void machine_real_restart(unsigned int type)
{
void *restart_va;
unsigned long restart_pa;
void (*restart_lowmem)(unsigned int);
u64 *lowmem_gdt;
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(&rtc_lock);
CMOS_WRITE(0x00, 0x8f);
spin_unlock(&rtc_lock);
/*
* Switch back to the initial page table.
*/
load_cr3(initial_page_table);
/* 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;
/* Patch the GDT in the low memory trampoline */
lowmem_gdt = TRAMPOLINE_SYM(machine_real_restart_gdt);
restart_va = TRAMPOLINE_SYM(machine_real_restart_asm);
restart_pa = virt_to_phys(restart_va);
restart_lowmem = (void (*)(unsigned int))restart_pa;
/* GDT[0]: GDT self-pointer */
lowmem_gdt[0] =
(u64)(sizeof(machine_real_restart_gdt) - 1) +
((u64)virt_to_phys(lowmem_gdt) << 16);
/* GDT[1]: 64K real mode code segment */
lowmem_gdt[1] =
GDT_ENTRY(0x009b, restart_pa, 0xffff);
/* Jump to the identity-mapped low memory code */
restart_lowmem(type);
}
void machine_real_restart(unsigned int type)
{
void (*restart_lowmem)(unsigned int) = (void (*)(unsigned int))
real_mode_header->machine_real_restart_asm;
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(&rtc_lock);
CMOS_WRITE(0x00, 0x8f);
spin_unlock(&rtc_lock);
/*
* Switch back to the initial page table.
*/
load_cr3(initial_page_table);
/*
* 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;
/* Jump to the identity-mapped low memory code */
restart_lowmem(type);
}
