6e3fbee5f1
So why are we calling smp_send_stop from machine_halt? We don't. Looking more closely at the bug report the problem here is that halt -p is called which triggers not a halt but an attempt to power off. machine_power_off calls machine_shutdown which calls smp_send_stop. If pm_power_off is set we should never make it out machine_power_off to the call of do_exit. So pm_power_off must not be set in this case. When pm_power_off is not set we expect machine_power_off to devolve into machine_halt. So how do we fix this? Playing too much with smp_send_stop is dangerous because it must also be safe to be called from panic. It looks like the obviously correct fix is to only call machine_shutdown when pm_power_off is defined. Doing that will make Andi's assumption about not scheduling true and generally simplify what must be supported. This turns machine_power_off into a noop like machine_halt when pm_power_off is not defined. If the expected behavior is that sys_reboot(LINUX_REBOOT_CMD_POWER_OFF) becomes sys_reboot(LINUX_REBOOT_CMD_HALT) if pm_power_off is NULL this is not quite a comprehensive fix as we pass a different parameter to the reboot notifier and we set system_state to a different value before calling device_shutdown(). Unfortunately any fix more comprehensive I can think of is not obviously correct. The core problem is that there is no architecture independent way to detect if machine_power will become a noop, without calling it. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
166 lines
2.9 KiB
C
166 lines
2.9 KiB
C
/* Various gunk just to reboot the machine. */
|
|
#include <linux/module.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/init.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/ctype.h>
|
|
#include <linux/string.h>
|
|
#include <linux/pm.h>
|
|
#include <asm/io.h>
|
|
#include <asm/kdebug.h>
|
|
#include <asm/delay.h>
|
|
#include <asm/hw_irq.h>
|
|
#include <asm/system.h>
|
|
#include <asm/pgtable.h>
|
|
#include <asm/tlbflush.h>
|
|
#include <asm/apic.h>
|
|
|
|
/*
|
|
* Power off function, if any
|
|
*/
|
|
void (*pm_power_off)(void);
|
|
|
|
static long no_idt[3];
|
|
static enum {
|
|
BOOT_TRIPLE = 't',
|
|
BOOT_KBD = 'k'
|
|
} reboot_type = BOOT_KBD;
|
|
static int reboot_mode = 0;
|
|
int reboot_force;
|
|
|
|
/* reboot=t[riple] | k[bd] [, [w]arm | [c]old]
|
|
warm Don't set the cold reboot flag
|
|
cold Set the cold reboot flag
|
|
triple Force a triple fault (init)
|
|
kbd Use the keyboard controller. cold reset (default)
|
|
force Avoid anything that could hang.
|
|
*/
|
|
static int __init reboot_setup(char *str)
|
|
{
|
|
for (;;) {
|
|
switch (*str) {
|
|
case 'w':
|
|
reboot_mode = 0x1234;
|
|
break;
|
|
|
|
case 'c':
|
|
reboot_mode = 0;
|
|
break;
|
|
|
|
case 't':
|
|
case 'b':
|
|
case 'k':
|
|
reboot_type = *str;
|
|
break;
|
|
case 'f':
|
|
reboot_force = 1;
|
|
break;
|
|
}
|
|
if((str = strchr(str,',')) != NULL)
|
|
str++;
|
|
else
|
|
break;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
__setup("reboot=", reboot_setup);
|
|
|
|
static inline void kb_wait(void)
|
|
{
|
|
int i;
|
|
|
|
for (i=0; i<0x10000; i++)
|
|
if ((inb_p(0x64) & 0x02) == 0)
|
|
break;
|
|
}
|
|
|
|
void machine_shutdown(void)
|
|
{
|
|
unsigned long flags;
|
|
/* Stop the cpus and apics */
|
|
#ifdef CONFIG_SMP
|
|
int reboot_cpu_id;
|
|
|
|
/* The boot cpu is always logical cpu 0 */
|
|
reboot_cpu_id = 0;
|
|
|
|
/* Make certain the cpu I'm about to reboot on is online */
|
|
if (!cpu_isset(reboot_cpu_id, cpu_online_map)) {
|
|
reboot_cpu_id = smp_processor_id();
|
|
}
|
|
|
|
/* Make certain I only run on the appropriate processor */
|
|
set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
|
|
|
|
/* O.K Now that I'm on the appropriate processor,
|
|
* stop all of the others.
|
|
*/
|
|
smp_send_stop();
|
|
#endif
|
|
|
|
local_irq_save(flags);
|
|
|
|
#ifndef CONFIG_SMP
|
|
disable_local_APIC();
|
|
#endif
|
|
|
|
disable_IO_APIC();
|
|
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
void machine_emergency_restart(void)
|
|
{
|
|
int i;
|
|
|
|
/* Tell the BIOS if we want cold or warm reboot */
|
|
*((unsigned short *)__va(0x472)) = reboot_mode;
|
|
|
|
for (;;) {
|
|
/* Could also try the reset bit in the Hammer NB */
|
|
switch (reboot_type) {
|
|
case BOOT_KBD:
|
|
for (i=0; i<10; i++) {
|
|
kb_wait();
|
|
udelay(50);
|
|
outb(0xfe,0x64); /* pulse reset low */
|
|
udelay(50);
|
|
}
|
|
|
|
case BOOT_TRIPLE:
|
|
__asm__ __volatile__("lidt (%0)": :"r" (&no_idt));
|
|
__asm__ __volatile__("int3");
|
|
|
|
reboot_type = BOOT_KBD;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void machine_restart(char * __unused)
|
|
{
|
|
printk("machine restart\n");
|
|
|
|
if (!reboot_force) {
|
|
machine_shutdown();
|
|
}
|
|
machine_emergency_restart();
|
|
}
|
|
|
|
void machine_halt(void)
|
|
{
|
|
}
|
|
|
|
void machine_power_off(void)
|
|
{
|
|
if (pm_power_off) {
|
|
if (!reboot_force) {
|
|
machine_shutdown();
|
|
}
|
|
pm_power_off();
|
|
}
|
|
}
|
|
|