2 * linux/arch/i386/kernel/reboot.c
8 #endif /* CONFIG_KDB */
9 #include <linux/module.h>
10 #include <linux/delay.h>
11 #include <linux/init.h>
12 #include <linux/interrupt.h>
13 #include <linux/mc146818rtc.h>
14 #include <linux/efi.h>
15 #include <linux/dmi.h>
16 #include <linux/ctype.h>
18 #include <linux/reboot.h>
19 #include <asm/uaccess.h>
22 #include "mach_reboot.h"
23 #include <asm/reboot_fixups.h>
24 #include <asm/reboot.h>
27 * Power off function, if any
29 void (*pm_power_off)(void);
30 EXPORT_SYMBOL(pm_power_off);
32 static int reboot_mode;
33 static int reboot_thru_bios;
36 static int reboot_cpu = -1;
38 static int __init reboot_setup(char *str)
42 case 'w': /* "warm" reboot (no memory testing etc) */
45 case 'c': /* "cold" reboot (with memory testing etc) */
48 case 'b': /* "bios" reboot by jumping through the BIOS */
51 case 'h': /* "hard" reboot by toggling RESET and/or crashing the CPU */
55 case 's': /* "smp" reboot by executing reset on BSP or other CPU*/
56 if (isdigit(*(str+1))) {
57 reboot_cpu = (int) (*(str+1) - '0');
58 if (isdigit(*(str+2)))
59 reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
61 /* we will leave sorting out the final value
62 when we are ready to reboot, since we might not
63 have set up boot_cpu_id or smp_num_cpu */
67 if((str = strchr(str,',')) != NULL)
75 __setup("reboot=", reboot_setup);
78 * Reboot options and system auto-detection code provided by
79 * Dell Inc. so their systems "just work". :-)
83 * Some machines require the "reboot=b" commandline option, this quirk makes that automatic.
85 static int __init set_bios_reboot(struct dmi_system_id *d)
87 if (!reboot_thru_bios) {
89 printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
94 static struct dmi_system_id __initdata reboot_dmi_table[] = {
95 { /* Handle problems with rebooting on Dell 1300's */
96 .callback = set_bios_reboot,
97 .ident = "Dell PowerEdge 1300",
99 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
100 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
103 { /* Handle problems with rebooting on Dell 300's */
104 .callback = set_bios_reboot,
105 .ident = "Dell PowerEdge 300",
107 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
108 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
111 { /* Handle problems with rebooting on Dell 2400's */
112 .callback = set_bios_reboot,
113 .ident = "Dell PowerEdge 2400",
115 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
116 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
119 { /* Handle problems with rebooting on HP laptops */
120 .callback = set_bios_reboot,
121 .ident = "HP Compaq Laptop",
123 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
124 DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
130 static int __init reboot_init(void)
132 dmi_check_system(reboot_dmi_table);
136 core_initcall(reboot_init);
138 /* The following code and data reboots the machine by switching to real
139 mode and jumping to the BIOS reset entry point, as if the CPU has
140 really been reset. The previous version asked the keyboard
141 controller to pulse the CPU reset line, which is more thorough, but
142 doesn't work with at least one type of 486 motherboard. It is easy
143 to stop this code working; hence the copious comments. */
145 static unsigned long long
146 real_mode_gdt_entries [3] =
148 0x0000000000000000ULL, /* Null descriptor */
149 0x00009a000000ffffULL, /* 16-bit real-mode 64k code at 0x00000000 */
150 0x000092000100ffffULL /* 16-bit real-mode 64k data at 0x00000100 */
153 static struct Xgt_desc_struct
154 real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, (long)real_mode_gdt_entries },
155 real_mode_idt = { 0x3ff, 0 },
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.
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
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.
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. */
178 static unsigned char real_mode_switch [] =
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 */
192 static unsigned char jump_to_bios [] =
194 0xea, 0x00, 0x00, 0xff, 0xff /* ljmp $0xffff,$0x0000 */
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!
202 void machine_real_restart(unsigned char *code, int length)
206 /* Write zero to CMOS register number 0x0f, which the BIOS POST
207 routine will recognize as telling it to do a proper reboot. (Well
208 that's what this book in front of me says -- it may only apply to
209 the Phoenix BIOS though, it's not clear). At the same time,
210 disable NMIs by setting the top bit in the CMOS address register,
211 as we're about to do peculiar things to the CPU. I'm not sure if
212 `outb_p' is needed instead of just `outb'. Use it to be on the
213 safe side. (Yes, CMOS_WRITE does outb_p's. - Paul G.)
216 spin_lock(&rtc_lock);
217 CMOS_WRITE(0x00, 0x8f);
218 spin_unlock(&rtc_lock);
220 /* Remap the kernel at virtual address zero, as well as offset zero
221 from the kernel segment. This assumes the kernel segment starts at
222 virtual address PAGE_OFFSET. */
224 memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
225 sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
228 * Use `swapper_pg_dir' as our page directory.
230 load_cr3(swapper_pg_dir);
232 /* Write 0x1234 to absolute memory location 0x472. The BIOS reads
233 this on booting to tell it to "Bypass memory test (also warm
234 boot)". This seems like a fairly standard thing that gets set by
235 REBOOT.COM programs, and the previous reset routine did this
238 *((unsigned short *)0x472) = reboot_mode;
240 /* For the switch to real mode, copy some code to low memory. It has
241 to be in the first 64k because it is running in 16-bit mode, and it
242 has to have the same physical and virtual address, because it turns
243 off paging. Copy it near the end of the first page, out of the way
244 of BIOS variables. */
246 memcpy ((void *) (0x1000 - sizeof (real_mode_switch) - 100),
247 real_mode_switch, sizeof (real_mode_switch));
248 memcpy ((void *) (0x1000 - 100), code, length);
250 /* Set up the IDT for real mode. */
252 load_idt(&real_mode_idt);
254 /* Set up a GDT from which we can load segment descriptors for real
255 mode. The GDT is not used in real mode; it is just needed here to
256 prepare the descriptors. */
258 load_gdt(&real_mode_gdt);
260 /* Load the data segment registers, and thus the descriptors ready for
261 real mode. The base address of each segment is 0x100, 16 times the
262 selector value being loaded here. This is so that the segment
263 registers don't have to be reloaded after switching to real mode:
264 the values are consistent for real mode operation already. */
266 __asm__ __volatile__ ("movl $0x0010,%%eax\n"
267 "\tmovl %%eax,%%ds\n"
268 "\tmovl %%eax,%%es\n"
269 "\tmovl %%eax,%%fs\n"
270 "\tmovl %%eax,%%gs\n"
271 "\tmovl %%eax,%%ss" : : : "eax");
273 /* Jump to the 16-bit code that we copied earlier. It disables paging
274 and the cache, switches to real mode, and jumps to the BIOS reset
277 __asm__ __volatile__ ("ljmp $0x0008,%0"
279 : "i" ((void *) (0x1000 - sizeof (real_mode_switch) - 100)));
281 #ifdef CONFIG_APM_MODULE
282 EXPORT_SYMBOL(machine_real_restart);
285 static void native_machine_shutdown(void)
290 /* The boot cpu is always logical cpu 0 */
293 /* See if there has been given a command line override */
294 if ((reboot_cpu != -1) && (reboot_cpu < NR_CPUS) &&
295 cpu_isset(reboot_cpu, cpu_online_map)) {
296 reboot_cpu_id = reboot_cpu;
299 /* Make certain the cpu I'm rebooting on is online */
300 if (!cpu_isset(reboot_cpu_id, cpu_online_map)) {
301 reboot_cpu_id = smp_processor_id();
304 /* Make certain I only run on the appropriate processor */
305 set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
307 /* O.K. Now that I'm on the appropriate processor, stop
308 * all of the others, and disable their local APICs.
313 * If this restart is occuring while kdb is running (e.g. reboot
314 * command), the other CPU's are already stopped. Don't try to
315 * stop them yet again.
317 if (!KDB_IS_RUNNING())
318 #endif /* CONFIG_KDB */
320 #endif /* CONFIG_SMP */
324 #ifdef CONFIG_X86_IO_APIC
329 void __attribute__((weak)) mach_reboot_fixups(void)
333 static void native_machine_emergency_restart(void)
335 if (!reboot_thru_bios) {
337 efi.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL);
339 __asm__ __volatile__("int3");
341 /* rebooting needs to touch the page at absolute addr 0 */
342 *((unsigned short *)__va(0x472)) = reboot_mode;
344 mach_reboot_fixups(); /* for board specific fixups */
346 /* That didn't work - force a triple fault.. */
348 __asm__ __volatile__("int3");
352 efi.reset_system(EFI_RESET_WARM, EFI_SUCCESS, 0, NULL);
354 machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
357 static void native_machine_restart(char * __unused)
360 machine_emergency_restart();
363 static void native_machine_halt(void)
367 static void native_machine_power_off(void)
376 struct machine_ops machine_ops = {
377 .power_off = native_machine_power_off,
378 .shutdown = native_machine_shutdown,
379 .emergency_restart = native_machine_emergency_restart,
380 .restart = native_machine_restart,
381 .halt = native_machine_halt,
384 void machine_power_off(void)
386 machine_ops.power_off();
389 void machine_shutdown(void)
391 machine_ops.shutdown();
394 void machine_emergency_restart(void)
396 machine_ops.emergency_restart();
399 void machine_restart(char *cmd)
401 machine_ops.restart(cmd);
404 void machine_halt(void)