modified & revised xv6 code

Author: Prashant47

.gdbinit.tmpl

@@ -0,0 +1,27 @@
+set $lastcs = -1
+
+define hook-stop
+  # There doesn't seem to be a good way to detect if we're in 16- or
+  # 32-bit mode, but in 32-bit mode we always run with CS == 8 in the
+  # kernel and CS == 35 in user space
+  if $cs == 8 || $cs == 35
+    if $lastcs != 8 && $lastcs != 35
+      set architecture i386
+    end
+    x/i $pc
+  else
+    if $lastcs == -1 || $lastcs == 8 || $lastcs == 35
+      set architecture i8086
+    end
+    # Translate the segment:offset into a physical address
+    printf "[%4x:%4x] ", $cs, $eip
+    x/i $cs*16+$eip
+  end
+  set $lastcs = $cs
+end
+
+echo + target remote localhost:1234\n
+target remote localhost:1234
+
+echo + symbol-file kernel\n
+symbol-file kernel

BUGS

@@ -0,0 +1,7 @@
+formatting:
+	need to fix PAGEBREAK mechanism
+
+sh:
+	can't always runcmd in child -- breaks cd.
+	maybe should hard-code PATH=/ ?
+

LICENSE

@@ -0,0 +1,24 @@
+The xv6 software is:
+
+Copyright (c) 2006-2009 Frans Kaashoek, Robert Morris, Russ Cox,
+                        Massachusetts Institute of Technology
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+

Makefile

@@ -0,0 +1,270 @@
+OBJS = \
+	bio.o\
+	console.o\
+	exec.o\
+	file.o\
+	fs.o\
+	ide.o\
+	ioapic.o\
+	kalloc.o\
+	kbd.o\
+	lapic.o\
+	log.o\
+	main.o\
+	mp.o\
+	picirq.o\
+	pipe.o\
+	proc.o\
+	spinlock.o\
+	string.o\
+	swtch.o\
+	syscall.o\
+	sysfile.o\
+	sysproc.o\
+	timer.o\
+	trapasm.o\
+	trap.o\
+	uart.o\
+	vectors.o\
+	vm.o\
+
+# Cross-compiling (e.g., on Mac OS X)
+#TOOLPREFIX = i386-jos-elf-
+
+# Using native tools (e.g., on X86 Linux)
+#TOOLPREFIX = 
+
+# Try to infer the correct TOOLPREFIX if not set
+ifndef TOOLPREFIX
+TOOLPREFIX := $(shell if i386-jos-elf-objdump -i 2>&1 | grep '^elf32-i386$$' >/dev/null 2>&1; \
+	then echo 'i386-jos-elf-'; \
+	elif objdump -i 2>&1 | grep 'elf32-i386' >/dev/null 2>&1; \
+	then echo ''; \
+	else echo "***" 1>&2; \
+	echo "*** Error: Couldn't find an i386-*-elf version of GCC/binutils." 1>&2; \
+	echo "*** Is the directory with i386-jos-elf-gcc in your PATH?" 1>&2; \
+	echo "*** If your i386-*-elf toolchain is installed with a command" 1>&2; \
+	echo "*** prefix other than 'i386-jos-elf-', set your TOOLPREFIX" 1>&2; \
+	echo "*** environment variable to that prefix and run 'make' again." 1>&2; \
+	echo "*** To turn off this error, run 'gmake TOOLPREFIX= ...'." 1>&2; \
+	echo "***" 1>&2; exit 1; fi)
+endif
+
+# If the makefile can't find QEMU, specify its path here
+QEMU = /usr/bin/qemu-system-i386
+
+# Try to infer the correct QEMU
+ifndef QEMU
+QEMU = $(shell if which qemu > /dev/null; \
+	then echo qemu; exit; \
+	else \
+	qemu=/Applications/Q.app/Contents/MacOS/i386-softmmu.app/Contents/MacOS/i386-softmmu; \
+	if test -x $$qemu; then echo $$qemu; exit; fi; fi; \
+	echo "***" 1>&2; \
+	echo "*** Error: Couldn't find a working QEMU executable." 1>&2; \
+	echo "*** Is the directory containing the qemu binary in your PATH" 1>&2; \
+	echo "*** or have you tried setting the QEMU variable in Makefile?" 1>&2; \
+	echo "***" 1>&2; exit 1)
+endif
+
+CC = $(TOOLPREFIX)gcc
+AS = $(TOOLPREFIX)gas
+LD = $(TOOLPREFIX)ld
+OBJCOPY = $(TOOLPREFIX)objcopy
+OBJDUMP = $(TOOLPREFIX)objdump
+#CFLAGS = -fno-pic -static -fno-builtin -fno-strict-aliasing -O2 -Wall -MD -ggdb -m32 -Werror -fno-omit-frame-pointer
+CFLAGS = -fno-pic -static -fno-builtin -fno-strict-aliasing -Wall -MD -ggdb -m32 -Werror -fno-omit-frame-pointer
+CFLAGS += $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
+ASFLAGS = -m32 -gdwarf-2 -Wa,-divide
+# FreeBSD ld wants ``elf_i386_fbsd''
+LDFLAGS += -m $(shell $(LD) -V | grep elf_i386 2>/dev/null)
+
+xv6.img: bootblock kernel fs.img
+	dd if=/dev/zero of=xv6.img count=10000
+	dd if=bootblock of=xv6.img conv=notrunc
+	dd if=kernel of=xv6.img seek=1 conv=notrunc
+
+xv6memfs.img: bootblock kernelmemfs
+	dd if=/dev/zero of=xv6memfs.img count=10000
+	dd if=bootblock of=xv6memfs.img conv=notrunc
+	dd if=kernelmemfs of=xv6memfs.img seek=1 conv=notrunc
+
+bootblock: bootasm.S bootmain.c
+	$(CC) $(CFLAGS) -fno-pic -O -nostdinc -I. -c bootmain.c
+	$(CC) $(CFLAGS) -fno-pic -nostdinc -I. -c bootasm.S
+	$(LD) $(LDFLAGS) -N -e start -Ttext 0x7C00 -o bootblock.o bootasm.o bootmain.o
+	$(OBJDUMP) -S bootblock.o > bootblock.asm
+	$(OBJCOPY) -S -O binary -j .text bootblock.o bootblock
+	./sign.pl bootblock
+
+entryother: entryother.S
+	$(CC) $(CFLAGS) -fno-pic -nostdinc -I. -c entryother.S
+	$(LD) $(LDFLAGS) -N -e start -Ttext 0x7000 -o bootblockother.o entryother.o
+	$(OBJCOPY) -S -O binary -j .text bootblockother.o entryother
+	$(OBJDUMP) -S bootblockother.o > entryother.asm
+
+initcode: initcode.S
+	$(CC) $(CFLAGS) -nostdinc -I. -c initcode.S
+	$(LD) $(LDFLAGS) -N -e start -Ttext 0 -o initcode.out initcode.o
+	$(OBJCOPY) -S -O binary initcode.out initcode
+	$(OBJDUMP) -S initcode.o > initcode.asm
+
+kernel: $(OBJS) entry.o entryother initcode kernel.ld
+	$(LD) $(LDFLAGS) -T kernel.ld -o kernel entry.o $(OBJS) -b binary initcode entryother
+	$(OBJDUMP) -S kernel > kernel.asm
+	$(OBJDUMP) -t kernel | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernel.sym
+
+# kernelmemfs is a copy of kernel that maintains the
+# disk image in memory instead of writing to a disk.
+# This is not so useful for testing persistent storage or
+# exploring disk buffering implementations, but it is
+# great for testing the kernel on real hardware without
+# needing a scratch disk.
+MEMFSOBJS = $(filter-out ide.o,$(OBJS)) memide.o
+kernelmemfs: $(MEMFSOBJS) entry.o entryother initcode fs.img
+	$(LD) $(LDFLAGS) -Ttext 0x100000 -e main -o kernelmemfs entry.o  $(MEMFSOBJS) -b binary initcode entryother fs.img
+	$(OBJDUMP) -S kernelmemfs > kernelmemfs.asm
+	$(OBJDUMP) -t kernelmemfs | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernelmemfs.sym
+
+tags: $(OBJS) entryother.S _init
+	etags *.S *.c
+
+vectors.S: vectors.pl
+	perl vectors.pl > vectors.S
+
+ULIB = pow.o ulib.o usys.o printf.o umalloc.o libfile.o\
+       liblog.o exp.o\
+
+_%: %.o $(ULIB)
+	$(LD) $(LDFLAGS) -N -e main -Ttext 0 -o $@ $^
+	$(OBJDUMP) -S $@ > $*.asm
+	$(OBJDUMP) -t $@ | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > $*.sym
+
+_forktest: forktest.o $(ULIB)
+	# forktest has less library code linked in - needs to be small
+	# in order to be able to max out the proc table.
+	$(LD) $(LDFLAGS) -N -e main -Ttext 0 -o _forktest forktest.o ulib.o usys.o
+	$(OBJDUMP) -S _forktest > forktest.asm
+
+mkfs: mkfs.c fs.h
+	gcc -m32 -Werror -Wall -o mkfs mkfs.c
+
+UPROGS=\
+	_cat\
+	_echo\
+	_forktest\
+	_grep\
+	_init\
+	_kill\
+	_ln\
+	_ls\
+	_mkdir\
+	_rm\
+	_sh\
+	_stressfs\
+	_wc\
+	_zombie\
+	_test\
+
+fs.img: mkfs a test1 $(UPROGS)
+	./mkfs fs.img a test1 $(UPROGS)
+
+-include *.d
+
+clean: 
+	rm -f *.tex *.dvi *.idx *.aux *.log *.ind *.ilg \
+	*.o *.d *.asm *.sym vectors.S bootblock entryother \
+	initcode initcode.out kernel xv6.img fs.img kernelmemfs mkfs \
+	.gdbinit \
+	$(UPROGS)
+
+# make a printout
+FILES = $(shell grep -v '^\#' runoff.list)
+PRINT = runoff.list runoff.spec README toc.hdr toc.ftr $(FILES)
+
+xv6.pdf: $(PRINT)
+	./runoff
+	ls -l xv6.pdf
+
+print: xv6.pdf
+
+# run in emulators
+
+bochs : fs.img xv6.img
+	if [ ! -e .bochsrc ]; then ln -s dot-bochsrc .bochsrc; fi
+	bochs -q
+
+# try to generate a unique GDB port
+GDBPORT = $(shell expr `id -u` % 5000 + 25000)
+# QEMU's gdb stub command line changed in 0.11
+QEMUGDB = $(shell if $(QEMU) -help | grep -q '^-gdb'; \
+	then echo "-gdb tcp::$(GDBPORT)"; \
+	else echo "-s -p $(GDBPORT)"; fi)
+ifndef CPUS
+CPUS := 2
+endif
+QEMUOPTS = -hdb fs.img xv6.img -smp $(CPUS) -m 512 $(QEMUEXTRA)
+
+qemu: fs.img xv6.img
+	$(QEMU) -serial mon:stdio $(QEMUOPTS)
+
+qemu-memfs: xv6memfs.img
+	$(QEMU) xv6memfs.img -smp $(CPUS)
+
+qemu-nox: fs.img xv6.img
+	$(QEMU) -nographic $(QEMUOPTS)
+
+.gdbinit: .gdbinit.tmpl
+	sed "s/localhost:1234/localhost:$(GDBPORT)/" < $^ > $@
+
+qemu-gdb: fs.img xv6.img .gdbinit
+	@echo "*** Now run 'gdb'." 1>&2
+	$(QEMU) -serial mon:stdio $(QEMUOPTS) -S $(QEMUGDB)
+
+qemu-nox-gdb: fs.img xv6.img .gdbinit
+	@echo "*** Now run 'gdb'." 1>&2
+	$(QEMU) -nographic $(QEMUOPTS) -S $(QEMUGDB)
+
+# CUT HERE
+# prepare dist for students
+# after running make dist, probably want to
+# rename it to rev0 or rev1 or so on and then
+# check in that version.
+
+EXTRA=\
+	mkfs.c ulib.c user.h cat.c echo.c forktest.c grep.c kill.c\
+	ln.c ls.c mkdir.c rm.c stressfs.c wc.c zombie.c\
+	printf.c umalloc.c  \
+	README picoc dot-bochsrc *.pl toc.* runoff runoff1 runoff.list\
+	.gdbinit.tmpl gdbutil\
+
+dist:
+	rm -rf dist
+	mkdir dist
+	for i in $(FILES); \
+	do \
+		grep -v PAGEBREAK $$i >dist/$$i; \
+	done
+	sed '/CUT HERE/,$$d' Makefile >dist/Makefile
+	echo >dist/runoff.spec
+	cp $(EXTRA) dist
+
+dist-test:
+	rm -rf dist
+	make dist
+	rm -rf dist-test
+	mkdir dist-test
+	cp dist/* dist-test
+	cd dist-test; $(MAKE) print
+	cd dist-test; $(MAKE) bochs || true
+	cd dist-test; $(MAKE) qemu
+
+# update this rule (change rev#) when it is time to
+# make a new revision.
+tar:
+	rm -rf /tmp/xv6
+	mkdir -p /tmp/xv6
+	cp dist/* dist/.gdbinit.tmpl /tmp/xv6
+	(cd /tmp; tar cf - xv6) | gzip >xv6-rev5.tar.gz
+
+.PHONY: dist-test dist