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 cf006d4..6705b23 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1876,6 +1876,15 @@
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 4df9c38..0e977fc 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -31,6 +31,7 @@
#include <linux/random.h>
#include <linux/hw_breakpoint.h>
#include <linux/cpuidle.h>
+#include <linux/console.h>
#include <asm/cacheflush.h>
#include <asm/leds.h>
@@ -92,6 +93,31 @@
extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
typedef void (*phys_reset_t)(unsigned long);
+#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
+
/*
* A temporary stack to use for CPU reset. This is static so that we
* don't clobber it with the identity mapping. When running with this
@@ -281,6 +307,10 @@
{
machine_shutdown();
+ /* Flush the console to make sure all the relevant messages make it
+ * out to the console drivers */
+ arm_machine_flush_console();
+
arm_pm_restart(reboot_mode, cmd);
/* Give a grace period for failure to restart of 1s */