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authorH. Peter Anvin <hpa@zytor.com>2007-02-04 15:59:37 -0800
committerH. Peter Anvin <hpa@zytor.com>2007-02-04 15:59:37 -0800
commit56810d7d98194e14c354ac58e1ac5b9d07ce6a2b (patch)
tree8e18c868a39b1ee657014f717a43c31face9db19
parent7cfd6f9dd9a73eb18c10948aaa0e56a52e0a4228 (diff)
downloadsyslinux.git-56810d7d98194e14c354ac58e1ac5b9d07ce6a2b.tar.gz
syslinux.git-56810d7d98194e14c354ac58e1ac5b9d07ce6a2b.tar.xz
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New MBR which supports logical partitions.
New MBR which supports logical partitions. Move the MBR to a subdirectory, and convert it to gas with the expectation of including it in util-linux.
-rw-r--r--Makefile18
-rw-r--r--mbr/Makefile47
-rwxr-xr-xmbr/checksize.pl31
-rw-r--r--mbr/mbr.S290
4 files changed, 378 insertions, 8 deletions
diff --git a/Makefile b/Makefile
index 7673cf5c..5814897f 100644
--- a/Makefile
+++ b/Makefile
@@ -63,12 +63,16 @@ BINFILES = bootsect_bin.c ldlinux_bin.c mbr_bin.c \
# mingw suite installed
BTARGET = kwdhash.gen version.gen version.h \
ldlinux.bss ldlinux.sys ldlinux.bin \
- pxelinux.0 mbr.bin isolinux.bin isolinux-debug.bin \
+ pxelinux.0 isolinux.bin isolinux-debug.bin \
extlinux.bin extlinux.bss extlinux.sys
-BOBJECTS = $(BTARGET) dos/syslinux.com win32/syslinux.exe memdisk/memdisk
+BOBJECTS = $(BTARGET) mbr/mbr.bin dos/syslinux.com win32/syslinux.exe memdisk/memdisk
+# BESUBDIRS and IESUBDIRS are "early", i.e. before the root; BSUBDIRS
+# and ISUBDIRS are "late", after the root.
+BESUBDIRS = mbr
BSUBDIRS = memdisk dos win32
ITARGET = copybs.com gethostip mkdiskimage
IOBJECTS = $(ITARGET) mtools/syslinux unix/syslinux extlinux/extlinux
+IESUBDIRS =
ISUBDIRS = mtools unix extlinux sample com32
DOCS = COPYING NEWS README TODO BUGS *.doc sample menu com32
OTHER = Makefile bin2c.pl now.pl genhash.pl keywords findpatch.pl \
@@ -102,9 +106,10 @@ MAKE += DATE=$(DATE) HEXDATE=$(HEXDATE)
# error every time you try to build.
#
-all: all-local
- set -e ; for i in $(BSUBDIRS) $(ISUBDIRS) ; do $(MAKE) -C $$i $@ ; done
+all:
+ set -e ; for i in $(BESUBDIRS) $(IESUBDIRS) ; do $(MAKE) -C $$i $@ ; done
$(MAKE) all-local
+ set -e ; for i in $(BSUBDIRS) $(ISUBDIRS) ; do $(MAKE) -C $$i $@ ; done
-ls -l $(BOBJECTS) $(IOBJECTS)
all-local: $(BTARGET) $(ITARGET) $(BINFILES)
@@ -167,10 +172,7 @@ extlinux.bss: extlinux.bin
extlinux.sys: extlinux.bin
dd if=$< of=$@ bs=512 skip=1
-mbr.bin: mbr.asm
- $(NASM) -f bin -l mbr.lst -o mbr.bin mbr.asm
-
-mbr_bin.c: mbr.bin bin2c.pl
+mbr_bin.c: mbr/mbr.bin bin2c.pl
$(PERL) bin2c.pl syslinux_mbr < $< > $@
copybs.com: copybs.asm
diff --git a/mbr/Makefile b/mbr/Makefile
new file mode 100644
index 00000000..d96ee467
--- /dev/null
+++ b/mbr/Makefile
@@ -0,0 +1,47 @@
+## -----------------------------------------------------------------------
+##
+## Copyright 2007 H. Peter Anvin - All Rights Reserved
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+## Boston MA 02111-1307, USA; either version 2 of the License, or
+## (at your option) any later version; incorporated herein by reference.
+##
+## -----------------------------------------------------------------------
+
+#
+# Makefile for MBR
+#
+
+gcc_ok = $(shell if gcc $(1) -c -x c /dev/null -o /dev/null 2>/dev/null; \
+ then echo $(1); else echo $(2); fi)
+
+M32 := $(call gcc_ok,-m32,) $(call gcc_ok,-ffreestanding,)
+
+CC = gcc
+LD = ld -m elf_i386
+SFLAGS = $(M32) -march=i386
+OBJCOPY = objcopy
+PERL = perl
+
+.SUFFIXES: .S .s .o .elf
+
+all: mbr.bin
+
+.PRECIOUS: %.o
+%.o: %.S
+ $(CC) $(SFLAGS) -c -o $@ $<
+
+mbr.elf: mbr.o
+ $(LD) -Ttext 0x600 -e _start -o $@ $^
+
+mbr.bin: mbr.elf checksize.pl
+ $(OBJCOPY) -O binary $< $@
+ $(PERL) checksize.pl mbr.bin 440
+
+tidy:
+ rm -f *.o *.elf
+
+clean:
+ rm -f *.o *.elf *.bin
diff --git a/mbr/checksize.pl b/mbr/checksize.pl
new file mode 100755
index 00000000..b7d560a0
--- /dev/null
+++ b/mbr/checksize.pl
@@ -0,0 +1,31 @@
+## -----------------------------------------------------------------------
+##
+## Copyright 2007 H. Peter Anvin - All Rights Reserved
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+## Boston MA 02111-1307, USA; either version 2 of the License, or
+## (at your option) any later version; incorporated herein by reference.
+##
+## -----------------------------------------------------------------------
+
+##
+## checksize.pl
+##
+## Check the size of a binary file
+##
+
+($file, $maxsize) = @ARGV;
+
+@st = stat($file);
+if (!defined($size = $st[7])) {
+ die "$0: $file: $!\n";
+}
+if ($size > $maxsize) {
+ print STDERR "$file: too big ($size > $maxsize)\n";
+ exit 1;
+} else {
+ exit 0;
+}
+
diff --git a/mbr/mbr.S b/mbr/mbr.S
new file mode 100644
index 00000000..edfccfb1
--- /dev/null
+++ b/mbr/mbr.S
@@ -0,0 +1,290 @@
+/* -----------------------------------------------------------------------
+ *
+ * Copyright 2007 H. Peter Anvin - All Rights Reserved
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall
+ * be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+ .code16
+ .text
+
+bootsec = 0x7c00
+stack = bootsec
+driveno = (stack-4)
+heads = (stack-6)
+sectors = (stack-8)
+
+BIOS_page = 0x462
+
+ .globl _start
+_start:
+ cli
+ xorw %ax, %ax
+ movw %ax, %ds
+ movw %ax, %ss
+ movw $stack, %sp
+ pushw %es /* es:di -> $PnP header */
+ pushw %di
+ pushw %dx /* dl -> drive number */
+ movw %ax, %es
+ sti
+ cld
+
+ /* Copy down to 0:0x600 */
+ movw %sp, %si
+ movw $_start, %di
+ movw $(512/2), %cx
+ rep; movsw
+
+ ljmpw $0, $next
+
+next:
+ /* Check to see if we have EBIOS */
+ pushw %dx /* drive number */
+ movw $0x4100, %ax
+ movw $0x55aa, %bx
+ xorw %cx, %cx
+ xorb %dh, %dh
+ stc
+ int $0x13
+ jc 1f
+ cmpw $0xaa55, %bx
+ jne 1f
+ testb $0x01, %cl
+ jz 1f
+
+ /* We have EBIOS; patch in a jump to read_sector_ebios */
+ movw $0xeb+((read_sector_ebios-read_sector_cbios+2)<< 8), (read_sector_cbios)
+
+1:
+ popw %dx
+
+ /* Get (C)HS geometry */
+ movb $0x08, %ah
+ int $0x13
+ xorw %ax, %ax
+ movb %dh, %al /* dh = number of heads */
+ incw %ax /* From 0-based to count */
+ pushw %ax /* Save heads on the stack */
+ andw $0x3f, %cx /* Sector count */
+ pushw %cx /* Save sectors on the stack */
+
+ xorl %eax, %eax
+ pushl %eax /* Base */
+ pushl %eax /* Root */
+ call scan_partition_table
+
+
+ /* If we get here, we have no OS */
+ jmp missing_os
+
+/*
+ * read_sector: read a single sector pointed to by %eax to 0x7c00.
+ * CF is set on error. All registers clobbered.
+ */
+read_sector:
+read_sector_cbios:
+ movl %eax, %edx
+ shrl $16, %edx
+ divw (sectors)
+ incw %dx
+ movw %dx, %cx
+ xorw %dx, %dx
+ divw (heads)
+ /* dx = head, ax = cylinder */
+ movb %al, %ch
+ shrw $2, %ax
+ shrw %ax
+ andb $0xc0, %al
+ orb %al, %cl
+ movb %dl, %dh
+ movw $bootsec, %bx
+ movw $0x0201, %ax
+ jmp read_common
+read_sector_ebios:
+ movw $dapa, %si
+ movl %eax, 8(%si)
+ movb $0x42, %ah
+read_common:
+ int $0x13
+ ret
+
+/*
+ * read_partition_table:
+ * Read a partition table (pointed to by %eax), and copy
+ * the partition table into the ptab buffer.
+ * Preserve registers.
+ */
+ptab = _start+446
+
+read_partition_table:
+ pushal
+ call read_sector
+ jc 20f
+ movw $bootsec+446, %si
+ movw $ptab, %di
+ movw $(16*4/2), %cx
+ rep ; movsw
+20:
+ popal
+ ret
+
+/*
+ * scan_partition_table:
+ * Scan a partition table currently loaded in the partition table
+ * area. Preserve 16-bit registers.
+ *
+ * On stack:
+ * 18(%bp) - root (offset from MBR, or 0 for MBR)
+ * 22(%bp) - base (location of this partition table)
+ */
+
+scan_partition_table:
+ pusha
+ movw %sp, %bp
+
+ /* Search for active partitions */
+ movw $ptab, %di
+ movw $4, %cx
+ xorw %ax, %ax
+5:
+ testb $0x80, (%di)
+ jz 6f
+ incw %ax
+ movw %di, %si
+6:
+ addw $16, %di
+ loopw 5b
+
+ cmpw $1, %ax /* Number of active partitions found */
+ je boot
+ ja too_many_active
+
+ /* No active partitions found, look for extended partitions */
+ movw $ptab, %di
+ movb $4, %cl /* cx == 0 here */
+7:
+ movb 4(%di), %al
+ cmpb $0x05, %al /* MS-DOS extended */
+ je 8f
+ cmpb $0x0f, %al /* Win9x extended */
+ je 8f
+ cmpb $0x85, %al /* Linux extended */
+ jne 9f
+
+ /* It is an extended partition. Read the extended partition and
+ try to scan it. If the scan returns, re-load the current
+ partition table and resume scan. */
+8:
+ movl 8(%di), %eax /* Partition table offset */
+ movl 18(%bp), %edx /* "Root" */
+ addl %edx, %eax /* Compute location of new ptab */
+ andl %edx, %edx /* Is this the MBR? */
+ jnz 10f
+ movl %eax, %edx /* Offset -> root if this was MBR */
+10:
+ pushl %eax /* Push new base */
+ pushl %edx /* Push new root */
+ call read_partition_table
+ jc 11f
+ call scan_partition_table
+11:
+ addw $8, %sp
+ /* This returned, so we need to reload the current partition table */
+ movl 22(%bp), %eax
+ call read_partition_table
+
+ /* fall through */
+9:
+ /* Not an extended partition */
+ addw $16, %di
+ loopw 7b
+
+ /* Nothing found, return */
+ popa
+ ret
+
+/*
+ * boot: invoke the actual bootstrap. (%si) points to the partition
+ * table entry, and 22(%bp) has the partition table base.
+ */
+boot:
+ movl 8(%si), %eax
+ addl 22(%bp), %eax
+ movl %eax, 8(%si)
+ call read_sector
+ jc disk_error
+ cmpw $0xaa55, (bootsec+0x510)
+ je missing_os /* Not a valid boot sector */
+ movw $stack-6, %sp
+ popw %dx /* dl -> drive number */
+ popw %di /* es:di -> $PnP vector */
+ popw %es
+ cli
+ jmp bootsec
+
+/*
+ * error messages
+ */
+missing_os:
+ movw $missing_os_msg, %si
+ jmp error
+disk_error:
+ movw $disk_error_msg, %si
+ jmp error
+too_many_active:
+ movw $too_many_active_msg, %si
+ /* jmp error */
+
+error:
+2:
+ lodsb
+ andb %al, %al
+ jz 3f
+ movb $0x0e, %ah
+ movb (BIOS_page), %bh
+ movb $0x07, %bl
+ int $0x10
+ jmp 2b
+3:
+ int $0x18 /* Boot failure */
+ jmp . /* Die */
+
+missing_os_msg:
+ .ascii "Missing operating system."
+ .byte 0
+disk_error_msg:
+ .ascii "Failed to load operating system."
+ .byte 0
+too_many_active_msg:
+ .ascii "Multiple active partititons."
+ .byte 0
+
+ .balign 4
+dapa:
+ .short 16 /* Size of packet */
+ .short 1 /* Sector count */
+ .short 0x7c00 /* Buffer offset */
+ .short 0 /* Buffer segment */
+ .long 0 /* LSW of LBA */
+ .long 0 /* MSW of LBA */