Merge "Convert modules to kernel builtins."
diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
index 36f957f..8733a86 100644
--- a/arch/powerpc/platforms/pseries/nvram.c
+++ b/arch/powerpc/platforms/pseries/nvram.c
@@ -68,9 +68,7 @@
};
static void oops_to_nvram(struct kmsg_dumper *dumper,
- enum kmsg_dump_reason reason,
- const char *old_msgs, unsigned long old_len,
- const char *new_msgs, unsigned long new_len);
+ enum kmsg_dump_reason reason);
static struct kmsg_dumper nvram_kmsg_dumper = {
.dump = oops_to_nvram
@@ -504,28 +502,6 @@
}
/*
- * Try to capture the last capture_len bytes of the printk buffer. Return
- * the amount actually captured.
- */
-static size_t capture_last_msgs(const char *old_msgs, size_t old_len,
- const char *new_msgs, size_t new_len,
- char *captured, size_t capture_len)
-{
- if (new_len >= capture_len) {
- memcpy(captured, new_msgs + (new_len - capture_len),
- capture_len);
- return capture_len;
- } else {
- /* Grab the end of old_msgs. */
- size_t old_tail_len = min(old_len, capture_len - new_len);
- memcpy(captured, old_msgs + (old_len - old_tail_len),
- old_tail_len);
- memcpy(captured + old_tail_len, new_msgs, new_len);
- return old_tail_len + new_len;
- }
-}
-
-/*
* Are we using the ibm,rtas-log for oops/panic reports? And if so,
* would logging this oops/panic overwrite an RTAS event that rtas_errd
* hasn't had a chance to read and process? Return 1 if so, else 0.
@@ -541,27 +517,6 @@
NVRAM_RTAS_READ_TIMEOUT);
}
-/* Squeeze out each line's <n> severity prefix. */
-static size_t elide_severities(char *buf, size_t len)
-{
- char *in, *out, *buf_end = buf + len;
- /* Assume a <n> at the very beginning marks the start of a line. */
- int newline = 1;
-
- in = out = buf;
- while (in < buf_end) {
- if (newline && in+3 <= buf_end &&
- *in == '<' && isdigit(in[1]) && in[2] == '>') {
- in += 3;
- newline = 0;
- } else {
- newline = (*in == '\n');
- *out++ = *in++;
- }
- }
- return out - buf;
-}
-
/* Derived from logfs_compress() */
static int nvram_compress(const void *in, void *out, size_t inlen,
size_t outlen)
@@ -619,9 +574,7 @@
* partition. If that's too much, go back and capture uncompressed text.
*/
static void oops_to_nvram(struct kmsg_dumper *dumper,
- enum kmsg_dump_reason reason,
- const char *old_msgs, unsigned long old_len,
- const char *new_msgs, unsigned long new_len)
+ enum kmsg_dump_reason reason)
{
static unsigned int oops_count = 0;
static bool panicking = false;
@@ -660,14 +613,14 @@
return;
if (big_oops_buf) {
- text_len = capture_last_msgs(old_msgs, old_len,
- new_msgs, new_len, big_oops_buf, big_oops_buf_sz);
- text_len = elide_severities(big_oops_buf, text_len);
+ kmsg_dump_get_buffer(dumper, false,
+ big_oops_buf, big_oops_buf_sz, &text_len);
rc = zip_oops(text_len);
}
if (rc != 0) {
- text_len = capture_last_msgs(old_msgs, old_len,
- new_msgs, new_len, oops_data, oops_data_sz);
+ kmsg_dump_rewind(dumper);
+ kmsg_dump_get_buffer(dumper, true,
+ oops_data, oops_data_sz, &text_len);
err_type = ERR_TYPE_KERNEL_PANIC;
*oops_len = (u16) text_len;
}
diff --git a/arch/x86/platform/mrst/early_printk_mrst.c b/arch/x86/platform/mrst/early_printk_mrst.c
index 3c6e328..028454f 100644
--- a/arch/x86/platform/mrst/early_printk_mrst.c
+++ b/arch/x86/platform/mrst/early_printk_mrst.c
@@ -110,19 +110,16 @@
static int dumper_registered;
static void dw_kmsg_dump(struct kmsg_dumper *dumper,
- enum kmsg_dump_reason reason,
- const char *s1, unsigned long l1,
- const char *s2, unsigned long l2)
+ enum kmsg_dump_reason reason)
{
- int i;
+ static char line[1024];
+ size_t len;
/* When run to this, we'd better re-init the HW */
mrst_early_console_init();
- for (i = 0; i < l1; i++)
- early_mrst_console.write(&early_mrst_console, s1 + i, 1);
- for (i = 0; i < l2; i++)
- early_mrst_console.write(&early_mrst_console, s2 + i, 1);
+ while (kmsg_dump_get_line(dumper, true, line, sizeof(line), &len))
+ early_mrst_console.write(&early_mrst_console, line, len);
}
/* Set the ratio rate to 115200, 8n1, IRQ disabled */
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index d6e9d08..67c3371 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -807,44 +807,6 @@
};
#endif
-static ssize_t kmsg_writev(struct kiocb *iocb, const struct iovec *iv,
- unsigned long count, loff_t pos)
-{
- char *line, *p;
- int i;
- ssize_t ret = -EFAULT;
- size_t len = iov_length(iv, count);
-
- line = kmalloc(len + 1, GFP_KERNEL);
- if (line == NULL)
- return -ENOMEM;
-
- /*
- * copy all vectors into a single string, to ensure we do
- * not interleave our log line with other printk calls
- */
- p = line;
- for (i = 0; i < count; i++) {
- if (copy_from_user(p, iv[i].iov_base, iv[i].iov_len))
- goto out;
- p += iv[i].iov_len;
- }
- p[0] = '\0';
-
- ret = printk("%s", line);
- /* printk can add a prefix */
- if (ret > len)
- ret = len;
-out:
- kfree(line);
- return ret;
-}
-
-static const struct file_operations kmsg_fops = {
- .aio_write = kmsg_writev,
- .llseek = noop_llseek,
-};
-
static const struct memdev {
const char *name;
umode_t mode;
@@ -863,7 +825,9 @@
[7] = { "full", 0666, &full_fops, NULL },
[8] = { "random", 0666, &random_fops, NULL },
[9] = { "urandom", 0666, &urandom_fops, NULL },
- [11] = { "kmsg", 0, &kmsg_fops, NULL },
+#ifdef CONFIG_PRINTK
+ [11] = { "kmsg", 0644, &kmsg_fops, NULL },
+#endif
#ifdef CONFIG_CRASH_DUMP
[12] = { "oldmem", 0, &oldmem_fops, NULL },
#endif
diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index 3ce99e0..48beb91 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -305,32 +305,17 @@
}
static void mtdoops_do_dump(struct kmsg_dumper *dumper,
- enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
- const char *s2, unsigned long l2)
+ enum kmsg_dump_reason reason)
{
struct mtdoops_context *cxt = container_of(dumper,
struct mtdoops_context, dump);
- unsigned long s1_start, s2_start;
- unsigned long l1_cpy, l2_cpy;
- char *dst;
-
- if (reason != KMSG_DUMP_OOPS &&
- reason != KMSG_DUMP_PANIC)
- return;
/* Only dump oopses if dump_oops is set */
if (reason == KMSG_DUMP_OOPS && !dump_oops)
return;
- dst = cxt->oops_buf + MTDOOPS_HEADER_SIZE; /* Skip the header */
- l2_cpy = min(l2, record_size - MTDOOPS_HEADER_SIZE);
- l1_cpy = min(l1, record_size - MTDOOPS_HEADER_SIZE - l2_cpy);
-
- s2_start = l2 - l2_cpy;
- s1_start = l1 - l1_cpy;
-
- memcpy(dst, s1 + s1_start, l1_cpy);
- memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
+ kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
+ record_size - MTDOOPS_HEADER_SIZE, NULL);
/* Panics must be written immediately */
if (reason != KMSG_DUMP_OOPS)
@@ -376,6 +361,7 @@
return;
}
+ cxt->dump.max_reason = KMSG_DUMP_OOPS;
cxt->dump.dump = mtdoops_do_dump;
err = kmsg_dump_register(&cxt->dump);
if (err) {
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 9ec22d3..7651c82 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -78,19 +78,15 @@
* as we can from the end of the buffer.
*/
static void pstore_dump(struct kmsg_dumper *dumper,
- enum kmsg_dump_reason reason,
- const char *s1, unsigned long l1,
- const char *s2, unsigned long l2)
+ enum kmsg_dump_reason reason)
{
- unsigned long s1_start, s2_start;
- unsigned long l1_cpy, l2_cpy;
- unsigned long size, total = 0;
- char *dst, *why;
+ unsigned long total = 0;
+ const char *why;
u64 id;
- int hsize, ret;
unsigned int part = 1;
unsigned long flags = 0;
int is_locked = 0;
+ int ret;
if (reason < ARRAY_SIZE(reason_str))
why = reason_str[reason];
@@ -105,30 +101,25 @@
spin_lock_irqsave(&psinfo->buf_lock, flags);
oopscount++;
while (total < kmsg_bytes) {
+ char *dst;
+ unsigned long size;
+ int hsize;
+ size_t len;
+
dst = psinfo->buf;
hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
size = psinfo->bufsize - hsize;
dst += hsize;
- l2_cpy = min(l2, size);
- l1_cpy = min(l1, size - l2_cpy);
-
- if (l1_cpy + l2_cpy == 0)
+ if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len))
break;
- s2_start = l2 - l2_cpy;
- s1_start = l1 - l1_cpy;
-
- memcpy(dst, s1 + s1_start, l1_cpy);
- memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
-
ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
- hsize + l1_cpy + l2_cpy, psinfo);
+ hsize + len, psinfo);
if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
pstore_new_entry = 1;
- l1 -= l1_cpy;
- l2 -= l2_cpy;
- total += l1_cpy + l2_cpy;
+
+ total += hsize + len;
part++;
}
if (in_nmi()) {
diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
index 35f7237..2e7a1e0 100644
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -21,6 +21,7 @@
* is passed to the kernel.
*/
enum kmsg_dump_reason {
+ KMSG_DUMP_UNDEF,
KMSG_DUMP_PANIC,
KMSG_DUMP_OOPS,
KMSG_DUMP_EMERG,
@@ -31,23 +32,42 @@
/**
* struct kmsg_dumper - kernel crash message dumper structure
- * @dump: The callback which gets called on crashes. The buffer is passed
- * as two sections, where s1 (length l1) contains the older
- * messages and s2 (length l2) contains the newer.
* @list: Entry in the dumper list (private)
+ * @dump: Call into dumping code which will retrieve the data with
+ * through the record iterator
+ * @max_reason: filter for highest reason number that should be dumped
* @registered: Flag that specifies if this is already registered
*/
struct kmsg_dumper {
- void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason,
- const char *s1, unsigned long l1,
- const char *s2, unsigned long l2);
struct list_head list;
- int registered;
+ void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason);
+ enum kmsg_dump_reason max_reason;
+ bool active;
+ bool registered;
+
+ /* private state of the kmsg iterator */
+ u32 cur_idx;
+ u32 next_idx;
+ u64 cur_seq;
+ u64 next_seq;
};
#ifdef CONFIG_PRINTK
void kmsg_dump(enum kmsg_dump_reason reason);
+bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
+ char *line, size_t size, size_t *len);
+
+bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
+ char *line, size_t size, size_t *len);
+
+bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ char *buf, size_t size, size_t *len);
+
+void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper);
+
+void kmsg_dump_rewind(struct kmsg_dumper *dumper);
+
int kmsg_dump_register(struct kmsg_dumper *dumper);
int kmsg_dump_unregister(struct kmsg_dumper *dumper);
@@ -56,6 +76,33 @@
{
}
+static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper,
+ bool syslog, const char *line,
+ size_t size, size_t *len)
+{
+ return false;
+}
+
+static inline bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
+ const char *line, size_t size, size_t *len)
+{
+ return false;
+}
+
+static inline bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ char *buf, size_t size, size_t *len)
+{
+ return false;
+}
+
+static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
+{
+}
+
+static inline void kmsg_dump_rewind(struct kmsg_dumper *dumper)
+{
+}
+
static inline int kmsg_dump_register(struct kmsg_dumper *dumper)
{
return -EINVAL;
diff --git a/include/linux/printk.h b/include/linux/printk.h
index f0e22f7..a517da2 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -95,8 +95,19 @@
extern void printk_tick(void);
#ifdef CONFIG_PRINTK
+asmlinkage __printf(5, 0)
+int vprintk_emit(int facility, int level,
+ const char *dict, size_t dictlen,
+ const char *fmt, va_list args);
+
asmlinkage __printf(1, 0)
int vprintk(const char *fmt, va_list args);
+
+asmlinkage __printf(5, 6) __cold
+asmlinkage int printk_emit(int facility, int level,
+ const char *dict, size_t dictlen,
+ const char *fmt, ...);
+
asmlinkage __printf(1, 2) __cold
int printk(const char *fmt, ...);
@@ -279,6 +290,8 @@
no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#endif
+extern const struct file_operations kmsg_fops;
+
enum {
DUMP_PREFIX_NONE,
DUMP_PREFIX_ADDRESS,
diff --git a/include/trace/events/printk.h b/include/trace/events/printk.h
new file mode 100644
index 0000000..94ec79c
--- /dev/null
+++ b/include/trace/events/printk.h
@@ -0,0 +1,41 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM printk
+
+#if !defined(_TRACE_PRINTK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PRINTK_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT_CONDITION(console,
+ TP_PROTO(const char *log_buf, unsigned start, unsigned end,
+ unsigned log_buf_len),
+
+ TP_ARGS(log_buf, start, end, log_buf_len),
+
+ TP_CONDITION(start != end),
+
+ TP_STRUCT__entry(
+ __dynamic_array(char, msg, end - start + 1)
+ ),
+
+ TP_fast_assign(
+ if ((start & (log_buf_len - 1)) > (end & (log_buf_len - 1))) {
+ memcpy(__get_dynamic_array(msg),
+ log_buf + (start & (log_buf_len - 1)),
+ log_buf_len - (start & (log_buf_len - 1)));
+ memcpy((char *)__get_dynamic_array(msg) +
+ log_buf_len - (start & (log_buf_len - 1)),
+ log_buf, end & (log_buf_len - 1));
+ } else
+ memcpy(__get_dynamic_array(msg),
+ log_buf + (start & (log_buf_len - 1)),
+ end - start);
+ ((char *)__get_dynamic_array(msg))[end - start] = 0;
+ ),
+
+ TP_printk("%s", __get_str(msg))
+);
+#endif /* _TRACE_PRINTK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
index e381d10..46fbe56 100644
--- a/kernel/debug/kdb/kdb_private.h
+++ b/kernel/debug/kdb/kdb_private.h
@@ -205,7 +205,6 @@
extern int kdb_grep_leading;
extern int kdb_grep_trailing;
extern char *kdb_cmds[];
-extern void kdb_syslog_data(char *syslog_data[]);
extern unsigned long kdb_task_state_string(const char *);
extern char kdb_task_state_char (const struct task_struct *);
extern unsigned long kdb_task_state(const struct task_struct *p,
diff --git a/kernel/printk.c b/kernel/printk.c
index 32690a0..ff14e1c 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -41,9 +41,13 @@
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/rculist.h>
+#include <linux/poll.h>
#include <asm/uaccess.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/printk.h>
+
/*
* Architectures can override it:
*/
@@ -51,8 +55,6 @@
{
}
-#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
-
/* printk's without a loglevel use this.. */
#define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL
@@ -96,24 +98,6 @@
static int console_locked, console_suspended;
/*
- * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars
- * It is also used in interesting ways to provide interlocking in
- * console_unlock();.
- */
-static DEFINE_RAW_SPINLOCK(logbuf_lock);
-
-#define LOG_BUF_MASK (log_buf_len-1)
-#define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK])
-
-/*
- * The indices into log_buf are not constrained to log_buf_len - they
- * must be masked before subscripting
- */
-static unsigned log_start; /* Index into log_buf: next char to be read by syslog() */
-static unsigned con_start; /* Index into log_buf: next char to be sent to consoles */
-static unsigned log_end; /* Index into log_buf: most-recently-written-char + 1 */
-
-/*
* If exclusive_console is non-NULL then only this console is to be printed to.
*/
static struct console *exclusive_console;
@@ -142,13 +126,510 @@
/* Flag: console code may call schedule() */
static int console_may_schedule;
-#ifdef CONFIG_PRINTK
+/*
+ * 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 heads to the first and last entry in the buffer, as well as the
+ * sequence numbers of these both entries are maintained when messages
+ * are stored..
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * Examples for well-defined, commonly used property names are:
+ * DEVICE=b12:8 device identifier
+ * b12:8 block dev_t
+ * c127:3 char dev_t
+ * n8 netdev ifindex
+ * +sound:card0 subsystem:devname
+ * SUBSYSTEM=pci driver-core subsystem name
+ *
+ * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value
+ * 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 log' buffer header 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.
+ *
+ * /dev/kmsg exports the structured data in the following line format:
+ * "level,sequnum,timestamp;<message text>\n"
+ *
+ * The optional key/value pairs are attached as continuation lines starting
+ * with a space character and terminated by a newline. All possible
+ * non-prinatable characters are escaped in the "\xff" notation.
+ *
+ * Users of the export format should ignore possible additional values
+ * separated by ',', and find the message after the ';' character.
+ */
-static char __log_buf[__LOG_BUF_LEN];
+enum log_flags {
+ LOG_NOCONS = 1, /* already flushed, do not print to console */
+ LOG_NEWLINE = 2, /* text ended with a newline */
+ LOG_PREFIX = 4, /* text started with a prefix */
+ LOG_CONT = 8, /* text is a fragment of a continuation line */
+};
+
+struct 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 */
+};
+
+/*
+ * The logbuf_lock protects kmsg buffer, indices, counters. It is also
+ * used in interesting ways to provide interlocking in console_unlock();
+ */
+static DEFINE_RAW_SPINLOCK(logbuf_lock);
+
+/* the next printk record to read by syslog(READ) or /proc/kmsg */
+static u64 syslog_seq;
+static u32 syslog_idx;
+static enum log_flags syslog_prev;
+static size_t syslog_partial;
+
+/* 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;
+#ifdef CONFIG_PRINTK
+static u32 log_next_idx;
+
+/* the next printk record to read after the last 'clear' command */
+static u64 clear_seq;
+static u32 clear_idx;
+
+#define LOG_LINE_MAX 1024
+
+/* record buffer */
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+#define LOG_ALIGN 4
+#else
+#define LOG_ALIGN __alignof__(struct log)
+#endif
+#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
+static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
static char *log_buf = __log_buf;
-static int log_buf_len = __LOG_BUF_LEN;
-static unsigned logged_chars; /* Number of chars produced since last read+clear operation */
-static int saved_console_loglevel = -1;
+static u32 log_buf_len = __LOG_BUF_LEN;
+
+/* cpu currently holding logbuf_lock */
+static volatile unsigned int logbuf_cpu = UINT_MAX;
+
+/* human readable text of the record */
+static char *log_text(const struct log *msg)
+{
+ return (char *)msg + sizeof(struct log);
+}
+
+/* optional key/value pair dictionary attached to the record */
+static char *log_dict(const struct log *msg)
+{
+ return (char *)msg + sizeof(struct log) + msg->text_len;
+}
+
+/* get record by index; idx must point to valid msg */
+static struct log *log_from_idx(u32 idx)
+{
+ struct log *msg = (struct 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 log *)log_buf;
+ return msg;
+}
+
+/* get next record; idx must point to valid msg */
+static u32 log_next(u32 idx)
+{
+ struct log *msg = (struct 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 log *)log_buf;
+ return msg->len;
+ }
+ return idx + msg->len;
+}
+
+/* insert record into the buffer, discard old ones, update heads */
+static void log_store(int facility, int level,
+ enum log_flags flags, u64 ts_nsec,
+ const char *dict, u16 dict_len,
+ const char *text, u16 text_len)
+{
+ struct log *msg;
+ u32 size, pad_len;
+
+ /* number of '\0' padding bytes to next message */
+ size = sizeof(struct log) + text_len + dict_len;
+ pad_len = (-size) & (LOG_ALIGN - 1);
+ size += pad_len;
+
+ while (log_first_seq < log_next_seq) {
+ u32 free;
+
+ if (log_next_idx > log_first_idx)
+ free = max(log_buf_len - log_next_idx, log_first_idx);
+ else
+ free = log_first_idx - log_next_idx;
+
+ if (free > size + sizeof(struct log))
+ break;
+
+ /* drop old messages until we have enough contiuous space */
+ log_first_idx = log_next(log_first_idx);
+ log_first_seq++;
+ }
+
+ if (log_next_idx + size + sizeof(struct 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 log));
+ log_next_idx = 0;
+ }
+
+ /* fill message */
+ msg = (struct log *)(log_buf + log_next_idx);
+ memcpy(log_text(msg), text, text_len);
+ msg->text_len = text_len;
+ memcpy(log_dict(msg), dict, dict_len);
+ msg->dict_len = dict_len;
+ msg->facility = facility;
+ msg->level = level & 7;
+ msg->flags = flags & 0x1f;
+ if (ts_nsec > 0)
+ msg->ts_nsec = ts_nsec;
+ else
+ msg->ts_nsec = local_clock();
+ memset(log_dict(msg) + dict_len, 0, pad_len);
+ msg->len = sizeof(struct log) + text_len + dict_len + pad_len;
+
+ /* insert message */
+ log_next_idx += msg->len;
+ log_next_seq++;
+}
+
+/* /dev/kmsg - userspace message inject/listen interface */
+struct devkmsg_user {
+ u64 seq;
+ u32 idx;
+ struct mutex lock;
+ char buf[8192];
+};
+
+static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv,
+ unsigned long count, loff_t pos)
+{
+ char *buf, *line;
+ int i;
+ int level = default_message_loglevel;
+ int facility = 1; /* LOG_USER */
+ size_t len = iov_length(iv, count);
+ ssize_t ret = len;
+
+ if (len > LOG_LINE_MAX)
+ return -EINVAL;
+ buf = kmalloc(len+1, GFP_KERNEL);
+ if (buf == NULL)
+ return -ENOMEM;
+
+ line = buf;
+ for (i = 0; i < count; i++) {
+ if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len))
+ goto out;
+ line += iv[i].iov_len;
+ }
+
+ /*
+ * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace
+ * the decimal value represents 32bit, the lower 3 bit are the log
+ * level, the rest are the log facility.
+ *
+ * If no prefix or no userspace facility is specified, we
+ * enforce LOG_USER, to be able to reliably distinguish
+ * kernel-generated messages from userspace-injected ones.
+ */
+ line = buf;
+ if (line[0] == '<') {
+ char *endp = NULL;
+
+ i = simple_strtoul(line+1, &endp, 10);
+ if (endp && endp[0] == '>') {
+ level = i & 7;
+ if (i >> 3)
+ facility = i >> 3;
+ endp++;
+ len -= endp - line;
+ line = endp;
+ }
+ }
+ line[len] = '\0';
+
+ printk_emit(facility, level, NULL, 0, "%s", line);
+out:
+ kfree(buf);
+ return ret;
+}
+
+static ssize_t devkmsg_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct devkmsg_user *user = file->private_data;
+ struct log *msg;
+ u64 ts_usec;
+ size_t i;
+ size_t len;
+ ssize_t ret;
+
+ if (!user)
+ return -EBADF;
+
+ ret = mutex_lock_interruptible(&user->lock);
+ if (ret)
+ return ret;
+ raw_spin_lock_irq(&logbuf_lock);
+ while (user->seq == log_next_seq) {
+ if (file->f_flags & O_NONBLOCK) {
+ ret = -EAGAIN;
+ raw_spin_unlock_irq(&logbuf_lock);
+ goto out;
+ }
+
+ raw_spin_unlock_irq(&logbuf_lock);
+ ret = wait_event_interruptible(log_wait,
+ user->seq != log_next_seq);
+ if (ret)
+ goto out;
+ raw_spin_lock_irq(&logbuf_lock);
+ }
+
+ if (user->seq < log_first_seq) {
+ /* our last seen message is gone, return error and reset */
+ user->idx = log_first_idx;
+ user->seq = log_first_seq;
+ ret = -EPIPE;
+ raw_spin_unlock_irq(&logbuf_lock);
+ goto out;
+ }
+
+ msg = log_from_idx(user->idx);
+ ts_usec = msg->ts_nsec;
+ do_div(ts_usec, 1000);
+ len = sprintf(user->buf, "%u,%llu,%llu;",
+ (msg->facility << 3) | msg->level, user->seq, ts_usec);
+
+ /* escape non-printable characters */
+ for (i = 0; i < msg->text_len; i++) {
+ unsigned char c = log_text(msg)[i];
+
+ if (c < ' ' || c >= 127 || c == '\\')
+ len += sprintf(user->buf + len, "\\x%02x", c);
+ else
+ user->buf[len++] = c;
+ }
+ user->buf[len++] = '\n';
+
+ if (msg->dict_len) {
+ bool line = true;
+
+ for (i = 0; i < msg->dict_len; i++) {
+ unsigned char c = log_dict(msg)[i];
+
+ if (line) {
+ user->buf[len++] = ' ';
+ line = false;
+ }
+
+ if (c == '\0') {
+ user->buf[len++] = '\n';
+ line = true;
+ continue;
+ }
+
+ if (c < ' ' || c >= 127 || c == '\\') {
+ len += sprintf(user->buf + len, "\\x%02x", c);
+ continue;
+ }
+
+ user->buf[len++] = c;
+ }
+ user->buf[len++] = '\n';
+ }
+
+ user->idx = log_next(user->idx);
+ user->seq++;
+ raw_spin_unlock_irq(&logbuf_lock);
+
+ if (len > count) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (copy_to_user(buf, user->buf, len)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ ret = len;
+out:
+ mutex_unlock(&user->lock);
+ return ret;
+}
+
+static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct devkmsg_user *user = file->private_data;
+ loff_t ret = 0;
+
+ if (!user)
+ return -EBADF;
+ if (offset)
+ return -ESPIPE;
+
+ raw_spin_lock_irq(&logbuf_lock);
+ switch (whence) {
+ case SEEK_SET:
+ /* the first record */
+ user->idx = log_first_idx;
+ user->seq = log_first_seq;
+ break;
+ case SEEK_DATA:
+ /*
+ * The first record after the last SYSLOG_ACTION_CLEAR,
+ * 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;
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ raw_spin_unlock_irq(&logbuf_lock);
+ return ret;
+}
+
+static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
+{
+ struct devkmsg_user *user = file->private_data;
+ int ret = 0;
+
+ if (!user)
+ return POLLERR|POLLNVAL;
+
+ poll_wait(file, &log_wait, wait);
+
+ raw_spin_lock_irq(&logbuf_lock);
+ if (user->seq < log_next_seq) {
+ /* return error when data has vanished underneath us */
+ if (user->seq < log_first_seq)
+ ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI;
+ ret = POLLIN|POLLRDNORM;
+ }
+ raw_spin_unlock_irq(&logbuf_lock);
+
+ return ret;
+}
+
+static int devkmsg_open(struct inode *inode, struct file *file)
+{
+ struct devkmsg_user *user;
+ int err;
+
+ /* write-only does not need any file context */
+ if ((file->f_flags & O_ACCMODE) == O_WRONLY)
+ return 0;
+
+ err = security_syslog(SYSLOG_ACTION_READ_ALL);
+ if (err)
+ return err;
+
+ user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL);
+ if (!user)
+ return -ENOMEM;
+
+ mutex_init(&user->lock);
+
+ raw_spin_lock_irq(&logbuf_lock);
+ user->idx = log_first_idx;
+ user->seq = log_first_seq;
+ raw_spin_unlock_irq(&logbuf_lock);
+
+ file->private_data = user;
+ return 0;
+}
+
+static int devkmsg_release(struct inode *inode, struct file *file)
+{
+ struct devkmsg_user *user = file->private_data;
+
+ if (!user)
+ return 0;
+
+ mutex_destroy(&user->lock);
+ kfree(user);
+ return 0;
+}
+
+const struct file_operations kmsg_fops = {
+ .open = devkmsg_open,
+ .read = devkmsg_read,
+ .aio_write = devkmsg_writev,
+ .llseek = devkmsg_llseek,
+ .poll = devkmsg_poll,
+ .release = devkmsg_release,
+};
#ifdef CONFIG_KEXEC
/*
@@ -162,9 +643,9 @@
void log_buf_kexec_setup(void)
{
VMCOREINFO_SYMBOL(log_buf);
- VMCOREINFO_SYMBOL(log_end);
VMCOREINFO_SYMBOL(log_buf_len);
- VMCOREINFO_SYMBOL(logged_chars);
+ VMCOREINFO_SYMBOL(log_first_idx);
+ VMCOREINFO_SYMBOL(log_next_idx);
}
#endif
@@ -188,7 +669,6 @@
void __init setup_log_buf(int early)
{
unsigned long flags;
- unsigned start, dest_idx, offset;
char *new_log_buf;
int free;
@@ -216,20 +696,8 @@
log_buf_len = new_log_buf_len;
log_buf = new_log_buf;
new_log_buf_len = 0;
- free = __LOG_BUF_LEN - log_end;
-
- offset = start = min(con_start, log_start);
- dest_idx = 0;
- while (start != log_end) {
- unsigned log_idx_mask = start & (__LOG_BUF_LEN - 1);
-
- log_buf[dest_idx] = __log_buf[log_idx_mask];
- start++;
- dest_idx++;
- }
- log_start -= offset;
- con_start -= offset;
- log_end -= offset;
+ free = __LOG_BUF_LEN - log_next_idx;
+ memcpy(log_buf, __log_buf, __LOG_BUF_LEN);
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
pr_info("log_buf_len: %d\n", log_buf_len);
@@ -329,11 +797,270 @@
return 0;
}
+#if defined(CONFIG_PRINTK_TIME)
+static bool printk_time = 1;
+#else
+static bool printk_time;
+#endif
+module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
+
+static size_t print_time(u64 ts, char *buf)
+{
+ unsigned long rem_nsec;
+
+ if (!printk_time)
+ return 0;
+
+ if (!buf)
+ return 15;
+
+ rem_nsec = do_div(ts, 1000000000);
+ return sprintf(buf, "[%5lu.%06lu] ",
+ (unsigned long)ts, rem_nsec / 1000);
+}
+
+static size_t print_prefix(const struct log *msg, bool syslog, char *buf)
+{
+ size_t len = 0;
+ unsigned int prefix = (msg->facility << 3) | msg->level;
+
+ if (syslog) {
+ if (buf) {
+ len += sprintf(buf, "<%u>", prefix);
+ } else {
+ len += 3;
+ if (prefix > 999)
+ len += 3;
+ else if (prefix > 99)
+ len += 2;
+ else if (prefix > 9)
+ len++;
+ }
+ }
+
+ len += print_time(msg->ts_nsec, buf ? buf + len : NULL);
+ return len;
+}
+
+static size_t msg_print_text(const struct log *msg, enum log_flags prev,
+ bool syslog, char *buf, size_t size)
+{
+ const char *text = log_text(msg);
+ size_t text_size = msg->text_len;
+ bool prefix = true;
+ bool newline = true;
+ size_t len = 0;
+
+ if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))
+ prefix = false;
+
+ if (msg->flags & LOG_CONT) {
+ if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE))
+ prefix = false;
+
+ if (!(msg->flags & LOG_NEWLINE))
+ newline = false;
+ }
+
+ do {
+ const char *next = memchr(text, '\n', text_size);
+ size_t text_len;
+
+ if (next) {
+ text_len = next - text;
+ next++;
+ text_size -= next - text;
+ } else {
+ text_len = text_size;
+ }
+
+ if (buf) {
+ if (print_prefix(msg, syslog, NULL) +
+ text_len + 1>= size - len)
+ break;
+
+ if (prefix)
+ len += print_prefix(msg, syslog, buf + len);
+ memcpy(buf + len, text, text_len);
+ len += text_len;
+ if (next || newline)
+ buf[len++] = '\n';
+ } else {
+ /* SYSLOG_ACTION_* buffer size only calculation */
+ if (prefix)
+ len += print_prefix(msg, syslog, NULL);
+ len += text_len;
+ if (next || newline)
+ len++;
+ }
+
+ prefix = true;
+ text = next;
+ } while (text);
+
+ return len;
+}
+
+static int syslog_print(char __user *buf, int size)
+{
+ char *text;
+ struct log *msg;
+ int len = 0;
+
+ text = kmalloc(LOG_LINE_MAX, GFP_KERNEL);
+ if (!text)
+ return -ENOMEM;
+
+ while (size > 0) {
+ size_t n;
+ size_t skip;
+
+ raw_spin_lock_irq(&logbuf_lock);
+ if (syslog_seq < log_first_seq) {
+ /* messages are gone, move to first one */
+ syslog_seq = log_first_seq;
+ syslog_idx = log_first_idx;
+ syslog_prev = 0;
+ syslog_partial = 0;
+ }
+ if (syslog_seq == log_next_seq) {
+ raw_spin_unlock_irq(&logbuf_lock);
+ break;
+ }
+
+ skip = syslog_partial;
+ msg = log_from_idx(syslog_idx);
+ n = msg_print_text(msg, syslog_prev, true, text, LOG_LINE_MAX);
+ if (n - syslog_partial <= size) {
+ /* message fits into buffer, move forward */
+ syslog_idx = log_next(syslog_idx);
+ syslog_seq++;
+ syslog_prev = msg->flags;
+ n -= syslog_partial;
+ syslog_partial = 0;
+ } else if (!len){
+ /* partial read(), remember position */
+ n = size;
+ syslog_partial += n;
+ } else
+ n = 0;
+ raw_spin_unlock_irq(&logbuf_lock);
+
+ if (!n)
+ break;
+
+ if (copy_to_user(buf, text + skip, n)) {
+ if (!len)
+ len = -EFAULT;
+ break;
+ }
+
+ len += n;
+ size -= n;
+ buf += n;
+ }
+
+ kfree(text);
+ return len;
+}
+
+static int syslog_print_all(char __user *buf, int size, bool clear)
+{
+ char *text;
+ int len = 0;
+
+ text = kmalloc(LOG_LINE_MAX, GFP_KERNEL);
+ if (!text)
+ return -ENOMEM;
+
+ raw_spin_lock_irq(&logbuf_lock);
+ if (buf) {
+ u64 next_seq;
+ u64 seq;
+ u32 idx;
+ enum log_flags prev;
+
+ if (clear_seq < log_first_seq) {
+ /* messages are gone, move to first available one */
+ clear_seq = log_first_seq;
+ clear_idx = log_first_idx;
+ }
+
+ /*
+ * Find first record that fits, including all following records,
+ * into the user-provided buffer for this dump.
+ */
+ seq = clear_seq;
+ idx = clear_idx;
+ prev = 0;
+ while (seq < log_next_seq) {
+ struct log *msg = log_from_idx(idx);
+
+ len += msg_print_text(msg, prev, true, NULL, 0);
+ idx = log_next(idx);
+ seq++;
+ }
+
+ /* move first record forward until length fits into the buffer */
+ seq = clear_seq;
+ idx = clear_idx;
+ prev = 0;
+ while (len > size && seq < log_next_seq) {
+ struct log *msg = log_from_idx(idx);
+
+ len -= msg_print_text(msg, prev, true, NULL, 0);
+ idx = log_next(idx);
+ seq++;
+ }
+
+ /* last message fitting into this dump */
+ next_seq = log_next_seq;
+
+ len = 0;
+ prev = 0;
+ while (len >= 0 && seq < next_seq) {
+ struct log *msg = log_from_idx(idx);
+ int textlen;
+
+ textlen = msg_print_text(msg, prev, true, text, LOG_LINE_MAX);
+ if (textlen < 0) {
+ len = textlen;
+ break;
+ }
+ idx = log_next(idx);
+ seq++;
+ prev = msg->flags;
+
+ raw_spin_unlock_irq(&logbuf_lock);
+ if (copy_to_user(buf + len, text, textlen))
+ len = -EFAULT;
+ else
+ len += textlen;
+ raw_spin_lock_irq(&logbuf_lock);
+
+ if (seq < log_first_seq) {
+ /* messages are gone, move to next one */
+ seq = log_first_seq;
+ idx = log_first_idx;
+ prev = 0;
+ }
+ }
+ }
+
+ if (clear) {
+ clear_seq = log_next_seq;
+ clear_idx = log_next_idx;
+ }
+ raw_spin_unlock_irq(&logbuf_lock);
+
+ kfree(text);
+ return len;
+}
+
int do_syslog(int type, char __user *buf, int len, bool from_file)
{
- unsigned i, j, limit, count;
- int do_clear = 0;
- char c;
+ bool clear = false;
+ static int saved_console_loglevel = -1;
int error;
error = check_syslog_permissions(type, from_file);
@@ -361,28 +1088,14 @@
goto out;
}
error = wait_event_interruptible(log_wait,
- (log_start - log_end));
+ syslog_seq != log_next_seq);
if (error)
goto out;
- i = 0;
- raw_spin_lock_irq(&logbuf_lock);
- while (!error && (log_start != log_end) && i < len) {
- c = LOG_BUF(log_start);
- log_start++;
- raw_spin_unlock_irq(&logbuf_lock);
- error = __put_user(c,buf);
- buf++;
- i++;
- cond_resched();
- raw_spin_lock_irq(&logbuf_lock);
- }
- raw_spin_unlock_irq(&logbuf_lock);
- if (!error)
- error = i;
+ error = syslog_print(buf, len);
break;
/* Read/clear last kernel messages */
case SYSLOG_ACTION_READ_CLEAR:
- do_clear = 1;
+ clear = true;
/* FALL THRU */
/* Read last kernel messages */
case SYSLOG_ACTION_READ_ALL:
@@ -396,51 +1109,11 @@
error = -EFAULT;
goto out;
}
- count = len;
- if (count > log_buf_len)
- count = log_buf_len;
- raw_spin_lock_irq(&logbuf_lock);
- if (count > logged_chars)
- count = logged_chars;
- if (do_clear)
- logged_chars = 0;
- limit = log_end;
- /*
- * __put_user() could sleep, and while we sleep
- * printk() could overwrite the messages
- * we try to copy to user space. Therefore
- * the messages are copied in reverse. <manfreds>
- */
- for (i = 0; i < count && !error; i++) {
- j = limit-1-i;
- if (j + log_buf_len < log_end)
- break;
- c = LOG_BUF(j);
- raw_spin_unlock_irq(&logbuf_lock);
- error = __put_user(c,&buf[count-1-i]);
- cond_resched();
- raw_spin_lock_irq(&logbuf_lock);
- }
- raw_spin_unlock_irq(&logbuf_lock);
- if (error)
- break;
- error = i;
- if (i != count) {
- int offset = count-error;
- /* buffer overflow during copy, correct user buffer. */
- for (i = 0; i < error; i++) {
- if (__get_user(c,&buf[i+offset]) ||
- __put_user(c,&buf[i])) {
- error = -EFAULT;
- break;
- }
- cond_resched();
- }
- }
+ error = syslog_print_all(buf, len, clear);
break;
/* Clear ring buffer */
case SYSLOG_ACTION_CLEAR:
- logged_chars = 0;
+ syslog_print_all(NULL, 0, true);
break;
/* Disable logging to console */
case SYSLOG_ACTION_CONSOLE_OFF:
@@ -469,7 +1142,38 @@
break;
/* Number of chars in the log buffer */
case SYSLOG_ACTION_SIZE_UNREAD:
- error = log_end - log_start;
+ raw_spin_lock_irq(&logbuf_lock);
+ if (syslog_seq < log_first_seq) {
+ /* messages are gone, move to first one */
+ syslog_seq = log_first_seq;
+ syslog_idx = log_first_idx;
+ syslog_prev = 0;
+ syslog_partial = 0;
+ }
+ if (from_file) {
+ /*
+ * Short-cut for poll(/"proc/kmsg") which simply checks
+ * for pending data, not the size; return the count of
+ * records, not the length.
+ */
+ error = log_next_idx - syslog_idx;
+ } else {
+ u64 seq = syslog_seq;
+ u32 idx = syslog_idx;
+ enum log_flags prev = syslog_prev;
+
+ error = 0;
+ while (seq < log_next_seq) {
+ struct log *msg = log_from_idx(idx);
+
+ error += msg_print_text(msg, prev, true, NULL, 0);
+ idx = log_next(idx);
+ seq++;
+ prev = msg->flags;
+ }
+ error -= syslog_partial;
+ }
+ raw_spin_unlock_irq(&logbuf_lock);
break;
/* Size of the log buffer */
case SYSLOG_ACTION_SIZE_BUFFER:
@@ -488,39 +1192,6 @@
return do_syslog(type, buf, len, SYSLOG_FROM_CALL);
}
-#ifdef CONFIG_KGDB_KDB
-/* kdb dmesg command needs access to the syslog buffer. do_syslog()
- * uses locks so it cannot be used during debugging. Just tell kdb
- * where the start and end of the physical and logical logs are. This
- * is equivalent to do_syslog(3).
- */
-void kdb_syslog_data(char *syslog_data[4])
-{
- syslog_data[0] = log_buf;
- syslog_data[1] = log_buf + log_buf_len;
- syslog_data[2] = log_buf + log_end -
- (logged_chars < log_buf_len ? logged_chars : log_buf_len);
- syslog_data[3] = log_buf + log_end;
-}
-#endif /* CONFIG_KGDB_KDB */
-
-/*
- * Call the console drivers on a range of log_buf
- */
-static void __call_console_drivers(unsigned start, unsigned end)
-{
- struct console *con;
-
- for_each_console(con) {
- if (exclusive_console && con != exclusive_console)
- continue;
- if ((con->flags & CON_ENABLED) && con->write &&
- (cpu_online(smp_processor_id()) ||
- (con->flags & CON_ANYTIME)))
- con->write(con, &LOG_BUF(start), end - start);
- }
-}
-
static bool __read_mostly ignore_loglevel;
static int __init ignore_loglevel_setup(char *str)
@@ -537,140 +1208,33 @@
"print all kernel messages to the console.");
/*
- * Write out chars from start to end - 1 inclusive
- */
-static void _call_console_drivers(unsigned start,
- unsigned end, int msg_log_level)
-{
- if ((msg_log_level < console_loglevel || ignore_loglevel) &&
- console_drivers && start != end) {
- if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {
- /* wrapped write */
- __call_console_drivers(start & LOG_BUF_MASK,
- log_buf_len);
- __call_console_drivers(0, end & LOG_BUF_MASK);
- } else {
- __call_console_drivers(start, end);
- }
- }
-}
-
-/*
- * Parse the syslog header <[0-9]*>. The decimal value represents 32bit, the
- * lower 3 bit are the log level, the rest are the log facility. In case
- * userspace passes usual userspace syslog messages to /dev/kmsg or
- * /dev/ttyprintk, the log prefix might contain the facility. Printk needs
- * to extract the correct log level for in-kernel processing, and not mangle
- * the original value.
- *
- * If a prefix is found, the length of the prefix is returned. If 'level' is
- * passed, it will be filled in with the log level without a possible facility
- * value. If 'special' is passed, the special printk prefix chars are accepted
- * and returned. If no valid header is found, 0 is returned and the passed
- * variables are not touched.
- */
-static size_t log_prefix(const char *p, unsigned int *level, char *special)
-{
- unsigned int lev = 0;
- char sp = '\0';
- size_t len;
-
- if (p[0] != '<' || !p[1])
- return 0;
- if (p[2] == '>') {
- /* usual single digit level number or special char */
- switch (p[1]) {
- case '0' ... '7':
- lev = p[1] - '0';
- break;
- case 'c': /* KERN_CONT */
- case 'd': /* KERN_DEFAULT */
- sp = p[1];
- break;
- default:
- return 0;
- }
- len = 3;
- } else {
- /* multi digit including the level and facility number */
- char *endp = NULL;
-
- lev = (simple_strtoul(&p[1], &endp, 10) & 7);
- if (endp == NULL || endp[0] != '>')
- return 0;
- len = (endp + 1) - p;
- }
-
- /* do not accept special char if not asked for */
- if (sp && !special)
- return 0;
-
- if (special) {
- *special = sp;
- /* return special char, do not touch level */
- if (sp)
- return len;
- }
-
- if (level)
- *level = lev;
- return len;
-}
-
-/*
* Call the console drivers, asking them to write out
* log_buf[start] to log_buf[end - 1].
* The console_lock must be held.
*/
-static void call_console_drivers(unsigned start, unsigned end)
+static void call_console_drivers(int level, const char *text, size_t len)
{
- unsigned cur_index, start_print;
- static int msg_level = -1;
+ struct console *con;
- BUG_ON(((int)(start - end)) > 0);
+ trace_console(text, 0, len, len);
- cur_index = start;
- start_print = start;
- while (cur_index != end) {
- if (msg_level < 0 && ((end - cur_index) > 2)) {
- /* strip log prefix */
- cur_index += log_prefix(&LOG_BUF(cur_index), &msg_level, NULL);
- start_print = cur_index;
- }
- while (cur_index != end) {
- char c = LOG_BUF(cur_index);
+ if (level >= console_loglevel && !ignore_loglevel)
+ return;
+ if (!console_drivers)
+ return;
- cur_index++;
- if (c == '\n') {
- if (msg_level < 0) {
- /*
- * printk() has already given us loglevel tags in
- * the buffer. This code is here in case the
- * log buffer has wrapped right round and scribbled
- * on those tags
- */
- msg_level = default_message_loglevel;
- }
- _call_console_drivers(start_print, cur_index, msg_level);
- msg_level = -1;
- start_print = cur_index;
- break;
- }
- }
+ for_each_console(con) {
+ if (exclusive_console && con != exclusive_console)
+ continue;
+ if (!(con->flags & CON_ENABLED))
+ continue;
+ if (!con->write)
+ continue;
+ if (!cpu_online(smp_processor_id()) &&
+ !(con->flags & CON_ANYTIME))
+ continue;
+ con->write(con, text, len);
}
- _call_console_drivers(start_print, end, msg_level);
-}
-
-static void emit_log_char(char c)
-{
- LOG_BUF(log_end) = c;
- log_end++;
- if (log_end - log_start > log_buf_len)
- log_start = log_end - log_buf_len;
- if (log_end - con_start > log_buf_len)
- con_start = log_end - log_buf_len;
- if (logged_chars < log_buf_len)
- logged_chars++;
}
/*
@@ -695,16 +1259,6 @@
sema_init(&console_sem, 1);
}
-#if defined(CONFIG_PRINTK_TIME)
-static bool printk_time = 1;
-#else
-static bool printk_time = 0;
-#endif
-module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
-
-static bool always_kmsg_dump;
-module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
-
/* Check if we have any console registered that can be called early in boot. */
static int have_callable_console(void)
{
@@ -717,51 +1271,6 @@
return 0;
}
-/**
- * printk - print a kernel message
- * @fmt: format string
- *
- * This is printk(). It can be called from any context. We want it to work.
- *
- * We try to grab the console_lock. If we succeed, it's easy - we log the output and
- * call the console drivers. If we fail to get the semaphore we place the output
- * into the log buffer and return. The current holder of the console_sem will
- * notice the new output in console_unlock(); and will send it to the
- * consoles before releasing the lock.
- *
- * One effect of this deferred printing is that code which calls printk() and
- * then changes console_loglevel may break. This is because console_loglevel
- * is inspected when the actual printing occurs.
- *
- * See also:
- * printf(3)
- *
- * See the vsnprintf() documentation for format string extensions over C99.
- */
-
-asmlinkage int printk(const char *fmt, ...)
-{
- va_list args;
- int r;
-
-#ifdef CONFIG_KGDB_KDB
- if (unlikely(kdb_trap_printk)) {
- va_start(args, fmt);
- r = vkdb_printf(fmt, args);
- va_end(args);
- return r;
- }
-#endif
- va_start(args, fmt);
- r = vprintk(fmt, args);
- va_end(args);
-
- return r;
-}
-
-/* cpu currently holding logbuf_lock */
-static volatile unsigned int printk_cpu = UINT_MAX;
-
/*
* Can we actually use the console at this time on this cpu?
*
@@ -805,17 +1314,12 @@
retval = 0;
}
}
- printk_cpu = UINT_MAX;
+ logbuf_cpu = UINT_MAX;
if (wake)
up(&console_sem);
raw_spin_unlock(&logbuf_lock);
return retval;
}
-static const char recursion_bug_msg [] =
- KERN_CRIT "BUG: recent printk recursion!\n";
-static int recursion_bug;
-static int new_text_line = 1;
-static char printk_buf[1024];
int printk_delay_msec __read_mostly;
@@ -831,15 +1335,99 @@
}
}
-asmlinkage int vprintk(const char *fmt, va_list args)
+/*
+ * Continuation lines are buffered, and not committed to the record buffer
+ * until the line is complete, or a race forces it. The line fragments
+ * though, are printed immediately to the consoles to ensure everything has
+ * reached the console in case of a kernel crash.
+ */
+static struct cont {
+ char buf[LOG_LINE_MAX];
+ size_t len; /* length == 0 means unused buffer */
+ size_t cons; /* bytes written to console */
+ struct task_struct *owner; /* task of first print*/
+ u64 ts_nsec; /* time of first print */
+ u8 level; /* log level of first message */
+ u8 facility; /* log level of first message */
+ bool flushed:1; /* buffer sealed and committed */
+} cont;
+
+static void cont_flush(void)
{
- int printed_len = 0;
- int current_log_level = default_message_loglevel;
+ if (cont.flushed)
+ return;
+ if (cont.len == 0)
+ return;
+
+ log_store(cont.facility, cont.level, LOG_NOCONS, cont.ts_nsec,
+ NULL, 0, cont.buf, cont.len);
+
+ cont.flushed = true;
+}
+
+static bool cont_add(int facility, int level, const char *text, size_t len)
+{
+ if (cont.len && cont.flushed)
+ return false;
+
+ if (cont.len + len > sizeof(cont.buf)) {
+ cont_flush();
+ return false;
+ }
+
+ if (!cont.len) {
+ cont.facility = facility;
+ cont.level = level;
+ cont.owner = current;
+ cont.ts_nsec = local_clock();
+ cont.cons = 0;
+ cont.flushed = false;
+ }
+
+ memcpy(cont.buf + cont.len, text, len);
+ cont.len += len;
+ return true;
+}
+
+static size_t cont_print_text(char *text, size_t size)
+{
+ size_t textlen = 0;
+ size_t len;
+
+ if (cont.cons == 0) {
+ textlen += print_time(cont.ts_nsec, text);
+ size -= textlen;
+ }
+
+ len = cont.len - cont.cons;
+ if (len > 0) {
+ if (len+1 > size)
+ len = size-1;
+ memcpy(text + textlen, cont.buf + cont.cons, len);
+ textlen += len;
+ cont.cons = cont.len;
+ }
+
+ if (cont.flushed) {
+ text[textlen++] = '\n';
+ /* got everything, release buffer */
+ cont.len = 0;
+ }
+ return textlen;
+}
+
+asmlinkage int vprintk_emit(int facility, int level,
+ const char *dict, size_t dictlen,
+ const char *fmt, va_list args)
+{
+ static int recursion_bug;
+ static char textbuf[LOG_LINE_MAX];
+ char *text = textbuf;
+ size_t text_len;
+ enum log_flags lflags = 0;
unsigned long flags;
int this_cpu;
- char *p;
- size_t plen;
- char special;
+ int printed_len = 0;
boot_delay_msec();
printk_delay();
@@ -851,7 +1439,7 @@
/*
* Ouch, printk recursed into itself!
*/
- if (unlikely(printk_cpu == this_cpu)) {
+ if (unlikely(logbuf_cpu == this_cpu)) {
/*
* If a crash is occurring during printk() on this CPU,
* then try to get the crash message out but make sure
@@ -868,97 +1456,91 @@
lockdep_off();
raw_spin_lock(&logbuf_lock);
- printk_cpu = this_cpu;
+ logbuf_cpu = this_cpu;
if (recursion_bug) {
+ static const char recursion_msg[] =
+ "BUG: recent printk recursion!";
+
recursion_bug = 0;
- strcpy(printk_buf, recursion_bug_msg);
- printed_len = strlen(recursion_bug_msg);
- }
- /* Emit the output into the temporary buffer */
- printed_len += vscnprintf(printk_buf + printed_len,
- sizeof(printk_buf) - printed_len, fmt, args);
-
- p = printk_buf;
-
- /* Read log level and handle special printk prefix */
- plen = log_prefix(p, ¤t_log_level, &special);
- if (plen) {
- p += plen;
-
- switch (special) {
- case 'c': /* Strip <c> KERN_CONT, continue line */
- plen = 0;
- break;
- case 'd': /* Strip <d> KERN_DEFAULT, start new line */
- plen = 0;
- default:
- if (!new_text_line) {
- emit_log_char('\n');
- new_text_line = 1;
- }
- }
+ printed_len += strlen(recursion_msg);
+ /* emit KERN_CRIT message */
+ log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0,
+ NULL, 0, recursion_msg, printed_len);
}
/*
- * Copy the output into log_buf. If the caller didn't provide
- * the appropriate log prefix, we insert them here
+ * The printf needs to come first; we need the syslog
+ * prefix which might be passed-in as a parameter.
*/
- for (; *p; p++) {
- if (new_text_line) {
- new_text_line = 0;
+ text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
- if (plen) {
- /* Copy original log prefix */
- int i;
-
- for (i = 0; i < plen; i++)
- emit_log_char(printk_buf[i]);
- printed_len += plen;
- } else {
- /* Add log prefix */
- emit_log_char('<');
- emit_log_char(current_log_level + '0');
- emit_log_char('>');
- printed_len += 3;
- }
-
- if (printk_time) {
- /* Add the current time stamp */
- char tbuf[50], *tp;
- unsigned tlen;
- unsigned long long t;
- unsigned long nanosec_rem;
-
- t = cpu_clock(printk_cpu);
- nanosec_rem = do_div(t, 1000000000);
- tlen = sprintf(tbuf, "[%5lu.%06lu] ",
- (unsigned long) t,
- nanosec_rem / 1000);
-
- for (tp = tbuf; tp < tbuf + tlen; tp++)
- emit_log_char(*tp);
- printed_len += tlen;
- }
-
- if (!*p)
- break;
- }
-
- emit_log_char(*p);
- if (*p == '\n')
- new_text_line = 1;
+ /* mark and strip a trailing newline */
+ if (text_len && text[text_len-1] == '\n') {
+ text_len--;
+ lflags |= LOG_NEWLINE;
}
+ /* strip syslog prefix and extract log level or control flags */
+ if (text[0] == '<' && text[1] && text[2] == '>') {
+ switch (text[1]) {
+ case '0' ... '7':
+ if (level == -1)
+ level = text[1] - '0';
+ case 'd': /* KERN_DEFAULT */
+ lflags |= LOG_PREFIX;
+ case 'c': /* KERN_CONT */
+ text += 3;
+ text_len -= 3;
+ }
+ }
+
+ if (level == -1)
+ level = default_message_loglevel;
+
+ if (dict)
+ lflags |= LOG_PREFIX|LOG_NEWLINE;
+
+ if (!(lflags & LOG_NEWLINE)) {
+ /*
+ * Flush the conflicting buffer. An earlier newline was missing,
+ * or another task also prints continuation lines.
+ */
+ if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
+ cont_flush();
+
+ /* buffer line if possible, otherwise store it right away */
+ if (!cont_add(facility, level, text, text_len))
+ log_store(facility, level, lflags | LOG_CONT, 0,
+ dict, dictlen, text, text_len);
+ } else {
+ bool stored = false;
+
+ /*
+ * If an earlier newline was missing and it was the same task,
+ * either merge it with the current buffer and flush, or if
+ * there was a race with interrupts (prefix == true) then just
+ * flush it out and store this line separately.
+ */
+ if (cont.len && cont.owner == current) {
+ if (!(lflags & LOG_PREFIX))
+ stored = cont_add(facility, level, text, text_len);
+ cont_flush();
+ }
+
+ if (!stored)
+ log_store(facility, level, lflags, 0,
+ dict, dictlen, text, text_len);
+ }
+ printed_len += text_len;
+
/*
- * Try to acquire and then immediately release the
- * console semaphore. The release will do all the
- * actual magic (print out buffers, wake up klogd,
- * etc).
+ * Try to acquire and then immediately release the console semaphore.
+ * The release will print out buffers and wake up /dev/kmsg and syslog()
+ * users.
*
- * The console_trylock_for_printk() function
- * will release 'logbuf_lock' regardless of whether it
- * actually gets the semaphore or not.
+ * The console_trylock_for_printk() function will release 'logbuf_lock'
+ * regardless of whether it actually gets the console semaphore or not.
*/
if (console_trylock_for_printk(this_cpu))
console_unlock();
@@ -969,16 +1551,88 @@
return printed_len;
}
-EXPORT_SYMBOL(printk);
+EXPORT_SYMBOL(vprintk_emit);
+
+asmlinkage int vprintk(const char *fmt, va_list args)
+{
+ return vprintk_emit(0, -1, NULL, 0, fmt, args);
+}
EXPORT_SYMBOL(vprintk);
+asmlinkage int printk_emit(int facility, int level,
+ const char *dict, size_t dictlen,
+ const char *fmt, ...)
+{
+ va_list args;
+ int r;
+
+ va_start(args, fmt);
+ r = vprintk_emit(facility, level, dict, dictlen, fmt, args);
+ va_end(args);
+
+ return r;
+}
+EXPORT_SYMBOL(printk_emit);
+
+/**
+ * printk - print a kernel message
+ * @fmt: format string
+ *
+ * This is printk(). It can be called from any context. We want it to work.
+ *
+ * We try to grab the console_lock. If we succeed, it's easy - we log the
+ * output and call the console drivers. If we fail to get the semaphore, we
+ * place the output into the log buffer and return. The current holder of
+ * the console_sem will notice the new output in console_unlock(); and will
+ * send it to the consoles before releasing the lock.
+ *
+ * One effect of this deferred printing is that code which calls printk() and
+ * then changes console_loglevel may break. This is because console_loglevel
+ * is inspected when the actual printing occurs.
+ *
+ * See also:
+ * printf(3)
+ *
+ * See the vsnprintf() documentation for format string extensions over C99.
+ */
+asmlinkage int printk(const char *fmt, ...)
+{
+ va_list args;
+ int r;
+
+#ifdef CONFIG_KGDB_KDB
+ if (unlikely(kdb_trap_printk)) {
+ va_start(args, fmt);
+ r = vkdb_printf(fmt, args);
+ va_end(args);
+ return r;
+ }
+#endif
+ va_start(args, fmt);
+ r = vprintk_emit(0, -1, NULL, 0, fmt, args);
+ va_end(args);
+
+ return r;
+}
+EXPORT_SYMBOL(printk);
+
#else
-static void call_console_drivers(unsigned start, unsigned end)
-{
-}
+#define LOG_LINE_MAX 0
+static struct cont {
+ size_t len;
+ size_t cons;
+ u8 level;
+ bool flushed:1;
+} cont;
+static struct log *log_from_idx(u32 idx) { return NULL; }
+static u32 log_next(u32 idx) { return 0; }
+static void call_console_drivers(int level, const char *text, size_t len) {}
+static size_t msg_print_text(const struct log *msg, enum log_flags prev,
+ bool syslog, char *buf, size_t size) { return 0; }
+static size_t cont_print_text(char *text, size_t size) { return 0; }
-#endif
+#endif /* CONFIG_PRINTK */
static int __add_preferred_console(char *name, int idx, char *options,
char *brl_options)
@@ -1211,6 +1865,14 @@
return console_locked;
}
+/*
+ * Delayed printk version, for scheduler-internal messages:
+ */
+#define PRINTK_BUF_SIZE 512
+
+#define PRINTK_PENDING_WAKEUP 0x01
+#define PRINTK_PENDING_SCHED 0x02
+
static DEFINE_PER_CPU(int, printk_pending);
void printk_tick(void)
@@ -1234,6 +1896,11 @@
this_cpu_write(printk_pending, 1);
}
+/* the next printk record to write to the console */
+static u64 console_seq;
+static u32 console_idx;
+static enum log_flags console_prev;
+
/**
* console_unlock - unlock the console system
*
@@ -1244,15 +1911,17 @@
* by printk(). If this is the case, console_unlock(); emits
* the output prior to releasing the lock.
*
- * If there is output waiting for klogd, we wake it up.
+ * If there is output waiting, we wake /dev/kmsg and syslog() users.
*
* console_unlock(); may be called from any context.
*/
void console_unlock(void)
{
+ static char text[LOG_LINE_MAX];
+ static u64 seen_seq;
unsigned long flags;
- unsigned _con_start, _log_end;
- unsigned wake_klogd = 0, retry = 0;
+ bool wake_klogd = false;
+ bool retry;
if (console_suspended) {
up(&console_sem);
@@ -1261,18 +1930,69 @@
console_may_schedule = 0;
-again:
- for ( ; ; ) {
- raw_spin_lock_irqsave(&logbuf_lock, flags);
- wake_klogd |= log_start - log_end;
- if (con_start == log_end)
- break; /* Nothing to print */
- _con_start = con_start;
- _log_end = log_end;
- con_start = log_end; /* Flush */
+ /* flush buffered message fragment immediately to console */
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ if (cont.len && (cont.cons < cont.len || cont.flushed)) {
+ size_t len;
+
+ len = cont_print_text(text, sizeof(text));
raw_spin_unlock(&logbuf_lock);
+ stop_critical_timings();
+ call_console_drivers(cont.level, text, len);
+ start_critical_timings();
+ local_irq_restore(flags);
+ } else
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
+again:
+ for (;;) {
+ struct log *msg;
+ size_t len;
+ int level;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ if (seen_seq != log_next_seq) {
+ wake_klogd = true;
+ seen_seq = log_next_seq;
+ }
+
+ if (console_seq < log_first_seq) {
+ /* messages are gone, move to first one */
+ console_seq = log_first_seq;
+ console_idx = log_first_idx;
+ console_prev = 0;
+ }
+skip:
+ if (console_seq == log_next_seq)
+ break;
+
+ msg = log_from_idx(console_idx);
+ if (msg->flags & LOG_NOCONS) {
+ /*
+ * Skip record we have buffered and already printed
+ * directly to the console when we received it.
+ */
+ console_idx = log_next(console_idx);
+ console_seq++;
+ /*
+ * We will get here again when we register a new
+ * CON_PRINTBUFFER console. Clear the flag so we
+ * will properly dump everything later.
+ */
+ msg->flags &= ~LOG_NOCONS;
+ goto skip;
+ }
+
+ level = msg->level;
+ len = msg_print_text(msg, console_prev, false,
+ text, sizeof(text));
+ console_idx = log_next(console_idx);
+ console_seq++;
+ console_prev = msg->flags;
+ raw_spin_unlock(&logbuf_lock);
+
stop_critical_timings(); /* don't trace print latency */
- call_console_drivers(_con_start, _log_end);
+ call_console_drivers(level, text, len);
start_critical_timings();
local_irq_restore(flags);
}
@@ -1293,8 +2013,7 @@
* flush, no worries.
*/
raw_spin_lock(&logbuf_lock);
- if (con_start != log_end)
- retry = 1;
+ retry = console_seq != log_next_seq;
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
if (retry && console_trylock())
@@ -1530,7 +2249,9 @@
* for us.
*/
raw_spin_lock_irqsave(&logbuf_lock, flags);
- con_start = log_start;
+ console_seq = syslog_seq;
+ console_idx = syslog_idx;
+ console_prev = syslog_prev;
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
/*
* We're about to replay the log buffer. Only do this to the
@@ -1719,50 +2440,263 @@
}
EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
+static bool always_kmsg_dump;
+module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
+
/**
* kmsg_dump - dump kernel log to kernel message dumpers.
* @reason: the reason (oops, panic etc) for dumping
*
- * Iterate through each of the dump devices and call the oops/panic
- * callbacks with the log buffer.
+ * Call each of the registered dumper's dump() callback, which can
+ * retrieve the kmsg records with kmsg_dump_get_line() or
+ * kmsg_dump_get_buffer().
*/
void kmsg_dump(enum kmsg_dump_reason reason)
{
- unsigned long end;
- unsigned chars;
struct kmsg_dumper *dumper;
- const char *s1, *s2;
- unsigned long l1, l2;
unsigned long flags;
if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
return;
- /* Theoretically, the log could move on after we do this, but
- there's not a lot we can do about that. The new messages
- will overwrite the start of what we dump. */
- raw_spin_lock_irqsave(&logbuf_lock, flags);
- end = log_end & LOG_BUF_MASK;
- chars = logged_chars;
- raw_spin_unlock_irqrestore(&logbuf_lock, flags);
-
- if (chars > end) {
- s1 = log_buf + log_buf_len - chars + end;
- l1 = chars - end;
-
- s2 = log_buf;
- l2 = end;
- } else {
- s1 = "";
- l1 = 0;
-
- s2 = log_buf + end - chars;
- l2 = chars;
- }
-
rcu_read_lock();
- list_for_each_entry_rcu(dumper, &dump_list, list)
- dumper->dump(dumper, reason, s1, l1, s2, l2);
+ list_for_each_entry_rcu(dumper, &dump_list, list) {
+ if (dumper->max_reason && reason > dumper->max_reason)
+ continue;
+
+ /* initialize iterator with data about the stored records */
+ dumper->active = true;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ dumper->cur_seq = clear_seq;
+ dumper->cur_idx = clear_idx;
+ dumper->next_seq = log_next_seq;
+ dumper->next_idx = log_next_idx;
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
+ /* invoke dumper which will iterate over records */
+ dumper->dump(dumper, reason);
+
+ /* reset iterator */
+ dumper->active = false;
+ }
rcu_read_unlock();
}
+
+/**
+ * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
+ * @dumper: registered kmsg dumper
+ * @syslog: include the "<4>" prefixes
+ * @line: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len: length of line placed into buffer
+ *
+ * Start at the beginning of the kmsg buffer, with the oldest kmsg
+ * record, and copy one record into the provided buffer.
+ *
+ * Consecutive calls will return the next available record moving
+ * towards the end of the buffer with the youngest messages.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ *
+ * The function is similar to kmsg_dump_get_line(), but grabs no locks.
+ */
+bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
+ char *line, size_t size, size_t *len)
+{
+ struct log *msg;
+ size_t l = 0;
+ bool ret = false;
+
+ 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;
+
+ msg = log_from_idx(dumper->cur_idx);
+ l = msg_print_text(msg, 0, syslog, line, size);
+
+ dumper->cur_idx = log_next(dumper->cur_idx);
+ dumper->cur_seq++;
+ ret = true;
+out:
+ if (len)
+ *len = l;
+ return ret;
+}
+
+/**
+ * kmsg_dump_get_line - retrieve one kmsg log line
+ * @dumper: registered kmsg dumper
+ * @syslog: include the "<4>" prefixes
+ * @line: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len: length of line placed into buffer
+ *
+ * Start at the beginning of the kmsg buffer, with the oldest kmsg
+ * record, and copy one record into the provided buffer.
+ *
+ * Consecutive calls will return the next available record moving
+ * towards the end of the buffer with the youngest messages.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ */
+bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
+ char *line, size_t size, size_t *len)
+{
+ unsigned long flags;
+ bool ret;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
+
+/**
+ * kmsg_dump_get_buffer - copy kmsg log lines
+ * @dumper: registered kmsg dumper
+ * @syslog: include the "<4>" prefixes
+ * @buf: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len: length of line placed into buffer
+ *
+ * Start at the end of the kmsg buffer and fill the provided buffer
+ * with as many of the the *youngest* kmsg records that fit into it.
+ * If the buffer is large enough, all available kmsg records will be
+ * copied with a single call.
+ *
+ * Consecutive calls will fill the buffer with the next block of
+ * available older records, not including the earlier retrieved ones.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ */
+bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ char *buf, size_t size, size_t *len)
+{
+ unsigned long flags;
+ u64 seq;
+ u32 idx;
+ u64 next_seq;
+ u32 next_idx;
+ enum log_flags prev;
+ size_t l = 0;
+ bool ret = false;
+
+ if (!dumper->active)
+ goto out;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ 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 >= dumper->next_seq) {
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+ goto out;
+ }
+
+ /* calculate length of entire buffer */
+ seq = dumper->cur_seq;
+ idx = dumper->cur_idx;
+ prev = 0;
+ while (seq < dumper->next_seq) {
+ struct log *msg = log_from_idx(idx);
+
+ l += msg_print_text(msg, prev, true, NULL, 0);
+ idx = log_next(idx);
+ seq++;
+ prev = msg->flags;
+ }
+
+ /* move first record forward until length fits into the buffer */
+ seq = dumper->cur_seq;
+ idx = dumper->cur_idx;
+ prev = 0;
+ while (l > size && seq < dumper->next_seq) {
+ struct log *msg = log_from_idx(idx);
+
+ l -= msg_print_text(msg, prev, true, NULL, 0);
+ idx = log_next(idx);
+ seq++;
+ prev = msg->flags;
+ }
+
+ /* last message in next interation */
+ next_seq = seq;
+ next_idx = idx;
+
+ l = 0;
+ prev = 0;
+ while (seq < dumper->next_seq) {
+ struct log *msg = log_from_idx(idx);
+
+ l += msg_print_text(msg, prev, syslog, buf + l, size - l);
+ idx = log_next(idx);
+ seq++;
+ prev = msg->flags;
+ }
+
+ dumper->next_seq = next_seq;
+ dumper->next_idx = next_idx;
+ ret = true;
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+out:
+ if (len)
+ *len = l;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+
+/**
+ * kmsg_dump_rewind_nolock - reset the interator (unlocked version)
+ * @dumper: registered kmsg dumper
+ *
+ * Reset the dumper's iterator so that kmsg_dump_get_line() and
+ * kmsg_dump_get_buffer() can be called again and used multiple
+ * times within the same dumper.dump() callback.
+ *
+ * The function is similar to kmsg_dump_rewind(), but grabs no locks.
+ */
+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;
+}
+
+/**
+ * kmsg_dump_rewind - reset the interator
+ * @dumper: registered kmsg dumper
+ *
+ * Reset the dumper's iterator so that kmsg_dump_get_line() and
+ * kmsg_dump_get_buffer() can be called again and used multiple
+ * times within the same dumper.dump() callback.
+ */
+void kmsg_dump_rewind(struct kmsg_dumper *dumper)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ kmsg_dump_rewind_nolock(dumper);
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
#endif
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 8745ac7..7115788 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -3,12 +3,16 @@
bool "Show timing information on printks"
depends on PRINTK
help
- Selecting this option causes timing information to be
- included in printk output. This allows you to measure
- the interval between kernel operations, including bootup
- operations. This is useful for identifying long delays
- in kernel startup. Or add printk.time=1 at boot-time.
- See Documentation/kernel-parameters.txt
+ Selecting this option causes time stamps of the printk()
+ messages to be added to the output of the syslog() system
+ call and at the console.
+
+ The timestamp is always recorded internally, and exported
+ to /dev/kmsg. This flag just specifies if the timestamp should
+ be included, not that the timestamp is recorded.
+
+ The behavior is also controlled by the kernel command line
+ parameter printk.time=1. See Documentation/kernel-parameters.txt
config DEFAULT_MESSAGE_LOGLEVEL
int "Default message log level (1-7)"
