info.facility = 0 (LOG_KERN)
+ * record.info.flags = 0
+ * record.info.level = 3 (LOG_ERR)
+ * record.info.caller_id = 299 (task 299)
+ *
+ * The 'struct printk_info' buffer must never be directly exported to
* userspace, it is a kernel-private implementation detail that might
* need to be changed in the future, when the requirements change.
*
LOG_CONT = 8, /* text is a fragment of a continuation line */
};
-struct printk_log {
- u64 ts_nsec; /* timestamp in nanoseconds */
- u16 len; /* length of entire record */
- u16 text_len; /* length of text buffer */
- u16 dict_len; /* length of dictionary buffer */
- u8 facility; /* syslog facility */
- u8 flags:5; /* internal record flags */
- u8 level:3; /* syslog level */
-#ifdef CONFIG_PRINTK_CALLER
- u32 caller_id; /* thread id or processor id */
-#endif
-}
-#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
-__packed __aligned(4)
-#endif
-;
-
/*
* The logbuf_lock protects kmsg buffer, indices, counters. This can be taken
* within the scheduler's rq lock. It must be released before calling
DECLARE_WAIT_QUEUE_HEAD(log_wait);
/* the next printk record to read by syslog(READ) or /proc/kmsg */
static u64 syslog_seq;
-static u32 syslog_idx;
static size_t syslog_partial;
static bool syslog_time;
-/* index and sequence number of the first record stored in the buffer */
-static u64 log_first_seq;
-static u32 log_first_idx;
-
-/* index and sequence number of the next record to store in the buffer */
-static u64 log_next_seq;
-static u32 log_next_idx;
-
/* the next printk record to write to the console */
static u64 console_seq;
-static u32 console_idx;
static u64 exclusive_console_stop_seq;
+static unsigned long console_dropped;
/* the next printk record to read after the last 'clear' command */
static u64 clear_seq;
-static u32 clear_idx;
#ifdef CONFIG_PRINTK_CALLER
#define PREFIX_MAX 48
#define LOG_FACILITY(v) ((v) >> 3 & 0xff)
/* record buffer */
-#define LOG_ALIGN __alignof__(struct printk_log)
+#define LOG_ALIGN __alignof__(unsigned long)
#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
#define LOG_BUF_LEN_MAX (u32)(1 << 31)
static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
static char *log_buf = __log_buf;
static u32 log_buf_len = __LOG_BUF_LEN;
+/*
+ * Define the average message size. This only affects the number of
+ * descriptors that will be available. Underestimating is better than
+ * overestimating (too many available descriptors is better than not enough).
+ * The dictionary buffer will be the same size as the text buffer.
+ */
+#define PRB_AVGBITS 5 /* 32 character average length */
+
+#if CONFIG_LOG_BUF_SHIFT <= PRB_AVGBITS
+#error CONFIG_LOG_BUF_SHIFT value too small.
+#endif
+_DEFINE_PRINTKRB(printk_rb_static, CONFIG_LOG_BUF_SHIFT - PRB_AVGBITS,
+ PRB_AVGBITS, PRB_AVGBITS, &__log_buf[0]);
+
+static struct printk_ringbuffer printk_rb_dynamic;
+
+static struct printk_ringbuffer *prb = &printk_rb_static;
+
/*
* We cannot access per-CPU data (e.g. per-CPU flush irq_work) before
* per_cpu_areas are initialised. This variable is set to true when
return log_buf_len;
}
-/* human readable text of the record */
-static char *log_text(const struct printk_log *msg)
-{
- return (char *)msg + sizeof(struct printk_log);
-}
-
-/* optional key/value pair dictionary attached to the record */
-static char *log_dict(const struct printk_log *msg)
-{
- return (char *)msg + sizeof(struct printk_log) + msg->text_len;
-}
-
-/* get record by index; idx must point to valid msg */
-static struct printk_log *log_from_idx(u32 idx)
-{
- struct printk_log *msg = (struct printk_log *)(log_buf + idx);
-
- /*
- * A length == 0 record is the end of buffer marker. Wrap around and
- * read the message at the start of the buffer.
- */
- if (!msg->len)
- return (struct printk_log *)log_buf;
- return msg;
-}
-
-/* get next record; idx must point to valid msg */
-static u32 log_next(u32 idx)
-{
- struct printk_log *msg = (struct printk_log *)(log_buf + idx);
-
- /* length == 0 indicates the end of the buffer; wrap */
- /*
- * A length == 0 record is the end of buffer marker. Wrap around and
- * read the message at the start of the buffer as *this* one, and
- * return the one after that.
- */
- if (!msg->len) {
- msg = (struct printk_log *)log_buf;
- return msg->len;
- }
- return idx + msg->len;
-}
-
-/*
- * Check whether there is enough free space for the given message.
- *
- * The same values of first_idx and next_idx mean that the buffer
- * is either empty or full.
- *
- * If the buffer is empty, we must respect the position of the indexes.
- * They cannot be reset to the beginning of the buffer.
- */
-static int logbuf_has_space(u32 msg_size, bool empty)
-{
- u32 free;
-
- if (log_next_idx > log_first_idx || empty)
- free = max(log_buf_len - log_next_idx, log_first_idx);
- else
- free = log_first_idx - log_next_idx;
-
- /*
- * We need space also for an empty header that signalizes wrapping
- * of the buffer.
- */
- return free >= msg_size + sizeof(struct printk_log);
-}
-
-static int log_make_free_space(u32 msg_size)
-{
- while (log_first_seq < log_next_seq &&
- !logbuf_has_space(msg_size, false)) {
- /* drop old messages until we have enough contiguous space */
- log_first_idx = log_next(log_first_idx);
- log_first_seq++;
- }
-
- if (clear_seq < log_first_seq) {
- clear_seq = log_first_seq;
- clear_idx = log_first_idx;
- }
-
- /* sequence numbers are equal, so the log buffer is empty */
- if (logbuf_has_space(msg_size, log_first_seq == log_next_seq))
- return 0;
-
- return -ENOMEM;
-}
-
-/* compute the message size including the padding bytes */
-static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len)
-{
- u32 size;
-
- size = sizeof(struct printk_log) + text_len + dict_len;
- *pad_len = (-size) & (LOG_ALIGN - 1);
- size += *pad_len;
-
- return size;
-}
-
/*
* Define how much of the log buffer we could take at maximum. The value
* must be greater than two. Note that only half of the buffer is available
#define MAX_LOG_TAKE_PART 4
static const char trunc_msg[] = "<truncated>";
-static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len,
- u16 *dict_len, u32 *pad_len)
+static void truncate_msg(u16 *text_len, u16 *trunc_msg_len)
{
/*
* The message should not take the whole buffer. Otherwise, it might
* get removed too soon.
*/
u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART;
+
if (*text_len > max_text_len)
*text_len = max_text_len;
- /* enable the warning message */
+
+ /* enable the warning message (if there is room) */
*trunc_msg_len = strlen(trunc_msg);
- /* disable the "dict" completely */
- *dict_len = 0;
- /* compute the size again, count also the warning message */
- return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len);
+ if (*text_len >= *trunc_msg_len)
+ *text_len -= *trunc_msg_len;
+ else
+ *trunc_msg_len = 0;
}
/* insert record into the buffer, discard old ones, update heads */
const char *dict, u16 dict_len,
const char *text, u16 text_len)
{
- struct printk_log *msg;
- u32 size, pad_len;
+ struct prb_reserved_entry e;
+ struct printk_record r;
u16 trunc_msg_len = 0;
- /* number of '\0' padding bytes to next message */
- size = msg_used_size(text_len, dict_len, &pad_len);
+ prb_rec_init_wr(&r, text_len, dict_len);
- if (log_make_free_space(size)) {
+ if (!prb_reserve(&e, prb, &r)) {
/* truncate the message if it is too long for empty buffer */
- size = truncate_msg(&text_len, &trunc_msg_len,
- &dict_len, &pad_len);
+ truncate_msg(&text_len, &trunc_msg_len);
+ prb_rec_init_wr(&r, text_len + trunc_msg_len, dict_len);
/* survive when the log buffer is too small for trunc_msg */
- if (log_make_free_space(size))
+ if (!prb_reserve(&e, prb, &r))
return 0;
}
- if (log_next_idx + size + sizeof(struct printk_log) > log_buf_len) {
- /*
- * This message + an additional empty header does not fit
- * at the end of the buffer. Add an empty header with len == 0
- * to signify a wrap around.
- */
- memset(log_buf + log_next_idx, 0, sizeof(struct printk_log));
- log_next_idx = 0;
- }
-
/* fill message */
- msg = (struct printk_log *)(log_buf + log_next_idx);
- memcpy(log_text(msg), text, text_len);
- msg->text_len = text_len;
- if (trunc_msg_len) {
- memcpy(log_text(msg) + text_len, trunc_msg, trunc_msg_len);
- msg->text_len += trunc_msg_len;
- }
- memcpy(log_dict(msg), dict, dict_len);
- msg->dict_len = dict_len;
- msg->facility = facility;
- msg->level = level & 7;
- msg->flags = flags & 0x1f;
+ memcpy(&r.text_buf[0], text, text_len);
+ if (trunc_msg_len)
+ memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);
+ if (r.dict_buf)
+ memcpy(&r.dict_buf[0], dict, dict_len);
+ r.info->facility = facility;
+ r.info->level = level & 7;
+ r.info->flags = flags & 0x1f;
if (ts_nsec > 0)
- msg->ts_nsec = ts_nsec;
+ r.info->ts_nsec = ts_nsec;
else
- msg->ts_nsec = local_clock();
-#ifdef CONFIG_PRINTK_CALLER
- msg->caller_id = caller_id;
-#endif
- memset(log_dict(msg) + dict_len, 0, pad_len);
- msg->len = size;
+ r.info->ts_nsec = local_clock();
+ r.info->caller_id = caller_id;
/* insert message */
- log_next_idx += msg->len;
- log_next_seq++;
+ prb_commit(&e);
- return msg->text_len;
+ return (text_len + trunc_msg_len);
}
int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT);
*(*pp)++ = c;
}
-static ssize_t msg_print_ext_header(char *buf, size_t size,
- struct printk_log *msg, u64 seq)
+static ssize_t info_print_ext_header(char *buf, size_t size,
+ struct printk_info *info)
{
- u64 ts_usec = msg->ts_nsec;
+ u64 ts_usec = info->ts_nsec;
char caller[20];
#ifdef CONFIG_PRINTK_CALLER
- u32 id = msg->caller_id;
+ u32 id = info->caller_id;
snprintf(caller, sizeof(caller), ",caller=%c%u",
id & 0x80000000 ? 'C' : 'T', id & ~0x80000000);
do_div(ts_usec, 1000);
return scnprintf(buf, size, "%u,%llu,%llu,%c%s;",
- (msg->facility << 3) | msg->level, seq, ts_usec,
- msg->flags & LOG_CONT ? 'c' : '-', caller);
+ (info->facility << 3) | info->level, info->seq,
+ ts_usec, info->flags & LOG_CONT ? 'c' : '-', caller);
}
static ssize_t msg_print_ext_body(char *buf, size_t size,
/* /dev/kmsg - userspace message inject/listen interface */
struct devkmsg_user {
u64 seq;
- u32 idx;
struct ratelimit_state rs;
struct mutex lock;
char buf[CONSOLE_EXT_LOG_MAX];
+
+ struct printk_info info;
+ char text_buf[CONSOLE_EXT_LOG_MAX];
+ char dict_buf[CONSOLE_EXT_LOG_MAX];
+ struct printk_record record;
};
static __printf(3, 4) __cold
size_t count, loff_t *ppos)
{
struct devkmsg_user *user = file->private_data;
- struct printk_log *msg;
+ struct printk_record *r = &user->record;
size_t len;
ssize_t ret;
return ret;
logbuf_lock_irq();
- while (user->seq == log_next_seq) {
+ if (!prb_read_valid(prb, user->seq, r)) {
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
logbuf_unlock_irq();
logbuf_unlock_irq();
ret = wait_event_interruptible(log_wait,
- user->seq != log_next_seq);
+ prb_read_valid(prb, user->seq, r));
if (ret)
goto out;
logbuf_lock_irq();
}
- if (user->seq < log_first_seq) {
+ if (user->seq < prb_first_valid_seq(prb)) {
/* our last seen message is gone, return error and reset */
- user->idx = log_first_idx;
- user->seq = log_first_seq;
+ user->seq = prb_first_valid_seq(prb);
ret = -EPIPE;
logbuf_unlock_irq();
goto out;
}
- msg = log_from_idx(user->idx);
- len = msg_print_ext_header(user->buf, sizeof(user->buf),
- msg, user->seq);
+ len = info_print_ext_header(user->buf, sizeof(user->buf), r->info);
len += msg_print_ext_body(user->buf + len, sizeof(user->buf) - len,
- log_dict(msg), msg->dict_len,
- log_text(msg), msg->text_len);
+ &r->dict_buf[0], r->info->dict_len,
+ &r->text_buf[0], r->info->text_len);
- user->idx = log_next(user->idx);
- user->seq++;
+ user->seq = r->info->seq + 1;
logbuf_unlock_irq();
if (len > count) {
switch (whence) {
case SEEK_SET:
/* the first record */
- user->idx = log_first_idx;
- user->seq = log_first_seq;
+ user->seq = prb_first_valid_seq(prb);
break;
case SEEK_DATA:
/*
* like issued by 'dmesg -c'. Reading /dev/kmsg itself
* changes no global state, and does not clear anything.
*/
- user->idx = clear_idx;
user->seq = clear_seq;
break;
case SEEK_END:
/* after the last record */
- user->idx = log_next_idx;
- user->seq = log_next_seq;
+ user->seq = prb_next_seq(prb);
break;
default:
ret = -EINVAL;
poll_wait(file, &log_wait, wait);
logbuf_lock_irq();
- if (user->seq < log_next_seq) {
+ if (prb_read_valid(prb, user->seq, NULL)) {
/* return error when data has vanished underneath us */
- if (user->seq < log_first_seq)
+ if (user->seq < prb_first_valid_seq(prb))
ret = EPOLLIN|EPOLLRDNORM|EPOLLERR|EPOLLPRI;
else
ret = EPOLLIN|EPOLLRDNORM;
mutex_init(&user->lock);
+ prb_rec_init_rd(&user->record, &user->info,
+ &user->text_buf[0], sizeof(user->text_buf),
+ &user->dict_buf[0], sizeof(user->dict_buf));
+
logbuf_lock_irq();
- user->idx = log_first_idx;
- user->seq = log_first_seq;
+ user->seq = prb_first_valid_seq(prb);
logbuf_unlock_irq();
file->private_data = user;
*/
void log_buf_vmcoreinfo_setup(void)
{
- VMCOREINFO_SYMBOL(log_buf);
- VMCOREINFO_SYMBOL(log_buf_len);
- VMCOREINFO_SYMBOL(log_first_idx);
- VMCOREINFO_SYMBOL(clear_idx);
- VMCOREINFO_SYMBOL(log_next_idx);
+ VMCOREINFO_SYMBOL(prb);
+ VMCOREINFO_SYMBOL(printk_rb_static);
+ VMCOREINFO_SYMBOL(clear_seq);
+
/*
- * Export struct printk_log size and field offsets. User space tools can
+ * Export struct size and field offsets. User space tools can
* parse it and detect any changes to structure down the line.
*/
- VMCOREINFO_STRUCT_SIZE(printk_log);
- VMCOREINFO_OFFSET(printk_log, ts_nsec);
- VMCOREINFO_OFFSET(printk_log, len);
- VMCOREINFO_OFFSET(printk_log, text_len);
- VMCOREINFO_OFFSET(printk_log, dict_len);
-#ifdef CONFIG_PRINTK_CALLER
- VMCOREINFO_OFFSET(printk_log, caller_id);
-#endif
+
+ VMCOREINFO_STRUCT_SIZE(printk_ringbuffer);
+ VMCOREINFO_OFFSET(printk_ringbuffer, desc_ring);
+ VMCOREINFO_OFFSET(printk_ringbuffer, text_data_ring);
+ VMCOREINFO_OFFSET(printk_ringbuffer, dict_data_ring);
+ VMCOREINFO_OFFSET(printk_ringbuffer, fail);
+
+ VMCOREINFO_STRUCT_SIZE(prb_desc_ring);
+ VMCOREINFO_OFFSET(prb_desc_ring, count_bits);
+ VMCOREINFO_OFFSET(prb_desc_ring, descs);
+ VMCOREINFO_OFFSET(prb_desc_ring, head_id);
+ VMCOREINFO_OFFSET(prb_desc_ring, tail_id);
+
+ VMCOREINFO_STRUCT_SIZE(prb_desc);
+ VMCOREINFO_OFFSET(prb_desc, info);
+ VMCOREINFO_OFFSET(prb_desc, state_var);
+ VMCOREINFO_OFFSET(prb_desc, text_blk_lpos);
+ VMCOREINFO_OFFSET(prb_desc, dict_blk_lpos);
+
+ VMCOREINFO_STRUCT_SIZE(prb_data_blk_lpos);
+ VMCOREINFO_OFFSET(prb_data_blk_lpos, begin);
+ VMCOREINFO_OFFSET(prb_data_blk_lpos, next);
+
+ VMCOREINFO_STRUCT_SIZE(printk_info);
+ VMCOREINFO_OFFSET(printk_info, seq);
+ VMCOREINFO_OFFSET(printk_info, ts_nsec);
+ VMCOREINFO_OFFSET(printk_info, text_len);
+ VMCOREINFO_OFFSET(printk_info, dict_len);
+ VMCOREINFO_OFFSET(printk_info, caller_id);
+
+ VMCOREINFO_STRUCT_SIZE(prb_data_ring);
+ VMCOREINFO_OFFSET(prb_data_ring, size_bits);
+ VMCOREINFO_OFFSET(prb_data_ring, data);
+ VMCOREINFO_OFFSET(prb_data_ring, head_lpos);
+ VMCOREINFO_OFFSET(prb_data_ring, tail_lpos);
+
+ VMCOREINFO_SIZE(atomic_long_t);
+ VMCOREINFO_TYPE_OFFSET(atomic_long_t, counter);
}
#endif
__printk_percpu_data_ready = true;
}
+static unsigned int __init add_to_rb(struct printk_ringbuffer *rb,
+ struct printk_record *r)
+{
+ struct prb_reserved_entry e;
+ struct printk_record dest_r;
+
+ prb_rec_init_wr(&dest_r, r->info->text_len, r->info->dict_len);
+
+ if (!prb_reserve(&e, rb, &dest_r))
+ return 0;
+
+ memcpy(&dest_r.text_buf[0], &r->text_buf[0], dest_r.text_buf_size);
+ if (dest_r.dict_buf) {
+ memcpy(&dest_r.dict_buf[0], &r->dict_buf[0],
+ dest_r.dict_buf_size);
+ }
+ dest_r.info->facility = r->info->facility;
+ dest_r.info->level = r->info->level;
+ dest_r.info->flags = r->info->flags;
+ dest_r.info->ts_nsec = r->info->ts_nsec;
+ dest_r.info->caller_id = r->info->caller_id;
+
+ prb_commit(&e);
+
+ return prb_record_text_space(&e);
+}
+
+static char setup_text_buf[CONSOLE_EXT_LOG_MAX] __initdata;
+static char setup_dict_buf[CONSOLE_EXT_LOG_MAX] __initdata;
+
void __init setup_log_buf(int early)
{
+ unsigned int new_descs_count;
+ struct prb_desc *new_descs;
+ struct printk_info info;
+ struct printk_record r;
+ size_t new_descs_size;
unsigned long flags;
+ char *new_dict_buf;
char *new_log_buf;
unsigned int free;
+ u64 seq;
/*
* Some archs call setup_log_buf() multiple times - first is very
if (!new_log_buf_len)
return;
+ new_descs_count = new_log_buf_len >> PRB_AVGBITS;
+ if (new_descs_count == 0) {
+ pr_err("new_log_buf_len: %lu too small\n", new_log_buf_len);
+ return;
+ }
+
new_log_buf = memblock_alloc(new_log_buf_len, LOG_ALIGN);
if (unlikely(!new_log_buf)) {
- pr_err("log_buf_len: %lu bytes not available\n",
- new_log_buf_len);
+ pr_err("log_buf_len: %lu text bytes not available\n",
+ new_log_buf_len);
return;
}
+ new_dict_buf = memblock_alloc(new_log_buf_len, LOG_ALIGN);
+ if (unlikely(!new_dict_buf)) {
+ pr_err("log_buf_len: %lu dict bytes not available\n",
+ new_log_buf_len);
+ memblock_free(__pa(new_log_buf), new_log_buf_len);
+ return;
+ }
+
+ new_descs_size = new_descs_count * sizeof(struct prb_desc);
+ new_descs = memblock_alloc(new_descs_size, LOG_ALIGN);
+ if (unlikely(!new_descs)) {
+ pr_err("log_buf_len: %zu desc bytes not available\n",
+ new_descs_size);
+ memblock_free(__pa(new_dict_buf), new_log_buf_len);
+ memblock_free(__pa(new_log_buf), new_log_buf_len);
+ return;
+ }
+
+ prb_rec_init_rd(&r, &info,
+ &setup_text_buf[0], sizeof(setup_text_buf),
+ &setup_dict_buf[0], sizeof(setup_dict_buf));
+
+ prb_init(&printk_rb_dynamic,
+ new_log_buf, ilog2(new_log_buf_len),
+ new_dict_buf, ilog2(new_log_buf_len),
+ new_descs, ilog2(new_descs_count));
+
logbuf_lock_irqsave(flags);
+
log_buf_len = new_log_buf_len;
log_buf = new_log_buf;
new_log_buf_len = 0;
- free = __LOG_BUF_LEN - log_next_idx;
- memcpy(log_buf, __log_buf, __LOG_BUF_LEN);
+
+ free = __LOG_BUF_LEN;
+ prb_for_each_record(0, &printk_rb_static, seq, &r)
+ free -= add_to_rb(&printk_rb_dynamic, &r);
+
+ /*
+ * This is early enough that everything is still running on the
+ * boot CPU and interrupts are disabled. So no new messages will
+ * appear during the transition to the dynamic buffer.
+ */
+ prb = &printk_rb_dynamic;
+
logbuf_unlock_irqrestore(flags);
+ if (seq != prb_next_seq(&printk_rb_static)) {
+ pr_err("dropped %llu messages\n",
+ prb_next_seq(&printk_rb_static) - seq);
+ }
+
pr_info("log_buf_len: %u bytes\n", log_buf_len);
pr_info("early log buf free: %u(%u%%)\n",
free, (free * 100) / __LOG_BUF_LEN);
#define print_caller(id, buf) 0
#endif
-static size_t print_prefix(const struct printk_log *msg, bool syslog,
- bool time, char *buf)
+static size_t info_print_prefix(const struct printk_info *info, bool syslog,
+ bool time, char *buf)
{
size_t len = 0;
if (syslog)
- len = print_syslog((msg->facility << 3) | msg->level, buf);
+ len = print_syslog((info->facility << 3) | info->level, buf);
if (time)
- len += print_time(msg->ts_nsec, buf + len);
+ len += print_time(info->ts_nsec, buf + len);
- len += print_caller(msg->caller_id, buf + len);
+ len += print_caller(info->caller_id, buf + len);
if (IS_ENABLED(CONFIG_PRINTK_CALLER) || time) {
buf[len++] = ' ';
return len;
}
-static size_t msg_print_text(const struct printk_log *msg, bool syslog,
- bool time, char *buf, size_t size)
+/*
+ * Prepare the record for printing. The text is shifted within the given
+ * buffer to avoid a need for another one. The following operations are
+ * done:
+ *
+ * - Add prefix for each line.
+ * - Add the trailing newline that has been removed in vprintk_store().
+ * - Drop truncated lines that do not longer fit into the buffer.
+ *
+ * Return: The length of the updated/prepared text, including the added
+ * prefixes and the newline. The dropped line(s) are not counted.
+ */
+static size_t record_print_text(struct printk_record *r, bool syslog,
+ bool time)
{
- const char *text = log_text(msg);
- size_t text_size = msg->text_len;
- size_t len = 0;
+ size_t text_len = r->info->text_len;
+ size_t buf_size = r->text_buf_size;
+ char *text = r->text_buf;
char prefix[PREFIX_MAX];
- const size_t prefix_len = print_prefix(msg, syslog, time, prefix);
+ bool truncated = false;
+ size_t prefix_len;
+ size_t line_len;
+ size_t len = 0;
+ char *next;
- do {
- const char *next = memchr(text, '\n', text_size);
- size_t text_len;
+ prefix_len = info_print_prefix(r->info, syslog, time, prefix);
+ /*
+ * @text_len: bytes of unprocessed text
+ * @line_len: bytes of current line _without_ newline
+ * @text: pointer to beginning of current line
+ * @len: number of bytes prepared in r->text_buf
+ */
+ for (;;) {
+ next = memchr(text, '\n', text_len);
if (next) {
- text_len = next - text;
- next++;
- text_size -= next - text;
+ line_len = next - text;
} else {
- text_len = text_size;
+ /* Drop truncated line(s). */
+ if (truncated)
+ break;
+ line_len = text_len;
}
- if (buf) {
- if (prefix_len + text_len + 1 >= size - len)
+ /*
+ * Truncate the text if there is not enough space to add the
+ * prefix and a trailing newline.
+ */
+ if (len + prefix_len + text_len + 1 > buf_size) {
+ /* Drop even the current line if no space. */
+ if (len + prefix_len + line_len + 1 > buf_size)
break;
- memcpy(buf + len, prefix, prefix_len);
- len += prefix_len;
- memcpy(buf + len, text, text_len);
- len += text_len;
- buf[len++] = '\n';
- } else {
- /* SYSLOG_ACTION_* buffer size only calculation */
- len += prefix_len + text_len + 1;
+ text_len = buf_size - len - prefix_len - 1;
+ truncated = true;
}
- text = next;
- } while (text);
+ memmove(text + prefix_len, text, text_len);
+ memcpy(text, prefix, prefix_len);
+
+ len += prefix_len + line_len + 1;
+
+ if (text_len == line_len) {
+ /*
+ * Add the trailing newline removed in
+ * vprintk_store().
+ */
+ text[prefix_len + line_len] = '\n';
+ break;
+ }
+
+ /*
+ * Advance beyond the added prefix and the related line with
+ * its newline.
+ */
+ text += prefix_len + line_len + 1;
+
+ /*
+ * The remaining text has only decreased by the line with its
+ * newline.
+ *
+ * Note that @text_len can become zero. It happens when @text
+ * ended with a newline (either due to truncation or the
+ * original string ending with "\n\n"). The loop is correctly
+ * repeated and (if not truncated) an empty line with a prefix
+ * will be prepared.
+ */
+ text_len -= line_len + 1;
+ }
return len;
}
+static size_t get_record_print_text_size(struct printk_info *info,
+ unsigned int line_count,
+ bool syslog, bool time)
+{
+ char prefix[PREFIX_MAX];
+ size_t prefix_len;
+
+ prefix_len = info_print_prefix(info, syslog, time, prefix);
+
+ /*
+ * Each line will be preceded with a prefix. The intermediate
+ * newlines are already within the text, but a final trailing
+ * newline will be added.
+ */
+ return ((prefix_len * line_count) + info->text_len + 1);
+}
+
static int syslog_print(char __user *buf, int size)
{
+ struct printk_info info;
+ struct printk_record r;
char *text;
- struct printk_log *msg;
int len = 0;
text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
if (!text)
return -ENOMEM;
+ prb_rec_init_rd(&r, &info, text, LOG_LINE_MAX + PREFIX_MAX, NULL, 0);
+
while (size > 0) {
size_t n;
size_t skip;
logbuf_lock_irq();
- if (syslog_seq < log_first_seq) {
- /* messages are gone, move to first one */
- syslog_seq = log_first_seq;
- syslog_idx = log_first_idx;
- syslog_partial = 0;
- }
- if (syslog_seq == log_next_seq) {
+ if (!prb_read_valid(prb, syslog_seq, &r)) {
logbuf_unlock_irq();
break;
}
+ if (r.info->seq != syslog_seq) {
+ /* message is gone, move to next valid one */
+ syslog_seq = r.info->seq;
+ syslog_partial = 0;
+ }
/*
* To keep reading/counting partial line consistent,
syslog_time = printk_time;
skip = syslog_partial;
- msg = log_from_idx(syslog_idx);
- n = msg_print_text(msg, true, syslog_time, text,
- LOG_LINE_MAX + PREFIX_MAX);
+ n = record_print_text(&r, true, syslog_time);
if (n - syslog_partial <= size) {
/* message fits into buffer, move forward */
- syslog_idx = log_next(syslog_idx);
- syslog_seq++;
+ syslog_seq = r.info->seq + 1;
n -= syslog_partial;
syslog_partial = 0;
} else if (!len){
static int syslog_print_all(char __user *buf, int size, bool clear)
{
+ struct printk_info info;
+ unsigned int line_count;
+ struct printk_record r;
char *text;
int len = 0;
- u64 next_seq;
u64 seq;
- u32 idx;
bool time;
text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
* Find first record that fits, including all following records,
* into the user-provided buffer for this dump.
*/
- seq = clear_seq;
- idx = clear_idx;
- while (seq < log_next_seq) {
- struct printk_log *msg = log_from_idx(idx);
-
- len += msg_print_text(msg, true, time, NULL, 0);
- idx = log_next(idx);
- seq++;
- }
+ prb_for_each_info(clear_seq, prb, seq, &info, &line_count)
+ len += get_record_print_text_size(&info, line_count, true, time);
/* move first record forward until length fits into the buffer */
- seq = clear_seq;
- idx = clear_idx;
- while (len > size && seq < log_next_seq) {
- struct printk_log *msg = log_from_idx(idx);
-
- len -= msg_print_text(msg, true, time, NULL, 0);
- idx = log_next(idx);
- seq++;
+ prb_for_each_info(clear_seq, prb, seq, &info, &line_count) {
+ if (len <= size)
+ break;
+ len -= get_record_print_text_size(&info, line_count, true, time);
}
- /* last message fitting into this dump */
- next_seq = log_next_seq;
+ prb_rec_init_rd(&r, &info, text, LOG_LINE_MAX + PREFIX_MAX, NULL, 0);
len = 0;
- while (len >= 0 && seq < next_seq) {
- struct printk_log *msg = log_from_idx(idx);
- int textlen = msg_print_text(msg, true, time, text,
- LOG_LINE_MAX + PREFIX_MAX);
+ prb_for_each_record(seq, prb, seq, &r) {
+ int textlen;
- idx = log_next(idx);
- seq++;
+ textlen = record_print_text(&r, true, time);
+
+ if (len + textlen > size) {
+ seq--;
+ break;
+ }
logbuf_unlock_irq();
if (copy_to_user(buf + len, text, textlen))
len += textlen;
logbuf_lock_irq();
- if (seq < log_first_seq) {
- /* messages are gone, move to next one */
- seq = log_first_seq;
- idx = log_first_idx;
- }
+ if (len < 0)
+ break;
}
- if (clear) {
- clear_seq = log_next_seq;
- clear_idx = log_next_idx;
- }
+ if (clear)
+ clear_seq = seq;
logbuf_unlock_irq();
kfree(text);
static void syslog_clear(void)
{
logbuf_lock_irq();
- clear_seq = log_next_seq;
- clear_idx = log_next_idx;
+ clear_seq = prb_next_seq(prb);
logbuf_unlock_irq();
}
if (!access_ok(buf, len))
return -EFAULT;
error = wait_event_interruptible(log_wait,
- syslog_seq != log_next_seq);
+ prb_read_valid(prb, syslog_seq, NULL));
if (error)
return error;
error = syslog_print(buf, len);
/* Number of chars in the log buffer */
case SYSLOG_ACTION_SIZE_UNREAD:
logbuf_lock_irq();
- if (syslog_seq < log_first_seq) {
+ if (syslog_seq < prb_first_valid_seq(prb)) {
/* messages are gone, move to first one */
- syslog_seq = log_first_seq;
- syslog_idx = log_first_idx;
+ syslog_seq = prb_first_valid_seq(prb);
syslog_partial = 0;
}
if (source == SYSLOG_FROM_PROC) {
* for pending data, not the size; return the count of
* records, not the length.
*/
- error = log_next_seq - syslog_seq;
+ error = prb_next_seq(prb) - syslog_seq;
} else {
- u64 seq = syslog_seq;
- u32 idx = syslog_idx;
bool time = syslog_partial ? syslog_time : printk_time;
-
- while (seq < log_next_seq) {
- struct printk_log *msg = log_from_idx(idx);
-
- error += msg_print_text(msg, true, time, NULL,
- 0);
+ struct printk_info info;
+ unsigned int line_count;
+ u64 seq;
+
+ prb_for_each_info(syslog_seq, prb, seq, &info,
+ &line_count) {
+ error += get_record_print_text_size(&info, line_count,
+ true, time);
time = printk_time;
- idx = log_next(idx);
- seq++;
}
error -= syslog_partial;
}
static void call_console_drivers(const char *ext_text, size_t ext_len,
const char *text, size_t len)
{
+ static char dropped_text[64];
+ size_t dropped_len = 0;
struct console *con;
trace_console_rcuidle(text, len);
+ if (!console_drivers)
+ return;
+
+ if (console_dropped) {
+ dropped_len = snprintf(dropped_text, sizeof(dropped_text),
+ "** %lu printk messages dropped **\n",
+ console_dropped);
+ console_dropped = 0;
+ }
+
for_each_console(con) {
if (exclusive_console && con != exclusive_console)
continue;
continue;
if (con->flags & CON_EXTENDED)
con->write(con, ext_text, ext_len);
- else
+ else {
+ if (dropped_len)
+ con->write(con, dropped_text, dropped_len);
con->write(con, text, len);
+ }
}
}
#define PREFIX_MAX 0
#define printk_time false
+#define prb_read_valid(rb, seq, r) false
+#define prb_first_valid_seq(rb) 0
+
static u64 syslog_seq;
-static u32 syslog_idx;
static u64 console_seq;
-static u32 console_idx;
static u64 exclusive_console_stop_seq;
-static u64 log_first_seq;
-static u32 log_first_idx;
-static u64 log_next_seq;
-static char *log_text(const struct printk_log *msg) { return NULL; }
-static char *log_dict(const struct printk_log *msg) { return NULL; }
-static struct printk_log *log_from_idx(u32 idx) { return NULL; }
-static u32 log_next(u32 idx) { return 0; }
-static ssize_t msg_print_ext_header(char *buf, size_t size,
- struct printk_log *msg,
- u64 seq) { return 0; }
+static unsigned long console_dropped;
+
+static size_t record_print_text(const struct printk_record *r,
+ bool syslog, bool time)
+{
+ return 0;
+}
+static ssize_t info_print_ext_header(char *buf, size_t size,
+ struct printk_info *info)
+{
+ return 0;
+}
static ssize_t msg_print_ext_body(char *buf, size_t size,
char *dict, size_t dict_len,
char *text, size_t text_len) { return 0; }
static int console_lock_spinning_disable_and_check(void) { return 0; }
static void call_console_drivers(const char *ext_text, size_t ext_len,
const char *text, size_t len) {}
-static size_t msg_print_text(const struct printk_log *msg, bool syslog,
- bool time, char *buf, size_t size) { return 0; }
static bool suppress_message_printing(int level) { return false; }
#endif /* CONFIG_PRINTK */
{
static char ext_text[CONSOLE_EXT_LOG_MAX];
static char text[LOG_LINE_MAX + PREFIX_MAX];
+ static char dict[LOG_LINE_MAX];
unsigned long flags;
bool do_cond_resched, retry;
+ struct printk_info info;
+ struct printk_record r;
if (console_suspended) {
up_console_sem();
return;
}
+ prb_rec_init_rd(&r, &info, text, sizeof(text), dict, sizeof(dict));
+
/*
* Console drivers are called with interrupts disabled, so
* @console_may_schedule should be cleared before; however, we may
}
for (;;) {
- struct printk_log *msg;
size_t ext_len = 0;
size_t len;
printk_safe_enter_irqsave(flags);
raw_spin_lock(&logbuf_lock);
- if (console_seq < log_first_seq) {
- len = snprintf(text, sizeof(text),
- "** %llu printk messages dropped **\n",
- log_first_seq - console_seq);
-
- /* messages are gone, move to first one */
- console_seq = log_first_seq;
- console_idx = log_first_idx;
- } else {
- len = 0;
- }
skip:
- if (console_seq == log_next_seq)
+ if (!prb_read_valid(prb, console_seq, &r))
break;
- msg = log_from_idx(console_idx);
- if (suppress_message_printing(msg->level)) {
+ if (console_seq != r.info->seq) {
+ console_dropped += r.info->seq - console_seq;
+ console_seq = r.info->seq;
+ }
+
+ if (suppress_message_printing(r.info->level)) {
/*
* Skip record we have buffered and already printed
* directly to the console when we received it, and
* record that has level above the console loglevel.
*/
- console_idx = log_next(console_idx);
console_seq++;
goto skip;
}
exclusive_console = NULL;
}
- len += msg_print_text(msg,
- console_msg_format & MSG_FORMAT_SYSLOG,
- printk_time, text + len, sizeof(text) - len);
+ /*
+ * Handle extended console text first because later
+ * record_print_text() will modify the record buffer in-place.
+ */
if (nr_ext_console_drivers) {
- ext_len = msg_print_ext_header(ext_text,
+ ext_len = info_print_ext_header(ext_text,
sizeof(ext_text),
- msg, console_seq);
+ r.info);
ext_len += msg_print_ext_body(ext_text + ext_len,
sizeof(ext_text) - ext_len,
- log_dict(msg), msg->dict_len,
- log_text(msg), msg->text_len);
+ &r.dict_buf[0],
+ r.info->dict_len,
+ &r.text_buf[0],
+ r.info->text_len);
}
- console_idx = log_next(console_idx);
+ len = record_print_text(&r,
+ console_msg_format & MSG_FORMAT_SYSLOG,
+ printk_time);
console_seq++;
raw_spin_unlock(&logbuf_lock);
* flush, no worries.
*/
raw_spin_lock(&logbuf_lock);
- retry = console_seq != log_next_seq;
+ retry = prb_read_valid(prb, console_seq, NULL);
raw_spin_unlock(&logbuf_lock);
printk_safe_exit_irqrestore(flags);
unsigned long flags;
logbuf_lock_irqsave(flags);
- console_seq = log_first_seq;
- console_idx = log_first_idx;
+ console_seq = prb_first_valid_seq(prb);
logbuf_unlock_irqrestore(flags);
}
console_unlock();
exclusive_console = newcon;
exclusive_console_stop_seq = console_seq;
console_seq = syslog_seq;
- console_idx = syslog_idx;
logbuf_unlock_irqrestore(flags);
}
console_unlock();
logbuf_lock_irqsave(flags);
dumper->cur_seq = clear_seq;
- dumper->cur_idx = clear_idx;
- dumper->next_seq = log_next_seq;
- dumper->next_idx = log_next_idx;
+ dumper->next_seq = prb_next_seq(prb);
logbuf_unlock_irqrestore(flags);
/* invoke dumper which will iterate over records */
bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
char *line, size_t size, size_t *len)
{
- struct printk_log *msg;
+ struct printk_info info;
+ unsigned int line_count;
+ struct printk_record r;
size_t l = 0;
bool ret = false;
+ prb_rec_init_rd(&r, &info, line, size, NULL, 0);
+
if (!dumper->active)
goto out;
- if (dumper->cur_seq < log_first_seq) {
- /* messages are gone, move to first available one */
- dumper->cur_seq = log_first_seq;
- dumper->cur_idx = log_first_idx;
- }
-
- /* last entry */
- if (dumper->cur_seq >= log_next_seq)
- goto out;
+ /* Read text or count text lines? */
+ if (line) {
+ if (!prb_read_valid(prb, dumper->cur_seq, &r))
+ goto out;
+ l = record_print_text(&r, syslog, printk_time);
+ } else {
+ if (!prb_read_valid_info(prb, dumper->cur_seq,
+ &info, &line_count)) {
+ goto out;
+ }
+ l = get_record_print_text_size(&info, line_count, syslog,
+ printk_time);
- msg = log_from_idx(dumper->cur_idx);
- l = msg_print_text(msg, syslog, printk_time, line, size);
+ }
- dumper->cur_idx = log_next(dumper->cur_idx);
- dumper->cur_seq++;
+ dumper->cur_seq = r.info->seq + 1;
ret = true;
out:
if (len)
bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
char *buf, size_t size, size_t *len)
{
+ struct printk_info info;
+ unsigned int line_count;
+ struct printk_record r;
unsigned long flags;
u64 seq;
- u32 idx;
u64 next_seq;
- u32 next_idx;
size_t l = 0;
bool ret = false;
bool time = printk_time;
- if (!dumper->active)
+ prb_rec_init_rd(&r, &info, buf, size, NULL, 0);
+
+ if (!dumper->active || !buf || !size)
goto out;
logbuf_lock_irqsave(flags);
- if (dumper->cur_seq < log_first_seq) {
+ if (dumper->cur_seq < prb_first_valid_seq(prb)) {
/* messages are gone, move to first available one */
- dumper->cur_seq = log_first_seq;
- dumper->cur_idx = log_first_idx;
+ dumper->cur_seq = prb_first_valid_seq(prb);
}
/* last entry */
/* calculate length of entire buffer */
seq = dumper->cur_seq;
- idx = dumper->cur_idx;
- while (seq < dumper->next_seq) {
- struct printk_log *msg = log_from_idx(idx);
-
- l += msg_print_text(msg, true, time, NULL, 0);
- idx = log_next(idx);
- seq++;
+ while (prb_read_valid_info(prb, seq, &info, &line_count)) {
+ if (r.info->seq >= dumper->next_seq)
+ break;
+ l += get_record_print_text_size(&info, line_count, true, time);
+ seq = r.info->seq + 1;
}
/* move first record forward until length fits into the buffer */
seq = dumper->cur_seq;
- idx = dumper->cur_idx;
- while (l >= size && seq < dumper->next_seq) {
- struct printk_log *msg = log_from_idx(idx);
-
- l -= msg_print_text(msg, true, time, NULL, 0);
- idx = log_next(idx);
- seq++;
+ while (l >= size && prb_read_valid_info(prb, seq,
+ &info, &line_count)) {
+ if (r.info->seq >= dumper->next_seq)
+ break;
+ l -= get_record_print_text_size(&info, line_count, true, time);
+ seq = r.info->seq + 1;
}
/* last message in next interation */
next_seq = seq;
- next_idx = idx;
+ /* actually read text into the buffer now */
l = 0;
- while (seq < dumper->next_seq) {
- struct printk_log *msg = log_from_idx(idx);
+ while (prb_read_valid(prb, seq, &r)) {
+ if (r.info->seq >= dumper->next_seq)
+ break;
+
+ l += record_print_text(&r, syslog, time);
+
+ /* adjust record to store to remaining buffer space */
+ prb_rec_init_rd(&r, &info, buf + l, size - l, NULL, 0);
- l += msg_print_text(msg, syslog, time, buf + l, size - l);
- idx = log_next(idx);
- seq++;
+ seq = r.info->seq + 1;
}
dumper->next_seq = next_seq;
- dumper->next_idx = next_idx;
ret = true;
logbuf_unlock_irqrestore(flags);
out:
void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
{
dumper->cur_seq = clear_seq;
- dumper->cur_idx = clear_idx;
- dumper->next_seq = log_next_seq;
- dumper->next_idx = log_next_idx;
+ dumper->next_seq = prb_next_seq(prb);
}
/**
projects / users / dwmw2 / linux.git / commitdiff