在 linux 内核的 qemu 中执行 make 命令时出错 "undefined reference to `cprintf''"
Error "undefined reference to `cprintf''" during executing make command in qemu in linux kernel
(1) 这是主要函数(runproctest.c):
#include "defs.h"
void
runproctest(void)
{
cprintf("testing runnable: test1\n");
}
(2) defs.h:
// console.c
void cprintf(char*, ...);
(3) console.c
#include "defs.h"
void
cprintf(char *fmt, ...)
{
int i, c, locking;
uint *argp;
char *s;
locking = cons.locking;
if(locking)
acquire(&cons.lock);
if (fmt == 0)
...
}
(4) main.c
#include "types.h"
#include "defs.h"
#include "param.h"
#include "memlayout.h"
#include "mmu.h"
#include "proc.h"
#include "x86.h"
static void startothers(void);
static void mpmain(void) __attribute__((noreturn));
extern pde_t *kpgdir;
extern char end[]; // first address after kernel loaded from ELF file
// Bootstrap processor starts running C code here.
// Allocate a real stack and switch to it, first
// doing some setup required for memory allocator to work.
int
main(void)
{
kinit1(end, P2V(4*1024*1024)); // phys page allocator
kvmalloc(); // kernel page table
mpinit(); // detect other processors
lapicinit(); // interrupt controller
seginit(); // segment descriptors
cprintf("\ncpu%d: starting xv6\n\n", cpunum());
picinit(); // another interrupt controller
ioapicinit(); // another interrupt controller
consoleinit(); // console hardware
uartinit(); // serial port
pinit(); // process table
tvinit(); // trap vectors
binit(); // buffer cache
fileinit(); // file table
ideinit(); // disk
if(!ismp)
timerinit(); // uniprocessor timer
startothers(); // start other processors
kinit2(P2V(4*1024*1024), P2V(PHYSTOP)); // must come after startothers()
userinit(); // first user process
mpmain(); // finish this processor's setup
}
// Other CPUs jump here from entryother.S.
static void
mpenter(void)
{
switchkvm();
seginit();
lapicinit();
mpmain();
}
// Common CPU setup code.
static void
mpmain(void)
{
cprintf("cpu%d: starting\n", cpunum());
idtinit(); // load idt register
xchg(&cpu->started, 1); // tell startothers() we're up
scheduler(); // start running processes
}
pde_t entrypgdir[]; // For entry.S
// Start the non-boot (AP) processors.
static void
startothers(void)
{
extern uchar _binary_entryother_start[], _binary_entryother_size[];
uchar *code;
struct cpu *c;
char *stack;
// Write entry code to unused memory at 0x7000.
// The linker has placed the image of entryother.S in
// _binary_entryother_start.
code = P2V(0x7000);
memmove(code, _binary_entryother_start, (uint)_binary_entryother_size);
for(c = cpus; c < cpus+ncpu; c++){
if(c == cpus+cpunum()) // We've started already.
continue;
// Tell entryother.S what stack to use, where to enter, and what
// pgdir to use. We cannot use kpgdir yet, because the AP processor
// is running in low memory, so we use entrypgdir for the APs too.
stack = kalloc();
*(void**)(code-4) = stack + KSTACKSIZE;
*(void**)(code-8) = mpenter;
*(int**)(code-12) = (void *) V2P(entrypgdir);
lapicstartap(c->apicid, V2P(code));
// wait for cpu to finish mpmain()
while(c->started == 0)
;
}
}
// The boot page table used in entry.S and entryother.S.
// Page directories (and page tables) must start on page boundaries,
// hence the __aligned__ attribute.
// PTE_PS in a page directory entry enables 4Mbyte pages.
__attribute__((__aligned__(PGSIZE)))
pde_t entrypgdir[NPDENTRIES] = {
// Map VA's [0, 4MB) to PA's [0, 4MB)
[0] = (0) | PTE_P | PTE_W | PTE_PS,
// Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB)
[KERNBASE>>PDXSHIFT] = (0) | PTE_P | PTE_W | PTE_PS,
};
(5) 这是我的 Makefile:
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\
runproctest.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$$' >/dev/null 2>&1; \
then echo 'i386-jos-elf-'; \
elif objdump -i 2>&1 | grep 'elf32-i386' >/dev/null 2>&1; \
then echo ''; \
else echo "***" 1>&2; \
echo "*** Error: Couldn't find an i386-*-elf version of GCC/binutils." 1>&2; \
echo "*** Is the directory with i386-jos-elf-gcc in your PATH?" 1>&2; \
echo "*** If your i386-*-elf toolchain is installed with a command" 1>&2; \
echo "*** prefix other than 'i386-jos-elf-', set your TOOLPREFIX" 1>&2; \
echo "*** environment variable to that prefix and run 'make' again." 1>&2; \
echo "*** To turn off this error, run 'gmake TOOLPREFIX= ...'." 1>&2; \
echo "***" 1>&2; exit 1; fi)
endif
# If the makefile can't find QEMU, specify its path here
QEMU = /home/yuanzheng/Qemu_installed/bin/qemu-system-i386
# Try to infer the correct QEMU
ifndef QEMU
QEMU = $(shell if which qemu > /dev/null; \
then echo qemu; exit; \
elif which qemu-system-i386 > /dev/null; \
then echo qemu-system-i386; exit; \
else \
qemu=/Applications/Q.app/Contents/MacOS/i386-softmmu.app/Contents/MacOS/i386-softmmu; \
if test -x $$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 -fvar-tracking -fvar-tracking-assignments -O0 -g -Wall -MD -gdwarf-2 -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 kernel.ld fs.img
$(LD) $(LDFLAGS) -T kernel.ld -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/ .* / /; /^$$/d' > kernelmemfs.sym
tags: $(OBJS) entryother.S _init
etags *.S *.c
vectors.S: vectors.pl
perl vectors.pl > vectors.S
ULIB = ulib.o usys.o printf.o umalloc.o
_%: %.o $(ULIB)
$(LD) $(LDFLAGS) -N -e main -Ttext 0 -o $@ $^
$(OBJDUMP) -S $@ > $*.asm
$(OBJDUMP) -t $@ | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/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 -Werror -Wall -o mkfs mkfs.c
# Prevent deletion of intermediate files, e.g. cat.o, after first build, so
# that disk image changes after first build are persistent until clean. More
# details:
# http://www.gnu.org/software/make/manual/html_node/Chained-Rules.html
.PRECIOUS: %.o
UPROGS=\
_cat\
_echo\
_forktest\
_grep\
_init\
_kill\
_ln\
_ls\
_mkdir\
_rm\
_sh\
_stressfs\
_usertests\
_wc\
_zombie\
_runnable\
_runnabletest\
_runproctest\
fs.img: mkfs README $(UPROGS)
./mkfs fs.img README $(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 = -drive file=fs.img,index=1,media=disk,format=raw -drive file=xv6.img,index=0,media=disk,format=raw -smp $(CPUS) -m 512 $(QEMUEXTRA)
qemu: fs.img xv6.img
$(QEMU) -serial mon:stdio $(QEMUOPTS)
qemu-memfs: xv6memfs.img
$(QEMU) -drive file=xv6memfs.img,index=0,media=disk,format=raw -smp $(CPUS) -m 256
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 usertests.c wc.c zombie.c\
printf.c umalloc.c runnable.c printf.h runnabletest.c runproctest.c\
README 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-rev9.tar.gz # the next one will be 9 (6/27/15)
.PHONY: dist-test dist
当我输入make qemu时出现问题：
yuanzheng@ubuntu:~/Operating_System/xv6_sourcecode/xv6-public$ make qemu
ld -m elf_i386 -N -e main -Ttext 0 -o _runproctest runproctest.o ulib.o usys.o printf.o umalloc.o
ld: warning: cannot find entry symbol main; defaulting to 0000000000000000
runproctest.o: In function `runproctest':
/home/yuanzheng/Operating_System/xv6_sourcecode/xv6-public/runproctest.c:26: undefined reference to `cprintf'
Makefile:141: recipe for target '_runproctest' failed
make: *** [_runproctest] Error 1
我不知道为什么会这样..
在 makefile 中，这一行：
ld -m elf_i386 -N -e main -Ttext 0 -o _runproctest runproctest.o ulib.o usys.o printf.o umalloc.o
应该是：
ld -m elf_i386 -N -e main -Ttext 0 -o _runproctest runproctest.o ulib.o usys.o printf.o umalloc.o console.o
make 文件中可能还有其他 ld 命令有类似的问题。
此外，根据错误消息，用于创建 _runproctest 可执行文件的文件中的任何地方都没有 main() 函数。这（通常）强烈表明代码将无法正确执行。
顺便说一句：
以__或_开头后跟大写字母的名称是为环境保留的。
用前导下划线命名您自己的项目（可能）会起作用，但它会使环境名称混乱 space。强烈建议不要在您的名字中使用任何前导 _
(1) 这是主要函数(runproctest.c):
#include "defs.h"
void
runproctest(void)
{
cprintf("testing runnable: test1\n");
}
(2) defs.h:
// console.c
void cprintf(char*, ...);
(3) console.c
#include "defs.h"
void
cprintf(char *fmt, ...)
{
int i, c, locking;
uint *argp;
char *s;
locking = cons.locking;
if(locking)
acquire(&cons.lock);
if (fmt == 0)
...
}
(4) main.c
#include "types.h"
#include "defs.h"
#include "param.h"
#include "memlayout.h"
#include "mmu.h"
#include "proc.h"
#include "x86.h"
static void startothers(void);
static void mpmain(void) __attribute__((noreturn));
extern pde_t *kpgdir;
extern char end[]; // first address after kernel loaded from ELF file
// Bootstrap processor starts running C code here.
// Allocate a real stack and switch to it, first
// doing some setup required for memory allocator to work.
int
main(void)
{
kinit1(end, P2V(4*1024*1024)); // phys page allocator
kvmalloc(); // kernel page table
mpinit(); // detect other processors
lapicinit(); // interrupt controller
seginit(); // segment descriptors
cprintf("\ncpu%d: starting xv6\n\n", cpunum());
picinit(); // another interrupt controller
ioapicinit(); // another interrupt controller
consoleinit(); // console hardware
uartinit(); // serial port
pinit(); // process table
tvinit(); // trap vectors
binit(); // buffer cache
fileinit(); // file table
ideinit(); // disk
if(!ismp)
timerinit(); // uniprocessor timer
startothers(); // start other processors
kinit2(P2V(4*1024*1024), P2V(PHYSTOP)); // must come after startothers()
userinit(); // first user process
mpmain(); // finish this processor's setup
}
// Other CPUs jump here from entryother.S.
static void
mpenter(void)
{
switchkvm();
seginit();
lapicinit();
mpmain();
}
// Common CPU setup code.
static void
mpmain(void)
{
cprintf("cpu%d: starting\n", cpunum());
idtinit(); // load idt register
xchg(&cpu->started, 1); // tell startothers() we're up
scheduler(); // start running processes
}
pde_t entrypgdir[]; // For entry.S
// Start the non-boot (AP) processors.
static void
startothers(void)
{
extern uchar _binary_entryother_start[], _binary_entryother_size[];
uchar *code;
struct cpu *c;
char *stack;
// Write entry code to unused memory at 0x7000.
// The linker has placed the image of entryother.S in
// _binary_entryother_start.
code = P2V(0x7000);
memmove(code, _binary_entryother_start, (uint)_binary_entryother_size);
for(c = cpus; c < cpus+ncpu; c++){
if(c == cpus+cpunum()) // We've started already.
continue;
// Tell entryother.S what stack to use, where to enter, and what
// pgdir to use. We cannot use kpgdir yet, because the AP processor
// is running in low memory, so we use entrypgdir for the APs too.
stack = kalloc();
*(void**)(code-4) = stack + KSTACKSIZE;
*(void**)(code-8) = mpenter;
*(int**)(code-12) = (void *) V2P(entrypgdir);
lapicstartap(c->apicid, V2P(code));
// wait for cpu to finish mpmain()
while(c->started == 0)
;
}
}
// The boot page table used in entry.S and entryother.S.
// Page directories (and page tables) must start on page boundaries,
// hence the __aligned__ attribute.
// PTE_PS in a page directory entry enables 4Mbyte pages.
__attribute__((__aligned__(PGSIZE)))
pde_t entrypgdir[NPDENTRIES] = {
// Map VA's [0, 4MB) to PA's [0, 4MB)
[0] = (0) | PTE_P | PTE_W | PTE_PS,
// Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB)
[KERNBASE>>PDXSHIFT] = (0) | PTE_P | PTE_W | PTE_PS,
};
(5) 这是我的 Makefile:
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\
runproctest.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 = /home/yuanzheng/Qemu_installed/bin/qemu-system-i386
# Try to infer the correct QEMU
ifndef QEMU
QEMU = $(shell if which qemu > /dev/null; \
then echo qemu; exit; \
elif which qemu-system-i386 > /dev/null; \
then echo qemu-system-i386; 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 -fvar-tracking -fvar-tracking-assignments -O0 -g -Wall -MD -gdwarf-2 -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/ .* / /; /^$$/d' > kernel.sym
# kernelmemfs is a copy of kernel that maintains the
# disk image in memory instead of writing to a disk.
# This is not so useful for testing persistent storage or
# exploring disk buffering implementations, but it is
# great for testing the kernel on real hardware without
# needing a scratch disk.
MEMFSOBJS = $(filter-out ide.o,$(OBJS)) memide.o
kernelmemfs: $(MEMFSOBJS) entry.o entryother initcode kernel.ld fs.img
$(LD) $(LDFLAGS) -T kernel.ld -o kernelmemfs entry.o $(MEMFSOBJS) -b binary initcode entryother fs.img
$(OBJDUMP) -S kernelmemfs > kernelmemfs.asm
$(OBJDUMP) -t kernelmemfs | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernelmemfs.sym
tags: $(OBJS) entryother.S _init
etags *.S *.c
vectors.S: vectors.pl
perl vectors.pl > vectors.S
ULIB = ulib.o usys.o printf.o umalloc.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 -Werror -Wall -o mkfs mkfs.c
# Prevent deletion of intermediate files, e.g. cat.o, after first build, so
# that disk image changes after first build are persistent until clean. More
# details:
# http://www.gnu.org/software/make/manual/html_node/Chained-Rules.html
.PRECIOUS: %.o
UPROGS=\
_cat\
_echo\
_forktest\
_grep\
_init\
_kill\
_ln\
_ls\
_mkdir\
_rm\
_sh\
_stressfs\
_usertests\
_wc\
_zombie\
_runnable\
_runnabletest\
_runproctest\
fs.img: mkfs README $(UPROGS)
./mkfs fs.img README $(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 = -drive file=fs.img,index=1,media=disk,format=raw -drive file=xv6.img,index=0,media=disk,format=raw -smp $(CPUS) -m 512 $(QEMUEXTRA)
qemu: fs.img xv6.img
$(QEMU) -serial mon:stdio $(QEMUOPTS)
qemu-memfs: xv6memfs.img
$(QEMU) -drive file=xv6memfs.img,index=0,media=disk,format=raw -smp $(CPUS) -m 256
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 usertests.c wc.c zombie.c\
printf.c umalloc.c runnable.c printf.h runnabletest.c runproctest.c\
README 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; $(MAKE) qemu
# update this rule (change rev#) when it is time to
# make a new revision.
tar:
rm -rf /tmp/xv6
mkdir -p /tmp/xv6
cp dist/* dist/.gdbinit.tmpl /tmp/xv6
(cd /tmp; tar cf - xv6) | gzip >xv6-rev9.tar.gz # the next one will be 9 (6/27/15)
.PHONY: dist-test dist
当我输入make qemu时出现问题：
yuanzheng@ubuntu:~/Operating_System/xv6_sourcecode/xv6-public$ make qemu
ld -m elf_i386 -N -e main -Ttext 0 -o _runproctest runproctest.o ulib.o usys.o printf.o umalloc.o
ld: warning: cannot find entry symbol main; defaulting to 0000000000000000
runproctest.o: In function `runproctest':
/home/yuanzheng/Operating_System/xv6_sourcecode/xv6-public/runproctest.c:26: undefined reference to `cprintf'
Makefile:141: recipe for target '_runproctest' failed
make: *** [_runproctest] Error 1
我不知道为什么会这样..
在 makefile 中，这一行：
ld -m elf_i386 -N -e main -Ttext 0 -o _runproctest runproctest.o ulib.o usys.o printf.o umalloc.o
应该是：
ld -m elf_i386 -N -e main -Ttext 0 -o _runproctest runproctest.o ulib.o usys.o printf.o umalloc.o console.o
make 文件中可能还有其他 ld 命令有类似的问题。
此外，根据错误消息，用于创建 _runproctest 可执行文件的文件中的任何地方都没有 main() 函数。这（通常）强烈表明代码将无法正确执行。
顺便说一句：
以__或_开头后跟大写字母的名称是为环境保留的。
用前导下划线命名您自己的项目（可能）会起作用，但它会使环境名称混乱 space。强烈建议不要在您的名字中使用任何前导 _