Mega i386 loader commit.

- Don't hard code 0x10000 as the entry point for the loader.  Instead add
  src/sys/boot/i386/Makefile.inc which defines a make variable with the
  entry point for the loader.  Move the loader's entry point up to
  0x20000, which makes PXE happy.
- Don't try to use cpp to parse btxldr for the optional BTXLDR_VERBOSE,
  instead use m4 to achieve this.  Also, add a BTXLDR_VERBOSE knob in the
  btxldr Makefile to turn this option on.
- Redo parts of cdldr's Makefile so that it now builds and installs cdboot
  instead of having i386/loader/Makefile do that.  Also, add in some more
  variables to make the pxeldr Makefile almost identical and thus to ease
  maintainability.
- Teach cdldr about the a.out format.  Cdldr now parsers the a.out header
  of the loader binary and relocates it based on that.  The entry point of
  the loader no longer has to be hardcoded into cdldr.  Also, the boot
  info table from mkisofs is no longer required to get a useful cdboot.
- Update the lsdev function for BIOS disks to parse other file systems
  (such as DOS FAT) that we currently support.  This is still buggy as
  it assumes that a floppy with a DOS boot sector actually has a MBR and
  parses it as such.  I'll be fixing this in the future.
- The biggie:  Add in support for booting off of PXE-enabled network
  adapters.  Currently, we use the TFTP API provided by the PXE BIOS.
  Eventually we will switch to using the low-level NIC driver thus
  allowing both TFTP and NFS to be used, but for now it's just TFTP.

Submitted by:	ps, alfred
Testing by:	Benno Rice <benno@netizen.com.au>

3 files changed, 121 insertions, 95 deletions

diff --git a/sys/boot/i386/btx/btxldr/Makefile b/sys/boot/i386/btx/btxldr/Makefile
index 33e6275..0d61889 100644
--- a/sys/boot/i386/btx/btxldr/Makefile
+++ b/sys/boot/i386/btx/btxldr/Makefile
@@ -1,22 +1,28 @@
 # $FreeBSD$
 
-ORG=0x100000
-AFLAGS+=	--assembler-with-cpp
+M4?=	m4
+M4FLAGS+=	-DLOADER_ADDRESS=${LOADER_ADDRESS}
+
+.if defined(BTXLDR_VERBOSE)
+M4FLAGS+=	-DBTXLDR_VERBOSE
+.endif
 
 all: btxldr
 
 btxldr: btxldr.o
 .if ${OBJFORMAT} == aout
-	${LD} -nostdlib -N -s -T ${ORG} -o btxldr.out btxldr.o
+	${LD} -nostdlib -N -s -T ${LOADER_ADDRESS} -o btxldr.out btxldr.o
 	dd if=btxldr.out of=${.TARGET} ibs=32 skip=1
 .else
-	${LD} -N -e start -Ttext ${ORG} -o btxldr.out btxldr.o
+	${LD} -N -e start -Ttext ${LOADER_ADDRESS} -o btxldr.out btxldr.o
 	objcopy -S -O binary btxldr.out ${.TARGET}
 .endif
 
 btxldr.o: btxldr.s
-	${CC} ${AFLAGS} -c -o ${.TARGET} ${.CURDIR}/btxldr.s
+	(cd ${.CURDIR}; ${M4} ${M4FLAGS} btxldr.s ) | \
+		${AS} ${AFLAGS} -o ${.TARGET}
 
 CLEANFILES+= btxldr btxldr.out btxldr.o
 
+.include <${.CURDIR}/../../Makefile.inc>
 .include <bsd.prog.mk>
diff --git a/sys/boot/i386/btx/btxldr/btxldr.S b/sys/boot/i386/btx/btxldr/btxldr.S
index d506a62..a1f7ee8 100644
--- a/sys/boot/i386/btx/btxldr/btxldr.S
+++ b/sys/boot/i386/btx/btxldr/btxldr.S
@@ -27,7 +27,7 @@
 		.set MEM_ESP,0x1000		# New stack pointer
 		.set MEM_TBL,0x5000		# BTX page tables
 		.set MEM_ENTRY,0x9010		# BTX entry point
-		.set MEM_DATA,0x101000		# Data segment
+		.set MEM_DATA,start+0x1000	# Data segment
 #
 # Segment selectors.
 #
@@ -57,7 +57,7 @@
 #
 		.set SIZ_STUB,0x1a		# Size of stub
 #
-# We expect to be loaded by boot2 at 0x100000.
+# We expect to be loaded by boot2 at the origin defined in ./Makefile.
 #
 		.globl start
 #
@@ -69,25 +69,29 @@ start:		cld				# String ops inc
 		movzwl BDA_MEM,%eax		# Get base memory
 		shll $0xa,%eax			#  in bytes
 		movl %eax,%ebp			# Base of user stack
+ifdef(`BTXLDR_VERBOSE',`
 		movl $m_mem,%esi		# Display
-		call dhexout			#  amount of
-		call dputstr			#  base memory
+		call hexout			#  amount of
+		call putstr			#  base memory
+')
 		lgdt gdtdesc			# Load new GDT
 #
 # Relocate caller's arguments.
 #
+ifdef('BTXLDR_VERBOSE',`
 		movl $m_esp,%esi		# Display
-		movl %esp,%eax			#  caller's
-		call dhexout			#  stack
-		call dputstr			#  pointer
+		movl %esp,%eax			#  caller
+		call hexout			#  stack
+		call putstr			#  pointer
 		movl $m_args,%esi		# Format string
 		leal 0x4(%esp,1),%ebx		# First argument
 		movl $0x6,%ecx			# Count
 start.1:	movl (%ebx),%eax		# Get argument and
 		addl $0x4,%ebx			#  bump pointer
-		call dhexout			# Display it
+		call hexout			# Display it
 		loop start.1			# Till done
-		call dputstr			# End message
+		call putstr			# End message
+')
 		movl $0x48,%ecx 		# Allocate space
 		subl %ecx,%ebp			#  for bootinfo
 		movl 0x18(%esp,1),%esi		# Source: bootinfo
@@ -97,20 +101,24 @@ start.1:	movl (%ebx),%eax		# Get argument and
 		rep				# Copy
 		movsb				#  it
 		movl %ebp,0x18(%esp,1)		# Update pointer
+ifdef(`BTXLDR_VERBOSE',`
 		movl $m_rel_bi,%esi		# Display
 		movl %ebp,%eax			#  bootinfo
-		call dhexout			#  relocation
-		call dputstr			#  message
+		call hexout			#  relocation
+		call putstr			#  message
+')
 start_null_bi:	movl $0x18,%ecx 		# Allocate space
 		subl %ecx,%ebp			#  for arguments
 		leal 0x4(%esp,1),%esi		# Source
 		movl %ebp,%edi			# Destination
 		rep				# Copy
 		movsb				#  them
+ifdef(`BTXLDR_VERBOSE',`
 		movl $m_rel_args,%esi		# Display
 		movl %ebp,%eax			#  argument
-		call dhexout			#  relocation
-		call dputstr			#  message
+		call hexout			#  relocation
+		call putstr			#  message
+')
 #
 # Set up BTX kernel.
 #
@@ -139,24 +147,32 @@ start_null_bi:	movl $0x18,%ecx 		# Allocate space
 		incl %edi			#  BTX
 		shll $0x2,%edi			#  load
 		addl $MEM_TBL,%edi		#  address
-		pushl %edi			# Save
+		pushl %edi			# Save load address
 		movzwl 0xa(%ebx),%ecx		# Image size
-		pushl %ecx			# Save
+ifdef(`BTXLDR_VERBOSE',`
+		pushl %ecx			# Save image size
+')
 		rep				# Relocate
 		movsb				#  BTX
 		movl %esi,%ebx			# Keep place
+ifdef(`BTXLDR_VERBOSE',`
 		movl $m_rel_btx,%esi		# Restore
 		popl %eax			#  parameters
-		call dhexout			#  and
+		call hexout			#  and
+')
 		popl %ebp			#  display
+ifdef(`BTXLDR_VERBOSE',`
 		movl %ebp,%eax			#  the
-		call dhexout			#  relocation
-		call dputstr			#  message
+		call hexout			#  relocation
+		call putstr			#  message
+')
 		addl $PAG_SIZ,%ebp		# Display
+ifdef(`BTXLDR_VERBOSE',`
 		movl $m_base,%esi		#  the
 		movl %ebp,%eax			#  user
-		call dhexout			#  base
-		call dputstr			#  address
+		call hexout			#  base
+		call putstr			#  address
+')
 #
 # Set up ELF-format client program.
 #
@@ -165,24 +181,29 @@ start_null_bi:	movl $0x18,%ecx 		# Allocate space
 		movl $e_fmt,%esi		# Display error
 		call putstr			#  message
 start.2:	jmp start.2			# Hang
-start.3:	movl $m_elf,%esi		# Display ELF
-		call dputstr			#  message
+start.3:
+ifdef(`BTXLDR_VERBOSE',`
+		movl $m_elf,%esi		# Display ELF
+		call putstr			#  message
 		movl $m_segs,%esi		# Format string
+')
 		movl $0x2,%edi			# Segment count
 		movl 0x1c(%ebx),%edx		# Get e_phoff
 		addl %ebx,%edx			# To pointer
 		movzwl 0x2c(%ebx),%ecx		# Get e_phnum
 start.4:	cmpl $0x1,(%edx)		# Is p_type PT_LOAD?
 		jne start.6			# No
+ifdef(`BTXLDR_VERBOSE',`
 		movl 0x4(%edx),%eax		# Display
-		call dhexout			#  p_offset
+		call hexout			#  p_offset
 		movl 0x8(%edx),%eax		# Display
-		call dhexout			#  p_vaddr
+		call hexout			#  p_vaddr
 		movl 0x10(%edx),%eax		# Display
-		call dhexout			#  p_filesz
+		call hexout			#  p_filesz
 		movl 0x14(%edx),%eax		# Display
-		call dhexout			#  p_memsz
-		call dputstr			# End message
+		call hexout			#  p_memsz
+		call putstr			# End message
+')
 		pushl %esi			# Save
 		pushl %edi			#  working
 		pushl %ecx			#  registers
@@ -206,8 +227,11 @@ start.5:	popl %ecx			# Restore
 		je start.7			# If none
 start.6:	addl $0x20,%edx 		# To next entry
 		loop start.4			# Till done
-start.7:	movl $m_done,%esi		# Display done
-		call dputstr			#  message
+start.7:
+ifdef(`BTXLDR_VERBOSE',`
+		movl $m_done,%esi		# Display done
+		call putstr			#  message
+')
 		movl $start.8,%esi		# Real mode stub
 		movl $MEM_STUB,%edi		# Destination
 		movl $SIZ_STUB,%ecx		# Size
@@ -231,10 +255,6 @@ start.9:
 #
 # Output message [ESI] followed by EAX in hex.
 #
-dhexout:
-#ifndef BTXLDR_VERBOSE
-		ret
-#endif
 hexout: 	pushl %eax			# Save
 		call putstr			# Display message
 		popl %eax			# Restore
@@ -260,12 +280,6 @@ hexout.2:	decl %esi			# Adjust for inc
 #
 # Output zero-terminated string [ESI] to the console.
 #
-dputstr:
-#ifndef BTXLDR_VERBOSE
-		ret
-#else
-		jmp putstr
-#endif
 putstr.0:	call putchr			# Output char
 putstr: 	lodsb				# Load char
 		testb %al,%al			# End of string?
@@ -274,10 +288,6 @@ putstr: 	lodsb				# Load char
 #
 # Output character AL to the console.
 #
-dputchr:
-#ifndef BTXLDR_VERBOSE
-		ret
-#endif
 putchr: 	pusha				# Save
 		xorl %ecx,%ecx			# Zero for loops
 		movb $SCR_MAT,%ah		# Mode/attribute
@@ -356,7 +366,7 @@ gdtdesc:	.word gdt.1-gdt-1		# Limit
 m_logo: 	.asciz " \nBTX loader 1.00  "
 m_vers: 	.asciz "BTX version is \0\n"
 e_fmt:		.asciz "Error: Client format not supported\n"
-#ifdef BTXLDR_VERBOSE
+ifdef(`BTXLDR_VERBOSE',`
 m_mem:		.asciz "Starting in protected mode (base mem=\0)\n"
 m_esp:		.asciz "Arguments passed (esp=\0):\n"
 m_args: 	.asciz"<howto="
@@ -379,7 +389,7 @@ m_segs: 	.asciz "text segment: offset="
 		.asciz " filesz="
 		.asciz " memsz=\0\n"
 m_done: 	.asciz "Loading complete\n"
-#endif
+')
 #
 # Uninitialized data area.
 #
diff --git a/sys/boot/i386/btx/btxldr/btxldr.s b/sys/boot/i386/btx/btxldr/btxldr.s
index d506a62..a1f7ee8 100644
--- a/sys/boot/i386/btx/btxldr/btxldr.s
+++ b/sys/boot/i386/btx/btxldr/btxldr.s
@@ -27,7 +27,7 @@
 		.set MEM_ESP,0x1000		# New stack pointer
 		.set MEM_TBL,0x5000		# BTX page tables
 		.set MEM_ENTRY,0x9010		# BTX entry point
-		.set MEM_DATA,0x101000		# Data segment
+		.set MEM_DATA,start+0x1000	# Data segment
 #
 # Segment selectors.
 #
@@ -57,7 +57,7 @@
 #
 		.set SIZ_STUB,0x1a		# Size of stub
 #
-# We expect to be loaded by boot2 at 0x100000.
+# We expect to be loaded by boot2 at the origin defined in ./Makefile.
 #
 		.globl start
 #
@@ -69,25 +69,29 @@ start:		cld				# String ops inc
 		movzwl BDA_MEM,%eax		# Get base memory
 		shll $0xa,%eax			#  in bytes
 		movl %eax,%ebp			# Base of user stack
+ifdef(`BTXLDR_VERBOSE',`
 		movl $m_mem,%esi		# Display
-		call dhexout			#  amount of
-		call dputstr			#  base memory
+		call hexout			#  amount of
+		call putstr			#  base memory
+')
 		lgdt gdtdesc			# Load new GDT
 #
 # Relocate caller's arguments.
 #
+ifdef('BTXLDR_VERBOSE',`
 		movl $m_esp,%esi		# Display
-		movl %esp,%eax			#  caller's
-		call dhexout			#  stack
-		call dputstr			#  pointer
+		movl %esp,%eax			#  caller
+		call hexout			#  stack
+		call putstr			#  pointer
 		movl $m_args,%esi		# Format string
 		leal 0x4(%esp,1),%ebx		# First argument
 		movl $0x6,%ecx			# Count
 start.1:	movl (%ebx),%eax		# Get argument and
 		addl $0x4,%ebx			#  bump pointer
-		call dhexout			# Display it
+		call hexout			# Display it
 		loop start.1			# Till done
-		call dputstr			# End message
+		call putstr			# End message
+')
 		movl $0x48,%ecx 		# Allocate space
 		subl %ecx,%ebp			#  for bootinfo
 		movl 0x18(%esp,1),%esi		# Source: bootinfo
@@ -97,20 +101,24 @@ start.1:	movl (%ebx),%eax		# Get argument and
 		rep				# Copy
 		movsb				#  it
 		movl %ebp,0x18(%esp,1)		# Update pointer
+ifdef(`BTXLDR_VERBOSE',`
 		movl $m_rel_bi,%esi		# Display
 		movl %ebp,%eax			#  bootinfo
-		call dhexout			#  relocation
-		call dputstr			#  message
+		call hexout			#  relocation
+		call putstr			#  message
+')
 start_null_bi:	movl $0x18,%ecx 		# Allocate space
 		subl %ecx,%ebp			#  for arguments
 		leal 0x4(%esp,1),%esi		# Source
 		movl %ebp,%edi			# Destination
 		rep				# Copy
 		movsb				#  them
+ifdef(`BTXLDR_VERBOSE',`
 		movl $m_rel_args,%esi		# Display
 		movl %ebp,%eax			#  argument
-		call dhexout			#  relocation
-		call dputstr			#  message
+		call hexout			#  relocation
+		call putstr			#  message
+')
 #
 # Set up BTX kernel.
 #
@@ -139,24 +147,32 @@ start_null_bi:	movl $0x18,%ecx 		# Allocate space
 		incl %edi			#  BTX
 		shll $0x2,%edi			#  load
 		addl $MEM_TBL,%edi		#  address
-		pushl %edi			# Save
+		pushl %edi			# Save load address
 		movzwl 0xa(%ebx),%ecx		# Image size
-		pushl %ecx			# Save
+ifdef(`BTXLDR_VERBOSE',`
+		pushl %ecx			# Save image size
+')
 		rep				# Relocate
 		movsb				#  BTX
 		movl %esi,%ebx			# Keep place
+ifdef(`BTXLDR_VERBOSE',`
 		movl $m_rel_btx,%esi		# Restore
 		popl %eax			#  parameters
-		call dhexout			#  and
+		call hexout			#  and
+')
 		popl %ebp			#  display
+ifdef(`BTXLDR_VERBOSE',`
 		movl %ebp,%eax			#  the
-		call dhexout			#  relocation
-		call dputstr			#  message
+		call hexout			#  relocation
+		call putstr			#  message
+')
 		addl $PAG_SIZ,%ebp		# Display
+ifdef(`BTXLDR_VERBOSE',`
 		movl $m_base,%esi		#  the
 		movl %ebp,%eax			#  user
-		call dhexout			#  base
-		call dputstr			#  address
+		call hexout			#  base
+		call putstr			#  address
+')
 #
 # Set up ELF-format client program.
 #
@@ -165,24 +181,29 @@ start_null_bi:	movl $0x18,%ecx 		# Allocate space
 		movl $e_fmt,%esi		# Display error
 		call putstr			#  message
 start.2:	jmp start.2			# Hang
-start.3:	movl $m_elf,%esi		# Display ELF
-		call dputstr			#  message
+start.3:
+ifdef(`BTXLDR_VERBOSE',`
+		movl $m_elf,%esi		# Display ELF
+		call putstr			#  message
 		movl $m_segs,%esi		# Format string
+')
 		movl $0x2,%edi			# Segment count
 		movl 0x1c(%ebx),%edx		# Get e_phoff
 		addl %ebx,%edx			# To pointer
 		movzwl 0x2c(%ebx),%ecx		# Get e_phnum
 start.4:	cmpl $0x1,(%edx)		# Is p_type PT_LOAD?
 		jne start.6			# No
+ifdef(`BTXLDR_VERBOSE',`
 		movl 0x4(%edx),%eax		# Display
-		call dhexout			#  p_offset
+		call hexout			#  p_offset
 		movl 0x8(%edx),%eax		# Display
-		call dhexout			#  p_vaddr
+		call hexout			#  p_vaddr
 		movl 0x10(%edx),%eax		# Display
-		call dhexout			#  p_filesz
+		call hexout			#  p_filesz
 		movl 0x14(%edx),%eax		# Display
-		call dhexout			#  p_memsz
-		call dputstr			# End message
+		call hexout			#  p_memsz
+		call putstr			# End message
+')
 		pushl %esi			# Save
 		pushl %edi			#  working
 		pushl %ecx			#  registers
@@ -206,8 +227,11 @@ start.5:	popl %ecx			# Restore
 		je start.7			# If none
 start.6:	addl $0x20,%edx 		# To next entry
 		loop start.4			# Till done
-start.7:	movl $m_done,%esi		# Display done
-		call dputstr			#  message
+start.7:
+ifdef(`BTXLDR_VERBOSE',`
+		movl $m_done,%esi		# Display done
+		call putstr			#  message
+')
 		movl $start.8,%esi		# Real mode stub
 		movl $MEM_STUB,%edi		# Destination
 		movl $SIZ_STUB,%ecx		# Size
@@ -231,10 +255,6 @@ start.9:
 #
 # Output message [ESI] followed by EAX in hex.
 #
-dhexout:
-#ifndef BTXLDR_VERBOSE
-		ret
-#endif
 hexout: 	pushl %eax			# Save
 		call putstr			# Display message
 		popl %eax			# Restore
@@ -260,12 +280,6 @@ hexout.2:	decl %esi			# Adjust for inc
 #
 # Output zero-terminated string [ESI] to the console.
 #
-dputstr:
-#ifndef BTXLDR_VERBOSE
-		ret
-#else
-		jmp putstr
-#endif
 putstr.0:	call putchr			# Output char
 putstr: 	lodsb				# Load char
 		testb %al,%al			# End of string?
@@ -274,10 +288,6 @@ putstr: 	lodsb				# Load char
 #
 # Output character AL to the console.
 #
-dputchr:
-#ifndef BTXLDR_VERBOSE
-		ret
-#endif
 putchr: 	pusha				# Save
 		xorl %ecx,%ecx			# Zero for loops
 		movb $SCR_MAT,%ah		# Mode/attribute
@@ -356,7 +366,7 @@ gdtdesc:	.word gdt.1-gdt-1		# Limit
 m_logo: 	.asciz " \nBTX loader 1.00  "
 m_vers: 	.asciz "BTX version is \0\n"
 e_fmt:		.asciz "Error: Client format not supported\n"
-#ifdef BTXLDR_VERBOSE
+ifdef(`BTXLDR_VERBOSE',`
 m_mem:		.asciz "Starting in protected mode (base mem=\0)\n"
 m_esp:		.asciz "Arguments passed (esp=\0):\n"
 m_args: 	.asciz"<howto="
@@ -379,7 +389,7 @@ m_segs: 	.asciz "text segment: offset="
 		.asciz " filesz="
 		.asciz " memsz=\0\n"
 m_done: 	.asciz "Loading complete\n"
-#endif
+')
 #
 # Uninitialized data area.
 #