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>
366 lines
11 KiB
C
366 lines
11 KiB
C
/*
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* linux/arch/i386/kernel/reboot.c
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*/
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#include <linux/config.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/mc146818rtc.h>
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#include <linux/efi.h>
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#include <linux/dmi.h>
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#include <linux/ctype.h>
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#include <linux/pm.h>
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#include <asm/uaccess.h>
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#include <asm/apic.h>
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#include <asm/desc.h>
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#include "mach_reboot.h"
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#include <linux/reboot_fixups.h>
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/*
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* Power off function, if any
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*/
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void (*pm_power_off)(void);
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EXPORT_SYMBOL(pm_power_off);
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static int reboot_mode;
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static int reboot_thru_bios;
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#ifdef CONFIG_SMP
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static int reboot_cpu = -1;
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#endif
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static int __init reboot_setup(char *str)
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{
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while(1) {
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switch (*str) {
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case 'w': /* "warm" reboot (no memory testing etc) */
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reboot_mode = 0x1234;
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break;
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case 'c': /* "cold" reboot (with memory testing etc) */
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reboot_mode = 0x0;
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break;
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case 'b': /* "bios" reboot by jumping through the BIOS */
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reboot_thru_bios = 1;
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break;
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case 'h': /* "hard" reboot by toggling RESET and/or crashing the CPU */
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reboot_thru_bios = 0;
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break;
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#ifdef CONFIG_SMP
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case 's': /* "smp" reboot by executing reset on BSP or other CPU*/
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if (isdigit(*(str+1))) {
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reboot_cpu = (int) (*(str+1) - '0');
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if (isdigit(*(str+2)))
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reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
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}
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/* we will leave sorting out the final value
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when we are ready to reboot, since we might not
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have set up boot_cpu_id or smp_num_cpu */
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break;
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#endif
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}
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if((str = strchr(str,',')) != NULL)
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str++;
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else
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break;
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}
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return 1;
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}
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__setup("reboot=", reboot_setup);
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/*
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* Reboot options and system auto-detection code provided by
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* Dell Inc. so their systems "just work". :-)
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*/
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/*
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* Some machines require the "reboot=b" commandline option, this quirk makes that automatic.
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*/
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static int __init set_bios_reboot(struct dmi_system_id *d)
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{
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if (!reboot_thru_bios) {
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reboot_thru_bios = 1;
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printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
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}
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return 0;
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}
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static struct dmi_system_id __initdata reboot_dmi_table[] = {
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{ /* Handle problems with rebooting on Dell 1300's */
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.callback = set_bios_reboot,
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.ident = "Dell PowerEdge 1300",
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.matches = {
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DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
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DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
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},
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},
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{ /* Handle problems with rebooting on Dell 300's */
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.callback = set_bios_reboot,
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.ident = "Dell PowerEdge 300",
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.matches = {
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DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
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DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
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},
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},
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{ /* Handle problems with rebooting on Dell 2400's */
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.callback = set_bios_reboot,
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.ident = "Dell PowerEdge 2400",
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.matches = {
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DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
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DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
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},
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},
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{ /* Handle problems with rebooting on HP laptops */
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.callback = set_bios_reboot,
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.ident = "HP Compaq Laptop",
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.matches = {
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DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
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DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
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},
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},
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{ }
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};
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static int __init reboot_init(void)
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{
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dmi_check_system(reboot_dmi_table);
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return 0;
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}
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core_initcall(reboot_init);
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/* The following code and data reboots the machine by switching to real
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mode and jumping to the BIOS reset entry point, as if the CPU has
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really been reset. The previous version asked the keyboard
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controller to pulse the CPU reset line, which is more thorough, but
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doesn't work with at least one type of 486 motherboard. It is easy
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to stop this code working; hence the copious comments. */
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static unsigned long long
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real_mode_gdt_entries [3] =
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{
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0x0000000000000000ULL, /* Null descriptor */
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0x00009a000000ffffULL, /* 16-bit real-mode 64k code at 0x00000000 */
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0x000092000100ffffULL /* 16-bit real-mode 64k data at 0x00000100 */
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};
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static struct
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{
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unsigned short size __attribute__ ((packed));
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unsigned long long * base __attribute__ ((packed));
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}
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real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, real_mode_gdt_entries },
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real_mode_idt = { 0x3ff, NULL },
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no_idt = { 0, NULL };
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/* This is 16-bit protected mode code to disable paging and the cache,
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switch to real mode and jump to the BIOS reset code.
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The instruction that switches to real mode by writing to CR0 must be
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followed immediately by a far jump instruction, which set CS to a
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valid value for real mode, and flushes the prefetch queue to avoid
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running instructions that have already been decoded in protected
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mode.
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Clears all the flags except ET, especially PG (paging), PE
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(protected-mode enable) and TS (task switch for coprocessor state
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save). Flushes the TLB after paging has been disabled. Sets CD and
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NW, to disable the cache on a 486, and invalidates the cache. This
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is more like the state of a 486 after reset. I don't know if
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something else should be done for other chips.
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More could be done here to set up the registers as if a CPU reset had
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occurred; hopefully real BIOSs don't assume much. */
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static unsigned char real_mode_switch [] =
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{
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0x66, 0x0f, 0x20, 0xc0, /* movl %cr0,%eax */
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0x66, 0x83, 0xe0, 0x11, /* andl $0x00000011,%eax */
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0x66, 0x0d, 0x00, 0x00, 0x00, 0x60, /* orl $0x60000000,%eax */
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0x66, 0x0f, 0x22, 0xc0, /* movl %eax,%cr0 */
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0x66, 0x0f, 0x22, 0xd8, /* movl %eax,%cr3 */
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0x66, 0x0f, 0x20, 0xc3, /* movl %cr0,%ebx */
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0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60, /* andl $0x60000000,%ebx */
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0x74, 0x02, /* jz f */
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0x0f, 0x09, /* wbinvd */
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0x24, 0x10, /* f: andb $0x10,al */
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0x66, 0x0f, 0x22, 0xc0 /* movl %eax,%cr0 */
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};
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static unsigned char jump_to_bios [] =
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{
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0xea, 0x00, 0x00, 0xff, 0xff /* ljmp $0xffff,$0x0000 */
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};
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/*
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* Switch to real mode and then execute the code
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* specified by the code and length parameters.
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* We assume that length will aways be less that 100!
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*/
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void machine_real_restart(unsigned char *code, int length)
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{
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unsigned long flags;
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local_irq_disable();
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/* Write zero to CMOS register number 0x0f, which the BIOS POST
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routine will recognize as telling it to do a proper reboot. (Well
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that's what this book in front of me says -- it may only apply to
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the Phoenix BIOS though, it's not clear). At the same time,
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disable NMIs by setting the top bit in the CMOS address register,
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as we're about to do peculiar things to the CPU. I'm not sure if
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`outb_p' is needed instead of just `outb'. Use it to be on the
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safe side. (Yes, CMOS_WRITE does outb_p's. - Paul G.)
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*/
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spin_lock_irqsave(&rtc_lock, flags);
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CMOS_WRITE(0x00, 0x8f);
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spin_unlock_irqrestore(&rtc_lock, flags);
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/* Remap the kernel at virtual address zero, as well as offset zero
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from the kernel segment. This assumes the kernel segment starts at
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virtual address PAGE_OFFSET. */
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memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
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sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
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/*
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* Use `swapper_pg_dir' as our page directory.
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*/
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load_cr3(swapper_pg_dir);
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/* Write 0x1234 to absolute memory location 0x472. The BIOS reads
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this on booting to tell it to "Bypass memory test (also warm
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boot)". This seems like a fairly standard thing that gets set by
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REBOOT.COM programs, and the previous reset routine did this
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too. */
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*((unsigned short *)0x472) = reboot_mode;
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/* For the switch to real mode, copy some code to low memory. It has
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to be in the first 64k because it is running in 16-bit mode, and it
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has to have the same physical and virtual address, because it turns
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off paging. Copy it near the end of the first page, out of the way
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of BIOS variables. */
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memcpy ((void *) (0x1000 - sizeof (real_mode_switch) - 100),
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real_mode_switch, sizeof (real_mode_switch));
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memcpy ((void *) (0x1000 - 100), code, length);
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/* Set up the IDT for real mode. */
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load_idt(&real_mode_idt);
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/* Set up a GDT from which we can load segment descriptors for real
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mode. The GDT is not used in real mode; it is just needed here to
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prepare the descriptors. */
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load_gdt(&real_mode_gdt);
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/* Load the data segment registers, and thus the descriptors ready for
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real mode. The base address of each segment is 0x100, 16 times the
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selector value being loaded here. This is so that the segment
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registers don't have to be reloaded after switching to real mode:
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the values are consistent for real mode operation already. */
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__asm__ __volatile__ ("movl $0x0010,%%eax\n"
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"\tmovl %%eax,%%ds\n"
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"\tmovl %%eax,%%es\n"
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"\tmovl %%eax,%%fs\n"
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"\tmovl %%eax,%%gs\n"
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"\tmovl %%eax,%%ss" : : : "eax");
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/* Jump to the 16-bit code that we copied earlier. It disables paging
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and the cache, switches to real mode, and jumps to the BIOS reset
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entry point. */
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__asm__ __volatile__ ("ljmp $0x0008,%0"
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:
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: "i" ((void *) (0x1000 - sizeof (real_mode_switch) - 100)));
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}
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#ifdef CONFIG_APM_MODULE
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EXPORT_SYMBOL(machine_real_restart);
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#endif
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void machine_shutdown(void)
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{
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#ifdef CONFIG_SMP
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int reboot_cpu_id;
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/* The boot cpu is always logical cpu 0 */
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reboot_cpu_id = 0;
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/* See if there has been given a command line override */
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if ((reboot_cpu != -1) && (reboot_cpu < NR_CPUS) &&
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cpu_isset(reboot_cpu, cpu_online_map)) {
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reboot_cpu_id = reboot_cpu;
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}
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/* Make certain the cpu I'm rebooting on is online */
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if (!cpu_isset(reboot_cpu_id, cpu_online_map)) {
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reboot_cpu_id = smp_processor_id();
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}
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/* Make certain I only run on the appropriate processor */
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set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
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/* O.K. Now that I'm on the appropriate processor, stop
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* all of the others, and disable their local APICs.
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*/
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smp_send_stop();
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#endif /* CONFIG_SMP */
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lapic_shutdown();
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#ifdef CONFIG_X86_IO_APIC
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disable_IO_APIC();
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#endif
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}
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void machine_emergency_restart(void)
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{
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if (!reboot_thru_bios) {
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if (efi_enabled) {
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efi.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL);
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load_idt(&no_idt);
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__asm__ __volatile__("int3");
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}
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/* rebooting needs to touch the page at absolute addr 0 */
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*((unsigned short *)__va(0x472)) = reboot_mode;
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for (;;) {
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mach_reboot_fixups(); /* for board specific fixups */
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mach_reboot();
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/* That didn't work - force a triple fault.. */
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load_idt(&no_idt);
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__asm__ __volatile__("int3");
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}
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}
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if (efi_enabled)
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efi.reset_system(EFI_RESET_WARM, EFI_SUCCESS, 0, NULL);
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machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
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}
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void machine_restart(char * __unused)
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{
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machine_shutdown();
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machine_emergency_restart();
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}
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void machine_halt(void)
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{
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}
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void machine_power_off(void)
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{
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if (pm_power_off) {
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machine_shutdown();
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pm_power_off();
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}
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}
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