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Differential D7418 Diff 19238 sys/boot/i386/zfsboot/zfsldr.S

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sys/boot/i386/zfsboot/zfsldr.S

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/* Partition Constants */ /* Partition Constants */
.set PRT_OFF,0x1be # Partition offset .set PRT_OFF,0x1be # Partition offset
.set PRT_NUM,0x4 # Partitions .set PRT_NUM,0x4 # Partitions
.set PRT_BSD,0xa5 # Partition type .set PRT_BSD,0xa5 # Partition type
/* Misc. Constants */ /* Misc. Constants */
.set SIZ_PAG,0x1000 # Page size .set SIZ_PAG,0x1000 # Page size
.set SIZ_SEC,0x200 # Sector size .set SIZ_SEC,0x200 # Sector size
.set COPY_BLKS,0x8 # Number of blocks
.set NSECT,0x80 # to copy for boot2
.set COPY_BLK_SZ,0x8000 # Copy in 32k blocks; must be
# a multiple of 16 bytes
.set NSECT,(COPY_BLK_SZ / SIZ_SEC * COPY_BLKS)
.globl start .globl start
.code16 .code16
/* /*
* Load the rest of zfsboot2 and BTX up, copy the parts to the right locations, * Load the rest of zfsboot2 and BTX up, copy the parts to the right locations,
* and start it all up. * and start it all up.
*/ */
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* error message and die. * error message and die.
*/ */
mov $msg_part,%si # Message mov $msg_part,%si # Message
jmp error # Error jmp error # Error
/* /*
* Ok, we have a slice and drive in %dx now, so use that to locate and * 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 * load boot2. %si references the start of the slice we are looking
* for, so go ahead and load up the 128 sectors starting at sector 1024 * for, so go ahead and load up the COPY_BLKS*COPY_BLK_SZ/SIZ_SEC sectors
* (i.e. after the two vdev labels). We don't have do anything fancy * starting at sector 1024 (i.e. after the two vdev labels). We don't
* here to allow for an extra copy of boot1 and a partition table * have do anything fancy here to allow for an extra copy of boot1 and
* (compare to this section of the UFS bootstrap) so we just load it * a partition table (compare to this section of the UFS bootstrap) so we
* all at 0x9000. The first part of boot2 is BTX, which wants to run * just load it all at 0x9000. The first part of boot2 is BTX, which wants
* at 0x9000. The boot2.bin binary starts right after the end of BTX, * 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 * so we have to figure out where the start of it is and then move the
* binary to 0xc000. Normally, BTX clients start at MEM_USR, or 0xa000, * 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 * 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 * 0x2000. That entry point is relative to MEM_USR; thus boot2.bin
* starts at 0xc000. * starts at 0xc000.
* *
* The load area and the target area for the client overlap so we have * 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 * to use a decrementing string move. We also play segment register
* games with the destination address for the move so that the client * games with the destination address for the move so that the client
* can be larger than 16k (which would overflow the zero segment since * can be larger than 16k (which would overflow the zero segment since
* the client starts at 0xc000). * the client starts at 0xc000).
*/ */
main.5: mov %dx,MEM_ARG # Save args main.5: mov %dx,MEM_ARG # Save args
mov $NSECT,%cx # Sector count mov $NSECT,%cx # Sector count
movl $1024,%eax # Offset to boot2 movl $1024,%eax # Offset to boot2
mov $MEM_BTX,%ebx # Destination buffer mov $MEM_BTX,%ebx # Destination buffer
main.6: pushal # Save params main.6: pushal # Save params
call read # Read disk call read # Read disk
popal # Restore popal # Restore
incl %eax # Advance to incl %eax # Advance to
add $SIZ_SEC,%ebx # next sector add $SIZ_SEC,%ebx # next sector
loop main.6 # If not last, read another 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 $MEM_BTX,%bx # BTX
mov %di,%si # End of load area, 0x9000 rel mov 0xa(%bx),%si # Get BTX length and set
sub %bx,%di # End of client, 0xc000 rel add %bx,%si # %si to start of boot2
mov %di,%cx # Size of dec %si # Set %ds:%si to point at the
inc %cx # client mov %si,%ax # last byte we want to copy
mov $(MEM_BTX)>>4,%dx # Segment shr $4,%ax # from boot2, with %si made as
mov %dx,%ds # addressing 0x9000 add $(COPY_BLKS*COPY_BLK_SZ/16),%ax # small as possible.
mov $(MEM_USR+2*SIZ_PAG)>>4,%dx # Segment and $0xf,%si #
mov %dx,%es # addressing 0xc000 mov %ax,%ds #
std # Move with decrement mov $(MEM_USR+2*SIZ_PAG)/16,%ax # Set %es:(-1) to point at
rep # Relocate add $(COPY_BLKS*COPY_BLK_SZ/16),%ax # the last byte we
movsb # client mov %ax,%es # want to copy boot2 into.
mov $COPY_BLKS,%bx # Copy COPY_BLKS 32k blocks
copyloop:
add $COPY_BLK_SZ,%si # Adjust %ds:%si to point at
mov %ds,%ax # the end of the next 32k to
sub $COPY_BLK_SZ/16,%ax # copy from boot2
mov %ax,%ds
mov $COPY_BLK_SZ-1,%di # Adjust %es:%di to point at
mov %es,%ax # the end of the next 32k into
sub $COPY_BLK_SZ/16,%ax # which we want boot2 copied
mov %ax,%es
mov $COPY_BLK_SZ,%cx # Copy 32k
std
rep movsb
dec %bx
jnz copyloop
mov %cx,%ds # Reset %ds and %es
mov %cx,%es
cld # Back to increment 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. * Enable A20 so we can access memory above 1 meg.
* Use the zero-valued %cx as a timeout for embedded hardware which do not * Use the zero-valued %cx as a timeout for embedded hardware which do not
* have a keyboard controller. * have a keyboard controller.
*/ */
seta20: cli # Disable interrupts seta20: cli # Disable interrupts
seta20.1: dec %cx # Timeout? seta20.1: dec %cx # Timeout?
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