myxv6

看代码并加上中文注释，还有就是做lab

代码基于2020 MIT 6.S081的xv6-riscv，lab也基于此

课程视频

b站中英文字幕

环境

我只在macos intel x86调试，所以下面环境就是macos环境要安装的，brew自行安装吧😄

$ brew tap riscv/riscv
$ brew install riscv-tools

重新配置下PATH环境变量，把riscv工具相关二进制加入到PATH

PATH=$PATH:/usr/local/opt/riscv-gnu-toolchain/bin

最后安装qemu

brew install qemu

原来xv6的代码在最新qemu里面起来卡住，改了些代码后可以启动，

所以不知道后面更新的qemu是否还能启动，

所以记下现在运行的版本：

$ riscv64-unknown-elf-gcc --version
riscv64-unknown-elf-gcc (GCC) 10.2.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ qemu-system-riscv64 --version
QEMU emulator version 6.0.0
Copyright (c) 2003-2021 Fabrice Bellard and the QEMU Project developers

运行

$ make qemu

退出qemu:

ctrl+a,松开,按x

测试

$ usertests # 进入系统后执行, 会运行很多测试，回归测试必用

Lab

这个lab跟原来的不同，是每个lab是基于上个lab基础继续做的，所以这样最后代码就基本是所有lab的集合，很有挑战哈

每个lab跑测试之前最好清空下文件

$ make clean

Utilities（工具）

$ ./grade-lab-util                             
make: `kernel/kernel' is up to date.
== Test sleep, no arguments == sleep, no arguments: OK (1.8s) 
== Test sleep, returns == sleep, returns: OK (0.7s) 
== Test sleep, makes syscall == sleep, makes syscall: OK (0.9s) 
== Test pingpong == pingpong: OK (1.0s) 
== Test primes == primes: OK (1.0s) 
== Test find, in current directory == find, in current directory: OK (1.2s) 
== Test find, recursive == find, recursive: OK (1.6s) 
== Test xargs == xargs: OK (1.5s) 
== Test time == 
time: OK 
Score: 100/100

System calls（系统调用）

$ ./grade-lab-syscall
make: `kernel/kernel' is up to date.
== Test trace 32 grep == trace 32 grep: OK (1.5s) 
== Test trace all grep == trace all grep: OK (0.8s) 
== Test trace nothing == trace nothing: OK (1.1s) 
== Test trace children == trace children: OK (15.1s) 
== Test sysinfotest == sysinfotest: OK (2.5s) 
== Test time == 
time: OK 
Score: 35/35

Page tables（页表）

$ LAB=pgtbl ./grade-lab-pgtbl
make: `kernel/kernel' is up to date.
== Test pte printout == pte printout: OK (0.9s) 
== Test answers-pgtbl.txt == answers-pgtbl.txt: OK 
== Test count copyin == count copyin: OK (0.9s) 
== Test usertests == (287.8s) 
== Test   usertests: copyin == 
usertests: copyin: OK 
== Test   usertests: copyinstr1 == 
usertests: copyinstr1: OK 
== Test   usertests: copyinstr2 == 
usertests: copyinstr2: OK 
== Test   usertests: copyinstr3 == 
usertests: copyinstr3: OK 
== Test   usertests: sbrkmuch == 
usertests: sbrkmuch: OK 
== Test   usertests: all tests == 
usertests: all tests: OK 
== Test time == 
time: OK 
Score: 66/66

Traps（陷阱）

$ LAB=traps ./grade-lab-traps
make: `kernel/kernel' is up to date.
== Test answers-traps.txt == answers-traps.txt: OK 
== Test backtrace test == backtrace test: OK (1.1s) 
== Test running alarmtest == (4.5s) 
== Test   alarmtest: test0 == 
alarmtest: test0: OK 
== Test   alarmtest: test1 == 
alarmtest: test1: OK 
== Test   alarmtest: test2 == 
alarmtest: test2: OK 
== Test usertests == usertests: OK (305.4s) 
    (Old xv6.out.usertests failure log removed)
== Test time == 
time: OK 
Score: 85/85

Lazy page allocation（页的延迟分配）

$ ./grade-lab-lazy
make: `kernel/kernel' is up to date.
== Test running lazytests == (1.6s) 
== Test   lazy: map == 
lazy: map: OK 
== Test   lazy: unmap == 
lazy: unmap: OK 
== Test usertests == (230.8s) 
== Test   usertests: pgbug == 
usertests: pgbug: OK 
== Test   usertests: sbrkbugs == 
usertests: sbrkbugs: OK 
== Test   usertests: argptest == 
usertests: argptest: OK 
== Test   usertests: sbrkmuch == 
usertests: sbrkmuch: OK 
== Test   usertests: sbrkfail == 
usertests: sbrkfail: OK 
== Test   usertests: sbrkarg == 
usertests: sbrkarg: OK 
== Test   usertests: stacktest == 
usertests: stacktest: OK 
== Test   usertests: execout == 
usertests: execout: OK 
== Test   usertests: copyin == 
usertests: copyin: OK 
== Test   usertests: copyout == 
usertests: copyout: OK 
== Test   usertests: copyinstr1 == 
usertests: copyinstr1: OK 
== Test   usertests: copyinstr2 == 
usertests: copyinstr2: OK 
== Test   usertests: copyinstr3 == 
usertests: copyinstr3: OK 
== Test   usertests: rwsbrk == 
usertests: rwsbrk: OK 
== Test   usertests: truncate1 == 
usertests: truncate1: OK 
== Test   usertests: truncate2 == 
usertests: truncate2: OK 
== Test   usertests: truncate3 == 
usertests: truncate3: OK 
== Test   usertests: reparent2 == 
usertests: reparent2: OK 
== Test   usertests: badarg == 
usertests: badarg: OK 
== Test   usertests: reparent == 
usertests: reparent: OK 
== Test   usertests: twochildren == 
usertests: twochildren: OK 
== Test   usertests: forkfork == 
usertests: forkfork: OK 
== Test   usertests: forkforkfork == 
usertests: forkforkfork: OK 
== Test   usertests: createdelete == 
usertests: createdelete: OK 
== Test   usertests: linkunlink == 
usertests: linkunlink: OK 
== Test   usertests: linktest == 
usertests: linktest: OK 
== Test   usertests: unlinkread == 
usertests: unlinkread: OK 
== Test   usertests: concreate == 
usertests: concreate: OK 
== Test   usertests: subdir == 
usertests: subdir: OK 
== Test   usertests: fourfiles == 
usertests: fourfiles: OK 
== Test   usertests: sharedfd == 
usertests: sharedfd: OK 
== Test   usertests: exectest == 
usertests: exectest: OK 
== Test   usertests: bigargtest == 
usertests: bigargtest: OK 
== Test   usertests: bigwrite == 
usertests: bigwrite: OK 
== Test   usertests: bsstest == 
usertests: bsstest: OK 
== Test   usertests: sbrkbasic == 
usertests: sbrkbasic: OK 
== Test   usertests: kernmem == 
usertests: kernmem: OK 
== Test   usertests: validatetest == 
usertests: validatetest: OK 
== Test   usertests: opentest == 
usertests: opentest: OK 
== Test   usertests: writetest == 
usertests: writetest: OK 
== Test   usertests: writebig == 
usertests: writebig: OK 
== Test   usertests: createtest == 
usertests: createtest: OK 
== Test   usertests: openiput == 
usertests: openiput: OK 
== Test   usertests: exitiput == 
usertests: exitiput: OK 
== Test   usertests: iput == 
usertests: iput: OK 
== Test   usertests: mem == 
usertests: mem: OK 
== Test   usertests: pipe1 == 
usertests: pipe1: OK 
== Test   usertests: preempt == 
usertests: preempt: OK 
== Test   usertests: exitwait == 
usertests: exitwait: OK 
== Test   usertests: rmdot == 
usertests: rmdot: OK 
== Test   usertests: fourteen == 
usertests: fourteen: OK 
== Test   usertests: bigfile == 
usertests: bigfile: OK 
== Test   usertests: dirfile == 
usertests: dirfile: OK 
== Test   usertests: iref == 
usertests: iref: OK 
== Test   usertests: forktest == 
usertests: forktest: OK 
== Test time == 
time: OK 
Score: 119/119

Copy-on-Write Fork（fork的写时复制）

$ ./grade-lab-cow 
== Test running cowtest == (11.4s) 
== Test   simple == 
simple: OK 
== Test   three == 
three: OK 
== Test   file == 
file: OK 
== Test usertests == (192.0s) 
== Test   usertests: copyin == 
usertests: copyin: OK 
== Test   usertests: copyout == 
usertests: copyout: OK 
== Test   usertests: all tests == 
usertests: all tests: OK 
== Test time == 
time: OK 
Score: 110/110

Multithreading（多线程）

$ ./grade-lab-thread
== Test uthread == uthread: OK (7.0s) 
== Test answers-thread.txt == answers-thread.txt: OK 
== Test ph_safe == gcc -o ph -g -O2 notxv6/ph.c -pthread
ph_safe: OK (8.9s) 
== Test ph_fast == make: `ph' is up to date.
ph_fast: OK (18.1s) 
== Test barrier == gcc -o barrier -g -O2 notxv6/barrier.c -pthread
barrier: OK (2.3s) 
== Test time == 
time: OK 
Score: 60/60

Lock（锁）

$ LAB=lock ./grade-lab-lock
make: `kernel/kernel' is up to date.
== Test running kalloctest == (413.1s) 
== Test   kalloctest: test1 == 
kalloctest: test1: OK 
== Test   kalloctest: test2 == 
kalloctest: test2: OK 
== Test kalloctest: sbrkmuch == kalloctest: sbrkmuch: OK (18.8s) 
== Test running bcachetest == (16.6s) 
== Test   bcachetest: test0 == 
bcachetest: test0: OK 
== Test   bcachetest: test1 == 
bcachetest: test1: OK 
== Test usertests == usertests: OK (244.3s) 
== Test time == 
time: OK 
Score: 70/70

File system（文件系统）

$ ./grade-lab-fs
== Test running bigfile == running bigfile: OK (636.2s) 
== Test running symlinktest == (3.1s) 
== Test   symlinktest: symlinks == 
symlinktest: symlinks: OK 
== Test   symlinktest: concurrent symlinks == 
symlinktest: concurrent symlinks: OK 
== Test usertests == usertests: OK (1362.6s) 
== Test time == 
time: OK 
Score: 100/100

[mmap（内存映射）](htt