diff options
Diffstat (limited to 'arch/i386/kernel/reboot.c')
| -rw-r--r-- | arch/i386/kernel/reboot.c | 382 |
1 files changed, 382 insertions, 0 deletions
diff --git a/arch/i386/kernel/reboot.c b/arch/i386/kernel/reboot.c new file mode 100644 index 000000000000..3d7e994563df --- /dev/null +++ b/arch/i386/kernel/reboot.c @@ -0,0 +1,382 @@ +/* + * linux/arch/i386/kernel/reboot.c + */ + +#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 <asm/uaccess.h> +#include <asm/apic.h> +#include "mach_reboot.h" + +/* + * Power off function, if any + */ +void (*pm_power_off)(void); + +static int reboot_mode; +static int reboot_thru_bios; + +#ifdef CONFIG_SMP +int reboot_smp = 0; +static int reboot_cpu = -1; +/* shamelessly grabbed from lib/vsprintf.c for readability */ +#define is_digit(c) ((c) >= '0' && (c) <= '9') +#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*/ + reboot_smp = 1; + if (is_digit(*(str+1))) { + reboot_cpu = (int) (*(str+1) - '0'); + if (is_digit(*(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; +} + +/* + * Some machines require the "reboot=s" commandline option, this quirk makes that automatic. + */ +static int __init set_smp_reboot(struct dmi_system_id *d) +{ +#ifdef CONFIG_SMP + if (!reboot_smp) { + reboot_smp = 1; + printk(KERN_INFO "%s series board detected. Selecting SMP-method for reboots.\n", d->ident); + } +#endif + return 0; +} + +/* + * Some machines require the "reboot=b,s" commandline option, this quirk makes that automatic. + */ +static int __init set_smp_bios_reboot(struct dmi_system_id *d) +{ + set_smp_reboot(d); + set_bios_reboot(d); + return 0; +} + +static struct dmi_system_id __initdata reboot_dmi_table[] = { + { /* Handle problems with rebooting on Dell 1300's */ + .callback = set_smp_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"), + }, + }, + { } +}; + +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. */ + + __asm__ __volatile__ ("lidt %0" : : "m" (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. */ + + __asm__ __volatile__ ("lgdt %0" : : "m" (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))); +} + +void machine_restart(char * __unused) +{ +#ifdef CONFIG_SMP + int cpuid; + + cpuid = GET_APIC_ID(apic_read(APIC_ID)); + + if (reboot_smp) { + + /* check to see if reboot_cpu is valid + if its not, default to the BSP */ + if ((reboot_cpu == -1) || + (reboot_cpu > (NR_CPUS -1)) || + !physid_isset(cpuid, phys_cpu_present_map)) + reboot_cpu = boot_cpu_physical_apicid; + + reboot_smp = 0; /* use this as a flag to only go through this once*/ + /* re-run this function on the other CPUs + it will fall though this section since we have + cleared reboot_smp, and do the reboot if it is the + correct CPU, otherwise it halts. */ + if (reboot_cpu != cpuid) + smp_call_function((void *)machine_restart , NULL, 1, 0); + } + + /* if reboot_cpu is still -1, then we want a tradional reboot, + and if we are not running on the reboot_cpu,, halt */ + if ((reboot_cpu != -1) && (cpuid != reboot_cpu)) { + for (;;) + __asm__ __volatile__ ("hlt"); + } + /* + * Stop all CPUs and turn off local APICs and the IO-APIC, so + * other OSs see a clean IRQ state. + */ + smp_send_stop(); +#endif /* CONFIG_SMP */ + + lapic_shutdown(); + +#ifdef CONFIG_X86_IO_APIC + disable_IO_APIC(); +#endif + + if (!reboot_thru_bios) { + if (efi_enabled) { + efi.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL); + __asm__ __volatile__("lidt %0": :"m" (no_idt)); + __asm__ __volatile__("int3"); + } + /* rebooting needs to touch the page at absolute addr 0 */ + *((unsigned short *)__va(0x472)) = reboot_mode; + for (;;) { + mach_reboot(); + /* That didn't work - force a triple fault.. */ + __asm__ __volatile__("lidt %0": :"m" (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)); +} + +EXPORT_SYMBOL(machine_restart); + +void machine_halt(void) +{ +} + +EXPORT_SYMBOL(machine_halt); + +void machine_power_off(void) +{ + lapic_shutdown(); + + if (efi_enabled) + efi.reset_system(EFI_RESET_SHUTDOWN, EFI_SUCCESS, 0, NULL); + if (pm_power_off) + pm_power_off(); +} + +EXPORT_SYMBOL(machine_power_off); + |