Subversion Repositories planix.SVN

/*

 * expand gzipped boot loader appended to this binary and execute it.

 *

 * due to Russ Cox, rsc@swtch.com.

 * see http://plan9.bell-labs.com/wiki/plan9/Replacing_9load

 */

#include <u.h>

#include <libc.h>

#include <a.out.h>

#include <flate.h>

#include "mem.h"

#include "expand.h"

#include "inflate.guts.c"

#define KB		1024

#define MB		(1024*1024)

extern char edata[];

/* ldecomp.s */

void mb586(void);

void splhi(void);

void wbinvd(void);

/* inflate.guts.c */

int gunzip(uchar*, int, uchar*, int);

int isexec(void*);

int isgzip(uchar*);

void run(void*);

#pragma varargck type "d" ulong

#pragma varargck type "x" ulong

static uchar *kernel = (uchar*)Bootkernaddr;

static char *dbrk = (char*)Mallocbase;

ulong

swap(ulong p)

{

	return p<<24 | p>>24 | (p<<8)&0x00FF0000 | (p>>8)&0x0000FF00;

}

enum {

	/* keyboard controller ports & cmds */

	Data=		0x60,		/* data port */

	Status=		0x64,		/* status port */

	 Inready=	0x01,		/*  input character ready */

	 Outbusy=	0x02,		/*  output busy */

	Cmd=		0x64,		/* command port (write only) */

	/* system control port a */

	Sysctla=	0x92,

	 Sysctlreset=	1<<0,

	 Sysctla20ena=	1<<1,

};

static int

isa20on(void)

{

	int r;

	ulong o;

	ulong *zp, *mb1p;

	zp = 0;

	mb1p = (ulong *)MB;

	o = *zp;

	*zp = 0x1234;

	*mb1p = 0x8765;

	mb586();

	wbinvd();

	r = *zp != *mb1p;

	*zp = o;

	return r;

}

static void

delay(uint ms)				/* approximate */

{

	int i;

	while(ms-- > 0)

		for(i = 1000*1000; i > 0; i--)

			;

}

static int

kbdinit(void)

{

	int c, try;

	/* wait for a quiescent controller */

	try = 500;			/* was 1000 */

	while(try-- > 0 && (c = inb(Status)) & (Outbusy | Inready)) {

		if(c & Inready)

			inb(Data);

		delay(1);

	}

	return try <= 0? -1: 0;

}

/*

 *  wait for output no longer busy (but not forever,

 *  there might not be a keyboard controller).

 */

static void

outready(void)

{

	int i;

	for (i = 1000; i > 0 && inb(Status) & Outbusy; i--)

		delay(1);

}

/*

 *  ask 8042 to enable the use of address bit 20

 */

int

i8042a20(void)

{

	if (kbdinit() < 0)

		return -1;

	outready();

	outb(Cmd, 0xD1);

	outready();

	outb(Data, 0xDF);

	outready();

	return 0;

}

void

a20init(void)

{

	int b;

	if (isa20on())

		return;

	if (i8042a20() < 0) {		/* original method, via kbd ctlr */

		/* newer method, last resort */

		b = inb(Sysctla);

		if (!(b & Sysctla20ena))

			outb(Sysctla, (b & ~Sysctlreset) | Sysctla20ena);

	}

	if (!isa20on()){

		print("a20 didn't come on!\n");

		for(;;)

			;

	}

}

void

_main(void)

{

	int ksize;

	Exec *exec;

	splhi();

	a20init();		/* don't wrap addresses at 1MB boundaries */

	ksize = Lowmemsz - (ulong)edata;	/* payload size */

	memmove(kernel, edata, ksize);

	memset(edata, 0, end - edata);

	cgainit();

	if(isgzip(kernel)) {

		print("gz...");

		memmove((uchar*)Unzipbuf, kernel, ksize);

		/* we have to uncompress the entire kernel to get OK status */

		if(gunzip(kernel, Bootkernmax, (uchar*)Unzipbuf, ksize) < 0){

			print("gzip failed.");

			exits(0);

		}

	}

	if(isexec(kernel))

		run(kernel);

	exec = (Exec *)kernel;

	print("unrecognized program; magic # 0x%x\n", swap(exec->magic));

	exits(0);

}

int

isexec(void *v)

{

	Exec *exec;

	exec = v;

	return swap(exec->magic) == I_MAGIC || swap(exec->magic) == S_MAGIC;

}

void

run(void *v)

{

	ulong entry, text, data;

	uchar *base;

	Exec *exec;

	base = v;

	exec = v;

	entry = swap(exec->entry) & ~KSEGM;

	text = swap(exec->text);

	data = swap(exec->data);

	/*

	 * align data segment on the expected page boundary.

	 * sizeof(Exec)+text is offset from base to data segment.

	 */

	memmove(base+PGROUND(sizeof(Exec)+text), base+sizeof(Exec)+text, data);

	print("starting protected-mode loader at 0x%x\n", entry);

	((void(*)(void))entry)();

	print("exec failed");

	exits(0);

}

int

isgzip(uchar *p)

{

	return p[0] == 0x1F && p[1] == 0x8B;

}

void*

malloc(ulong n)

{

	void *v;

	v = dbrk;

	dbrk += ROUND(n, BY2WD);

	return v;

}

void

free(void*)

{

}

void

puts(char *s)

{

	for(; *s; s++)

		cgaputc(*s);

}

int

print(char *fmt, ...)

{

	int sign;

	long d;

	ulong x;

	char *p, *s, buf[20];

	va_list arg;

	static char *hex = "0123456789abcdef";

	va_start(arg, fmt);

	for(p = fmt; *p; p++){

		if(*p != '%') {

			cgaputc(*p);

			continue;

		}

		SET(s);

		switch(*++p){

		case 'p':

		case 'x':

			x = va_arg(arg, ulong);

			if(x == 0){

				s = "0";

				break;

			}

			s = buf+sizeof buf;

			*--s = 0;

			while(x > 0){

				*--s = hex[x&15];

				x /= 16;

			}

			if(s == buf+sizeof buf)

				*--s = '0';

			break;

		case 'd':

			d = va_arg(arg, ulong);

			if(d == 0){

				s = "0";

				break;

			}

			if(d < 0){

				d = -d;

				sign = -1;

			}else

				sign = 1;

			s = buf+sizeof buf;

			*--s = 0;

			while(d > 0){

				*--s = (d%10)+'0';

				d /= 10;

			}

			if(sign < 0)

				*--s = '-';

			break;

		case 's':

			s = va_arg(arg, char*);

			break;

		case 0:

			return 0;

		}

		puts(s);

	}

	return 0;

}

void

exits(char*)

{

	for(;;)

		;

}