aThis patch updates the BTX to emulate the BIOS function "Copy Extended

Memory" called as function 0x87 of interrupt 0x15.  Since the Mylex RAID
adapter's BIOS used this function to access memory (actually PCI bus
space) beyond 16 MB, this patch also allows BTX to address all 4 Gig of
possible address space on i386+.  Since the loader does not have room for
4 MB of page tables, this was done by turning off paging.

Paging was turned off via a compile time setting which defaults to off.
To enable paging, simply define the make variable PAGING.

rnordier might want to clean this up later.

Submitted by:	W. Gerald Hicks <wghicks@bellsouth.net>,
		Bosko Milekic <bmilekic@ares.dsuper.net>
Reviewed by:	msmith
Required by:	Mylex RAID adapter's BIOS

3 files changed, 138 insertions, 9 deletions

diff --git a/sys/boot/i386/btx/btx/Makefile b/sys/boot/i386/btx/btx/Makefile
index c29339d..ac42dfb 100644
--- a/sys/boot/i386/btx/btx/Makefile
+++ b/sys/boot/i386/btx/btx/Makefile
@@ -2,6 +2,10 @@
 
 M4?=	m4
 
+.if defined(PAGING)
+M4FLAGS+=	-DPAGING
+.endif
+
 ORG=	0x9000
 
 all: btx
@@ -16,7 +20,8 @@ btx: btx.o
 .endif
 
 btx.o: btx.m4 btx.s
-	(cd ${.CURDIR}; ${M4} btx.m4 btx.s) | ${AS} ${AFLAGS} -o ${.TARGET}
+	(cd ${.CURDIR}; ${M4} ${M4FLAGS} btx.m4 btx.s) | \
+	   ${AS} ${AFLAGS} -o ${.TARGET}
 
 CLEANFILES+= btx btx.out btx.o
 
diff --git a/sys/boot/i386/btx/btx/btx.S b/sys/boot/i386/btx/btx/btx.S
index b3f3150..81bf7d1 100644
--- a/sys/boot/i386/btx/btx/btx.S
+++ b/sys/boot/i386/btx/btx/btx.S
@@ -155,6 +155,7 @@ init.4: 	movbi1(_ESP0H,TSS_ESP0+1,_di_)	# Set ESP0
 		movbi1(SEL_SDATA,TSS_SS0,_di_)	# Set SS0
 		movbi1(_ESP1H,TSS_ESP1+1,_di_)	# Set ESP1
 		movbi1(_TSSIO,TSS_MAP,_di_)	# Set I/O bit map base
+ifdef(`PAGING',`
 #
 # Create page directory.
 #
@@ -187,20 +188,23 @@ init.6: 	movb $0x7,%al			# Set U:W:P flags
 init.7: 	stosw				# Set entry
 		addw %dx,%ax			# Next address
 		loop init.6			# Till done
+')
 #
 # Bring up the system.
 #
 		movwir(0x2820,_bx)		# Set protected mode
 		callwi(setpic)			#  IRQ offsets
 		lidtwm(idtdesc) 		# Set IDT
+ifdef(`PAGING',`
 		xorw %ax,%ax			# Set base
 		movb $MEM_DIR>>0x8,%ah		#  of page
 		movl %eax,%cr3			#  directory
+')
 		lgdtwm(gdtdesc) 		# Set GDT
 		movl %cr0,%eax			# Switch to
 		o16				#  protected mode
-		orl $0x80000001,%eax		#  and enable
-		movl %eax,%cr0			#  paging
+		orl $0x01,%eax			# 
+		movl %eax,%cr0			#  
 		jmpfwi(SEL_SCODE,init.8)	# To 32-bit code
 init.8: 	xorl %ecx,%ecx			# Zero
 		movb $SEL_SDATA,%cl		# To 32-bit
@@ -240,14 +244,18 @@ init.9:		pushb $0x0			#  general
 #
 exit:		cli				# Disable interrupts
 		movl $MEM_ESP0,%esp		# Clear stack
+ifdef(`PAGING',`
 #
 # Turn off paging.
 #
 		movl %cr0,%eax			# Get CR0
 		andl $~0x80000000,%eax		# Disable
 		movl %eax,%cr0			#  paging
+')
 		xorl %ecx,%ecx			# Zero
+ifdef(`PAGING',`
 		movl %ecx,%cr3			# Flush TLB
+')
 #
 # To 16 bits.
 #
@@ -545,10 +553,64 @@ v86popf.1:	movl (%ebx),%eax		# Load flags
 		orl %eax,%edx			#  flags
 		jmp v86mon.5			# Finish up
 #
-# Emulate INT imm8.
+# trap int 15, function 87
+# reads %es:%si from saved registers on stack to find a GDT containing
+# source and destination locations
+# reads count of words from saved %cx
+# returns success by setting %ah to 0
+#
+int15_87:	pushl %eax			# Save 
+		pushl %ebx			#  some information 
+		pushl %esi			#  onto the stack.
+		pushl %edi
+		xorl %eax,%eax			# clean EAX 
+		xorl %ebx,%ebx			# clean EBX 
+		movl 0x4(%ebp),%esi		# Get user's ESI
+		movl 0x3C(%ebp),%ebx		# store ES
+		movw %si,%ax			# store SI
+		shll $0x4,%ebx			# Make it a seg.
+		addl %eax,%ebx			# ebx=(es<<4)+si
+		movb 0x14(%ebx),%al		# Grab the
+		movb 0x17(%ebx),%ah		#  necessary
+		shll $0x10,%eax			#  information
+		movw 0x12(%ebx),%ax		#  from
+		movl %eax,%esi			#  the
+		movb 0x1c(%ebx),%al		#  GDT in order to
+		movb 0x1f(%ebx),%ah		#  have %esi offset
+		shll $0x10,%eax			#  of source and %edi
+		movw 0x1a(%ebx),%ax		#  of destination.
+		movl %eax,%edi
+		pushl %ds			# Make:
+		popl %es			# es = ds
+		pushl %ecx			# stash ECX
+		xorl %ecx,%ecx			# highw of ECX is clear
+		movw 0x18(%ebp),%cx		# Get user's ECX
+		rep				# repeat...
+		movsb				#  perform copy.
+		popl %ecx			# Restore
+		popl %edi
+		popl %esi			#  previous
+		popl %ebx			#  register
+		popl %eax			#  values.
+		movb $0x0,0x1d(%ebp)		# set ah = 0 to indicate
+						#  success
+		andb $0xfe,%dl			# clear CF
+		jmp v86mon.5			# Finish up
+
+#
+# Emulate INT imm8... also make sure to check if it's int 15/87
 #
 v86intn:	lodsb				# Get int no
-		subl %edi,%esi			# From
+		cmpb $0x15,%al			# is it int 15?
+		jne v86intn.2			#  no, skip parse
+		pushl %eax                      # stash EAX
+		movl 0x1c(%ebp),%eax		# user's saved EAX
+		cmpb $0x87,%ah			# is it our sub function?
+		jne v86intn.1			#  no, don't handle it
+		popl %eax			# get the stack straight
+		jmp int15_87			# it's our cue
+v86intn.1:	popl %eax			# restore EAX
+v86intn.2:	subl %edi,%esi			# From
 		shrl $0x4,%edi			#  linear
 		movw %dx,-0x2(%ebx)		# Save flags
 		movw %di,-0x4(%ebx)		# Save CS
diff --git a/sys/boot/i386/btx/btx/btx.s b/sys/boot/i386/btx/btx/btx.s
index b3f3150..81bf7d1 100644
--- a/sys/boot/i386/btx/btx/btx.s
+++ b/sys/boot/i386/btx/btx/btx.s
@@ -155,6 +155,7 @@ init.4: 	movbi1(_ESP0H,TSS_ESP0+1,_di_)	# Set ESP0
 		movbi1(SEL_SDATA,TSS_SS0,_di_)	# Set SS0
 		movbi1(_ESP1H,TSS_ESP1+1,_di_)	# Set ESP1
 		movbi1(_TSSIO,TSS_MAP,_di_)	# Set I/O bit map base
+ifdef(`PAGING',`
 #
 # Create page directory.
 #
@@ -187,20 +188,23 @@ init.6: 	movb $0x7,%al			# Set U:W:P flags
 init.7: 	stosw				# Set entry
 		addw %dx,%ax			# Next address
 		loop init.6			# Till done
+')
 #
 # Bring up the system.
 #
 		movwir(0x2820,_bx)		# Set protected mode
 		callwi(setpic)			#  IRQ offsets
 		lidtwm(idtdesc) 		# Set IDT
+ifdef(`PAGING',`
 		xorw %ax,%ax			# Set base
 		movb $MEM_DIR>>0x8,%ah		#  of page
 		movl %eax,%cr3			#  directory
+')
 		lgdtwm(gdtdesc) 		# Set GDT
 		movl %cr0,%eax			# Switch to
 		o16				#  protected mode
-		orl $0x80000001,%eax		#  and enable
-		movl %eax,%cr0			#  paging
+		orl $0x01,%eax			# 
+		movl %eax,%cr0			#  
 		jmpfwi(SEL_SCODE,init.8)	# To 32-bit code
 init.8: 	xorl %ecx,%ecx			# Zero
 		movb $SEL_SDATA,%cl		# To 32-bit
@@ -240,14 +244,18 @@ init.9:		pushb $0x0			#  general
 #
 exit:		cli				# Disable interrupts
 		movl $MEM_ESP0,%esp		# Clear stack
+ifdef(`PAGING',`
 #
 # Turn off paging.
 #
 		movl %cr0,%eax			# Get CR0
 		andl $~0x80000000,%eax		# Disable
 		movl %eax,%cr0			#  paging
+')
 		xorl %ecx,%ecx			# Zero
+ifdef(`PAGING',`
 		movl %ecx,%cr3			# Flush TLB
+')
 #
 # To 16 bits.
 #
@@ -545,10 +553,64 @@ v86popf.1:	movl (%ebx),%eax		# Load flags
 		orl %eax,%edx			#  flags
 		jmp v86mon.5			# Finish up
 #
-# Emulate INT imm8.
+# trap int 15, function 87
+# reads %es:%si from saved registers on stack to find a GDT containing
+# source and destination locations
+# reads count of words from saved %cx
+# returns success by setting %ah to 0
+#
+int15_87:	pushl %eax			# Save 
+		pushl %ebx			#  some information 
+		pushl %esi			#  onto the stack.
+		pushl %edi
+		xorl %eax,%eax			# clean EAX 
+		xorl %ebx,%ebx			# clean EBX 
+		movl 0x4(%ebp),%esi		# Get user's ESI
+		movl 0x3C(%ebp),%ebx		# store ES
+		movw %si,%ax			# store SI
+		shll $0x4,%ebx			# Make it a seg.
+		addl %eax,%ebx			# ebx=(es<<4)+si
+		movb 0x14(%ebx),%al		# Grab the
+		movb 0x17(%ebx),%ah		#  necessary
+		shll $0x10,%eax			#  information
+		movw 0x12(%ebx),%ax		#  from
+		movl %eax,%esi			#  the
+		movb 0x1c(%ebx),%al		#  GDT in order to
+		movb 0x1f(%ebx),%ah		#  have %esi offset
+		shll $0x10,%eax			#  of source and %edi
+		movw 0x1a(%ebx),%ax		#  of destination.
+		movl %eax,%edi
+		pushl %ds			# Make:
+		popl %es			# es = ds
+		pushl %ecx			# stash ECX
+		xorl %ecx,%ecx			# highw of ECX is clear
+		movw 0x18(%ebp),%cx		# Get user's ECX
+		rep				# repeat...
+		movsb				#  perform copy.
+		popl %ecx			# Restore
+		popl %edi
+		popl %esi			#  previous
+		popl %ebx			#  register
+		popl %eax			#  values.
+		movb $0x0,0x1d(%ebp)		# set ah = 0 to indicate
+						#  success
+		andb $0xfe,%dl			# clear CF
+		jmp v86mon.5			# Finish up
+
+#
+# Emulate INT imm8... also make sure to check if it's int 15/87
 #
 v86intn:	lodsb				# Get int no
-		subl %edi,%esi			# From
+		cmpb $0x15,%al			# is it int 15?
+		jne v86intn.2			#  no, skip parse
+		pushl %eax                      # stash EAX
+		movl 0x1c(%ebp),%eax		# user's saved EAX
+		cmpb $0x87,%ah			# is it our sub function?
+		jne v86intn.1			#  no, don't handle it
+		popl %eax			# get the stack straight
+		jmp int15_87			# it's our cue
+v86intn.1:	popl %eax			# restore EAX
+v86intn.2:	subl %edi,%esi			# From
 		shrl $0x4,%edi			#  linear
 		movw %dx,-0x2(%ebx)		# Save flags
 		movw %di,-0x4(%ebx)		# Save CS