X-Git-Url: https://git.stricted.de/?a=blobdiff_plain;f=kernel%2Fprintk.c;h=b2b5c3a22a36b302da177fafae653740f7eeeddf;hb=a4d63e729edad704af95e5f2a56e8c8eaaa5216b;hp=8451dfc31d25b4e0e6903e84a55de230fb5363e2;hpb=cb00e99c0abd844b884c64c6b54aa3b7d345ebb1;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git

diff --git a/kernel/printk.c b/kernel/printk.c
index 8451dfc31d25..b2b5c3a22a36 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -22,6 +22,8 @@
 #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() */
@@ -162,6 +164,61 @@ out:
 
 __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:
  *
@@ -527,6 +584,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 	static char printk_buf[1024];
 	static int log_level_unknown = 1;
 
+	boot_delay_msec();
+
 	preempt_disable();
 	if (unlikely(oops_in_progress) && printk_cpu == smp_processor_id())
 		/* If a crash is occurring during printk() on this CPU,