Date: Sat, 2 May 2009 23:35:51 +0200 From: Anders Nordby <anders@FreeBSD.org> To: Luigi Rizzo <luigi@FreeBSD.org>, svn-src-stable-7@freebsd.org Subject: Re: svn commit: r187198 - in stable/7: sys/boot/i386/boot0 usr.sbin/boot0cfg Message-ID: <20090502213551.GA52946@fupp.net> In-Reply-To: <200901132228.n0DMSnai018184@svn.freebsd.org> References: <200901132228.n0DMSnai018184@svn.freebsd.org>
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Hi, It seems that recent commits to boot0cfg and/or loader in RELENG_7, makes the -s for boot0cfg not work anymore. At least, in my setup, currdev and loaddev in loader is always set to disk0s1a (the first partition), no matter if I try to boot another partition. Did you try boot0cfg -s option since doing your updates? Regards, Anders. On Tue, Jan 13, 2009 at 10:28:49PM +0000, Luigi Rizzo wrote: > Author: luigi > Date: Tue Jan 13 22:28:48 2009 > New Revision: 187198 > URL: http://svn.freebsd.org/changeset/base/187198 > > Log: > MFC: a number of small fixes and enhancements to the boot0 code, > and matching modifications to boot0cfg. > > The most noticeable features are preserving the 4-byte volume ID > that certain Windows versions put in the MBR, and an option (F6) > to boot through INT18 that on some modern BIOSes invokes PXE. > > Modified: > stable/7/sys/boot/i386/boot0/boot0.S > stable/7/usr.sbin/boot0cfg/boot0cfg.8 > stable/7/usr.sbin/boot0cfg/boot0cfg.c > > Modified: stable/7/sys/boot/i386/boot0/boot0.S > ============================================================================== > --- stable/7/sys/boot/i386/boot0/boot0.S Tue Jan 13 22:15:47 2009 (r187197) > +++ stable/7/sys/boot/i386/boot0/boot0.S Tue Jan 13 22:28:48 2009 (r187198) > @@ -1,4 +1,5 @@ > /* > + * Copyright (c) 2008 Luigi Rizzo (mostly documentation) > * Copyright (c) 2002 Bruce M. Simpson > * Copyright (c) 1998 Robert Nordier > * All rights reserved. > @@ -16,50 +17,166 @@ > * $FreeBSD$ > */ > > -/* A 512-byte boot manager. */ > -#ifdef SIO > -/* ... using a serial console on COM1. */ > +/* build options: */ > +#ifdef SIO /* use serial console on COM1. */ > #endif > > +#ifdef PXE /* enable PXE/INT18 booting with F6 */ > +#define SAVE_MORE_MEMORY > +#endif > + > +#ifdef CHECK_DRIVE /* make sure we boot from a HD. */ > +#endif > + > +#ifdef ONLY_F_KEYS /* Only F1..F6, no digits on console */ > +#endif > + > +#ifdef VOLUME_SERIAL /* support Volume serial number */ > +#define B0_BASE 0x1ae /* move the internal data area */ > +#define SAVE_MEMORY > +#else > +#define B0_BASE 0x1b2 > +#endif > + > +#ifdef TEST /* enable some test code */ > +#define SAVE_MEMORY > +#define SAVE_MORE_MEMORY > +#endif > + > +/* > + * Note - this code uses many tricks to save space and fit in one sector. > + * This includes using side effects of certain instructions, reusing > + * register values from previous operations, etc. > + * Be extremely careful when changing the code, even for simple things. > + */ > + > +/* > + * BOOT BLOCK STRUCTURE > + * > + * This code implements a Master Boot Record (MBR) for an Intel/PC disk. > + * It is 512 bytes long and it is normally loaded by the BIOS (or another > + * bootloader) at 0:0x7c00. This code depends on %cs:%ip being 0:0x7c00 > + * > + * The initial chunk of instructions is used as a signature by external > + * tools (e.g. boot0cfg) which can manipulate the block itself. > + * > + * The area at offset 0x1b2 contains a magic string ('Drive '), also > + * used as a signature to detect the block, and some variables that can > + * be updated by boot0cfg (and optionally written back to the disk). > + * These variables control the operation of the bootloader itself, > + * e.g. which partitions to enable, the timeout, the use of LBA > + * (called 'packet') or CHS mode, whether to force a drive number, > + * and whether to write back the user's selection back to disk. > + * > + * As in every Master Boot Record, the partition table is at 0x1be, > + * made of four 16-byte entries each containing: > + * > + * OFF SIZE DESCRIPTION > + * 0 1 status (0x80: bootable, 0: non bootable) > + * 1 3 start sector CHS > + * 8:head, 6:sector, 2:cyl bit 9..8, 8:cyl bit 7..0 > + * 4 1 partition type > + * 5 3 end sector CHS > + * 8 4 LBA of first sector > + * 12 4 partition size in sectors > + * > + * and followed by the two bytes 0x55, 0xAA (MBR signature). > + */ > + > + > +/* > + * BOOT BLOCK OPERATION > + * > + * On entry, the registers contain the following values: > + * > + * %cs:%ip 0:0x7c00 > + * %dl drive number (0x80, 0x81, ... ) > + * %si pointer to the partition table from which we were loaded. > + * Some boot code (e.g. syslinux) use this info to relocate > + * themselves, so we want to pass a valid one to the next stage. > + * NOTE: the use of %si is not a standard. > + * > + * This boot block first relocates itself at a different address (0:0x600), > + * to free the space at 0:0x7c00 for the next stage boot block. > + * > + * It then initializes some memory at 0:0x800 and above (pointed by %bp) > + * to store the original drive number (%dl) passed to us, and to construct a > + * fake partition entry. The latter is used by the disk I/O routine and, > + * in some cases, passed in %si to the next stage boot code. > + * > + * The variables at 0x1b2 are accessed as negative offsets from %bp. > + * > + * After the relocation, the code scans the partition table printing > + * out enabled partition or disks, and waits for user input. > + * > + * When a partition is selected, or a timeout expires, the currently > + * selected partition is used to load the next stage boot code, > + * %dl and %si are set appropriately as when we were called, and > + * control is transferred to the newly loaded code at 0:0x7c00. > + */ > + > +/* > + * CONSTANTS > + * > + * NHRDRV is the address in segment 0 where the BIOS writes the > + * total number of hard disks in the system. > + * LOAD is the original load address and cannot be changed. > + * ORIGIN is the relocation address. If you change it, you also need > + * to change the value passed to the linker in the Makefile > + * PRT_OFF is the location of the partition table (from the MBR standard). > + * B0_OFF is the location of the data area, known to boot0cfg so > + * it cannot be changed. Computed as a negative offset from 0x200 > + * MAGIC is the signature of a boot block. > + */ > + > .set NHRDRV,0x475 # Number of hard drives > .set ORIGIN,0x600 # Execution address > - .set FAKE,0x800 # Partition entry > .set LOAD,0x7c00 # Load address > > .set PRT_OFF,0x1be # Partition table > - > - .set TBL0SZ,0x3 # Table 0 size > - .set TBL1SZ,0xa # Table 1 size > + .set B0_OFF,(B0_BASE-0x200) # Offset of boot0 data > > .set MAGIC,0xaa55 # Magic: bootable > - .set B0MAGIC,0xbb66 # Identification > > .set KEY_ENTER,0x1c # Enter key scan code > .set KEY_F1,0x3b # F1 key scan code > .set KEY_1,0x02 # #1 key scan code > > - .set ASCII_BEL,0x07 # ASCII code for <BEL> > + .set ASCII_BEL,'#' # ASCII code for <BEL> > .set ASCII_CR,0x0D # ASCII code for <CR> > > /* > - * Addresses in the sector of embedded data values. > - * Accessed with negative offsets from the end of the relocated sector (%ebp). > - */ > - .set _NXTDRV,-0x48 # Next drive > - .set _OPT,-0x47 # Default option > - .set _SETDRV,-0x46 # Drive to force > - .set _FLAGS,-0x45 # Flags > - .set _TICKS,-0x44 # Timeout ticks > - .set _FAKE,0x0 # Fake partition entry > - .set _MNUOPT,0xc # Menu options > + * Offsets of variables in the block at B0_OFF, and in the volatile > + * data area, computed as displacement from %bp. > + * We need to define them as constant as the assembler cannot > + * compute them in its single pass. > + */ > + .set _NXTDRV, B0_OFF+6 # Next drive > + .set _OPT, B0_OFF+7 # Default option > + .set _SETDRV, B0_OFF+8 # Drive to force > + .set _FLAGS, B0_OFF+9 # Flags > + .set SETDRV, 0x20 # the 'setdrv' flag > + .set NOUPDATE, 0x40 # the 'noupdate' flag > + .set USEPACKET, 0x80 # the 'packet' flag > + > + /* ticks is at a fixed position */ > + .set _TICKS, (PRT_OFF - 0x200 - 2) # Timeout ticks > + .set _MNUOPT, 0x10 # Saved menu entries > > + .set TLEN, (desc_ofs - bootable_ids) # size of bootable ids > .globl start # Entry point > .code16 # This runs in real mode > > /* > + * MAIN ENTRY POINT > * Initialise segments and registers to known values. > * segments start at 0. > * The stack is immediately below the address we were loaded to. > + * NOTE: the initial section of the code (up to movw $LOAD,%sp) > + * is used by boot0cfg, together with the 'Drive ' string and > + * the 0x55, 0xaa at the end, as an identifier for version 1.0 > + * of the boot code. Do not change it. > + * In version 1.0 the parameter table (_NEXTDRV etc) is at 0x1b9 > */ > start: cld # String ops inc > xorw %ax,%ax # Zero > @@ -69,7 +186,7 @@ start: cld # String ops inc > movw $LOAD,%sp # stack > > /* > - * Copy this code to the address it was linked for > + * Copy this code to the address it was linked for, 0x600 by default. > */ > movw %sp,%si # Source > movw $start,%di # Destination > @@ -77,248 +194,301 @@ start: cld # String ops inc > rep # Relocate > movsw # code > /* > - * Set address for variable space beyond code, and clear it. > - * Notice that this is also used to point to the values embedded in the block, > - * by using negative offsets. > + * After the code, (i.e. at %di+0, 0x800) create a partition entry, > + * initialized to LBA 0 / CHS 0:0:1. > + * Set %bp to point to the partition and also, with negative offsets, > + * to the variables embedded in the bootblock (nextdrv and so on). > */ > movw %di,%bp # Address variables > movb $0x8,%cl # Words to clear > rep # Zero > stosw # them > -/* > - * Relocate to the new copy of the code. > - */ > - incb -0xe(%di) # Sector number > - jmp main-LOAD+ORIGIN # To relocated code > + incb -0xe(%di) # Set the S field to 1 > + > + jmp main-LOAD+ORIGIN # Jump to relocated code > > main: > #if defined(SIO) && COMSPEED != 0 > /* > - * Initialize the serial port. bioscom preserves the driver number in DX. > + * Init the serial port. bioscom preserves the driver number in DX. > */ > movw $COMSPEED,%ax # defined by Makefile > callw bioscom > #endif > + > /* > - * Check what flags were loaded with us, specifically if a predefined drive > - * number should be used. If what the bios gives us is bad, use the '0' in > - * the block instead. > - */ > - testb $0x20,_FLAGS(%bp) # Set drive number? > - jnz main.1 # Yes > + * If the 'setdrv' flag is set in the boot sector, use the drive > + * number from the boot sector at 'setdrv_num'. > + * Optionally, do the same if the BIOS gives us an invalid number > + * (note though that the override prevents booting from a floppy > + * or a ZIP/flash drive in floppy emulation). > + * The test costs 4 bytes of code so it is disabled by default. > + */ > + testb $SETDRV,_FLAGS(%bp) # Set drive number? > +#ifndef CHECK_DRIVE /* disable drive checks */ > + jz save_curdrive # no, use the default > +#else > + jnz disable_update # Yes > testb %dl,%dl # Drive number valid? > - js main.2 # Possibly (0x80 set) > + js save_curdrive # Possibly (0x80 set) > +#endif > /* > - * Only update the boot-sector when there is a valid drive number or > - * the drive number is set manually. > + * Disable updates if the drive number is forced. > */ > - orb $0x40,_FLAGS(%bp) # Disable updates > -main.1: movb _SETDRV(%bp),%dl # Drive number to use > +disable_update: orb $NOUPDATE,_FLAGS(%bp) # Disable updates > + movb _SETDRV(%bp),%dl # Use stored drive number > + > /* > - * Whatever we decided to use, now store it into the fake > - * partition entry that lives in the data space above us. > - */ > -main.2: movb %dl,_FAKE(%bp) # Save drive number > - callw putn # To new line > - pushw %dx # Save drive number > + * Whatever drive we decided to use, store it at (%bp). The byte > + * is normally used for the state of the partition (0x80 or 0x00), > + * but we abuse it as it is very convenient to access at offset 0. > + * The value is read back after 'check_selection' > + */ > +save_curdrive: movb %dl, (%bp) # Save drive number > + pushw %dx # Also in the stack > +#ifdef TEST /* test code, print internal bios drive */ > + rolb $1, %dl > + movw $drive, %si > + call putkey > +#endif > + callw putn # Print a newline > /* > * Start out with a pointer to the 4th byte of the first table entry > * so that after 4 iterations it's beyond the end of the sector > - * and beyond a 256 byte boundary and has overflowed 8 bits (see next comment). > - * Remember that the table starts 2 bytes earlier than you would expect > - * as the bootable flag is after it in the block. > + * and beyond a 256 byte boundary. We use the latter trick to check for > + * end of the loop without using an extra register (see start.5). > */ > movw $(partbl+0x4),%bx # Partition table (+4) > xorw %dx,%dx # Item number > + > /* > * Loop around on the partition table, printing values until we > - * pass a 256 byte boundary. The end of loop test is at main.5. > + * pass a 256 byte boundary. > */ > -main.3: movb %ch,-0x4(%bx) # Zero active flag (ch == 0) > +read_entry: movb %ch,-0x4(%bx) # Zero active flag (ch == 0) > btw %dx,_FLAGS(%bp) # Entry enabled? > - jnc main.5 # No > -/* > - * If any of the entries in the table are the same as the 'type' in the slice > - * table entry, then this is an empty or non bootable partition. Skip it. > - */ > + jnc next_entry # No > movb (%bx),%al # Load type > - movw $tables,%di # Lookup tables > - movb $TBL0SZ,%cl # Number of entries > - repne # Exclude > - scasb # partition? > - je main.5 # Yes > + test %al, %al # skip empty partition > + jz next_entry > /* > - * Now scan the table of known types > + * Scan the table of bootable ids, which starts at %di and has > + * length TLEN. On a match, %di points to the element following the > + * match; the corresponding offset to the description is $(TLEN-1) > + * bytes ahead. We use a count of TLEN+1 so if we don't find a match > + * within the first TLEN entries, we hit the 'unknown' entry. > */ > - movb $TBL1SZ+1,%cl # Number of entries > + movw $bootable_ids,%di # Lookup tables > + movb $(TLEN+1),%cl # Number of entries > repne # Locate > scasb # type > /* > * Get the matching element in the next array. > + * The byte at $(TLEN-1)(%di) contains the offset of the description > + * string from %di, so we add the number and print the string. > */ > - addw $TBL1SZ-1, %di # Adjust > + addw $(TLEN-1), %di # Adjust > movb (%di),%cl # Partition > addw %cx,%di # description > callw putx # Display it > -main.5: incw %dx # Next item > + > +next_entry: incw %dx # Next item > addb $0x10,%bl # Next entry > - jnc main.3 # Till done > + jnc read_entry # Till done > /* > - * Passed a 256 byte boundary; the table is finished. > + * We are past a 256 byte boundary: the partition table is finished. > * Add one to the drive number and check it is valid. > + * Note that if we started from a floppy, %dl was 0 so we still > + * get an entry for the next drive, which is the first Hard Disk. > */ > popw %ax # Drive number > subb $0x80-0x1,%al # Does next > cmpb NHRDRV,%al # drive exist? (from BIOS?) > - jb main.6 # Yes > + jb print_drive # Yes > /* > * If this is the only drive, don't display it as an option. > */ > decw %ax # Already drive 0? > - jz main.7 # Yes > + jz print_prompt # Yes > /* > * If it was illegal or we cycled through them, go back to drive 0. > */ > xorb %al,%al # Drive 0 > /* > - * Whatever drive we selected, make it an ascii digit and save it back to the > - * "next drive" location in the loaded block in case we want to save it later > - * for next time. This also is part of the printed drive string so add 0x80 > + * Whatever drive we selected, make it an ascii digit and save it > + * back to the "nxtdrv" location in case we want to save it to disk. > + * This digit is also part of the printed drive string, so add 0x80 > * to indicate end of string. > */ > -main.6: addb $'0'|0x80,%al # Save next > +print_drive: addb $'0'|0x80,%al # Save next > movb %al,_NXTDRV(%bp) # drive number > movw $drive,%di # Display > callw putx # item > /* > - * Now that we've printed the drive (if we needed to), display a prompt. > + * Menu is complete, display a prompt followed by current selection. > + * 'decw %si' makes the register point to the space after 'Boot: ' > + * so we do not see an extra CRLF on the screen. > */ > -main.7: movw $prompt,%si # Display > +print_prompt: movw $prompt,%si # Display > callw putstr # prompt > movb _OPT(%bp),%dl # Display > decw %si # default > callw putkey # key > - jmp main.7_1 # Skip beep > + jmp start_input # Skip beep > + > /* > - * Users's last try was bad, beep in displeasure. > + * Here we have the code waiting for user input or a timeout. > */ > -main.10: movb $ASCII_BEL,%al # Signal > - callw putchr # beep! > +beep: movb $ASCII_BEL,%al # Input error, print or beep > + callw putchr > + > +start_input: > /* > - * Start of input loop. Take note of time > + * Actual Start of input loop. Take note of time > */ > -main.7_1: xorb %ah,%ah # BIOS: Get > + xorb %ah,%ah # BIOS: Get > int $0x1a # system time > movw %dx,%di # Ticks when > addw _TICKS(%bp),%di # timeout > +read_key: > /* > * Busy loop, looking for keystrokes but keeping one eye on the time. > */ > -main.8: > #ifndef SIO > movb $0x1,%ah # BIOS: Check > int $0x16 # for keypress > - jnz main.11 # Have one > #else /* SIO */ > movb $0x03,%ah # BIOS: Read COM > call bioscom > testb $0x01,%ah # Check line status > - jnz main.11 # (bit 1 indicates input) > + # (bit 1 indicates input) > #endif /* SIO */ > - xorb %ah,%ah # BIOS: Get > - int $0x1a # system time > + jnz got_key # Have input > + xorb %ah,%ah # BIOS: int 0x1a, 00 > + int $0x1a # get system time > cmpw %di,%dx # Timeout? > - jb main.8 # No > + jb read_key # No > + > /* > - * If timed out or defaulting, come here. > + * Timed out or default selection > */ > -main.9: movb _OPT(%bp),%al # Load default > - jmp main.12 # Join common code > +use_default: movb _OPT(%bp),%al # Load default > + orb $NOUPDATE,_FLAGS(%bp) # Disable updates > + jmp check_selection # Join common code > + > /* > * Get the keystroke. > + * ENTER or CR confirm the current selection (same as a timeout). > + * Otherwise convert F1..F6 (or '1'..'6') to 0..5 and check if the > + * selection is valid. > + * The SIO code uses ascii chars, the console code uses scancodes. > */ > -main.11: > +got_key: > #ifndef SIO > - xorb %ah,%ah # BIOS: Get > - int $0x16 # keypress > - movb %ah,%al # Scan code > + xorb %ah,%ah # BIOS: int 0x16, 00 > + int $0x16 # get keypress > + movb %ah,%al # move scan code to %al > + cmpb $KEY_ENTER,%al > #else > movb $0x02,%ah # BIOS: Receive > call bioscom > + cmpb $ASCII_CR,%al > #endif > + je use_default # enter -> default > /* > - * If it's CR act as if timed out. > - */ > -#ifndef SIO > - cmpb $KEY_ENTER,%al # Enter pressed? > -#else > - cmpb $ASCII_CR,%al # Enter pressed? > -#endif > - je main.9 # Yes > -/* > - * Otherwise check if legal. If not ask again. > - */ > -#ifndef SIO > - subb $KEY_F1,%al # Less F1 scan code > - cmpb $0x4,%al # F1..F5? > - jna main.12 # Yes > + * Check if the key is acceptable, and loop back if not. > + * The console (non-SIO) code looks at scancodes and accepts > + * both F1..F6 and 1..6 (the latter costs 6 bytes of code), > + * relying on the fact that F1..F6 have higher scancodes than 1..6 > + * The SIO code only takes 1..6 > + */ > +#ifdef SIO /* SIO mode, use ascii values */ > + subb $'1',%al # Subtract '1' ascii code > +#else /* console mode -- use scancodes */ > + subb $KEY_F1,%al /* Subtract F1 scan code */ > +#if !defined(ONLY_F_KEYS) > + cmpb $0x5,%al # F1..F6 > + jna 3f # Yes > subb $(KEY_1 - KEY_F1),%al # Less #1 scan code > -#else > - subb $'1',%al # Less '1' ascii character > -#endif > - cmpb $0x4,%al # #1..#5? > - ja main.10 # No > + 3: > +#endif /* ONLY_F_KEYS */ > +#endif /* SIO */ > + cmpb $0x5,%al # F1..F6 or 1..6 ? > +#ifdef PXE /* enable PXE/INT18 using F6 */ > + jne 1f; > + int $0x18 # found F6, try INT18 > + 1: > +#endif /* PXE */ > + jae beep # Not in F1..F5, beep > + > +check_selection: > /* > * We have a selection. If it's a bad selection go back to complain. > * The bits in MNUOPT were set when the options were printed. > * Anything not printed is not an option. > */ > -main.12: cbtw # Option > - btw %ax,_MNUOPT(%bp) # enabled? > - jnc main.10 # No > + cbtw # Extend (%ah=0 used later) > + btw %ax,_MNUOPT(%bp) # Option enabled? > + jnc beep # No > /* > * Save the info in the original tables > * for rewriting to the disk. > */ > movb %al,_OPT(%bp) # Save option > - movw $FAKE,%si # Partition for write > - movb (%si),%dl # Drive number > + > + /* > + * Make %si and %bx point to the fake partition at LBA 0 (CHS 0:0:1). > + * Because the correct address is already in %bp, just use it. > + * Set %dl with the drive number saved in byte 0. > + * If we have pressed F5 or 5, then this is a good, fake value > + * to present to the next stage boot code. > + */ > + movw %bp,%si # Partition for write > + movb (%si),%dl # Drive number, saved above > movw %si,%bx # Partition for read > cmpb $0x4,%al # F5/#5 pressed? > - pushf # Save > - je main.13 # Yes > + pushf # Save results for later > + je 1f # Yes, F5 > + > + /* > + * F1..F4 was pressed, so make %bx point to the currently > + * selected partition, and leave the drive number unchanged. > + */ > shlb $0x4,%al # Point to > addw $partbl,%ax # selected > xchgw %bx,%ax # partition > movb $0x80,(%bx) # Flag active > /* > * If not asked to do a write-back (flags 0x40) don't do one. > + * Around the call, save the partition pointer to %bx and > + * restore to %si which is where the next stage expects it. > */ > -main.13: pushw %bx # Save > - testb $0x40,_FLAGS(%bp) # No updates? > - jnz main.14 # Yes > + 1: pushw %bx # Save > + testb $NOUPDATE,_FLAGS(%bp) # No updates? > + jnz 2f # skip update > movw $start,%bx # Data to write > movb $0x3,%ah # Write sector > callw intx13 # to disk > -main.14: popw %si # Restore > - popf # Restore > + 2: popw %si # Restore > + > /* > * If going to next drive, replace drive with selected one. > * Remember to un-ascii it. Hey 0x80 is already set, cool! > */ > - jne main.15 # If not F5/#5 > + popf # Restore %al test results > + jne 3f # If not F5/#5 > movb _NXTDRV(%bp),%dl # Next drive > subb $'0',%dl # number > /* > - * Load selected bootsector to the LOAD location in RAM. > - * If it fails to read or isn't marked bootable, treat it as a bad selection. > + * Load selected bootsector to the LOAD location in RAM. If read > + * fails or there is no 0x55aa marker, treat it as a bad selection. > */ > -main.15: movw $LOAD,%bx # Address for read > + 3: movw $LOAD,%bx # Address for read > movb $0x2,%ah # Read sector > callw intx13 # from disk > - jc main.10 # If error > + jc beep # If error > cmpw $MAGIC,0x1fe(%bx) # Bootable? > - jne main.10 # No > + jne beep # No > pushw %si # Save ptr to selected part. > callw putn # Leave some space > popw %si # Restore, next stage uses it > @@ -326,64 +496,80 @@ main.15: movw $LOAD,%bx # Address for > > /* > * Display routines > + * putkey prints the option selected in %dl (F1..F5 or 1..5) followed by > + * the string at %si > + * putx: print the option in %dl followed by the string at %di > + * also record the drive as valid. > + * putn: print a crlf > + * putstr: print the string at %si > + * putchr: print the char in al > */ > -putkey: > -#ifndef SIO > - movb $'F',%al # Display > - callw putchr # 'F' > -#endif > - movb $'1',%al # Prepare > - addb %dl,%al # digit > - jmp putstr.1 # Display the rest > > /* > - * Display the option and note that it is a valid option. > - * That last point is a bit tricky.. > + * Display the option and record the drive as valid in the options. > + * That last point is done using the btsw instruction which does > + * a test and set. We don't care for the test part. > */ > putx: btsw %dx,_MNUOPT(%bp) # Enable menu option > movw $item,%si # Display > callw putkey # key > movw %di,%si # Display the rest > - > -puts: callw putstr # Display string > + callw putstr # Display string > > putn: movw $crlf,%si # To next line > + jmp putstr > + > +putkey: > +#ifndef SIO > + movb $'F',%al # Display > + callw putchr # 'F' > +#endif > + movb $'1',%al # Prepare > + addb %dl,%al # digit > > +putstr.1: callw putchr # Display char > putstr: lodsb # Get byte > testb $0x80,%al # End of string? > - jnz putstr.2 # Yes > -putstr.1: callw putchr # Display char > - jmp putstr # Continue > -putstr.2: andb $~0x80,%al # Clear MSB > + jz putstr.1 # No > + andb $~0x80,%al # Clear MSB then print last > > -#ifndef SIO > putchr: > +#ifndef SIO > pushw %bx # Save > movw $0x7,%bx # Page:attribute > movb $0xe,%ah # BIOS: Display > int $0x10 # character > popw %bx # Restore > - retw # To caller > #else /* SIO */ > -putchr: > movb $0x01,%ah # BIOS: Send > bioscom: > pushw %dx # Save > xorw %dx,%dx # Use COM1 > int $0x14 # Character > popw %dx # Restore > - retw # To caller > #endif /* SIO */ > + retw # To caller > > /* One-sector disk I/O routine */ > > -intx13: movb 0x1(%si),%dh # Load head > +/* > + * %dl: drive, %si partition entry, %es:%bx transfer buffer. > + * Load the CHS values and possibly the LBA address from the block > + * at %si, and use the appropriate method to load the sector. > + * Don't use packet mode for a floppy. > + */ > +intx13: # Prepare CHS parameters > + movb 0x1(%si),%dh # Load head > movw 0x2(%si),%cx # Load cylinder:sector > movb $0x1,%al # Sector count > pushw %si # Save > movw %sp,%di # Save > - testb $0x80,_FLAGS(%bp) # Use packet interface? > - jz intx13.1 # No > +#ifndef CHECK_DRIVE /* floppy support */ > + testb %dl, %dl # is this a floppy ? > + jz 1f # Yes, use CHS mode > +#endif > + testb $USEPACKET,_FLAGS(%bp) # Use packet interface? > + jz 1f # No > pushl $0x0 # Set the > pushl 0x8(%si) # LBA address > pushw %es # Set the transfer > @@ -393,73 +579,104 @@ intx13: movb 0x1(%si),%dh # Load head > movw %sp,%si # Packet pointer > decw %ax # Verify off > orb $0x40,%ah # Use disk packet > -intx13.1: int $0x13 # BIOS: Disk I/O > + 1: int $0x13 # BIOS: Disk I/O > movw %di,%sp # Restore > popw %si # Restore > retw # To caller > > -/* Menu strings */ > - > +/* > + * Various menu strings. 'item' goes after 'prompt' to save space. > + * Also use shorter versions to make room for the PXE/INT18 code. > + */ > +prompt: > +#ifdef PXE > + .ascii "\nF6 PXE\r" > +#endif > + .ascii "\nBoot:" > item: .ascii " "; .byte ' '|0x80 > -prompt: .ascii "\nDefault:"; .byte ' '|0x80 > crlf: .ascii "\r"; .byte '\n'|0x80 > > /* Partition type tables */ > > -tables: > +bootable_ids: > /* > - * These entries identify invalid or NON BOOT types and partitions. > - */ > - .byte 0x0, 0x5, 0xf > + * These values indicate bootable types we know about. > + * Corresponding descriptions are at desc_ofs: > + * Entries don't need to be sorted. > + */ > + .byte 0x83, 0xa5, 0xa6, 0xa9, 0x06, 0x07, 0x0b > +#ifndef SAVE_MORE_MEMORY > + .byte 0x05 # extended partition > +#endif > +#ifndef SAVE_MEMORY /* other DOS partitions */ > + .byte 0x01 # FAT12 > + .byte 0x04 # FAT16 < 32M > +#endif > + > +desc_ofs: > /* > - * These values indicate bootable types we know the names of. > - */ > - .byte 0x1, 0x6, 0x7, 0xb, 0xc, 0xe, 0x83 > - .byte 0xa5, 0xa6, 0xa9 > -/* > - * These are offsets that match the known names above and point to the strings > - * that will be printed. os_misc will be used if the search of the above table > - * runs over. > - */ > - .byte os_dos-. # DOS > - .byte os_dos-. # DOS > - .byte os_dos-. # Windows > - .byte os_dos-. # Windows > - .byte os_dos-. # Windows > - .byte os_dos-. # Windows > - .byte os_linux-. # Linux > - .byte os_freebsd-. # FreeBSD > - .byte os_bsd-. # OpenBSD > - .byte os_bsd-. # NetBSD > + * Offsets that match the known types above, used to point to the > + * actual partition name. The last entry must point to os_misc, > + * which is used for non-matching names. > + */ > + .byte os_linux-. # 131, Linux > + .byte os_freebsd-. # 165, FreeBSD > + .byte os_bsd-. # 166, OpenBSD > + .byte os_bsd-. # 169, NetBSD > + .byte os_dos-. # 6, FAT16 >= 32M > + .byte os_win-. # 7, NTFS > + .byte os_win-. # 11, FAT32 > + > +#ifndef SAVE_MORE_MEMORY > + .byte os_ext-. # 5, DOS Ext > +#endif > +#ifndef SAVE_MEMORY > + .byte os_dos-. # 1, FAT12 DOS > + .byte os_dos-. # 4, FAT16 <32M > +#endif > .byte os_misc-. # Unknown > + > /* > - * And here are the strings themselves. 0x80 or'd into a byte indicates > - * the end of the string. (not so great for Russians but...) > + * And here are the strings themselves. The last byte of > + * the string has bit 7 set. > */ > -os_misc: .ascii "?"; .byte '?'|0x80 > -os_dos: .ascii "DO"; .byte 'S'|0x80 > +os_misc: .byte '?'|0x80 > +os_dos: > +#ifndef SAVE_MORE_MEMORY /* 'DOS' remapped to 'WIN' if no room */ > + .ascii "DO"; .byte 'S'|0x80 > +#endif > +os_win: .ascii "Wi"; .byte 'n'|0x80 > os_linux: .ascii "Linu"; .byte 'x'|0x80 > os_freebsd: .ascii "Free" > os_bsd: .ascii "BS"; .byte 'D'|0x80 > +#ifndef SAVE_MORE_MEMORY > +os_ext: .ascii "EX"; .byte 'T'|0x80 > +#endif > > - .org PRT_OFF-0xe,0x90 > - > - .word B0MAGIC # Magic number > - > + .org (0x200 + B0_OFF),0x90 > /* > - * These values are sometimes changed before writing back to the drive > + * The boot0 version 1.0 parameter table. > + * Do not move it nor change the "Drive " string, boot0cfg > + * uses its offset and content to identify the boot sector. > + * The other fields are sometimes changed before writing back to the drive > * Be especially careful that nxtdrv: must come after drive:, as it > * is part of the same string. > */ > drive: .ascii "Drive " > nxtdrv: .byte 0x0 # Next drive number > opt: .byte 0x0 # Option > -setdrv: .byte 0x80 # Drive to force > +setdrv_num: .byte 0x80 # Drive to force > flags: .byte FLAGS # Flags > +#ifdef VOLUME_SERIAL > + .byte 0xa8,0xa8,0xa8,0xa8 # Volume Serial Number > +#endif > ticks: .word TICKS # Delay > > + .org PRT_OFF > /* > * Here is the 64 byte partition table that fdisk would fiddle with. > */ > partbl: .fill 0x40,0x1,0x0 # Partition table > .word MAGIC # Magic number > + .org 0x200 # again, safety check > +endblock: > > Modified: stable/7/usr.sbin/boot0cfg/boot0cfg.8 > ============================================================================== > --- stable/7/usr.sbin/boot0cfg/boot0cfg.8 Tue Jan 13 22:15:47 2009 (r187197) > +++ stable/7/usr.sbin/boot0cfg/boot0cfg.8 Tue Jan 13 22:28:48 2009 (r187198) > @@ -24,7 +24,7 @@ > .\" > .\" $FreeBSD$ > .\" > -.Dd June 7, 2007 > +.Dd January 13, 2009 > .Dt BOOT0CFG 8 > .Os > .Sh NAME > @@ -35,7 +35,9 @@ > .Op Fl Bv > .Op Fl b Ar boot0 > .Op Fl d Ar drive > +.Op Fl e Ar bell character > .Op Fl f Ar file > +.Op Fl i Ar volume-id > .Op Fl m Ar mask > .Op Fl o Ar options > .Op Fl s Ar slice > @@ -96,10 +98,17 @@ which contains the specified > Typically this will be 0x80 for the first hard drive, 0x81 for the > second hard drive, and so on; however any integer between 0 and 0xff > is acceptable here. > +.It Fl e Ar bell character > +Set the character to be printed in case of input error. > .It Fl f Ar file > Specify that a backup copy of the preexisting MBR should be written to > .Ar file . > This file is created if it does not exist, and replaced if it does. > +.It Fl i Ar volume-id > +Specifies a volume-id (in the form XXXX-XXXX) to be saved at location > +0x1b8 in the MBR. This information is sometimes used by NT, XP and Vista > +to identify the disk drive. The option is only compatible with version 2.00 > +of the 512-byte boot block. > .It Fl m Ar mask > Specify slices to be enabled/disabled, where > .Ar mask > @@ -144,6 +153,21 @@ Set the timeout value to > .It Fl v > Verbose: display information about the slices defined, etc. > .El > +.Sh NOTE > +Protection mechanisms in the > +.Xr geom 4 > +subsystem might prevent > +.Nm > +from being able to update the MBR on a mounted disk. > +Instructions for temporarily disabling these protection mechanisms > +can be found in the > +.Xr geom 4 > +manpage. Specifically, do a > +.Pp > +.Dl sysctl kern.geom.debugflags=0x10 > +.Pp > +to allow writing to the MBR, and restore it to 0 afterwards. > +.Pp > .Sh FILES > .Bl -tag -width /boot/boot0sio -compact > .It Pa /boot/boot0 > @@ -177,16 +201,6 @@ to install the default MBR: > .Sh AUTHORS > .An Robert Nordier Aq rnordier@FreeBSD.org . > .Sh BUGS > -Protection mechanisms in the > -.Xr geom 4 > -subsystem might prevent > -.Nm > -from being able to update the MBR on a mounted disk. > -Instructions for temporarily disabling these protection mechanisms > -can be found in the > -.Xr geom 4 > -manpage. > -.Pp > Use of the > .Sq packet > option may cause > @@ -195,6 +209,6 @@ to fail, depending on the nature of BIOS > .Pp > Use of the > .Sq setdrv > -option with an incorrect -d operand may cause the MBR to be written > -to the wrong disk. > -Be careful! > +option with an incorrect -d operand may cause the boot0 code > +to write the MBR to the wrong disk, thus trashing its previous > +content. Be careful. > > Modified: stable/7/usr.sbin/boot0cfg/boot0cfg.c > ============================================================================== > --- stable/7/usr.sbin/boot0cfg/boot0cfg.c Tue Jan 13 22:15:47 2009 (r187197) > +++ stable/7/usr.sbin/boot0cfg/boot0cfg.c Tue Jan 13 22:28:48 2009 (r187198) > @@ -1,4 +1,5 @@ > /* > + * Copyright (c) 2008 Luigi Rizzo > * Copyright (c) 1999 Robert Nordier > * All rights reserved. > * > @@ -44,13 +45,34 @@ __FBSDID("$FreeBSD$"); > > #define MBRSIZE 512 /* master boot record size */ > > -#define OFF_VERSION 0x1b0 /* offset: version number */ > -#define OFF_OPT 0x1b9 /* offset: default boot option */ > -#define OFF_DRIVE 0x1ba /* offset: setdrv drive */ > -#define OFF_FLAGS 0x1bb /* offset: option flags */ > -#define OFF_TICKS 0x1bc /* offset: clock ticks */ > +#define OFF_VERSION 0x1b0 /* offset: version number, only boot0version */ > +#define OFF_SERIAL 0x1b8 /* offset: volume serial number */ > #define OFF_PTBL 0x1be /* offset: partition table */ > #define OFF_MAGIC 0x1fe /* offset: magic number */ > +/* > + * Offsets to the parameters of the 512-byte boot block. > + * For historical reasons they are set as macros > + */ > +struct opt_offsets { > + int opt; > + int drive; > + int flags; > + int ticks; > +}; > + > +struct opt_offsets b0_ofs[] = { > + { 0x0, 0x0, 0x0, 0x0 }, /* no boot block */ > + { 0x1b9, 0x1ba, 0x1bb, 0x1bc }, /* original block */ > + { 0x1b5, 0x1b6, 0x1b7, 0x1bc }, /* NT_SERIAL block */ > +}; > + > +int b0_ver; /* boot block version set by boot0bs */ > + > +#define OFF_OPT (b0_ofs[b0_ver].opt) /* default boot option */ > +#define OFF_DRIVE (b0_ofs[b0_ver].drive) /* setdrv drive */ > +#define OFF_FLAGS (b0_ofs[b0_ver].flags) /* option flags */ > +#define OFF_TICKS (b0_ofs[b0_ver].ticks) /* clock ticks */ > + > > #define cv2(p) ((p)[0] | (p)[1] << 010) > > @@ -82,8 +104,12 @@ static int boot0bs(const u_int8_t *); > > *** DIFF OUTPUT TRUNCATED AT 1000 LINES *** > _______________________________________________ > svn-src-stable-7@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/svn-src-stable-7 > To unsubscribe, send any mail to "svn-src-stable-7-unsubscribe@freebsd.org" -- Anders.
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