Reboot pc (code)

[marcio.f]

Hi,

Does anyone knows how to reboot the pc in protected-mode?
I've searched this forum and the FAQ, used google, searched at BonaFide, peeked at linux kernel (v1.0 and even v0.01) etc, and the closest source code I found was:

Code: Select all

static void reboot(void)
{
   unsigned temp;

   disable();
/* flush the keyboard controller */
   do
   {
      temp = inportb(0x64);
      if((temp & 0x01) != 0)
      {
         (void)inportb(0x60);
         continue;
      }
   } while((temp & 0x02) != 0);
/* pulse the CPU reset line */
   outportb(0x64, 0xFE);
/* ...and if that didn't work, just halt */
   while(1);
/* nothing */
}

but I can't get this one to work either. Does someone have a solution?

Thanks,

[Warrior]

What about saving everything and causing a tripple fault? :p

[GLneo]

Code: Select all

void reboot() 
{
    volatile unsigned char good = 0x02;
    while ((good & 0x02) != 0)
        good = inport(0x64);
    outport(0x64, 0xFE);
    frz();
}

[marcio.f]

@Nelson
That's an idea But for most incredibly it may sound, I don't know how to cause a triple fault..

[hr]
@GLneo
Thanks, but I can't get your code to work.. do I have to prepare something before calling the reboot() function?
Check the debugger log of Bochs I've attached, and go to line 2036:

00167067762d[CPU0 ] Enter Protected Mode
00167067959i[KBD ] io write 0x64: command 0xfe: reset cpu
00167067959i[SYS ] bx_pc_system_c::Reset(SOFTWARE) called
00167067959i[APIC0] local apic in CPU apicid=00 initializing
00167072123i[BIOS ] rombios.c,v 1.138 2005/05/07 15:55:26 vruppert Exp $
00167386060i[KBD ] reset-disable command received
00167488279i[VBIOS]
VGABios $Id: vgabios.c,v 1.61 2005/05/24 16:50:50 vruppert Exp $

After this, it starts again:

00167488349i[CLVGA] VBE known Display Interface b0c0
00167488381i[CLVGA] VBE known Display Interface b0c3
00167491306i[VBIOS] VBE Bios $Id: vbe.c,v 1.47 2005/05/24 16:50:50 vruppert Exp $
(...)

Until Bochs panics with:

(...)
00167897749p[BIOS ] >>PANIC<< floppy recal:f07: ctrl not ready
00167897771d[CPU0 ] interrupt(): vector = 16, INT = 1, EXT = 0
00167898415d[CPU0 ] interrupt(): vector = 16, INT = 1, EXT = 0
00167899083p[CPU0 ] >>PANIC<< HALT instruction encountered in the BIOS ROM
00167899083p[CPU0 ] >>PANIC<< WARNING: HLT instruction with IF=0!
00270276000p[WGUI ] >>PANIC<< POWER button turned off.
(...)

[hr]
Any ideas?

[srg_13]

You have tried it on a real pc, right?

[marcio.f]

You have tried it on a real pc, right?

Now I did and it works but shouldn't it run on Bochs too?
A friend of mine tested on MS Virtual PC and it did well.

PS: Why not add the code for reboot() in the OSFAQ?

[Solar]

Now I did and it works but shouldn't it run on Bochs too?

There are lots of things Bochs does differently from a "real" PC. Optimum is, of course, if it works on both, but sometimes you just have to accept that Bochs is an approximation, not more.

PS: Why not add the code for reboot() in the OSFAQ?

Just go ahead and add it, that's why we made the FAQ a Wiki.

[marcio.f]

Just go ahead and add it, that's why we made the FAQ a Wiki.

Thanks, but I've never used wiki :-[ and I even don't know where to add it.
Anyway, the code I would add is:

Code: Select all

typedef unsigned char uchar;
typedef uchar byte;

#define bit(n) (1<<(n)) /* Set to 1 bit n */
#define halt() asm volatile ("HLT") /* halt cpu */
#define disable() asm volatile ("CLI") /* disable interrupts */

/* keyboard interface IO port: data and control
   READ:   status port
   WRITE:   control register */
#define KBRD_INTRFC 0x64

/* keyboard interface bits */
#define KBRD_KDATA bit(0) /* keyboard data is (not) in buffer (bit 0) */
#define KBRD_UDATA bit(1) /* user data is (not) in buffer (bit 1) */

#define KBRD_IO 0x60 /* keyboard IO port */
#define KBRD_RESET 0xFE /* reset CPU command */

void reboot()
{
   byte temp;
   
   disable(); /* disable all interrupts */
   do /* empty user data in buffer */
   {
      temp = inb(KBRD_INTRFC);
      if ((temp & KBRD_KDATA) != 0)
         inb(KBRD_IO); /* empty keyboard data in buffer */
   } while ((temp & KBRD_UDATA) != 0);
   
   outb(KBRD_INTRFC, KBRD_RESET); /* pulse CPU reset line */
   halt(); /* if that didn't work, halt the CPU */
}

I've modified a bit the code; it might be ?big? but I think almost everything is explained, just as it should be
Please correct me if it's anything wrong.

[Slasher]

I have a function that works in both Bochs and on the real pc. Don't have it on me at the moment (at work), but will post it here.
(I don't know how to post on Wiki yet . Will figure out how to do it and post it there too)

[Solar]

Oh dudes, writing your own OS but not getting to grips with a Wiki?



To quote from the entry page of the FAQ:

• QuickGuide to the Wiki, by MartinBaute
• What is a WikiWikiWeb? A description of this application.
• Learn HowToUseWiki and learn about AddingPages.
• Use the SandBox page to experiment with Wiki pages, and find a GoodStyle.

Summary:

Go to the page you want to edit. Hit the "Edit" button. (Bottom left.) Edit the source. Use "Preview" button until satisfied. Use "Save" button.

Adding a comment (textbox bottom center) and logging in with a WikiName (textbox bottom right) is helpful and appreciated, but optional.

Come on. Writing OS code is harder.

And the markup is much simpler than HTML, believe me.

[marcio.f]

@all
Does someone knows the code to perform a shutdown/poweroff ?

@Code Slasher
Good, I'm looking forward to check it

@Solar
When the time is right, I'll learn how to use wiki

[smiddy]

Come on. Writing OS code is harder.

And the markup is much simpler than HTML, believe me.

I concur! I added my own stuff yesterday and it didn't hurt a bit.

[GLneo]

my code works on bochs, have you reset the a20 adderessing line ???, also to shut off the computer is very hard (i think) you have to go to real mode or something then comunicate with some protical api something.

p.s. there was a thead about it... somewhere

[marcio.f]

my code works on bochs, have you reset the a20 adderessing line ???

I don't think I did, but that's why I asked you in an early post if you did something before calling the reboot() function. If you want, take a look at the bochs log.

also to shut off the computer is very hard (i think) you have to go to real mode or something then comunicate with some protical api something.

p.s. there was a thead about it... somewhere

If there is I haven't found it because I searched the forum before creating this thread

[Slasher]

Here is the code I use. Works in both real pc and bochs

Code: Select all

KEYBOARD_BUSY     equ 0x02

_reset_pc:
                push ebp
                mov ebp,esp
                push eax

               cli

               call _wait_keyboard

               mov al,0xFE     ;send command to read output port to keyboard
               out 0x64,al

                sti
                pop eax
                mov esp,ebp
                pop ebp
                ret

_wait_keyboard:
               push eax
.wait:
               in al,0x64       ;wait for keyboard to be ready for next command
               test al,KEYBOARD_BUSY
               jnz .wait

               pop eax
               ret