diff options
| -rw-r--r-- | Documentation/admin-guide/kdump/gdbmacros.txt | 159 | ||||
| -rw-r--r-- | Documentation/admin-guide/kdump/vmcoreinfo.rst | 131 | ||||
| -rw-r--r-- | MAINTAINERS | 1 | ||||
| -rw-r--r-- | drivers/base/core.c | 46 | ||||
| -rw-r--r-- | include/linux/crash_core.h | 3 | ||||
| -rw-r--r-- | include/linux/debug_locks.h | 2 | ||||
| -rw-r--r-- | include/linux/dev_printk.h | 8 | ||||
| -rw-r--r-- | include/linux/kernel.h | 1 | ||||
| -rw-r--r-- | include/linux/printk.h | 8 | ||||
| -rw-r--r-- | init/Kconfig | 3 | ||||
| -rw-r--r-- | kernel/printk/Makefile | 1 | ||||
| -rw-r--r-- | kernel/printk/internal.h | 4 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 1153 | ||||
| -rw-r--r-- | kernel/printk/printk_ringbuffer.c | 2083 | ||||
| -rw-r--r-- | kernel/printk/printk_ringbuffer.h | 382 | ||||
| -rw-r--r-- | kernel/printk/printk_safe.c | 2 | ||||
| -rw-r--r-- | scripts/gdb/linux/dmesg.py | 147 | ||||
| -rw-r--r-- | scripts/gdb/linux/utils.py | 7 |
18 files changed, 3410 insertions, 731 deletions
diff --git a/Documentation/admin-guide/kdump/gdbmacros.txt b/Documentation/admin-guide/kdump/gdbmacros.txt index 220d0a80ca2c..82aecdcae8a6 100644 --- a/Documentation/admin-guide/kdump/gdbmacros.txt +++ b/Documentation/admin-guide/kdump/gdbmacros.txt @@ -170,57 +170,103 @@ document trapinfo address the kernel panicked. end -define dump_log_idx - set $idx = $arg0 - if ($argc > 1) - set $prev_flags = $arg1 +define dump_record + set var $desc = $arg0 + set var $info = $arg1 + if ($argc > 2) + set var $prev_flags = $arg2 else - set $prev_flags = 0 + set var $prev_flags = 0 end - set $msg = ((struct printk_log *) (log_buf + $idx)) - set $prefix = 1 - set $newline = 1 - set $log = log_buf + $idx + sizeof(*$msg) - - # prev & LOG_CONT && !(msg->flags & LOG_PREIX) - if (($prev_flags & 8) && !($msg->flags & 4)) - set $prefix = 0 + + set var $prefix = 1 + set var $newline = 1 + + set var $begin = $desc->text_blk_lpos.begin % (1U << prb->text_data_ring.size_bits) + set var $next = $desc->text_blk_lpos.next % (1U << prb->text_data_ring.size_bits) + + # handle data-less record + if ($begin & 1) + set var $text_len = 0 + set var $log = "" + else + # handle wrapping data block + if ($begin > $next) + set var $begin = 0 + end + + # skip over descriptor id + set var $begin = $begin + sizeof(long) + + # handle truncated message + if ($next - $begin < $info->text_len) + set var $text_len = $next - $begin + else + set var $text_len = $info->text_len + end + + set var $log = &prb->text_data_ring.data[$begin] + end + + # prev & LOG_CONT && !(info->flags & LOG_PREIX) + if (($prev_flags & 8) && !($info->flags & 4)) + set var $prefix = 0 end - # msg->flags & LOG_CONT - if ($msg->flags & 8) + # info->flags & LOG_CONT + if ($info->flags & 8) # (prev & LOG_CONT && !(prev & LOG_NEWLINE)) if (($prev_flags & 8) && !($prev_flags & 2)) - set $prefix = 0 + set var $prefix = 0 end - # (!(msg->flags & LOG_NEWLINE)) - if (!($msg->flags & 2)) - set $newline = 0 + # (!(info->flags & LOG_NEWLINE)) + if (!($info->flags & 2)) + set var $newline = 0 end end if ($prefix) - printf "[%5lu.%06lu] ", $msg->ts_nsec / 1000000000, $msg->ts_nsec % 1000000000 + printf "[%5lu.%06lu] ", $info->ts_nsec / 1000000000, $info->ts_nsec % 1000000000 end - if ($msg->text_len != 0) - eval "printf \"%%%d.%ds\", $log", $msg->text_len, $msg->text_len + if ($text_len) + eval "printf \"%%%d.%ds\", $log", $text_len, $text_len end if ($newline) printf "\n" end - if ($msg->dict_len > 0) - set $dict = $log + $msg->text_len - set $idx = 0 - set $line = 1 - while ($idx < $msg->dict_len) - if ($line) - printf " " - set $line = 0 + + # handle dictionary data + + set var $dict = &$info->dev_info.subsystem[0] + set var $dict_len = sizeof($info->dev_info.subsystem) + if ($dict[0] != '\0') + printf " SUBSYSTEM=" + set var $idx = 0 + while ($idx < $dict_len) + set var $c = $dict[$idx] + if ($c == '\0') + loop_break + else + if ($c < ' ' || $c >= 127 || $c == '\\') + printf "\\x%02x", $c + else + printf "%c", $c + end end - set $c = $dict[$idx] + set var $idx = $idx + 1 + end + printf "\n" + end + + set var $dict = &$info->dev_info.device[0] + set var $dict_len = sizeof($info->dev_info.device) + if ($dict[0] != '\0') + printf " DEVICE=" + set var $idx = 0 + while ($idx < $dict_len) + set var $c = $dict[$idx] if ($c == '\0') - printf "\n" - set $line = 1 + loop_break else if ($c < ' ' || $c >= 127 || $c == '\\') printf "\\x%02x", $c @@ -228,33 +274,46 @@ define dump_log_idx printf "%c", $c end end - set $idx = $idx + 1 + set var $idx = $idx + 1 end printf "\n" end end -document dump_log_idx - Dump a single log given its index in the log buffer. The first - parameter is the index into log_buf, the second is optional and - specified the previous log buffer's flags, used for properly - formatting continued lines. +document dump_record + Dump a single record. The first parameter is the descriptor, + the second parameter is the info, the third parameter is + optional and specifies the previous record's flags, used for + properly formatting continued lines. end define dmesg - set $i = log_first_idx - set $end_idx = log_first_idx - set $prev_flags = 0 + # definitions from kernel/printk/printk_ringbuffer.h + set var $desc_committed = 1 + set var $desc_finalized = 2 + set var $desc_sv_bits = sizeof(long) * 8 + set var $desc_flags_shift = $desc_sv_bits - 2 + set var $desc_flags_mask = 3 << $desc_flags_shift + set var $id_mask = ~$desc_flags_mask + + set var $desc_count = 1U << prb->desc_ring.count_bits + set var $prev_flags = 0 + + set var $id = prb->desc_ring.tail_id.counter + set var $end_id = prb->desc_ring.head_id.counter while (1) - set $msg = ((struct printk_log *) (log_buf + $i)) - if ($msg->len == 0) - set $i = 0 - else - dump_log_idx $i $prev_flags - set $i = $i + $msg->len - set $prev_flags = $msg->flags + set var $desc = &prb->desc_ring.descs[$id % $desc_count] + set var $info = &prb->desc_ring.infos[$id % $desc_count] + + # skip non-committed record + set var $state = 3 & ($desc->state_var.counter >> $desc_flags_shift) + if ($state == $desc_committed || $state == $desc_finalized) + dump_record $desc $info $prev_flags + set var $prev_flags = $info->flags end - if ($i == $end_idx) + + set var $id = ($id + 1) & $id_mask + if ($id == $end_id) loop_break end end diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst index 2baad0bfb09d..e44a6c01f336 100644 --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst @@ -189,50 +189,123 @@ from this. Free areas descriptor. User-space tools use this value to iterate the free_area ranges. MAX_ORDER is used by the zone buddy allocator. -log_first_idx +prb +--- + +A pointer to the printk ringbuffer (struct printk_ringbuffer). This +may be pointing to the static boot ringbuffer or the dynamically +allocated ringbuffer, depending on when the the core dump occurred. +Used by user-space tools to read the active kernel log buffer. + +printk_rb_static +---------------- + +A pointer to the static boot printk ringbuffer. If @prb has a +different value, this is useful for viewing the initial boot messages, +which may have been overwritten in the dynamically allocated +ringbuffer. + +clear_seq +--------- + +The sequence number of the printk() record after the last clear +command. It indicates the first record after the last +SYSLOG_ACTION_CLEAR, like issued by 'dmesg -c'. Used by user-space +tools to dump a subset of the dmesg log. + +printk_ringbuffer +----------------- + +The size of a printk_ringbuffer structure. This structure contains all +information required for accessing the various components of the +kernel log buffer. + +(printk_ringbuffer, desc_ring|text_data_ring|dict_data_ring|fail) +----------------------------------------------------------------- + +Offsets for the various components of the printk ringbuffer. Used by +user-space tools to view the kernel log buffer without requiring the +declaration of the structure. + +prb_desc_ring ------------- -Index of the first record stored in the buffer log_buf. Used by -user-space tools to read the strings in the log_buf. +The size of the prb_desc_ring structure. This structure contains +information about the set of record descriptors. -log_buf -------- +(prb_desc_ring, count_bits|descs|head_id|tail_id) +------------------------------------------------- + +Offsets for the fields describing the set of record descriptors. Used +by user-space tools to be able to traverse the descriptors without +requiring the declaration of the structure. + +prb_desc +-------- + +The size of the prb_desc structure. This structure contains +information about a single record descriptor. + +(prb_desc, info|state_var|text_blk_lpos|dict_blk_lpos) +------------------------------------------------------ + +Offsets for the fields describing a record descriptors. Used by +user-space tools to be able to read descriptors without requiring +the declaration of the structure. + +prb_data_blk_lpos +----------------- + +The size of the prb_data_blk_lpos structure. This structure contains +information about where the text or dictionary data (data block) is +located within the respective data ring. + +(prb_data_blk_lpos, begin|next) +------------------------------- -Console output is written to the ring buffer log_buf at index -log_first_idx. Used to get the kernel log. +Offsets for the fields describing the location of a data block. Used +by user-space tools to be able to locate data blocks without +requiring the declaration of the structure. -log_buf_len +printk_info ----------- -log_buf's length. +The size of the printk_info structure. This structure contains all +the meta-data for a record. -clear_idx ---------- +(printk_info, seq|ts_nsec|text_len|dict_len|caller_id) +------------------------------------------------------ -The index that the next printk() record to read after the last clear -command. It indicates the first record after the last SYSLOG_ACTION -_CLEAR, like issued by 'dmesg -c'. Used by user-space tools to dump -the dmesg log. +Offsets for the fields providing the meta-data for a record. Used by +user-space tools to be able to read the information without requiring +the declaration of the structure. -log_next_idx ------------- +prb_data_ring +------------- -The index of the next record to store in the buffer log_buf. Used to -compute the index of the current buffer position. +The size of the prb_data_ring structure. This structure contains +information about a set of data blocks. -printk_log ----------- +(prb_data_ring, size_bits|data|head_lpos|tail_lpos) +--------------------------------------------------- -The size of a structure printk_log. Used to compute the size of -messages, and extract dmesg log. It encapsulates header information for -log_buf, such as timestamp, syslog level, etc. +Offsets for the fields describing a set of data blocks. Used by +user-space tools to be able to access the data blocks without +requiring the declaration of the structure. -(printk_log, ts_nsec|len|text_len|dict_len) -------------------------------------------- +atomic_long_t +------------- + +The size of the atomic_long_t structure. Used by user-space tools to +be able to copy the full structure, regardless of its +architecture-specific implementation. + +(atomic_long_t, counter) +------------------------ -It represents field offsets in struct printk_log. User space tools -parse it and check whether the values of printk_log's members have been -changed. +Offset for the long value of an atomic_long_t variable. Used by +user-space tools to access the long value without requiring the +architecture-specific declaration. (free_area.free_list, MIGRATE_TYPES) ------------------------------------ diff --git a/MAINTAINERS b/MAINTAINERS index 71291bb26a07..6da16c3707c6 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13970,6 +13970,7 @@ PRINTK M: Petr Mladek <pmladek@suse.com> M: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> R: Steven Rostedt <rostedt@goodmis.org> +R: John Ogness <john.ogness@linutronix.de> S: Maintained F: include/linux/printk.h F: kernel/printk/ diff --git a/drivers/base/core.c b/drivers/base/core.c index bb5806a2bd4c..f90e9f77bf8c 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4061,22 +4061,21 @@ void device_shutdown(void) */ #ifdef CONFIG_PRINTK -static int -create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen) +static void +set_dev_info(const struct device *dev, struct dev_printk_info *dev_info) { const char *subsys; - size_t pos = 0; + + memset(dev_info, 0, sizeof(*dev_info)); if (dev->class) subsys = dev->class->name; else if (dev->bus) subsys = dev->bus->name; else - return 0; + return; - pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys); - if (pos >= hdrlen) - goto overflow; + strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem)); /* * Add device identifier DEVICE=: @@ -4092,41 +4091,28 @@ create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen) c = 'b'; else c = 'c'; - pos++; - pos += snprintf(hdr + pos, hdrlen - pos, - "DEVICE=%c%u:%u", - c, MAJOR(dev->devt), MINOR(dev->devt)); + + snprintf(dev_info->device, sizeof(dev_info->device), + "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt)); } else if (strcmp(subsys, "net") == 0) { struct net_device *net = to_net_dev(dev); - pos++; - pos += snprintf(hdr + pos, hdrlen - pos, - "DEVICE=n%u", net->ifindex); + snprintf(dev_info->device, sizeof(dev_info->device), + "n%u", net->ifindex); } else { - pos++; - pos += snprintf(hdr + pos, hdrlen - pos, - "DEVICE=+%s:%s", subsys, dev_name(dev)); + snprintf(dev_info->device, sizeof(dev_info->device), + "+%s:%s", subsys, dev_name(dev)); } - - if (pos >= hdrlen) - goto overflow; - - return pos; - -overflow: - dev_WARN(dev, "device/subsystem name too long"); - return 0; } int dev_vprintk_emit(int level, const struct device *dev, const char *fmt, va_list args) { - char hdr[128]; - size_t hdrlen; + struct dev_printk_info dev_info; - hdrlen = create_syslog_header(dev, hdr, sizeof(hdr)); + set_dev_info(dev, &dev_info); - return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args); + return vprintk_emit(0, level, &dev_info, fmt, args); } EXPORT_SYMBOL(dev_vprintk_emit); diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h index 6594dbc34a37..206bde8308b2 100644 --- a/include/linux/crash_core.h +++ b/include/linux/crash_core.h @@ -55,6 +55,9 @@ phys_addr_t paddr_vmcoreinfo_note(void); #define VMCOREINFO_OFFSET(name, field) \ vmcoreinfo_append_str("OFFSET(%s.%s)=%lu\n", #name, #field, \ (unsigned long)offsetof(struct name, field)) +#define VMCOREINFO_TYPE_OFFSET(name, field) \ + vmcoreinfo_append_str("OFFSET(%s.%s)=%lu\n", #name, #field, \ + (unsigned long)offsetof(name, field)) #define VMCOREINFO_LENGTH(name, value) \ vmcoreinfo_append_str("LENGTH(%s)=%lu\n", #name, (unsigned long)value) #define VMCOREINFO_NUMBER(name) \ diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h index e7e45f0cc7da..2915f56ad421 100644 --- a/include/linux/debug_locks.h +++ b/include/linux/debug_locks.h @@ -2,9 +2,9 @@ #ifndef __LINUX_DEBUG_LOCKING_H #define __LINUX_DEBUG_LOCKING_H -#include <linux/kernel.h> #include <linux/atomic.h> #include <linux/bug.h> +#include <linux/printk.h> struct task_struct; diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h index 3028b644b4fb..6f009559ee54 100644 --- a/include/linux/dev_printk.h +++ b/include/linux/dev_printk.h @@ -21,6 +21,14 @@ struct device; +#define PRINTK_INFO_SUBSYSTEM_LEN 16 +#define PRINTK_INFO_DEVICE_LEN 48 + +struct dev_printk_info { + char subsystem[PRINTK_INFO_SUBSYSTEM_LEN]; + char device[PRINTK_INFO_DEVICE_LEN]; +}; + #ifdef CONFIG_PRINTK __printf(3, 0) __cold diff --git a/include/linux/kernel.h b/include/linux/kernel.h index c25b8e41c0ea..e4aa29b1ad62 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -526,7 +526,6 @@ extern unsigned int sysctl_oops_all_cpu_backtrace; #endif /* CONFIG_SMP */ extern void bust_spinlocks(int yes); -extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */ extern int panic_timeout; extern unsigned long panic_print; extern int panic_on_oops; diff --git a/include/linux/printk.h b/include/linux/printk.h index 34c1a7be3e01..78479633ccfc 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -12,6 +12,8 @@ extern const char linux_banner[]; extern const char linux_proc_banner[]; +extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */ + #define PRINTK_MAX_SINGLE_HEADER_LEN 2 static inline int printk_get_level(const char *buffer) @@ -159,10 +161,12 @@ static inline void printk_nmi_direct_enter(void) { } static inline void printk_nmi_direct_exit(void) { } #endif /* PRINTK_NMI */ +struct dev_printk_info; + #ifdef CONFIG_PRINTK -asmlinkage __printf(5, 0) +asmlinkage __printf(4, 0) int vprintk_emit(int facility, int level, - const char *dict, size_t dictlen, + const struct dev_printk_info *dev_info, const char *fmt, va_list args); asmlinkage __printf(1, 0) diff --git a/init/Kconfig b/init/Kconfig index c0f56e455dce..2a583ef2ff66 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -682,7 +682,8 @@ config IKHEADERS config LOG_BUF_SHIFT int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" - range 12 25 + range 12 25 if !H8300 + range 12 19 if H8300 default 17 depends on PRINTK help diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile index 4d052fc6bcde..eee3dc9b60a9 100644 --- a/kernel/printk/Makefile +++ b/kernel/printk/Makefile @@ -2,3 +2,4 @@ obj-y = printk.o obj-$(CONFIG_PRINTK) += printk_safe.o obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o +obj-$(CONFIG_PRINTK) += printk_ringbuffer.o diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index 660f9a6bf73a..3a8fd491758c 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -14,9 +14,9 @@ extern raw_spinlock_t logbuf_lock; -__printf(5, 0) +__printf(4, 0) int vprintk_store(int facility, int level, - const char *dict, size_t dictlen, + const struct dev_printk_info *dev_info, const char *fmt, va_list args); __printf(1, 0) int vprintk_default(const char *fmt, va_list args); diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 9b75f6bfc333..fe64a49344bf 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -55,6 +55,7 @@ #define CREATE_TRACE_POINTS #include <trace/events/printk.h> +#include "printk_ringbuffer.h" #include "console_cmdline.h" #include "braille.h" #include "internal.h" @@ -294,30 +295,22 @@ enum con_msg_format_flags { 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 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. * * Examples for well-defined, commonly used property names are: * DEVICE=b12:8 device identifier @@ -327,25 +320,22 @@ static int console_msg_format = MSG_FORMAT_DEFAULT; * +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 printk_log' buffer header must never be directly exported to + * Valid characters in property names are [a-zA-Z0-9.-_]. Property names + * and values are terminated by a '\0' character. + * + * Example of record values: + * record.text_buf = "it's a line" (unterminated) + * record.info.seq = 56 + * record.info.ts_nsec = 36863 + * record.info.text_len = 11 + * record.info.facility = 0 (LOG_KERN) + * record.info.flags = 0 + * record.info.level = 3 (LOG_ERR) + * record.info.caller_id = 299 (task 299) + * record.info.dev_info.subsystem = "pci" (terminated) + * record.info.dev_info.device = "+pci:0000:00:01.0" (terminated) + * + * 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. * @@ -365,23 +355,6 @@ enum log_flags { 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 @@ -421,26 +394,16 @@ DEFINE_RAW_SPINLOCK(logbuf_lock); 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 @@ -453,7 +416,7 @@ static u32 clear_idx; #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); @@ -461,6 +424,23 @@ 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). + */ +#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, &__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 * it's safe to access per-CPU data. @@ -484,108 +464,6 @@ u32 log_buf_len_get(void) 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 @@ -594,84 +472,69 @@ static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len) #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) */ |