Merge commit 'origin/master' into page

i-pu · Jul 28, 2011 · dccb915 · dccb915
2 parents 9acdfe0 + 13a96ba
commit dccb915
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diff --git a/.gitignore b/.gitignore
@@ -1,3 +1,4 @@
+*~
 _*
 *.o
 *.d

diff --git a/Makefile b/Makefile
@@ -26,19 +26,53 @@ OBJS = \
 	uart.o\
 	vectors.o\
 	vm.o\
+	log.o\
 
 # Cross-compiling (e.g., on Mac OS X)
-TOOLPREFIX = i386-jos-elf-
+#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$$' >/dev/null 2>&1; \
+	then echo 'i386-jos-elf-'; \
+	elif objdump -i 2>&1 | grep 'elf32-i386' >/dev/null 2>&1; \
+	then echo ''; \
+	else echo "***" 1>&2; \
+	echo "*** Error: Couldn't find an i386-*-elf version of GCC/binutils." 1>&2; \
+	echo "*** Is the directory with i386-jos-elf-gcc in your PATH?" 1>&2; \
+	echo "*** If your i386-*-elf toolchain is installed with a command" 1>&2; \
+	echo "*** prefix other than 'i386-jos-elf-', set your TOOLPREFIX" 1>&2; \
+	echo "*** environment variable to that prefix and run 'make' again." 1>&2; \
+	echo "*** To turn off this error, run 'gmake TOOLPREFIX= ...'." 1>&2; \
+	echo "***" 1>&2; exit 1; fi)
+endif
+
+# If the makefile can't find QEMU, specify its path here
+#QEMU = 
+
+# Try to infer the correct QEMU
+ifndef QEMU
+QEMU = $(shell if which qemu > /dev/null; \
+	then echo qemu; exit; \
+	else \
+	qemu=/Applications/Q.app/Contents/MacOS/i386-softmmu.app/Contents/MacOS/i386-softmmu; \
+	if test -x $$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
+CFLAGS = -fno-pic -static -fno-builtin -fno-strict-aliasing -O2 -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
 # FreeBSD ld wants ``elf_i386_fbsd''
@@ -49,6 +83,11 @@ xv6.img: bootblock kernel fs.img
 	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
@@ -69,11 +108,23 @@ initcode: initcode.S
 	$(OBJCOPY) -S -O binary initcode.out initcode
 	$(OBJDUMP) -S initcode.o > initcode.asm
 
-kernel: $(OBJS) bootother initcode
-	$(LD) $(LDFLAGS) -Ttext 0x100000 -e main -o kernel $(OBJS) -b binary initcode bootother
+kernel: $(OBJS) multiboot.o data.o bootother initcode
+	$(LD) $(LDFLAGS) -Ttext 0x100000 -e main -o kernel multiboot.o data.o $(OBJS) -b binary initcode bootother
 	$(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) multiboot.o data.o bootother initcode fs.img
+	$(LD) $(LDFLAGS) -Ttext 0x100000 -e main -o kernelmemfs multiboot.o data.o $(MEMFSOBJS) -b binary initcode bootother fs.img
+	$(OBJDUMP) -S kernelmemfs > kernelmemfs.asm
+	$(OBJDUMP) -t kernelmemfs | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernelmemfs.sym
+
 tags: $(OBJS) bootother.S _init
 	etags *.S *.c
 
@@ -94,7 +145,7 @@ _forktest: forktest.o $(ULIB)
 	$(OBJDUMP) -S _forktest > forktest.asm
 
 mkfs: mkfs.c fs.h
-	gcc -Wall -o mkfs mkfs.c
+	gcc -m32 -Werror -Wall -o mkfs mkfs.c
 
 UPROGS=\
 	_cat\
@@ -126,7 +177,7 @@ clean:
 
 # make a printout
 FILES = $(shell grep -v '^\#' runoff.list)
-PRINT = runoff.list $(FILES)
+PRINT = runoff.list runoff.spec $(FILES)
 
 xv6.pdf: $(PRINT)
 	./runoff
@@ -143,27 +194,33 @@ bochs : fs.img xv6.img
 # 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'; \
+QEMUGDB = $(shell if $(QEMU) -help | grep -q '^-gdb'; \
 	then echo "-gdb tcp::$(GDBPORT)"; \
 	else echo "-s -p $(GDBPORT)"; fi)
-QEMUOPTS = -smp 2 -hdb fs.img xv6.img
+ifndef CPUS
+CPUS := 2
+endif
+QEMUOPTS = -hdb fs.img xv6.img -smp $(CPUS)
 
 qemu: fs.img xv6.img
-	qemu -serial mon:stdio $(QEMUOPTS)
+	$(QEMU) -serial mon:stdio $(QEMUOPTS)
+
+qemu-memfs: xv6memfs.img
+	$(QEMU) xv6memfs.img -smp $(CPUS)
 
 qemu-nox: fs.img xv6.img
-	qemu -nographic $(QEMUOPTS)
+	$(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) -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)
+	$(QEMU) -nographic $(QEMUOPTS) -S $(QEMUGDB)
 
 # CUT HERE
 # prepare dist for students
@@ -195,14 +252,16 @@ dist-test:
 	rm -rf dist-test
 	mkdir dist-test
 	cp dist/* dist-test
-	cd dist-test; ../m print
-	cd dist-test; ../m bochs || true
-	cd dist-test; ../m qemu
+	cd dist-test; $(MAKE) print
+	cd dist-test; $(MAKE) bochs || true
+	cd dist-test; $(MAKE) qemu
 
-# update this rule (change rev1) when it is time to
+# 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-rev3.tar.gz
+	(cd /tmp; tar cf - xv6) | gzip >xv6-rev5.tar.gz
+
+.PHONY: dist-test dist
diff --git a/README b/README
@@ -19,6 +19,11 @@ The following people made contributions:
     Russ Cox (context switching, locking)
     Cliff Frey (MP)
     Xiao Yu (MP)
+    Nickolai Zeldovich
+    Austin Clements
+
+In addition, we are grateful for the patches contributed by Greg
+Price, Yandong Mao, and Hitoshi Mitake.
 
 The code in the files that constitute xv6 is
 Copyright 2006-2007 Frans Kaashoek, Robert Morris, and Russ Cox.
@@ -39,9 +44,7 @@ Then run "make TOOLPREFIX=i386-jos-elf-".
 To run xv6, you can use Bochs or QEMU, both PC simulators.
 Bochs makes debugging easier, but QEMU is much faster. 
 To run in Bochs, run "make bochs" and then type "c" at the bochs prompt.
-To run in QEMU, run "make qemu".  Both log the xv6 screen output to 
-standard output.
+To run in QEMU, run "make qemu".
 
-To create a typeset version of the code, run "make xv6.pdf".
-This requires the "mpage" text formatting utility.
-See http://www.mesa.nl/pub/mpage/.
+To create a typeset version of the code, run "make xv6.pdf".  This
+requires the "mpage" utility.  See http://www.mesa.nl/pub/mpage/.
diff --git a/bootasm.S b/bootasm.S
@@ -13,18 +13,16 @@
 .code16                       # Assemble for 16-bit mode
 .globl start
 start:
-  cli                         # Disable interrupts
+  cli                         # BIOS enabled interrupts; disable
 
   # Set up the important data segment registers (DS, ES, SS).
   xorw    %ax,%ax             # Segment number zero
   movw    %ax,%ds             # -> Data Segment
   movw    %ax,%es             # -> Extra Segment
   movw    %ax,%ss             # -> Stack Segment
 
-  # Enable A20:
-  #   For backwards compatibility with the earliest PCs, physical
-  #   address line 20 is tied low, so that addresses higher than
-  #   1MB wrap around to zero by default.  This code undoes this.
+  # Physical address line A20 is tied to zero so that the first PCs 
+  # with 2 MB would run software that assumed 1 MB.  Undo that.
 seta20.1:
   inb     $0x64,%al               # Wait for not busy
   testb   $0x2,%al
@@ -41,23 +39,21 @@ seta20.2:
   movb    $0xdf,%al               # 0xdf -> port 0x60
   outb    %al,$0x60
 
-//PAGEBREAK!
-  # Switch from real to protected mode, using a bootstrap GDT
-  # and segment translation that makes virtual addresses 
-  # identical to physical addresses, so that the 
-  # effective memory map does not change during the switch.
+  # Switch from real to protected mode.  Use a bootstrap GDT that makes
+  # virtual addresses map dierctly to  physical addresses so that the
+  # effective memory map doesn't change during the transition.
   lgdt    gdtdesc
   movl    %cr0, %eax
   orl     $CR0_PE, %eax
   movl    %eax, %cr0
-  
-  # This ljmp is how you load the CS (Code Segment) register.
-  # SEG_ASM produces segment descriptors with the 32-bit mode
-  # flag set (the D flag), so addresses and word operands will
-  # default to 32 bits after this jump.
+
+//PAGEBREAK!
+  # Complete transition to 32-bit protected mode by using long jmp
+  # to reload %cs and %eip.  The segment registers are set up with no
+  # translation, so that the mapping is still the identity mapping.
   ljmp    $(SEG_KCODE<<3), $start32
 
-.code32                       # Assemble for 32-bit mode
+.code32  # Tell assembler to generate 32-bit code now.
 start32:
   # Set up the protected-mode data segment registers
   movw    $(SEG_KDATA<<3), %ax    # Our data segment selector

diff --git a/bootmain.c b/bootmain.c
@@ -33,16 +33,16 @@ bootmain(void)
   // Load each program segment (ignores ph flags).
   ph = (struct proghdr*)((uchar*)elf + elf->phoff);
   eph = ph + elf->phnum;
-  for(; ph < eph; ph++) {
-    va = (uchar*)(ph->va & 0xFFFFFF);
+  for(; ph < eph; ph++){
+    va = (uchar*)ph->va;
     readseg(va, ph->filesz, ph->offset);
     if(ph->memsz > ph->filesz)
       stosb(va + ph->filesz, 0, ph->memsz - ph->filesz);
   }
 
   // Call the entry point from the ELF header.
   // Does not return!
-  entry = (void(*)(void))(elf->entry & 0xFFFFFF);
+  entry = (void(*)(void))(elf->entry);
   entry();
 }
 

diff --git a/bootother.S b/bootother.S
@@ -9,80 +9,69 @@
 # Because this code sets DS to zero, it must sit
 # at an address in the low 2^16 bytes.
 #
-# Bootothers (in main.c) sends the STARTUPs, one at a time.
-# It puts this code (start) at 0x7000.
-# It puts the correct %esp in start-4,
-# and the place to jump to in start-8.
+# Bootothers (in main.c) sends the STARTUPs one at a time.
+# It copies this code (start) at 0x7000.
+# It puts the address of a newly allocated per-core stack in start-4,
+# and the address of the place to jump to (mpmain) in start-8.
 #
 # This code is identical to bootasm.S except:
 #   - it does not need to enable A20
 #   - it uses the address at start-4 for the %esp
 #   - it jumps to the address at start-8 instead of calling bootmain
 
-#define SEG_KCODE 1  // kernel code
-#define SEG_KDATA 2  // kernel data+stack
+#define SEG_KCODE 1
+#define SEG_KDATA 2
 
-#define CR0_PE    1  // protected mode enable bit
+#define CR0_PE    1
 
-.code16                       # Assemble for 16-bit mode
+.code16           
 .globl start
 start:
-  cli                         # Disable interrupts
+  cli            
 
-  # Set up the important data segment registers (DS, ES, SS).
-  xorw    %ax,%ax             # Segment number zero
-  movw    %ax,%ds             # -> Data Segment
-  movw    %ax,%es             # -> Extra Segment
-  movw    %ax,%ss             # -> Stack Segment
+  xorw    %ax,%ax
+  movw    %ax,%ds
+  movw    %ax,%es
+  movw    %ax,%ss
 
-//PAGEBREAK!
-  # Switch from real to protected mode, using a bootstrap GDT
-  # and segment translation that makes virtual addresses 
-  # identical to physical addresses, so that the 
-  # effective memory map does not change during the switch.
   lgdt    gdtdesc
   movl    %cr0, %eax
   orl     $CR0_PE, %eax
   movl    %eax, %cr0
 
-  # This ljmp is how you load the CS (Code Segment) register.
-  # SEG_ASM produces segment descriptors with the 32-bit mode
-  # flag set (the D flag), so addresses and word operands will
-  # default to 32 bits after this jump.
+//PAGEBREAK!
   ljmp    $(SEG_KCODE<<3), $start32
 
-.code32                       # Assemble for 32-bit mode
+.code32
 start32:
-  # Set up the protected-mode data segment registers
-  movw    $(SEG_KDATA<<3), %ax    # Our data segment selector
-  movw    %ax, %ds                # -> DS: Data Segment
-  movw    %ax, %es                # -> ES: Extra Segment
-  movw    %ax, %ss                # -> SS: Stack Segment
-  movw    $0, %ax                 # Zero segments not ready for use
-  movw    %ax, %fs                # -> FS
-  movw    %ax, %gs                # -> GS
+  movw    $(SEG_KDATA<<3), %ax
+  movw    %ax, %ds
+  movw    %ax, %es
+  movw    %ax, %ss
+  movw    $0, %ax
+  movw    %ax, %fs
+  movw    %ax, %gs
 
-  # Set up the stack pointer and call into C.
+  # switch to the stack allocated by bootothers()
   movl    start-4, %esp
+
+  # call mpmain()
   call	*(start-8)
 
-  # If the call returns (it shouldn't), trigger a Bochs
-  # breakpoint if running under Bochs, then loop.
-  movw    $0x8a00, %ax            # 0x8a00 -> port 0x8a00
+  movw    $0x8a00, %ax
   movw    %ax, %dx
   outw    %ax, %dx
-  movw    $0x8ae0, %ax            # 0x8ae0 -> port 0x8a00
+  movw    $0x8ae0, %ax
   outw    %ax, %dx
 spin:
   jmp     spin
 
-# Bootstrap GDT
-.p2align 2                                # force 4 byte alignment
+.p2align 2
 gdt:
-  SEG_NULLASM                             # null seg
-  SEG_ASM(STA_X|STA_R, 0x0, 0xffffffff)   # code seg
-  SEG_ASM(STA_W, 0x0, 0xffffffff)         # data seg
+  SEG_NULLASM
+  SEG_ASM(STA_X|STA_R, 0x0, 0xffffffff)
+  SEG_ASM(STA_W, 0x0, 0xffffffff)
 
 gdtdesc:
-  .word   (gdtdesc - gdt - 1)                            # sizeof(gdt) - 1
-  .long   gdt                             # address gdt
+  .word   (gdtdesc - gdt - 1)
+  .long   gdt
-Original file line number
+Diff line change
@@ -1,3 +1,4 @@
+    *~
     _*
     *.o
     *.d
@@ Expand Down @@