shithub: riscv

--- a/sys/src/boot/pc/pbs.s

+++ b/sys/src/boot/pc/pbs.s

@@ -76,6 +76,7 @@

 	MTSR(rAX, rES)

 	LWI(0x100, rCX)

+	MW(rSI,rBX)			/* address of partition record -> rBX */

 	LWI(RELOC, rSI)

 	MW(rSI, rSP)

 	LWI(_magic(SB), rDI)

@@ -97,10 +98,38 @@

STI

 	LWI(hello(SB), rSI)

 	CALL16(print16(SB))

-	LWI(crnl(SB), rSI)

-	CALL16(print16(SB))

-	LW(_volid(SB), rAX)		/* Xrootlo */

-	LW(_volid+2(SB), rBX)		/* Xroothi */

+	PUSHR(rDX)

+	PUSHR(rBX)

+	LB(_nfats(SB), rCL)		/* # of fats */

+	LW(_fatsize(SB), rAX)	/* fat size */

+	MUL(rCX)				/* DX:AX = #sectors */

+	JNE	_fatszok			/* zero? it's FAT32 */

+	LW(_fatsz32+2(SB), rBX)	/* hi word */

+	IMUL(rCX, rBX)			/* ... in sectors */

+	LW(_fatsz32(SB), rAX)	/* lo word */

+	MUL(rCX)				/* ... in sectors */

+	ADD(rBX, rDX)			/* DX:AX = #sectors */

+_fatszok:

+	POPR(rBX)			/* address of partition record */

+	LXW(8, xBX, rCX)	/* lo partition LBA */

+	ADD(rCX, rAX)

+	LXW(10, xBX, rCX)	/* hi partition LBA */

+	ADC(rCX, rDX)

+	CLR(rBX)

+	LW(_nresrv(SB), rCX)	/* # of reserved */

+	ADD(rCX, rAX)

+	ADC(rDX, rBX)

+	SW(rAX, _volid(SB))		/* save for later use */

+	SW(rDX, _volid+2(SB))

+	POPR(rDX)

 	PUSHR(rBP)

 	LW(_sectsize(SB), rCX)

 	SUB(rCX, rSP)

@@ -270,7 +299,5 @@

 	BYTE $'e'; BYTE $'r'; BYTE $'r'; BYTE $0

 TEXT hello(SB), $0

-	BYTE $'p'; BYTE $'b'; BYTE $'s'; BYTE $0

-TEXT crnl(SB), $0

-	BYTE $'\r'; BYTE $'\n'; BYTE $0

+	BYTE $'p'; BYTE $'b'; BYTE $'s'; BYTE $'\r';

+	BYTE $'\n'; BYTE $0

--- a/sys/src/cmd/disk/format.c

+++ b/sys/src/cmd/disk/format.c

@@ -560,14 +560,6 @@

 if(chatty) print("driveno = %ux\n", b->driveno);

 		b->bootsig = 0x29;

-		x = disk->offset + b->nfats*fatsecs + nresrv;

-		PUTLONG(b->volid, x);

-		/*

-		 * FAT32 9boot PBS requires volid at this

-		 * offset even for FAT16/FAT12 partitions.

-		 */

-		PUTLONG(b->volid+28, x);

-if(chatty) print("volid = %lux %lux\n", x, GETLONG(b->volid));

 		memmove(b->label, label, sizeof(b->label));

 		sprint(r, "FAT%d    ", fatbits);

 		memmove(b->type, r, sizeof(b->type));

--- a/sys/src/cmd/unix/mbrfix.c

+++ /dev/null

@@ -1,196 +1,0 @@

-#include <stdio.h>

-#include <stdlib.h>

-#include <stdarg.h>

-#include <sys/types.h>

-#include <fcntl.h>

-#include <unistd.h>

-#include <string.h>

-typedef unsigned char uchar;

-typedef unsigned int uint;

-typedef unsigned long long vlong;

-enum {

-	Sectsz = 0x200,

-	Psectsz = 11,

-	Pclustsc = 13,

-	Presvd = 14,

-	Pnumfat = 16,

-	Pfatsz = 22,

-	Pfatsz32 = 36,

-	Pvolid = 67,

-};

-int

-readn(int f, void *av, int n)

-{

-	char *a;

-	int m, t;

-	a = av;

-	t = 0;

-	while(t < n){

-		m = read(f, a+t, n-t);

-		if(m <= 0){

-			if(t == 0)

-				return m;

-			break;

-		}

-		t += m;

-	}

-	return t;

-}

-void

-sysfatal(char *fmt, ...)

-{

-	va_list va;

-	va_start(va, fmt);

-	vfprintf(stderr, fmt, va);

-	va_end(va);

-	fprintf(stderr, "\n");

-	exit(1);

-}

-void

-readsect(int fd, uint n, void *data)

-{

-	loff_t off;

-	off = (loff_t) n * Sectsz;

-	if(llseek(fd, off, SEEK_SET) != off)

-		sysfatal("seek to sector 0x%x failed", n);

-	if(readn(fd, data, Sectsz) != Sectsz)

-		sysfatal("short read: %m");

-}

-void

-writesect(int fd, uint n, void *data)

-{

-	loff_t off;

-	off = (loff_t) n * Sectsz;

-	if(llseek(fd, off, SEEK_SET) != off)

-		sysfatal("seek to sector 0x%x failed", n);

-	if(write(fd, data, Sectsz) != Sectsz)

-		sysfatal("short write: %m");

-}

-uint

-getulong(uchar *s)

-{

-	return s[0] | (s[1] << 8) | (s[2] << 16) | (s[3] << 24);

-}

-void

-putulong(uchar *s, uint n)

-{

-	*s++ = n & 0xff;

-	*s++ = (n >> 8) & 0xff;

-	*s++ = (n >> 16) & 0xff;

-	*s++ = (n >> 24) & 0xff;

-}

-uint

-getushort(uchar *s)

-{

-	return s[0] | (s[1] << 8);

-}

-int

-checksig(uchar *s)

-{

-	return s[0x1fe] == 0x55 && s[0x1ff] == 0xaa;

-}

-void

-fixpbs(uchar *pbs, uchar *pbs9, uint lba)

-{

-	uint a;

-	uint fatsz, resvd, numfat;

-	numfat = pbs[Pnumfat];

-	fatsz = getushort(&pbs[Pfatsz]);

-	if(fatsz == 0)

-		fatsz = getulong(&pbs[Pfatsz32]);

-	resvd = getushort(&pbs[Presvd]);

-	a = pbs9[1] + 2;

-	memcpy(pbs, pbs9, 3);

-	memcpy(pbs+a, pbs9+a, Sectsz-a-2);

-	a = lba + numfat * fatsz + resvd;

-	printf("Xroot=%x\n", a);

-	putulong(&pbs[Pvolid], a);

-}

-int

-main(int argc, char *argv[])

-{

-	int dev, fd, i;

-	uchar mbr9[Sectsz], pbs9[Sectsz];

-	uchar mbr[Sectsz], pbs[Sectsz];

-	uint lba;

-	int part, want;

-	char *mbrfn, *pbsfn, *devfn;

-	if(argc < 4)

-		sysfatal("usage: <device> <mbrfile> <pbsfile> [part]");

-	devfn = argv[1];

-	mbrfn = argv[2];

-	pbsfn = argv[3];

-	want = argc >= 5 ? atoi(argv[4]) : -1;

-	part = -1;

-	dev = open(devfn, O_RDWR);

-	if(dev < 0)

-		sysfatal("%s: %m", devfn);

-	if((fd = open(mbrfn, O_RDONLY)) < 0)

-		sysfatal("%s: %m", mbrfn);

-	if(readn(fd, mbr9, Sectsz) < 3)

-		sysfatal("%s: too short", mbrfn);

-	close(fd);

-	fd = open(pbsfn, O_RDONLY);

-	if(fd < 0)

-		sysfatal("%s: %m", pbsfn);

-	if(readn(fd, pbs9, Sectsz) < 3)

-		sysfatal("%s: too short", pbsfn);

-	if(pbs9[0] != 0xeb)

-		sysfatal("first byte of pbs not a short jump");

-	close(fd);

-	readsect(dev, 0, mbr);

-	if(!checksig(mbr))

-		sysfatal("sector 0 is missing signature");

-	for(i=0; i<4; i++){

-		if(mbr[0x1be + i*16] == 0x80 && (part == -1 || i == want))

-			part = i;

-	}

-	if(part == -1)

-		sysfatal("no bootable partitions found");

-	if(want != -1 && part != want)

-		sysfatal("partition %d is not bootable", want);

-	lba = getulong(&mbr[0x1be + part*16 + 8]);

-	if(lba == 0)

-		sysfatal("partition %d has zero LBA", part);

-	readsect(dev, lba, pbs);

-	if(!checksig(pbs))

-		sysfatal("partition %d (LBA=0x%x) is missing signaure", part, lba);

-	if(getushort(&pbs[Psectsz]) != 512)

-		sysfatal("sector size not 512");

-	printf("using partition %d, LBA=0x%x\n", part, lba);

-	memcpy(mbr, mbr9, 446);

-	fixpbs(pbs, pbs9, lba);

-	writesect(dev, 0, mbr);

-	writesect(dev, lba, pbs);

-	close(dev);

-	return 0;

-}