From owner-svn-src-all@FreeBSD.ORG Thu Jul 14 18:58:19 2011 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 099A7106566B; Thu, 14 Jul 2011 18:58:19 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id E42B98FC17; Thu, 14 Jul 2011 18:58:18 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.4/8.14.4) with ESMTP id p6EIwIPZ041752; Thu, 14 Jul 2011 18:58:18 GMT (envelope-from jhb@svn.freebsd.org) Received: (from jhb@localhost) by svn.freebsd.org (8.14.4/8.14.4/Submit) id p6EIwIpH041750; Thu, 14 Jul 2011 18:58:18 GMT (envelope-from jhb@svn.freebsd.org) Message-Id: <201107141858.p6EIwIpH041750@svn.freebsd.org> From: John Baldwin Date: Thu, 14 Jul 2011 18:58:18 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org X-SVN-Group: stable-8 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r224033 - stable/8/sys/boot/i386/zfsboot X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Jul 2011 18:58:19 -0000 Author: jhb Date: Thu Jul 14 18:58:18 2011 New Revision: 224033 URL: http://svn.freebsd.org/changeset/base/224033 Log: MFC 223477,223597,223611: - The recent change to increase the zfsboot size to 64k made a few BIOSes unhappy (probably they don't handle crossing the 64k boundary, etc.). Fix this by changing zfsldr to use a loop reading from the disk one sector at a time. To avoid trashing the saved copy of the MBR which is used for disk I/O, read zfsboot2 at address 0x9000. This has the advantage that BTX no longer needs to be relocated as it is read into the correct location. However, the loop to relocate zfsboot2.bin can now cross a 64k boundary, so change it to use relative segments instead. (This will need further work if zfsboot2.bin ever exceeds 64k.) While here, stop storing a relocated copy of zfsldr at 0x700. This was only used by the xread hack which has recently been removed (and even that use was dubious). Also, include the BIOS error code as hex when reporting read errors to aid in debugging. - Remove the fake BPB from zfsldr. zfsldr doesn't support booting from floppies, so it will not be used as the start of an emulated floppy image on a bootable CD which is what the fake BPB was used for. - Only check that EDD packet mode is available once at the start of zfsldr rather than for each disk sector now that we read data in one sector at a time. As a result, collapse the remaining bits of read up into nread and rename nread to read. Modified: stable/8/sys/boot/i386/zfsboot/zfsldr.S Directory Properties: stable/8/sys/ (props changed) stable/8/sys/amd64/include/xen/ (props changed) stable/8/sys/cddl/contrib/opensolaris/ (props changed) stable/8/sys/contrib/dev/acpica/ (props changed) stable/8/sys/contrib/pf/ (props changed) Modified: stable/8/sys/boot/i386/zfsboot/zfsldr.S ============================================================================== --- stable/8/sys/boot/i386/zfsboot/zfsldr.S Thu Jul 14 18:49:23 2011 (r224032) +++ stable/8/sys/boot/i386/zfsboot/zfsldr.S Thu Jul 14 18:58:18 2011 (r224033) @@ -16,7 +16,6 @@ */ /* Memory Locations */ - .set MEM_REL,0x700 # Relocation address .set MEM_ARG,0x900 # Arguments .set MEM_ORG,0x7c00 # Origin .set MEM_BUF,0x8000 # Load area @@ -38,43 +37,6 @@ .globl start .code16 -start: jmp main # Start recognizably - -/* - * This is the start of a standard BIOS Parameter Block (BPB). Most bootable - * FAT disks have this at the start of their MBR. While normal BIOS's will - * work fine without this section, IBM's El Torito emulation "fixes" up the - * BPB by writing into the memory copy of the MBR. Rather than have data - * written into our code, we'll define a BPB to work around it. - * The data marked with (T) indicates a field required for a ThinkPad to - * recognize the disk and (W) indicates fields written from IBM BIOS code. - * The use of the BPB is based on what OpenBSD and NetBSD implemented in - * their boot code but the required fields were determined by trial and error. - * - * Note: If additional space is needed in boot1, one solution would be to - * move the "prompt" message data (below) to replace the OEM ID. - */ - .org 0x03, 0x00 -oemid: .space 0x08, 0x00 # OEM ID - - .org 0x0b, 0x00 -bpb: .word 512 # sector size (T) - .byte 0 # sectors/clustor - .word 0 # reserved sectors - .byte 0 # number of FATs - .word 0 # root entries - .word 0 # small sectors - .byte 0 # media type (W) - .word 0 # sectors/fat - .word 18 # sectors per track (T) - .word 2 # number of heads (T) - .long 0 # hidden sectors (W) - .long 0 # large sectors - - .org 0x24, 0x00 -ebpb: .byte 0 # BIOS physical drive number (W) - - .org 0x25,0x90 /* * Load the rest of zfsboot2 and BTX up, copy the parts to the right locations, * and start it all up. @@ -84,33 +46,24 @@ ebpb: .byte 0 # BIOS physical drive nu * Setup the segment registers to flat addressing (segment 0) and setup the * stack to end just below the start of our code. */ -main: cld # String ops inc +start: cld # String ops inc xor %cx,%cx # Zero mov %cx,%es # Address mov %cx,%ds # data mov %cx,%ss # Set up mov $start,%sp # stack /* - * Relocate ourself to MEM_REL. Since %cx == 0, the inc %ch sets - * %cx == 0x100. - */ - mov %sp,%si # Source - mov $MEM_REL,%di # Destination - incb %ch # Word count - rep # Copy - movsw # code -/* - * If we are on a hard drive, then load the MBR and look for the first - * FreeBSD slice. We use the fake partition entry below that points to - * the MBR when we call nread. The first pass looks for the first active - * FreeBSD slice. The second pass looks for the first non-active FreeBSD - * slice if the first one fails. - */ - mov $part4,%si # Partition - cmpb $0x80,%dl # Hard drive? - jb main.4 # No - movb $0x1,%dh # Block count - callw nread # Read MBR + * Load the MBR and look for the first FreeBSD slice. We use the fake + * partition entry below that points to the MBR when we call read. + * The first pass looks for the first active FreeBSD slice. The + * second pass looks for the first non-active FreeBSD slice if the + * first one fails. + */ + call check_edd # Make sure EDD works + mov $part4,%si # Dummy partition + xor %eax,%eax # Read MBR + movl $MEM_BUF,%ebx # from first + call read # sector mov $0x1,%cx # Two passes main.1: mov $MEM_BUF+PRT_OFF,%si # Partition table movb $0x1,%dh # Partition @@ -131,60 +84,55 @@ main.3: add $0x10,%si # Next entry */ mov $msg_part,%si # Message jmp error # Error -/* - * Floppies use partition 0 of drive 0. - */ -main.4: xor %dx,%dx # Partition:drive /* * Ok, we have a slice and drive in %dx now, so use that to locate and * load boot2. %si references the start of the slice we are looking - * for, so go ahead and load up the 64 sectors starting at sector 1024 + * for, so go ahead and load up the 128 sectors starting at sector 1024 * (i.e. after the two vdev labels). We don't have do anything fancy * here to allow for an extra copy of boot1 and a partition table * (compare to this section of the UFS bootstrap) so we just load it - * all at 0x8000. The first part of boot2 is BTX, which wants to run + * all at 0x9000. The first part of boot2 is BTX, which wants to run * at 0x9000. The boot2.bin binary starts right after the end of BTX, * so we have to figure out where the start of it is and then move the - * binary to 0xc000. After we have moved the client, we relocate BTX - * itself to 0x9000 - doing it in this order means that none of the - * memcpy regions overlap which would corrupt the copy. Normally, BTX - * clients start at MEM_USR, or 0xa000, but when we use btxld to - * create zfsboot2, we use an entry point of 0x2000. That entry point is - * relative to MEM_USR; thus boot2.bin starts at 0xc000. + * binary to 0xc000. Normally, BTX clients start at MEM_USR, or 0xa000, + * but when we use btxld to create zfsboot2, we use an entry point of + * 0x2000. That entry point is relative to MEM_USR; thus boot2.bin + * starts at 0xc000. * * The load area and the target area for the client overlap so we have * to use a decrementing string move. We also play segment register * games with the destination address for the move so that the client * can be larger than 16k (which would overflow the zero segment since - * the client starts at 0xc000). Relocating BTX is easy since the load - * area and target area do not overlap. + * the client starts at 0xc000). */ main.5: mov %dx,MEM_ARG # Save args - movb $NSECT,%dh # Sector count + mov $NSECT,%cx # Sector count movl $1024,%eax # Offset to boot2 - callw nread.1 # Read disk -main.6: mov $MEM_BUF,%si # BTX (before reloc) - mov 0xa(%si),%bx # Get BTX length and set + mov $MEM_BTX,%ebx # Destination buffer +main.6: pushal # Save params + call read # Read disk + popal # Restore + incl %eax # Advance to + add $SIZ_SEC,%ebx # next sector + loop main.6 # If not last, read another + mov MEM_BTX+0xa,%bx # Get BTX length mov $NSECT*SIZ_SEC-1,%di # Size of load area (less one) - mov %di,%si # End of load - add $MEM_BUF,%si # area + mov %di,%si # End of load area, 0x9000 rel sub %bx,%di # End of client, 0xc000 rel mov %di,%cx # Size of inc %cx # client + mov $(MEM_BTX)>>4,%dx # Segment + mov %dx,%ds # addressing 0x9000 mov $(MEM_USR+2*SIZ_PAG)>>4,%dx # Segment mov %dx,%es # addressing 0xc000 std # Move with decrement rep # Relocate movsb # client - mov %ds,%dx # Back to - mov %dx,%es # zero segment - mov $MEM_BUF,%si # BTX (before reloc) - mov $MEM_BTX,%di # BTX - mov %bx,%cx # Get BTX length - cld # Increment this time - rep # Relocate - movsb # BTX + cld # Back to increment + xor %dx,%dx # Back + mov %ds,%dx # to zero + mov %dx,%es # segment /* * Enable A20 so we can access memory above 1 meg. @@ -210,33 +158,37 @@ seta20.3: sti # Enable interrupts /* - * Trampoline used to call read from within zfsldr. Sets up an EDD - * packet on the stack and passes it to read. + * Read a sector from the disk. Sets up an EDD packet on the stack + * and passes it to read. We assume that the destination address is + * always segment-aligned. * * %eax - int - LBA to read in relative to partition start + * %ebx - ptr - destination address * %dl - byte - drive to read from - * %dh - byte - num sectors to read * %si - ptr - MBR partition entry */ -nread: xor %eax,%eax # Sector offset in partition -nread.1: xor %ecx,%ecx # Get +read: xor %ecx,%ecx # Get addl 0x8(%si),%eax # LBA adc $0,%ecx pushl %ecx # Starting absolute block pushl %eax # block number - push %es # Address of - push $MEM_BUF # transfer buffer - xor %ax,%ax # Number of - movb %dh,%al # blocks to - push %ax # transfer + shr $4,%ebx # Convert to segment + push %bx # Address of + push $0 # transfer buffer + push $0x1 # Read 1 sector push $0x10 # Size of packet - mov %sp,%bp # Packet pointer - callw read # Read from disk - lea 0x10(%bp),%sp # Clear stack - jnc return # If success, return - mov $msg_read,%si # Otherwise, set the error - # message and fall through to - # the error routine + mov %sp,%si # Packet pointer + mov $0x42,%ah # BIOS: Extended + int $0x13 # read + jc read.1 # If error, fail + lea 0x10(%si),%sp # Clear stack + ret # If success, return +read.1: mov %ah,%al # Format + mov $read_err,%di # error + call hex8 # code + mov $msg_read,%si # Set the error message and + # fall through to the error + # routine /* * Print out the error message pointed to by %ds:(%si) followed * by a prompt, wait for a keypress, and then reboot the machine. @@ -257,51 +209,49 @@ putstr.0: mov $0x7,%bx # Page:attribu putstr: lodsb # Get char testb %al,%al # End of string? jne putstr.0 # No - + ret # To caller /* - * Overused return code. ereturn is used to return an error from the - * read function. Since we assume putstr succeeds, we (ab)use the - * same code when we return from putstr. - */ -ereturn: movb $0x1,%ah # Invalid - stc # argument -return: retw # To caller -/* - * Reads sectors from the disk. If EDD is enabled, then check if it is - * installed and use it if it is. If it is not installed or not enabled, then - * fall back to using CHS. Since we use a LBA, if we are using CHS, we have to - * fetch the drive parameters from the BIOS and divide it out ourselves. - * Call with: - * - * %dl - byte - drive number - * stack - 10 bytes - EDD Packet + * Check to see if the disk supports EDD. zfsboot requires EDD and does not + * support older C/H/S disk I/O. */ -read: cmpb $0x80,%dl # Hard drive? - jb read.1 # No, use CHS +check_edd: cmpb $0x80,%dl # Hard drive? + jb check_edd.1 # No, fail to boot mov $0x55aa,%bx # Magic push %dx # Save movb $0x41,%ah # BIOS: Check int $0x13 # extensions present pop %dx # Restore - jc read.1 # If error, use CHS + jc check_edd.1 # If error, fail cmp $0xaa55,%bx # Magic? - jne read.1 # No, so use CHS + jne check_edd.1 # No, so fail testb $0x1,%cl # Packet interface? - jz read.1 # No, so use CHS - mov %bp,%si # Disk packet - movb $0x42,%ah # BIOS: Extended - int $0x13 # read - retw # To caller -read.1: mov $msg_chs,%si - jmp error -msg_chs: .asciz "CHS not supported" + jz check_edd.1 # No, so fail + ret # EDD ok, keep booting +check_edd.1: mov $msg_chs,%si # Warn that CHS is + jmp error # unsupported and fail +/* + * AL to hex, saving the result to [EDI]. + */ +hex8: push %ax # Save + shrb $0x4,%al # Do upper + call hex8.1 # 4 + pop %ax # Restore +hex8.1: andb $0xf,%al # Get lower 4 + cmpb $0xa,%al # Convert + sbbb $0x69,%al # to hex + das # digit + orb $0x20,%al # To lower case + stosb # Save char + ret # (Recursive) /* Messages */ -msg_read: .asciz "Read" -msg_part: .asciz "Boot" +msg_chs: .asciz "CHS not supported" +msg_read: .ascii "Read error: " +read_err: .asciz "XX" +msg_part: .asciz "Boot error" -prompt: .asciz " error\r\n" +prompt: .asciz "\r\n" .org PRT_OFF,0x90