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ARM: add option to flush console before reboot

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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>
This commit is contained in:
Dima Zavin
2011-08-23 15:56:50 -07:00
committed by Colin Cross
parent 847bb6f2bc
commit 2d1fe03b4f
2 changed files with 39 additions and 0 deletions
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9
arch/arm/Kconfig
View File

@@ -1876,6 +1876,15 @@ 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"

30
arch/arm/kernel/process.c
View File

@@ -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 @@ __setup("hlt", hlt_setup);
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 @@ void machine_restart(char *cmd)
{
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 */