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-rw-r--r--target/linux/realtek/files/kernel/printk_log.c1551
1 files changed, 1551 insertions, 0 deletions
diff --git a/target/linux/realtek/files/kernel/printk_log.c b/target/linux/realtek/files/kernel/printk_log.c
new file mode 100644
index 000000000..c53e16bc5
--- /dev/null
+++ b/target/linux/realtek/files/kernel/printk_log.c
@@ -0,0 +1,1551 @@
+/*
+ * linux/kernel/printk.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * Modified to make sys_syslog() more flexible: added commands to
+ * return the last 4k of kernel messages, regardless of whether
+ * they've been read or not. Added option to suppress kernel printk's
+ * to the console. Added hook for sending the console messages
+ * elsewhere, in preparation for a serial line console (someday).
+ * Ted Ts'o, 2/11/93.
+ * Modified for sysctl support, 1/8/97, Chris Horn.
+ * Fixed SMP synchronization, 08/08/99, Manfred Spraul
+ * manfred@colorfullife.com
+ * Rewrote bits to get rid of console_lock
+ * 01Mar01 Andrew Morton
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/nmi.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/interrupt.h> /* For in_interrupt() */
+#include <linux/delay.h>
+#include <linux/smp.h>
+#include <linux/security.h>
+#include <linux/bootmem.h>
+#include <linux/syscalls.h>
+#include <linux/kexec.h>
+
+#include <asm/uaccess.h>
+
+/*
+ * Architectures can override it:
+ */
+void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...)
+{
+}
+
+#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
+
+/* printk's without a loglevel use this.. */
+#define DEFAULT_MESSAGE_LOGLEVEL 4 /* KERN_WARNING */
+
+/* We show everything that is MORE important than this.. */
+#define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */
+#define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */
+
+DECLARE_WAIT_QUEUE_HEAD(log_wait);
+
+int console_printk[4] = {
+ DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */
+ DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */
+ MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */
+ DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */
+};
+
+/*
+ * Low level drivers may need that to know if they can schedule in
+ * their unblank() callback or not. So let's export it.
+ */
+int oops_in_progress;
+EXPORT_SYMBOL(oops_in_progress);
+
+/*
+ * console_sem protects the console_drivers list, and also
+ * provides serialisation for access to the entire console
+ * driver system.
+ */
+static DECLARE_MUTEX(console_sem);
+struct console *console_drivers;
+EXPORT_SYMBOL_GPL(console_drivers);
+
+/*
+ * This is used for debugging the mess that is the VT code by
+ * keeping track if we have the console semaphore held. It's
+ * definitely not the perfect debug tool (we don't know if _WE_
+ * hold it are racing, but it helps tracking those weird code
+ * path in the console code where we end up in places I want
+ * locked without the console sempahore held
+ */
+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
+ * release_console_sem().
+ */
+static DEFINE_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 defined (CONFIG_PRINTK) || defined(CONFIG_PANIC_PRINTK)
+/*
+ * If printk enable, below two indicates the buf to send to consoles
+ */
+static unsigned long prt_start; /* Index into prt_buf: next char to be sent to consoles */
+static unsigned long prt_end; /* Index into log_buf: most-recently-written-char + 1 */
+#endif
+/*
+ * Array of consoles built from command line options (console=)
+ */
+struct console_cmdline
+{
+ char name[8]; /* Name of the driver */
+ int index; /* Minor dev. to use */
+ char *options; /* Options for the driver */
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ char *brl_options; /* Options for braille driver */
+#endif
+};
+
+#define MAX_CMDLINECONSOLES 1
+
+static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];
+static int selected_console = -1;
+static int preferred_console = -1;
+int console_set_on_cmdline;
+EXPORT_SYMBOL(console_set_on_cmdline);
+
+/* Flag: console code may call schedule() */
+static int console_may_schedule;
+
+#ifdef CONFIG_PRINTK_FUNC
+
+static char __log_buf[__LOG_BUF_LEN];
+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 */
+
+#if defined (CONFIG_PRINTK) || defined(CONFIG_PANIC_PRINTK)
+static char prt_buf[__LOG_BUF_LEN];
+#define PRT_BUF(idx) (prt_buf[(idx) & LOG_BUF_MASK])
+#endif
+
+#ifdef CONFIG_KEXEC
+/*
+ * This appends the listed symbols to /proc/vmcoreinfo
+ *
+ * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to
+ * obtain access to symbols that are otherwise very difficult to locate. These
+ * symbols are specifically used so that utilities can access and extract the
+ * dmesg log from a vmcore file after a crash.
+ */
+void log_buf_kexec_setup(void)
+{
+ VMCOREINFO_SYMBOL(log_buf);
+ VMCOREINFO_SYMBOL(log_end);
+ VMCOREINFO_SYMBOL(log_buf_len);
+ VMCOREINFO_SYMBOL(logged_chars);
+}
+#endif
+
+static int __init log_buf_len_setup(char *str)
+{
+ unsigned size = memparse(str, &str);
+ unsigned long flags;
+
+ if (size)
+ size = roundup_pow_of_two(size);
+ if (size > log_buf_len) {
+ unsigned start, dest_idx, offset;
+ char *new_log_buf;
+
+ new_log_buf = alloc_bootmem(size);
+ if (!new_log_buf) {
+ printk(KERN_WARNING "log_buf_len: allocation failed\n");
+ goto out;
+ }
+
+ spin_lock_irqsave(&logbuf_lock, flags);
+ log_buf_len = size;
+ log_buf = new_log_buf;
+
+ offset = start = min(con_start, log_start);
+ dest_idx = 0;
+ while (start != log_end) {
+ log_buf[dest_idx] = __log_buf[start & (__LOG_BUF_LEN - 1)];
+ start++;
+ dest_idx++;
+ }
+ log_start -= offset;
+ con_start -= offset;
+ log_end -= offset;
+ spin_unlock_irqrestore(&logbuf_lock, flags);
+
+ printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len);
+ }
+out:
+ return 1;
+}
+
+__setup("log_buf_len=", log_buf_len_setup);
+
+#ifdef CONFIG_BOOT_PRINTK_DELAY
+
+static unsigned int boot_delay; /* msecs delay after each printk during bootup */
+static unsigned long long printk_delay_msec; /* per msec, based on boot_delay */
+
+static int __init boot_delay_setup(char *str)
+{
+ unsigned long lpj;
+ unsigned long long loops_per_msec;
+
+ lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */
+ loops_per_msec = (unsigned long long)lpj / 1000 * HZ;
+
+ get_option(&str, &boot_delay);
+ if (boot_delay > 10 * 1000)
+ boot_delay = 0;
+
+ printk_delay_msec = loops_per_msec;
+ printk(KERN_DEBUG "boot_delay: %u, preset_lpj: %ld, lpj: %lu, "
+ "HZ: %d, printk_delay_msec: %llu\n",
+ boot_delay, preset_lpj, lpj, HZ, printk_delay_msec);
+ return 1;
+}
+__setup("boot_delay=", boot_delay_setup);
+
+static void boot_delay_msec(void)
+{
+ unsigned long long k;
+ unsigned long timeout;
+
+ if (boot_delay == 0 || system_state != SYSTEM_BOOTING)
+ return;
+
+ k = (unsigned long long)printk_delay_msec * boot_delay;
+
+ timeout = jiffies + msecs_to_jiffies(boot_delay);
+ while (k) {
+ k--;
+ cpu_relax();
+ /*
+ * use (volatile) jiffies to prevent
+ * compiler reduction; loop termination via jiffies
+ * is secondary and may or may not happen.
+ */
+ if (time_after(jiffies, timeout))
+ break;
+ touch_nmi_watchdog();
+ }
+}
+#else
+static inline void boot_delay_msec(void)
+{
+}
+#endif
+
+/*
+ * Commands to do_syslog:
+ *
+ * 0 -- Close the log. Currently a NOP.
+ * 1 -- Open the log. Currently a NOP.
+ * 2 -- Read from the log.
+ * 3 -- Read all messages remaining in the ring buffer.
+ * 4 -- Read and clear all messages remaining in the ring buffer
+ * 5 -- Clear ring buffer.
+ * 6 -- Disable printk's to console
+ * 7 -- Enable printk's to console
+ * 8 -- Set level of messages printed to console
+ * 9 -- Return number of unread characters in the log buffer
+ * 10 -- Return size of the log buffer
+ */
+int do_syslog(int type, char __user *buf, int len)
+{
+ unsigned i, j, limit, count;
+ int do_clear = 0;
+ char c;
+ int error = 0;
+
+ error = security_syslog(type);
+ if (error)
+ return error;
+
+ switch (type) {
+ case 0: /* Close log */
+ break;
+ case 1: /* Open log */
+ break;
+ case 2: /* Read from log */
+ error = -EINVAL;
+ if (!buf || len < 0)
+ goto out;
+ error = 0;
+ if (!len)
+ goto out;
+ if (!access_ok(VERIFY_WRITE, buf, len)) {
+ error = -EFAULT;
+ goto out;
+ }
+ error = wait_event_interruptible(log_wait,
+ (log_start - log_end));
+ if (error)
+ goto out;
+ i = 0;
+ spin_lock_irq(&logbuf_lock);
+ while (!error && (log_start != log_end) && i < len) {
+ c = LOG_BUF(log_start);
+ log_start++;
+ spin_unlock_irq(&logbuf_lock);
+ error = __put_user(c,buf);
+ buf++;
+ i++;
+ cond_resched();
+ spin_lock_irq(&logbuf_lock);
+ }
+ spin_unlock_irq(&logbuf_lock);
+ if (!error)
+ error = i;
+ break;
+ case 4: /* Read/clear last kernel messages */
+ do_clear = 1;
+ /* FALL THRU */
+ case 3: /* Read last kernel messages */
+ error = -EINVAL;
+ if (!buf || len < 0)
+ goto out;
+ error = 0;
+ if (!len)
+ goto out;
+ if (!access_ok(VERIFY_WRITE, buf, len)) {
+ error = -EFAULT;
+ goto out;
+ }
+ count = len;
+ if (count > log_buf_len)
+ count = log_buf_len;
+ 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);
+ spin_unlock_irq(&logbuf_lock);
+ error = __put_user(c,&buf[count-1-i]);
+ cond_resched();
+ spin_lock_irq(&logbuf_lock);
+ }
+ 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();
+ }
+ }
+ break;
+ case 5: /* Clear ring buffer */
+ logged_chars = 0;
+ break;
+ case 6: /* Disable logging to console */
+ console_loglevel = minimum_console_loglevel;
+ break;
+ case 7: /* Enable logging to console */
+ console_loglevel = default_console_loglevel;
+ break;
+ case 8: /* Set level of messages printed to console */
+ error = -EINVAL;
+ if (len < 1 || len > 8)
+ goto out;
+ if (len < minimum_console_loglevel)
+ len = minimum_console_loglevel;
+ console_loglevel = len;
+ error = 0;
+ break;
+ case 9: /* Number of chars in the log buffer */
+ error = log_end - log_start;
+ break;
+ case 10: /* Size of the log buffer */
+ error = log_buf_len;
+ break;
+ default:
+ error = -EINVAL;
+ break;
+ }
+out:
+ return error;
+}
+
+SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
+{
+ return do_syslog(type, buf, len);
+}
+
+/*
+ * Call the console drivers on a range of log_buf
+ */
+static void __call_console_drivers(unsigned start, unsigned end)
+{
+ struct console *con;
+
+ for (con = console_drivers; con; con = con->next) {
+ if ((con->flags & CON_ENABLED) && con->write &&
+ (cpu_online(smp_processor_id()) ||
+ (con->flags & CON_ANYTIME)))
+ {
+ #if defined(CONFIG_PRINTK) || defined(CONFIG_PANIC_PRINTK)
+ con->write(con, &PRT_BUF(start), end - start);
+ #else
+ //con->write(con, &LOG_BUF(start), end - start);
+ #endif
+ }
+ }
+}
+
+static int __read_mostly ignore_loglevel;
+
+static int __init ignore_loglevel_setup(char *str)
+{
+ ignore_loglevel = 1;
+ printk(KERN_INFO "debug: ignoring loglevel setting.\n");
+
+ return 0;
+}
+
+early_param("ignore_loglevel", ignore_loglevel_setup);
+
+/*
+ * 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);
+ }
+ }
+}
+
+/*
+ * Call the console drivers, asking them to write out
+ * log_buf[start] to log_buf[end - 1].
+ * The console_sem must be held.
+ */
+#if defined (CONFIG_PRINTK) || defined(CONFIG_PANIC_PRINTK)
+static void call_console_drivers(unsigned start, unsigned end)
+{
+ unsigned cur_index, start_print;
+ static int msg_level = -1;
+
+ BUG_ON(((int)(start - end)) > 0);
+
+ cur_index = start;
+ start_print = start;
+ while (cur_index != end) {
+ if (msg_level < 0 && ((end - cur_index) > 2) &&
+ PRT_BUF(cur_index + 0) == '<' &&
+ PRT_BUF(cur_index + 1) >= '0' &&
+ PRT_BUF(cur_index + 1) <= '7' &&
+ PRT_BUF(cur_index + 2) == '>') {
+ msg_level = PRT_BUF(cur_index + 1) - '0';
+ cur_index += 3;
+ start_print = cur_index;
+ }
+ while (cur_index != end) {
+ char c = PRT_BUF(cur_index);
+
+ 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;
+ }
+ }
+ }
+ _call_console_drivers(start_print, end, msg_level);
+}
+#else
+static void call_console_drivers(unsigned start, unsigned end)
+{
+ unsigned cur_index, start_print;
+ static int msg_level = -1;
+
+ BUG_ON(((int)(start - end)) > 0);
+
+ cur_index = start;
+ start_print = start;
+ while (cur_index != end) {
+ if (msg_level < 0 && ((end - cur_index) > 2) &&
+ LOG_BUF(cur_index + 0) == '<' &&
+ LOG_BUF(cur_index + 1) >= '0' &&
+ LOG_BUF(cur_index + 1) <= '7' &&
+ LOG_BUF(cur_index + 2) == '>') {
+ msg_level = LOG_BUF(cur_index + 1) - '0';
+ cur_index += 3;
+ start_print = cur_index;
+ }
+ while (cur_index != end) {
+ char c = LOG_BUF(cur_index);
+
+ 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;
+ }
+ }
+ }
+ _call_console_drivers(start_print, end, msg_level);
+}
+#endif
+
+static void emit_log_char(char c,int prt_to_con)
+{
+ 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++;
+
+#if defined(CONFIG_PRINTK) || defined(CONFIG_PANIC_PRINTK)
+ if (prt_to_con) {
+ PRT_BUF(prt_end) = c;
+ prt_end++;
+ if (prt_end - prt_start > __LOG_BUF_LEN)
+ prt_start = prt_end - __LOG_BUF_LEN;
+ }
+#endif
+}
+
+/*
+ * Zap console related locks when oopsing. Only zap at most once
+ * every 10 seconds, to leave time for slow consoles to print a
+ * full oops.
+ */
+static void zap_locks(void)
+{
+ static unsigned long oops_timestamp;
+
+ if (time_after_eq(jiffies, oops_timestamp) &&
+ !time_after(jiffies, oops_timestamp + 30 * HZ))
+ return;
+
+ oops_timestamp = jiffies;
+
+ /* If a crash is occurring, make sure we can't deadlock */
+ spin_lock_init(&logbuf_lock);
+ /* And make sure that we print immediately */
+ init_MUTEX(&console_sem);
+}
+
+#if defined(CONFIG_PRINTK_TIME)
+static int printk_time = 1;
+#else
+static int printk_time = 0;
+#endif
+module_param_named(time, printk_time, 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)
+{
+ struct console *con;
+
+ for (con = console_drivers; con; con = con->next)
+ if (con->flags & CON_ANYTIME)
+ return 1;
+
+ 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_sem. 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 release_console_sem() and will send it to the
+ * consoles before releasing the semaphore.
+ *
+ * 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.
+ */
+
+#if defined (CONFIG_PRINTK)
+asmlinkage int printk(const char *fmt, ...)
+#elif defined(CONFIG_PANIC_PRINTK)
+asmlinkage int panic_printk(const char *fmt, ...)
+#else
+# error "CONFIG_PRINTK or CONFIG_PANIC_PRINTK must be defined"
+#endif
+{
+ va_list args;
+ int r;
+
+ 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?
+ *
+ * Console drivers may assume that per-cpu resources have
+ * been allocated. So unless they're explicitly marked as
+ * being able to cope (CON_ANYTIME) don't call them until
+ * this CPU is officially up.
+ */
+static inline int can_use_console(unsigned int cpu)
+{
+ return cpu_online(cpu) || have_callable_console();
+}
+
+/*
+ * Try to get console ownership to actually show the kernel
+ * messages from a 'printk'. Return true (and with the
+ * console_semaphore held, and 'console_locked' set) if it
+ * is successful, false otherwise.
+ *
+ * This gets called with the 'logbuf_lock' spinlock held and
+ * interrupts disabled. It should return with 'lockbuf_lock'
+ * released but interrupts still disabled.
+ */
+static int acquire_console_semaphore_for_printk(unsigned int cpu)
+{
+ int retval = 0;
+
+ if (!try_acquire_console_sem()) {
+ retval = 1;
+
+ /*
+ * If we can't use the console, we need to release
+ * the console semaphore by hand to avoid flushing
+ * the buffer. We need to hold the console semaphore
+ * in order to do this test safely.
+ */
+ if (!can_use_console(cpu)) {
+ console_locked = 0;
+ up(&console_sem);
+ retval = 0;
+ }
+ }
+ printk_cpu = UINT_MAX;
+ spin_unlock(&logbuf_lock);
+ return retval;
+}
+
+#if defined (CONFIG_PRINTK_FUNC)
+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];
+#if defined (CONFIG_PRINTK) || defined(CONFIG_PANIC_PRINTK)
+asmlinkage int vprintk(const char *fmt, va_list args)
+{
+ int printed_len = 0;
+ int current_log_level = default_message_loglevel;
+ unsigned long flags;
+ int this_cpu;
+ char *p;
+
+ boot_delay_msec();
+
+ preempt_disable();
+ /* This stops the holder of console_sem just where we want him */
+ raw_local_irq_save(flags);
+ this_cpu = smp_processor_id();
+
+ /*
+ * Ouch, printk recursed into itself!
+ */
+ if (unlikely(printk_cpu == this_cpu)) {
+ /*
+ * If a crash is occurring during printk() on this CPU,
+ * then try to get the crash message out but make sure
+ * we can't deadlock. Otherwise just return to avoid the
+ * recursion and return - but flag the recursion so that
+ * it can be printed at the next appropriate moment:
+ */
+ if (!oops_in_progress) {
+ recursion_bug = 1;
+ goto out_restore_irqs;
+ }
+ zap_locks();
+ }
+
+ lockdep_off();
+ spin_lock(&logbuf_lock);
+ printk_cpu = this_cpu;
+
+ if (recursion_bug) {
+ 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);
+
+
+ /*
+ * Copy the output into log_buf. If the caller didn't provide
+ * appropriate log level tags, we insert them here
+ */
+ for (p = printk_buf; *p; p++) {
+ if (new_text_line) {
+ /* If a token, set current_log_level and skip over */
+ if (p[0] == '<' && p[1] >= '0' && p[1] <= '7' &&
+ p[2] == '>') {
+ current_log_level = p[1] - '0';
+ p += 3;
+ printed_len -= 3;
+ }
+
+ /* Always output the token */
+ emit_log_char('<',1);
+ emit_log_char(current_log_level + '0',1);
+ emit_log_char('>',1);
+ printed_len += 3;
+ new_text_line = 0;
+
+ if (printk_time) {
+ /* Follow the token with the time */
+ 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,1);
+ printed_len += tlen;
+ }
+
+ if (!*p)
+ break;
+ }
+
+ emit_log_char(*p,1);
+ if (*p == '\n')
+ new_text_line = 1;
+ }
+
+ /*
+ * 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).
+ *
+ * The acquire_console_semaphore_for_printk() function
+ * will release 'logbuf_lock' regardless of whether it
+ * actually gets the semaphore or not.
+ */
+ if (acquire_console_semaphore_for_printk(this_cpu))
+ release_console_sem();
+
+ lockdep_on();
+out_restore_irqs:
+ raw_local_irq_restore(flags);
+
+ preempt_enable();
+ return printed_len;
+}
+EXPORT_SYMBOL(printk);
+EXPORT_SYMBOL(vprintk);
+#if defined(CONFIG_PANIC_PRINTK)
+EXPORT_SYMBOL(panic_printk);
+#endif
+
+#endif /*endof CONFIG_PRINTK*/
+
+asmlinkage int scrlog_vprintk(const char *fmt, va_list args)
+{
+ int printed_len = 0;
+ int current_log_level = default_message_loglevel;
+ unsigned long flags;
+ int this_cpu;
+ char *p;
+
+ boot_delay_msec();
+
+ preempt_disable();
+ /* This stops the holder of console_sem just where we want him */
+ raw_local_irq_save(flags);
+ this_cpu = smp_processor_id();
+
+ /*
+ * Ouch, printk recursed into itself!
+ */
+ if (unlikely(printk_cpu == this_cpu)) {
+ /*
+ * If a crash is occurring during printk() on this CPU,
+ * then try to get the crash message out but make sure
+ * we can't deadlock. Otherwise just return to avoid the
+ * recursion and return - but flag the recursion so that
+ * it can be printed at the next appropriate moment:
+ */
+ if (!oops_in_progress) {
+ recursion_bug = 1;
+ goto out_restore_irqs;
+ }
+ zap_locks();
+ }
+
+ lockdep_off();
+ spin_lock(&logbuf_lock);
+ printk_cpu = this_cpu;
+
+ if (recursion_bug) {
+ 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);
+
+
+ /*
+ * Copy the output into log_buf. If the caller didn't provide
+ * appropriate log level tags, we insert them here
+ */
+ for (p = printk_buf; *p; p++) {
+ if (new_text_line) {
+ /* If a token, set current_log_level and skip over */
+ if (p[0] == '<' && p[1] >= '0' && p[1] <= '7' &&
+ p[2] == '>') {
+ current_log_level = p[1] - '0';
+ p += 3;
+ printed_len -= 3;
+ }
+
+ /* Always output the token */
+ emit_log_char('<',0);
+ emit_log_char(current_log_level + '0',0);
+ emit_log_char('>',0);
+ printed_len += 3;
+ new_text_line = 0;
+
+ if (printk_time) {
+ /* Follow the token with the time */
+ 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,0);
+ printed_len += tlen;
+ }
+
+ if (!*p)
+ break;
+ }
+
+ emit_log_char(*p,0);
+ if (*p == '\n')
+ new_text_line = 1;
+ }
+
+ /*
+ * 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).
+ *
+ * The acquire_console_semaphore_for_printk() function
+ * will release 'logbuf_lock' regardless of whether it
+ * actually gets the semaphore or not.
+ */
+ if (acquire_console_semaphore_for_printk(this_cpu))
+ release_console_sem();
+
+ lockdep_on();
+out_restore_irqs:
+ raw_local_irq_restore(flags);
+
+ preempt_enable();
+ return printed_len;
+}
+
+asmlinkage int scrlog_printk(const char *fmt, ...)
+{
+ va_list args;
+ int r;
+
+ va_start(args, fmt);
+ r = scrlog_vprintk(fmt, args);
+ va_end(args);
+
+ return r;
+}
+
+EXPORT_SYMBOL(scrlog_vprintk);
+EXPORT_SYMBOL(scrlog_printk);
+
+#endif /*end CONFIG_PRINTK_FUNC*/
+
+#else
+
+static void call_console_drivers(unsigned start, unsigned end)
+{
+}
+
+#endif
+
+static int __add_preferred_console(char *name, int idx, char *options,
+ char *brl_options)
+{
+ struct console_cmdline *c;
+ int i;
+
+ /*
+ * See if this tty is not yet registered, and
+ * if we have a slot free.
+ */
+ for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
+ if (strcmp(console_cmdline[i].name, name) == 0 &&
+ console_cmdline[i].index == idx) {
+ if (!brl_options)
+ selected_console = i;
+ return 0;
+ }
+ if (i == MAX_CMDLINECONSOLES)
+ return -E2BIG;
+ if (!brl_options)
+ selected_console = i;
+ c = &console_cmdline[i];
+ strlcpy(c->name, name, sizeof(c->name));
+ c->options = options;
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ c->brl_options = brl_options;
+#endif
+ c->index = idx;
+ return 0;
+}
+/*
+ * Set up a list of consoles. Called from init/main.c
+ */
+static int __init console_setup(char *str)
+{
+ char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */
+ char *s, *options, *brl_options = NULL;
+ int idx;
+
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ if (!memcmp(str, "brl,", 4)) {
+ brl_options = "";
+ str += 4;
+ } else if (!memcmp(str, "brl=", 4)) {
+ brl_options = str + 4;
+ str = strchr(brl_options, ',');
+ if (!str) {
+ printk(KERN_ERR "need port name after brl=\n");
+ return 1;
+ }
+ *(str++) = 0;
+ }
+#endif
+
+ /*
+ * Decode str into name, index, options.
+ */
+ if (str[0] >= '0' && str[0] <= '9') {
+ strcpy(buf, "ttyS");
+ strncpy(buf + 4, str, sizeof(buf) - 5);
+ } else {
+ strncpy(buf, str, sizeof(buf) - 1);
+ }
+ buf[sizeof(buf) - 1] = 0;
+ if ((options = strchr(str, ',')) != NULL)
+ *(options++) = 0;
+#ifdef __sparc__
+ if (!strcmp(str, "ttya"))
+ strcpy(buf, "ttyS0");
+ if (!strcmp(str, "ttyb"))
+ strcpy(buf, "ttyS1");
+#endif
+ for (s = buf; *s; s++)
+ if ((*s >= '0' && *s <= '9') || *s == ',')
+ break;
+ idx = simple_strtoul(s, NULL, 10);
+ *s = 0;
+
+ __add_preferred_console(buf, idx, options, brl_options);
+ console_set_on_cmdline = 1;
+ return 1;
+}
+__setup("console=", console_setup);
+
+/**
+ * add_preferred_console - add a device to the list of preferred consoles.
+ * @name: device name
+ * @idx: device index
+ * @options: options for this console
+ *
+ * The last preferred console added will be used for kernel messages
+ * and stdin/out/err for init. Normally this is used by console_setup
+ * above to handle user-supplied console arguments; however it can also
+ * be used by arch-specific code either to override the user or more
+ * commonly to provide a default console (ie from PROM variables) when
+ * the user has not supplied one.
+ */
+int add_preferred_console(char *name, int idx, char *options)
+{
+ return __add_preferred_console(name, idx, options, NULL);
+}
+
+int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options)
+{
+ struct console_cmdline *c;
+ int i;
+
+ for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
+ if (strcmp(console_cmdline[i].name, name) == 0 &&
+ console_cmdline[i].index == idx) {
+ c = &console_cmdline[i];
+ strlcpy(c->name, name_new, sizeof(c->name));
+ c->name[sizeof(c->name) - 1] = 0;
+ c->options = options;
+ c->index = idx_new;
+ return i;
+ }
+ /* not found */
+ return -1;
+}
+
+int console_suspend_enabled = 1;
+EXPORT_SYMBOL(console_suspend_enabled);
+
+static int __init console_suspend_disable(char *str)
+{
+ console_suspend_enabled = 0;
+ return 1;
+}
+__setup("no_console_suspend", console_suspend_disable);
+
+/**
+ * suspend_console - suspend the console subsystem
+ *
+ * This disables printk() while we go into suspend states
+ */
+void suspend_console(void)
+{
+ if (!console_suspend_enabled)
+ return;
+ printk("Suspending console(s) (use no_console_suspend to debug)\n");
+ acquire_console_sem();
+ console_suspended = 1;
+ up(&console_sem);
+}
+
+void resume_console(void)
+{
+ if (!console_suspend_enabled)
+ return;
+ down(&console_sem);
+ console_suspended = 0;
+ release_console_sem();
+}
+
+/**
+ * acquire_console_sem - lock the console system for exclusive use.
+ *
+ * Acquires a semaphore which guarantees that the caller has
+ * exclusive access to the console system and the console_drivers list.
+ *
+ * Can sleep, returns nothing.
+ */
+void acquire_console_sem(void)
+{
+ BUG_ON(in_interrupt());
+ down(&console_sem);
+ if (console_suspended)
+ return;
+ console_locked = 1;
+ console_may_schedule = 1;
+}
+EXPORT_SYMBOL(acquire_console_sem);
+
+int try_acquire_console_sem(void)
+{
+ if (down_trylock(&console_sem))
+ return -1;
+ if (console_suspended) {
+ up(&console_sem);
+ return -1;
+ }
+ console_locked = 1;
+ console_may_schedule = 0;
+ return 0;
+}
+EXPORT_SYMBOL(try_acquire_console_sem);
+
+int is_console_locked(void)
+{
+ return console_locked;
+}
+
+static DEFINE_PER_CPU(int, printk_pending);
+
+void printk_tick(void)
+{
+ if (__get_cpu_var(printk_pending)) {
+ __get_cpu_var(printk_pending) = 0;
+ wake_up_interruptible(&log_wait);
+ }
+}
+
+int printk_needs_cpu(int cpu)
+{
+ return per_cpu(printk_pending, cpu);
+}
+
+void wake_up_klogd(void)
+{
+ if (waitqueue_active(&log_wait))
+ __raw_get_cpu_var(printk_pending) = 1;
+}
+
+/**
+ * release_console_sem - unlock the console system
+ *
+ * Releases the semaphore which the caller holds on the console system
+ * and the console driver list.
+ *
+ * While the semaphore was held, console output may have been buffered
+ * by printk(). If this is the case, release_console_sem() emits
+ * the output prior to releasing the semaphore.
+ *
+ * If there is output waiting for klogd, we wake it up.
+ *
+ * release_console_sem() may be called from any context.
+ */
+void release_console_sem(void)
+{
+ unsigned long flags;
+ unsigned _con_start, _log_end;
+ unsigned wake_klogd = 0;
+
+ if (console_suspended) {
+ up(&console_sem);
+ return;
+ }
+
+ console_may_schedule = 0;
+
+ for ( ; ; ) {
+ spin_lock_irqsave(&logbuf_lock, flags);
+ wake_klogd |= log_start - log_end;
+#if defined(CONFIG_PRINTK) || defined(CONFIG_PANIC_PRINTK)
+ if (prt_start == prt_end)
+ break;
+ _con_start = prt_start;
+ _log_end = prt_end;
+ prt_start = prt_end;
+#else
+ if (con_start == log_end)
+ break; /* Nothing to print */
+ _con_start = con_start;
+ _log_end = log_end;
+ con_start = log_end; /* Flush */
+#endif
+ spin_unlock(&logbuf_lock);
+ stop_critical_timings(); /* don't trace print latency */
+ call_console_drivers(_con_start, _log_end);
+ start_critical_timings();
+ local_irq_restore(flags);
+ }
+ console_locked = 0;
+ up(&console_sem);
+ spin_unlock_irqrestore(&logbuf_lock, flags);
+ if (wake_klogd)
+ wake_up_klogd();
+}
+EXPORT_SYMBOL(release_console_sem);
+
+/**
+ * console_conditional_schedule - yield the CPU if required
+ *
+ * If the console code is currently allowed to sleep, and
+ * if this CPU should yield the CPU to another task, do
+ * so here.
+ *
+ * Must be called within acquire_console_sem().
+ */
+void __sched console_conditional_schedule(void)
+{
+ if (console_may_schedule)
+ cond_resched();
+}
+EXPORT_SYMBOL(console_conditional_schedule);
+
+void console_print(const char *s)
+{
+ printk(KERN_EMERG "%s", s);
+}
+EXPORT_SYMBOL(console_print);
+
+void console_unblank(void)
+{
+ struct console *c;
+
+ /*
+ * console_unblank can no longer be called in interrupt context unless
+ * oops_in_progress is set to 1..
+ */
+ if (oops_in_progress) {
+ if (down_trylock(&console_sem) != 0)
+ return;
+ } else
+ acquire_console_sem();
+
+ console_locked = 1;
+ console_may_schedule = 0;
+ for (c = console_drivers; c != NULL; c = c->next)
+ if ((c->flags & CON_ENABLED) && c->unblank)
+ c->unblank();
+ release_console_sem();
+}
+
+/*
+ * Return the console tty driver structure and its associated index
+ */
+struct tty_driver *console_device(int *index)
+{
+ struct console *c;
+ struct tty_driver *driver = NULL;
+
+ acquire_console_sem();
+ for (c = console_drivers; c != NULL; c = c->next) {
+ if (!c->device)
+ continue;
+ driver = c->device(c, index);
+ if (driver)
+ break;
+ }
+ release_console_sem();
+ return driver;
+}
+
+/*
+ * Prevent further output on the passed console device so that (for example)
+ * serial drivers can disable console output before suspending a port, and can
+ * re-enable output afterwards.
+ */
+void console_stop(struct console *console)
+{
+ acquire_console_sem();
+ console->flags &= ~CON_ENABLED;
+ release_console_sem();
+}
+EXPORT_SYMBOL(console_stop);
+
+void console_start(struct console *console)
+{
+ acquire_console_sem();
+ console->flags |= CON_ENABLED;
+ release_console_sem();
+}
+EXPORT_SYMBOL(console_start);
+
+/*
+ * The console driver calls this routine during kernel initialization
+ * to register the console printing procedure with printk() and to
+ * print any messages that were printed by the kernel before the
+ * console driver was initialized.
+ */
+void register_console(struct console *console)
+{
+ int i;
+ unsigned long flags;
+ struct console *bootconsole = NULL;
+
+ if (console_drivers) {
+ if (console->flags & CON_BOOT)
+ return;
+ if (console_drivers->flags & CON_BOOT)
+ bootconsole = console_drivers;
+ }
+
+ if (preferred_console < 0 || bootconsole || !console_drivers)
+ preferred_console = selected_console;
+
+ if (console->early_setup)
+ console->early_setup();
+
+ /*
+ * See if we want to use this console driver. If we
+ * didn't select a console we take the first one
+ * that registers here.
+ */
+ if (preferred_console < 0) {
+ if (console->index < 0)
+ console->index = 0;
+ if (console->setup == NULL ||
+ console->setup(console, NULL) == 0) {
+ console->flags |= CON_ENABLED;
+ if (console->device) {
+ console->flags |= CON_CONSDEV;
+ preferred_console = 0;
+ }
+ }
+ }
+
+ /*
+ * See if this console matches one we selected on
+ * the command line.
+ */
+ for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0];
+ i++) {
+ if (strcmp(console_cmdline[i].name, console->name) != 0)
+ continue;
+ if (console->index >= 0 &&
+ console->index != console_cmdline[i].index)
+ continue;
+ if (console->index < 0)
+ console->index = console_cmdline[i].index;
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ if (console_cmdline[i].brl_options) {
+ console->flags |= CON_BRL;
+ braille_register_console(console,
+ console_cmdline[i].index,
+ console_cmdline[i].options,
+ console_cmdline[i].brl_options);
+ return;
+ }
+#endif
+ if (console->setup &&
+ console->setup(console, console_cmdline[i].options) != 0)
+ break;
+ console->flags |= CON_ENABLED;
+ console->index = console_cmdline[i].index;
+ if (i == selected_console) {
+ console->flags |= CON_CONSDEV;
+ preferred_console = selected_console;
+ }
+ break;
+ }
+
+ if (!(console->flags & CON_ENABLED))
+ return;
+
+ if (bootconsole && (console->flags & CON_CONSDEV)) {
+ printk(KERN_INFO "console handover: boot [%s%d] -> real [%s%d]\n",
+ bootconsole->name, bootconsole->index,
+ console->name, console->index);
+ unregister_console(bootconsole);
+ console->flags &= ~CON_PRINTBUFFER;
+ } else {
+ printk(KERN_INFO "console [%s%d] enabled\n",
+ console->name, console->index);
+ }
+
+ /*
+ * Put this console in the list - keep the
+ * preferred driver at the head of the list.
+ */
+ acquire_console_sem();
+ if ((console->flags & CON_CONSDEV) || console_drivers == NULL) {
+ console->next = console_drivers;
+ console_drivers = console;
+ if (console->next)
+ console->next->flags &= ~CON_CONSDEV;
+ } else {
+ console->next = console_drivers->next;
+ console_drivers->next = console;
+ }
+ if (console->flags & CON_PRINTBUFFER) {
+ /*
+ * release_console_sem() will print out the buffered messages
+ * for us.
+ */
+ spin_lock_irqsave(&logbuf_lock, flags);
+ con_start = log_start;
+ spin_unlock_irqrestore(&logbuf_lock, flags);
+ }
+ release_console_sem();
+}
+EXPORT_SYMBOL(register_console);
+
+int unregister_console(struct console *console)
+{
+ struct console *a, *b;
+ int res = 1;
+
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ if (console->flags & CON_BRL)
+ return braille_unregister_console(console);
+#endif
+
+ acquire_console_sem();
+ if (console_drivers == console) {
+ console_drivers=console->next;
+ res = 0;
+ } else if (console_drivers) {
+ for (a=console_drivers->next, b=console_drivers ;
+ a; b=a, a=b->next) {
+ if (a == console) {
+ b->next = a->next;
+ res = 0;
+ break;
+ }
+ }
+ }
+
+ /*
+ * If this isn't the last console and it has CON_CONSDEV set, we
+ * need to set it on the next preferred console.
+ */
+ if (console_drivers != NULL && console->flags & CON_CONSDEV)
+ console_drivers->flags |= CON_CONSDEV;
+
+ release_console_sem();
+ return res;
+}
+EXPORT_SYMBOL(unregister_console);
+
+static int __init disable_boot_consoles(void)
+{
+ if (console_drivers != NULL) {
+ if (console_drivers->flags & CON_BOOT) {
+ printk(KERN_INFO "turn off boot console %s%d\n",
+ console_drivers->name, console_drivers->index);
+ return unregister_console(console_drivers);
+ }
+ }
+ return 0;
+}
+late_initcall(disable_boot_consoles);
+
+#if defined(CONFIG_PRINTK) && !defined(CONFIG_PANIC_PRINTK)
+
+/*
+ * printk rate limiting, lifted from the networking subsystem.
+ *
+ * This enforces a rate limit: not more than 10 kernel messages
+ * every 5s to make a denial-of-service attack impossible.
+ */
+DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10);
+
+int printk_ratelimit(void)
+{
+ return __ratelimit(&printk_ratelimit_state);
+}
+EXPORT_SYMBOL(printk_ratelimit);
+
+/**
+ * printk_timed_ratelimit - caller-controlled printk ratelimiting
+ * @caller_jiffies: pointer to caller's state
+ * @interval_msecs: minimum interval between prints
+ *
+ * printk_timed_ratelimit() returns true if more than @interval_msecs
+ * milliseconds have elapsed since the last time printk_timed_ratelimit()
+ * returned true.
+ */
+bool printk_timed_ratelimit(unsigned long *caller_jiffies,
+ unsigned int interval_msecs)
+{
+ if (*caller_jiffies == 0
+ || !time_in_range(jiffies, *caller_jiffies,
+ *caller_jiffies
+ + msecs_to_jiffies(interval_msecs))) {
+ *caller_jiffies = jiffies;
+ return true;
+ }
+ return false;
+}
+EXPORT_SYMBOL(printk_timed_ratelimit);
+#endif