Date: Tue, 21 Jun 2011 22:13:20 +0200 From: Henri Hennebert <hlh@restart.be> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-stable@freebsd.org Subject: Re: ZFS boot inside on the second partition inside a slice Message-ID: <4E00FB60.8080407@restart.be> In-Reply-To: <201106211525.35938.jhb@freebsd.org> References: <BANLkTi=drd8vY84_4jqDZTFK%2Bsq=n0Kx9g@mail.gmail.com> <201106211351.45919.jhb@freebsd.org> <4E00EAC4.3050304@restart.be> <201106211525.35938.jhb@freebsd.org>
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On 06/21/2011 21:25, John Baldwin wrote:
> On Tuesday, June 21, 2011 3:02:28 pm Henri Hennebert wrote:
>> On 06/21/2011 19:51, John Baldwin wrote:
>>> On Tuesday, June 21, 2011 12:15:58 pm Henri Hennebert wrote:
>>>> On 06/21/2011 17:55, John Baldwin wrote:
>>>>> On Tuesday, June 21, 2011 10:50:14 am Henri Hennebert wrote:
>>>>>> On 06/21/2011 15:01, John Baldwin wrote:
>>>>>>> Index: zfsldr.S
>>>>>>> ===================================================================
>>>>>>> --- zfsldr.S (revision 223339)
>>>>>>> +++ zfsldr.S (working copy)
>>>>>>> @@ -234,9 +234,12 @@ nread.1: xor %ecx,%ecx # Get
>>>>>>> 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 %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.
>>>>>>> @@ -296,12 +299,28 @@ read.1: mov $msg_chs,%si
>>>>>>> jmp error
>>>>>>> msg_chs: .asciz "CHS not supported"
>>>>>>>
>>>>>>> +/*
>>>>>>> + * Convert 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_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
>>>>>>>
>>>>>> I get
>>>>>>
>>>>>> Read error: 01
>>>>>
>>>>> Hmm, that would be 'invalid parameter'.
>>>>>
>>>>> Can you add a 'foo: jmp foo' infinite loop and move it around to figure
>>> out
>>>>> which read call is failing?
>>>>>
>>>> main.5: mov %dx,MEM_ARG # Save args
>>>> movb $NSECT,%dh # Sector count
>>>> movl $1024,%eax # Offset to boot2
>>>> callw nread.1 # Read disk
>>>>
>>>> foo: jmp foo
>>>>
>>>> After this one I get
>>>>
>>>> 'Read error: 01'
>>>
>>> Hmm, ok. NSECT changed in the MFC (it is now larger). Try this patch.
> It
>>> changes the code to read zfsboot in one sector at a time:
>>>
>>
>> I encounter 2 problems - see in you patch
>>
>> Henri
>>
>>
>>> Index: zfsldr.S
>>> ===================================================================
>>> --- zfsldr.S (revision 223365)
>>> +++ zfsldr.S (working copy)
>>> @@ -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
>>> @@ -91,26 +90,19 @@ main: cld # String ops inc
>>> 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
>>> + mov $part4,%si # Dummy partition
>>> cmpb $0x80,%dl # Hard drive?
>>> jb main.4 # No
>>> - movb $0x1,%dh # Block count
>>> - callw nread # Read MBR
>>> + xor %eax,%eax # Read MBR from
>>> + movw $MEM_BUF,%bx # first sector
>>> + movb $0x1,%dh # on disk into
>>> + callw nread # $MEM_BUF
>>> mov $0x1,%cx # Two passes
>>> main.1: mov $MEM_BUF+PRT_OFF,%si # Partition table
>>> movb $0x1,%dh # Partition
>>> @@ -161,10 +153,18 @@ main.4: xor %dx,%dx # Partition:drive
>>> * area and target area do not overlap.
>>> */
>>> main.5: mov %dx,MEM_ARG # Save args
>>> - movb $NSECT,%dh # Sector count
>>> + movb $NSECT,%cl # Sector count
>>> movl $1024,%eax # Offset to boot2
>>> - callw nread.1 # Read disk
>>> -main.6: mov $MEM_BUF,%si # BTX (before reloc)
>>> + mov $MEM_BUF,%bx # Destination buffer
>>> +main.6: pushal # Save params
>>> + movb $1,$dh # One sector
>> %dh
>> |
>> ------------------------+
>>
>>> + callw nread # Read disk
>>> + popal # Restore
>>> + incl %eax # Update for
>>> + add $SIZ_SEC,%bx # next sector
>>> + dec %cx # Last sector?
>>> + jncxz main.6 # If not, read another.
>>
>> Error: no such instruction: `jncxz main.6'
>
> Ah, jcxnz instead (jump if cx is non-zero)
>
>
I have to use:
jcxz main.7 # If not, read another.
jmp main.6
main.7: mov $MEM_BUF,%si # BTX (before reloc)
and I get:
Read error: 04
Henri
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