+++ /dev/null
-/* (c) 2008, Jack Lange <jarusl@cs.northwestern.edu> */
-/* (c) 2008, The V3VEE Project <http://www.v3vee.org> */
-
-#include <geekos/reboot.h>
-#include <libc/string.h>
-// from linux...
-
-
-#define RTC_PORT(x) (0x70 + (x))
-
-/* 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, 0 };
-//no_idt = { 0, 0 };
-
-
-
-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 long flags;
-
- unsigned short rtp1, rtp2;
- unsigned char val1, val2;
-
- //JRL// 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.)
- */
-
-//JRL// spin_lock_irqsave(&rtc_lock, flags);
-//JRL// CMOS_WRITE(0x00, 0x8f);
- val1 = 0x8f;
- val2 = 0x00;
- rtp1 = RTC_PORT(0);
- rtp2 = RTC_PORT(1);
-
- // outb_p(0x8f, RTC_PORT(0));
- // outb_p(0x00, RTC_PORT(1));
-
- __asm__ __volatile__ (
- "outb %b0, %w1"
- :
- : "a" (val1), "Nd" (rtp1)
- );
-
- __asm__ __volatile__ (
- "outb %b0, %w1"
- :
- : "a" (val2), "Nd" (rtp2)
- );
-
-//JRL// 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. */
-
-//JRL// memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
-//JRL// sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
-
- /*
- * Use `swapper_pg_dir' as our page directory.
- */
-//JRL// 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) = 0x1234;
-
- /* 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), jump_to_bios, sizeof(jump_to_bios));
-
- /* 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)));
-}