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/******************************************************************************
* arch/x86/shutdown.c
*
* x86-specific shutdown handling.
*/
#include <xen/config.h>
#include <xen/init.h>
#include <xen/lib.h>
#include <xen/sched.h>
#include <xen/smp.h>
#include <xen/delay.h>
#include <xen/dmi.h>
#include <xen/irq.h>
#include <xen/console.h>
#include <xen/shutdown.h>
#include <asm/msr.h>
#include <asm/regs.h>
#include <asm/mc146818rtc.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/mpspec.h>
#include <asm/tboot.h>
/* reboot_str: comma-separated list of reboot options. */
static char __initdata reboot_str[10] = "";
string_param("reboot", reboot_str);
static long no_idt[2];
static int reboot_mode;
static inline void kb_wait(void)
{
int i;
for ( i = 0; i < 0x10000; i++ )
if ( (inb_p(0x64) & 0x02) == 0 )
break;
}
static void __attribute__((noreturn)) __machine_halt(void *unused)
{
local_irq_disable();
for ( ; ; )
halt();
}
void machine_halt(void)
{
watchdog_disable();
console_start_sync();
smp_call_function(__machine_halt, NULL, 1, 0);
__machine_halt(NULL);
}
#ifdef __i386__
static int reboot_thru_bios;
/* 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 const 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 };
/* 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 const unsigned char real_mode_switch [] =
{
0x0f, 0x20, 0xc0, /* movl %cr0,%eax */
0x66, 0x83, 0xe0, 0x11, /* andl $0x00000011,%eax */
0x66, 0x0d, 0x00, 0x00, 0x00, 0x60, /* orl $0x60000000,%eax */
0x0f, 0x22, 0xc0, /* movl %eax,%cr0 */
0x0f, 0x22, 0xd8, /* movl %eax,%cr3 */
0x0f, 0x20, 0xc2, /* movl %cr0,%edx */
0x66, 0x81, 0xe2, 0x00, 0x00, 0x00, 0x60, /* andl $0x60000000,%edx */
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