[deliverable/linux.git] / arch / i386 / kernel / reboot.c

/*
 *  linux/arch/i386/kernel/reboot.c
 */

#include <linux/config.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/mc146818rtc.h>
#include <linux/efi.h>
#include <linux/dmi.h>
#include <linux/ctype.h>
#include <linux/pm.h>
#include <asm/uaccess.h>
#include <asm/apic.h>
#include <asm/desc.h>
#include "mach_reboot.h"
#include <linux/reboot_fixups.h>

/*
 * Power off function, if any
 */
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);

static int reboot_mode;
static int reboot_thru_bios;

#ifdef CONFIG_SMP
static int reboot_cpu = -1;
#endif
static int __init reboot_setup(char *str)
{
	while(1) {
		switch (*str) {
		case 'w': /* "warm" reboot (no memory testing etc) */
			reboot_mode = 0x1234;
			break;
		case 'c': /* "cold" reboot (with memory testing etc) */
			reboot_mode = 0x0;
			break;
		case 'b': /* "bios" reboot by jumping through the BIOS */
			reboot_thru_bios = 1;
			break;
		case 'h': /* "hard" reboot by toggling RESET and/or crashing the CPU */
			reboot_thru_bios = 0;
			break;
#ifdef CONFIG_SMP
		case 's': /* "smp" reboot by executing reset on BSP or other CPU*/
			if (isdigit(*(str+1))) {
				reboot_cpu = (int) (*(str+1) - '0');
				if (isdigit(*(str+2)))
					reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
			}
				/* we will leave sorting out the final value 
				when we are ready to reboot, since we might not
 				have set up boot_cpu_id or smp_num_cpu */
			break;
#endif
		}
		if((str = strchr(str,',')) != NULL)
			str++;
		else
			break;
	}
	return 1;
}

__setup("reboot=", reboot_setup);

/*
 * Reboot options and system auto-detection code provided by
 * Dell Inc. so their systems "just work". :-)
 */

/*
 * Some machines require the "reboot=b"  commandline option, this quirk makes that automatic.
 */
static int __init set_bios_reboot(struct dmi_system_id *d)
{
	if (!reboot_thru_bios) {
		reboot_thru_bios = 1;
		printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
	}
	return 0;
}

static struct dmi_system_id __initdata reboot_dmi_table[] = {
	{	/* Handle problems with rebooting on Dell 1300's */
		.callback = set_bios_reboot,
		.ident = "Dell PowerEdge 1300",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
		},
	},
	{	/* Handle problems with rebooting on Dell 300's */
		.callback = set_bios_reboot,
		.ident = "Dell PowerEdge 300",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
		},
	},
	{	/* Handle problems with rebooting on Dell 2400's */
		.callback = set_bios_reboot,
		.ident = "Dell PowerEdge 2400",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
		},
	},
	{	/* Handle problems with rebooting on HP laptops */
		.callback = set_bios_reboot,
		.ident = "HP Compaq Laptop",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
			DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
		},
	},
	{ }
};

static int __init reboot_init(void)
{
	dmi_check_system(reboot_dmi_table);
	return 0;
}

core_initcall(reboot_init);

/* The following code and data reboots the machine by switching to real
   mode and jumping to the BIOS reset entry point, as if the CPU has
   really been reset.  The previous version asked the keyboard
   controller to pulse the CPU reset line, which is more thorough, but
   doesn't work with at least one type of 486 motherboard.  It is easy
   to stop this code working; hence the copious comments. */

static unsigned long long
real_mode_gdt_entries [3] =
{
	0x0000000000000000ULL,	/* Null descriptor */
	0x00009a000000ffffULL,	/* 16-bit real-mode 64k code at 0x00000000 */
	0x000092000100ffffULL	/* 16-bit real-mode 64k data at 0x00000100 */
};

static struct
{
	unsigned short       size __attribute__ ((packed));
	unsigned long long * base __attribute__ ((packed));
}
real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, real_mode_gdt_entries },
real_mode_idt = { 0x3ff, NULL },
no_idt = { 0, NULL };


/* This is 16-bit protected mode code to disable paging and the cache,
   switch to real mode and jump to the BIOS reset code.

   The instruction that switches to real mode by writing to CR0 must be
   followed immediately by a far jump instruction, which set CS to a
   valid value for real mode, and flushes the prefetch queue to avoid
   running instructions that have already been decoded in protected
   mode.

   Clears all the flags except ET, especially PG (paging), PE
   (protected-mode enable) and TS (task switch for coprocessor state
   save).  Flushes the TLB after paging has been disabled.  Sets CD and
   NW, to disable the cache on a 486, and invalidates the cache.  This
   is more like the state of a 486 after reset.  I don't know if
   something else should be done for other chips.

   More could be done here to set up the registers as if a CPU reset had
   occurred; hopefully real BIOSs don't assume much. */

static unsigned char real_mode_switch [] =
{
	0x66, 0x0f, 0x20, 0xc0,			/*    movl  %cr0,%eax        */
	0x66, 0x83, 0xe0, 0x11,			/*    andl  $0x00000011,%eax */
	0x66, 0x0d, 0x00, 0x00, 0x00, 0x60,	/*    orl   $0x60000000,%eax */
	0x66, 0x0f, 0x22, 0xc0,			/*    movl  %eax,%cr0        */
	0x66, 0x0f, 0x22, 0xd8,			/*    movl  %eax,%cr3        */
	0x66, 0x0f, 0x20, 0xc3,			/*    movl  %cr0,%ebx        */
	0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60,	/*    andl  $0x60000000,%ebx */
	0x74, 0x02,				/*    jz    f                */
	0x0f, 0x09,				/*    wbinvd                 */
	0x24, 0x10,				/* f: andb  $0x10,al         */
	0x66, 0x0f, 0x22, 0xc0			/*    movl  %eax,%cr0        */
};
static unsigned char jump_to_bios [] =
{
	0xea, 0x00, 0x00, 0xff, 0xff		/*    ljmp  $0xffff,$0x0000  */
};

/*
 * Switch to real mode and then execute the code
 * specified by the code and length parameters.
 * We assume that length will aways be less that 100!
 */
void machine_real_restart(unsigned char *code, int length)
{
	unsigned long flags;

	local_irq_disable();

	/* Write zero to CMOS register number 0x0f, which the BIOS POST
	   routine will recognize as telling it to do a proper reboot.  (Well
	   that's what this book in front of me says -- it may only apply to
	   the Phoenix BIOS though, it's not clear).  At the same time,
	   disable NMIs by setting the top bit in the CMOS address register,
	   as we're about to do peculiar things to the CPU.  I'm not sure if
	   `outb_p' is needed instead of just `outb'.  Use it to be on the
	   safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
	 */

	spin_lock_irqsave(&rtc_lock, flags);
	CMOS_WRITE(0x00, 0x8f);
	spin_unlock_irqrestore(&rtc_lock, flags);

	/* Remap the kernel at virtual address zero, as well as offset zero
	   from the kernel segment.  This assumes the kernel segment starts at
	   virtual address PAGE_OFFSET. */

	memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
		sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);

	/*
	 * Use `swapper_pg_dir' as our page directory.
	 */
	load_cr3(swapper_pg_dir);

	/* Write 0x1234 to absolute memory location 0x472.  The BIOS reads
	   this on booting to tell it to "Bypass memory test (also warm
	   boot)".  This seems like a fairly standard thing that gets set by
	   REBOOT.COM programs, and the previous reset routine did this
	   too. */

	*((unsigned short *)0x472) = reboot_mode;

	/* For the switch to real mode, copy some code to low memory.  It has
	   to be in the first 64k because it is running in 16-bit mode, and it
	   has to have the same physical and virtual address, because it turns
	   off paging.  Copy it near the end of the first page, out of the way
	   of BIOS variables. */

	memcpy ((void *) (0x1000 - sizeof (real_mode_switch) - 100),
		real_mode_switch, sizeof (real_mode_switch));
	memcpy ((void *) (0x1000 - 100), code, length);

	/* Set up the IDT for real mode. */

	load_idt(&real_mode_idt);

	/* Set up a GDT from which we can load segment descriptors for real
	   mode.  The GDT is not used in real mode; it is just needed here to
	   prepare the descriptors. */

	load_gdt(&real_mode_gdt);

	/* Load the data segment registers, and thus the descriptors ready for
	   real mode.  The base address of each segment is 0x100, 16 times the
	   selector value being loaded here.  This is so that the segment
	   registers don't have to be reloaded after switching to real mode:
	   the values are consistent for real mode operation already. */

	__asm__ __volatile__ ("movl $0x0010,%%eax\n"
				"\tmovl %%eax,%%ds\n"
				"\tmovl %%eax,%%es\n"
				"\tmovl %%eax,%%fs\n"
				"\tmovl %%eax,%%gs\n"
				"\tmovl %%eax,%%ss" : : : "eax");

	/* Jump to the 16-bit code that we copied earlier.  It disables paging
	   and the cache, switches to real mode, and jumps to the BIOS reset
	   entry point. */

	__asm__ __volatile__ ("ljmp $0x0008,%0"
				:
				: "i" ((void *) (0x1000 - sizeof (real_mode_switch) - 100)));
}
#ifdef CONFIG_APM_MODULE
EXPORT_SYMBOL(machine_real_restart);
#endif

void machine_shutdown(void)
{
#ifdef CONFIG_SMP
	int reboot_cpu_id;

	/* The boot cpu is always logical cpu 0 */
	reboot_cpu_id = 0;

	/* See if there has been given a command line override */
	if ((reboot_cpu != -1) && (reboot_cpu < NR_CPUS) &&
		cpu_isset(reboot_cpu, cpu_online_map)) {
		reboot_cpu_id = reboot_cpu;
	}

	/* Make certain the cpu I'm rebooting 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, and disable their local APICs.
	 */

	smp_send_stop();
#endif /* CONFIG_SMP */

	lapic_shutdown();

#ifdef CONFIG_X86_IO_APIC
	disable_IO_APIC();
#endif
}

void machine_emergency_restart(void)
{
	if (!reboot_thru_bios) {
		if (efi_enabled) {
			efi.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL);
			load_idt(&no_idt);
			__asm__ __volatile__("int3");
		}
		/* rebooting needs to touch the page at absolute addr 0 */
		*((unsigned short *)__va(0x472)) = reboot_mode;
		for (;;) {
			mach_reboot_fixups(); /* for board specific fixups */
			mach_reboot();
			/* That didn't work - force a triple fault.. */
			load_idt(&no_idt);
			__asm__ __volatile__("int3");
		}
	}
	if (efi_enabled)
		efi.reset_system(EFI_RESET_WARM, EFI_SUCCESS, 0, NULL);

	machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
}

void machine_restart(char * __unused)
{
	machine_shutdown();
	machine_emergency_restart();
}

void machine_halt(void)
{
}

void machine_power_off(void)
{
	if (pm_power_off) {
		machine_shutdown();
		pm_power_off();
	}
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/i386/kernel/reboot.c
	3	*/
	4
129f6946	5	#include <linux/config.h>
1da177e4 LT	6	#include <linux/mm.h>
	7	#include <linux/module.h>
	8	#include <linux/delay.h>
	9	#include <linux/init.h>
	10	#include <linux/interrupt.h>
	11	#include <linux/mc146818rtc.h>
	12	#include <linux/efi.h>
	13	#include <linux/dmi.h>
6f673d83	14	#include <linux/ctype.h>
6e3fbee5	15	#include <linux/pm.h>
1da177e4 LT	16	#include <asm/uaccess.h>
1da177e4 LT	17	#include <asm/apic.h>
4d37e7e3	18	#include <asm/desc.h>
1da177e4	19	#include "mach_reboot.h"
a2f7c354	20	#include <linux/reboot_fixups.h>
1da177e4 LT	21
	22	/*
	23	* Power off function, if any
	24	*/
	25	void (*pm_power_off)(void);
129f6946	26	EXPORT_SYMBOL(pm_power_off);
1da177e4 LT	27
	28	static int reboot_mode;
	29	static int reboot_thru_bios;
	30
	31	#ifdef CONFIG_SMP
1da177e4	32	static int reboot_cpu = -1;
1da177e4 LT	33	#endif
	34	static int __init reboot_setup(char *str)
	35	{
	36	while(1) {
	37	switch (*str) {
	38	case 'w': /* "warm" reboot (no memory testing etc) */
	39	reboot_mode = 0x1234;
	40	break;
	41	case 'c': /* "cold" reboot (with memory testing etc) */
	42	reboot_mode = 0x0;
	43	break;
	44	case 'b': /* "bios" reboot by jumping through the BIOS */
	45	reboot_thru_bios = 1;
	46	break;
	47	case 'h': /* "hard" reboot by toggling RESET and/or crashing the CPU */
	48	reboot_thru_bios = 0;
	49	break;
	50	#ifdef CONFIG_SMP
	51	case 's': /* "smp" reboot by executing reset on BSP or other CPU*/
6f673d83	52	if (isdigit(*(str+1))) {
1da177e4	53	reboot_cpu = (int) (*(str+1) - '0');
6f673d83	54	if (isdigit(*(str+2)))
1da177e4 LT	55	reboot_cpu = reboot_cpu10 + (int)((str+2) - '0');
	56	}
	57	/* we will leave sorting out the final value
	58	when we are ready to reboot, since we might not
	59	have set up boot_cpu_id or smp_num_cpu */
	60	break;
	61	#endif
	62	}
	63	if((str = strchr(str,',')) != NULL)
	64	str++;
	65	else
	66	break;
	67	}
	68	return 1;
	69	}
	70
	71	__setup("reboot=", reboot_setup);
	72
	73	/*
	74	* Reboot options and system auto-detection code provided by
	75	* Dell Inc. so their systems "just work". :-)
	76	*/
	77
	78	/*
	79	* Some machines require the "reboot=b" commandline option, this quirk makes that automatic.
	80	*/
	81	static int __init set_bios_reboot(struct dmi_system_id *d)
	82	{
	83	if (!reboot_thru_bios) {
	84	reboot_thru_bios = 1;
	85	printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
	86	}
	87	return 0;
	88	}
	89
1da177e4 LT	90	static struct dmi_system_id __initdata reboot_dmi_table[] = {
1da177e4 LT	91	{ /* Handle problems with rebooting on Dell 1300's */
dd2a1305	92	.callback = set_bios_reboot,
1da177e4 LT	93	.ident = "Dell PowerEdge 1300",
	94	.matches = {
	95	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
	96	DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
	97	},
	98	},
	99	{ /* Handle problems with rebooting on Dell 300's */
	100	.callback = set_bios_reboot,
	101	.ident = "Dell PowerEdge 300",
	102	.matches = {
	103	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
	104	DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
	105	},
	106	},
	107	{ /* Handle problems with rebooting on Dell 2400's */
	108	.callback = set_bios_reboot,
	109	.ident = "Dell PowerEdge 2400",
	110	.matches = {
	111	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
	112	DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
	113	},
	114	},
766c3f94	115	{ /* Handle problems with rebooting on HP laptops */
d91b14c4	116	.callback = set_bios_reboot,
766c3f94	117	.ident = "HP Compaq Laptop",
d91b14c4 TV	118	.matches = {
d91b14c4 TV	119	DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
766c3f94	120	DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
d91b14c4 TV	121	},
d91b14c4 TV	122	},
1da177e4 LT	123	{ }
	124	};
	125
	126	static int __init reboot_init(void)
	127	{
	128	dmi_check_system(reboot_dmi_table);
	129	return 0;
	130	}
	131
	132	core_initcall(reboot_init);
	133
	134	/* The following code and data reboots the machine by switching to real
	135	mode and jumping to the BIOS reset entry point, as if the CPU has
	136	really been reset. The previous version asked the keyboard
	137	controller to pulse the CPU reset line, which is more thorough, but
	138	doesn't work with at least one type of 486 motherboard. It is easy
	139	to stop this code working; hence the copious comments. */
	140
	141	static unsigned long long
	142	real_mode_gdt_entries [3] =
	143	{
	144	0x0000000000000000ULL, /* Null descriptor */
	145	0x00009a000000ffffULL, /* 16-bit real-mode 64k code at 0x00000000 */
	146	0x000092000100ffffULL /* 16-bit real-mode 64k data at 0x00000100 */
	147	};
	148
	149	static struct
	150	{
	151	unsigned short size __attribute__ ((packed));
	152	unsigned long long * base __attribute__ ((packed));
	153	}
	154	real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, real_mode_gdt_entries },
	155	real_mode_idt = { 0x3ff, NULL },
	156	no_idt = { 0, NULL };
	157
	158
	159	/* This is 16-bit protected mode code to disable paging and the cache,
	160	switch to real mode and jump to the BIOS reset code.
	161
	162	The instruction that switches to real mode by writing to CR0 must be
	163	followed immediately by a far jump instruction, which set CS to a
	164	valid value for real mode, and flushes the prefetch queue to avoid
	165	running instructions that have already been decoded in protected
	166	mode.
	167
	168	Clears all the flags except ET, especially PG (paging), PE
	169	(protected-mode enable) and TS (task switch for coprocessor state
	170	save). Flushes the TLB after paging has been disabled. Sets CD and
	171	NW, to disable the cache on a 486, and invalidates the cache. This
	172	is more like the state of a 486 after reset. I don't know if
	173	something else should be done for other chips.
	174
	175	More could be done here to set up the registers as if a CPU reset had
	176	occurred; hopefully real BIOSs don't assume much. */
	177
	178	static unsigned char real_mode_switch [] =
	179	{
	180	0x66, 0x0f, 0x20, 0xc0, /* movl %cr0,%eax */
	181	0x66, 0x83, 0xe0, 0x11, /* andl $0x00000011,%eax */
	182	0x66, 0x0d, 0x00, 0x00, 0x00, 0x60, /* orl $0x60000000,%eax */
	183	0x66, 0x0f, 0x22, 0xc0, /* movl %eax,%cr0 */
	184	0x66, 0x0f, 0x22, 0xd8, /* movl %eax,%cr3 */
	185	0x66, 0x0f, 0x20, 0xc3, /* movl %cr0,%ebx */
	186	0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60, /* andl $0x60000000,%ebx */
187	0x74, 0x02, /* jz f */
188	0x0f, 0x09, /* wbinvd */
189	0x24, 0x10, /* f: andb $0x10,al */
190	0x66, 0x0f, 0x22, 0xc0 /* movl %eax,%cr0 */
191	};
192	static unsigned char jump_to_bios [] =
193	{
194	0xea, 0x00, 0x00, 0xff, 0xff /* ljmp $0xffff,$0x0000 */
195	};
196
197	/*
198	* Switch to real mode and then execute the code
199	* specified by the code and length parameters.
200	* We assume that length will aways be less that 100!
201	*/
202	void machine_real_restart(unsigned char *code, int length)
203	{
204	unsigned long flags;
205
206	local_irq_disable();
207
208	/* Write zero to CMOS register number 0x0f, which the BIOS POST
209	routine will recognize as telling it to do a proper reboot. (Well
210	that's what this book in front of me says -- it may only apply to
211	the Phoenix BIOS though, it's not clear). At the same time,
212	disable NMIs by setting the top bit in the CMOS address register,
213	as we're about to do peculiar things to the CPU. I'm not sure if
214	`outb_p' is needed instead of just `outb'. Use it to be on the
215	safe side. (Yes, CMOS_WRITE does outb_p's. - Paul G.)
216	*/
217
218	spin_lock_irqsave(&rtc_lock, flags);
219	CMOS_WRITE(0x00, 0x8f);
220	spin_unlock_irqrestore(&rtc_lock, flags);
221
222	/* Remap the kernel at virtual address zero, as well as offset zero
223	from the kernel segment. This assumes the kernel segment starts at
224	virtual address PAGE_OFFSET. */
225
226	memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
227	sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
228
229	/*
230	* Use `swapper_pg_dir' as our page directory.
231	*/
232	load_cr3(swapper_pg_dir);
233
234	/* Write 0x1234 to absolute memory location 0x472. The BIOS reads
235	this on booting to tell it to "Bypass memory test (also warm
236	boot)". This seems like a fairly standard thing that gets set by
237	REBOOT.COM programs, and the previous reset routine did this
238	too. */
239
240	((unsigned short )0x472) = reboot_mode;
241
242	/* For the switch to real mode, copy some code to low memory. It has
243	to be in the first 64k because it is running in 16-bit mode, and it
244	has to have the same physical and virtual address, because it turns
245	off paging. Copy it near the end of the first page, out of the way
246	of BIOS variables. */
247
248	memcpy ((void *) (0x1000 - sizeof (real_mode_switch) - 100),
249	real_mode_switch, sizeof (real_mode_switch));
250	memcpy ((void *) (0x1000 - 100), code, length);
251
252	/* Set up the IDT for real mode. */
253
4d37e7e3	254	load_idt(&real_mode_idt);
1da177e4 LT	255
	256	/* Set up a GDT from which we can load segment descriptors for real
	257	mode. The GDT is not used in real mode; it is just needed here to
	258	prepare the descriptors. */
	259
4d37e7e3	260	load_gdt(&real_mode_gdt);
1da177e4 LT	261
	262	/* Load the data segment registers, and thus the descriptors ready for
	263	real mode. The base address of each segment is 0x100, 16 times the
	264	selector value being loaded here. This is so that the segment
	265	registers don't have to be reloaded after switching to real mode:
	266	the values are consistent for real mode operation already. */
	267
	268	__asm__ __volatile__ ("movl $0x0010,%%eax\n"
	269	"\tmovl %%eax,%%ds\n"
	270	"\tmovl %%eax,%%es\n"
	271	"\tmovl %%eax,%%fs\n"
	272	"\tmovl %%eax,%%gs\n"
	273	"\tmovl %%eax,%%ss" : : : "eax");
	274
	275	/* Jump to the 16-bit code that we copied earlier. It disables paging
	276	and the cache, switches to real mode, and jumps to the BIOS reset
	277	entry point. */
	278
	279	__asm__ __volatile__ ("ljmp $0x0008,%0"
	280	:
	281	: "i" ((void *) (0x1000 - sizeof (real_mode_switch) - 100)));
	282	}
129f6946 AD	283	#ifdef CONFIG_APM_MODULE
	284	EXPORT_SYMBOL(machine_real_restart);
	285	#endif
1da177e4	286
dd2a1305	287	void machine_shutdown(void)
1da177e4 LT	288	{
1da177e4 LT	289	#ifdef CONFIG_SMP
dd2a1305 EB	290	int reboot_cpu_id;
	291
	292	/* The boot cpu is always logical cpu 0 */
	293	reboot_cpu_id = 0;
	294
	295	/* See if there has been given a command line override */
d8e392e7	296	if ((reboot_cpu != -1) && (reboot_cpu < NR_CPUS) &&
dd2a1305 EB	297	cpu_isset(reboot_cpu, cpu_online_map)) {
dd2a1305 EB	298	reboot_cpu_id = reboot_cpu;
1da177e4 LT	299	}
1da177e4 LT	300
dd2a1305 EB	301	/* Make certain the cpu I'm rebooting on is online */
	302	if (!cpu_isset(reboot_cpu_id, cpu_online_map)) {
	303	reboot_cpu_id = smp_processor_id();
1da177e4	304	}
dd2a1305 EB	305
	306	/* Make certain I only run on the appropriate processor */
	307	set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
	308
	309	/* O.K. Now that I'm on the appropriate processor, stop
	310	* all of the others, and disable their local APICs.
1da177e4	311	*/
dd2a1305	312
1da177e4 LT	313	smp_send_stop();
	314	#endif /* CONFIG_SMP */
	315
	316	lapic_shutdown();
	317
	318	#ifdef CONFIG_X86_IO_APIC
	319	disable_IO_APIC();
	320	#endif
dd2a1305 EB	321	}
dd2a1305 EB	322
4a1421f8	323	void machine_emergency_restart(void)
dd2a1305	324	{
1da177e4 LT	325	if (!reboot_thru_bios) {
	326	if (efi_enabled) {
	327	efi.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL);
4d37e7e3	328	load_idt(&no_idt);
1da177e4 LT	329	__asm__ __volatile__("int3");
	330	}
	331	/* rebooting needs to touch the page at absolute addr 0 */
	332	((unsigned short )__va(0x472)) = reboot_mode;
	333	for (;;) {
a2f7c354	334	mach_reboot_fixups(); /* for board specific fixups */
1da177e4 LT	335	mach_reboot();
1da177e4 LT	336	/* That didn't work - force a triple fault.. */
4d37e7e3	337	load_idt(&no_idt);
1da177e4 LT	338	__asm__ __volatile__("int3");
	339	}
	340	}
	341	if (efi_enabled)
	342	efi.reset_system(EFI_RESET_WARM, EFI_SUCCESS, 0, NULL);
	343
	344	machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
	345	}
	346
4a1421f8 EB	347	void machine_restart(char * __unused)
	348	{
	349	machine_shutdown();
	350	machine_emergency_restart();
	351	}
	352
1da177e4 LT	353	void machine_halt(void)
	354	{
	355	}
	356
1da177e4 LT	357	void machine_power_off(void)
1da177e4 LT	358	{
6e3fbee5 EB	359	if (pm_power_off) {
6e3fbee5 EB	360	machine_shutdown();
1da177e4	361	pm_power_off();
6e3fbee5	362	}
1da177e4 LT	363	}
1da177e4 LT	364
1da177e4	365