ARM: add option to flush console before reboot

If the console_lock was held while the system was rebooted, the messages
in the temporary logbuffer would not have propogated to all the console
drivers.

This force releases the console lock if it failed to be acquired.

Change-Id: I193dcf7b968be17966833e50b8b8bc70d5d9fe89
Signed-off-by: Dima Zavin <dima@android.com>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 9adc278a22abb36df1bdfdacd1db1fe240f8d0fb..81f0b93a0cbbc4c635a198861bbc51700e65f2dd 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1671,6 +1671,15 @@ config DEPRECATED_PARAM_STRUCT
          This was deprecated in 2001 and announced to live on for 5 years.
          Some old boot loaders still use this way.
 
+config ARM_FLUSH_CONSOLE_ON_RESTART
+       bool "Force flush the console on restart"
+       help
+         If the console is locked while the system is rebooted, the messages
+         in the temporary logbuffer would not have propogated to all the
+         console drivers. This option forces the console lock to be
+         released if it failed to be acquired, which will cause all the
+         pending messages to be flushed.
+
 endmenu
 
 menu "Boot options"

diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 919de7c84f761586a8c48280fc5272e98913451f..34fca2e272cde6a7862b1c502c9462391b195ce9 100644 (file)
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -30,6 +30,7 @@
 #include <linux/uaccess.h>
 #include <linux/random.h>
 #include <linux/hw_breakpoint.h>
+#include <linux/console.h>
 
 #include <asm/cacheflush.h>
 #include <asm/processor.h>
@@ -90,8 +91,37 @@ static int __init hlt_setup(char *__unused)
 __setup("nohlt", nohlt_setup);
 __setup("hlt", hlt_setup);
 
+#ifdef CONFIG_ARM_FLUSH_CONSOLE_ON_RESTART
+void arm_machine_flush_console(void)
+{
+       printk("\n");
+       pr_emerg("Restarting %s\n", linux_banner);
+       if (console_trylock()) {
+               console_unlock();
+               return;
+       }
+
+       mdelay(50);
+
+       local_irq_disable();
+       if (!console_trylock())
+               pr_emerg("arm_restart: Console was locked! Busting\n");
+       else
+               pr_emerg("arm_restart: Console was locked!\n");
+       console_unlock();
+}
+#else
+void arm_machine_flush_console(void)
+{
+}
+#endif
+
 void arm_machine_restart(char mode, const char *cmd)
 {
+       /* Flush the console to make sure all the relevant messages make it
+        * out to the console drivers */
+       arm_machine_flush_console();
+
        /* Disable interrupts first */
        local_irq_disable();
        local_fiq_disable();