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:
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
+ 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.
+ mov $MEM_BUF,%si # BTX (before reloc)
mov 0xa(%si),%bx # Get BTX length and set
mov $NSECT*SIZ_SEC-1,%di # Size of load area (less one)
mov %di,%si # End of load
@@ -214,12 +214,12 @@ seta20.3: sti # Enable
interrupts
* packet on the stack and passes it to read.
*
* %eax - int - LBA to read in relative to partition start
+ * %es:%bx - 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
+nread: xor %ecx,%ecx # Get
addl 0x8(%si),%eax # LBA
adc $0,%ecx
pushl %ecx # Starting absolute block
@@ -234,9 +234,12 @@ seta20.3: sti # Enable
interrupts
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
--
John Baldwin
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