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Port of Xv6 for 25∞2
1004 commits 1 branch 0 tags 18 MiB
C 94.5%
Assembly 3.4%
Makefile 1.9%
Perl 0.2%
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Dan Cross 82638c019c Avoid rereading the superblock in bfree 
The superblock is read when the first process returns to
userspace (via the call to `iinit` from the first invocation of
`forkret`, when `first` is still set to 1) and cached in a
global; it is treated as immutable from that point on.  There is
no reason to re-read it in bfree.

Removing this call seems to have simply been missed in 8320d61b
when this general area was last touched.  Remove it now to avoid
potential confusion.

Signed-off-by: Dan Cross <cross@gajendra.net>
2019-08-19 19:25:43 -04:00
.cvsignore update .cvsignore 2008-10-15 04:54:24 +00:00
.dir-locals.el Setting indent-tabs-mode nil everywhere is dangerous 2011-09-05 15:22:16 -04:00
.gdbinit.tmpl Use the symbol file 2009-09-20 23:08:36 -04:00
.gitignore Sync up clean and gitignore better 2011-09-05 15:21:40 -04:00
asm.h Remove unused flags (thanks Wolfgang Keller) 2018-08-30 13:14:01 -04:00
bio.c nothing much 2017-08-09 14:16:55 -04:00
bootasm.S nits 2016-08-10 12:06:02 -04:00
bootmain.c Remove trailing white space with: 2016-08-25 09:13:00 -04:00
buf.h Move retry loop/sleep/wakeup in bio.c into sleeping locks 2016-09-11 20:17:22 -04:00
BUGS sh 2007-09-05 15:55:43 +00:00
cat.c Check result of write (thans to Alexander Kapshuk <alexander.kapshuk@gmail) 2016-09-19 07:01:30 -04:00
console.c Commit to running on an SMP (perhaps with only 1 core). Remove most code 2017-08-09 07:44:51 -04:00
cuth delete unnecessary #include lines 2007-08-27 23:26:33 +00:00
date.h coding style (per Jeremías Feltan <jeremias.feltan@gmail.com>) 2015-06-30 16:23:56 -04:00
defs.h A tiny bit of clean up (e.g., move code searching cpu array from lapic.c into 2017-02-01 20:36:41 -05:00
dot-bochsrc make bochsrc work for bochs 2.2.6 2008-09-03 14:10:47 +00:00
echo.c Remove puts in favor of printf. 2007-08-24 20:03:40 +00:00
elf.h fix runoff complaints about pagination and long lines 2017-08-29 14:11:59 -04:00
entry.S even more explicit that entry.S is linked into kernel, unlike bootasm.S. 2016-08-10 11:22:36 -04:00
entryother.S nits 2016-08-10 12:06:02 -04:00
exec.c Read curproc from cpu structure, but be careful because after a schedule event 2017-01-31 20:21:14 -05:00
fcntl.h nit 2007-08-28 04:13:24 +00:00
file.c stricter log consumption by write() 2017-10-24 08:49:31 -04:00
file.h fix runoff complaints about pagination and long lines 2017-08-29 14:11:59 -04:00
forktest.c thanks tyfkda 2018-08-31 09:21:19 -04:00
fs.c Avoid rereading the superblock in bfree 2019-08-19 19:25:43 -04:00
fs.h Fix a few lines that runoff is complaining about that they are too long 2016-09-02 14:59:00 -04:00
gdbutil GDB utilities 2009-11-23 17:47:57 -05:00
grep.c Remove trailing white space with: 2016-08-25 09:13:00 -04:00
ide.c Commit to running on an SMP (perhaps with only 1 core). Remove most code 2017-08-09 07:44:51 -04:00
init.c group locks into structs they protect. 2009-05-31 05:12:21 +00:00
initcode.S nothing much 2016-08-11 15:41:53 -04:00
ioapic.c Commit to running on an SMP (perhaps with only 1 core). Remove most code 2017-08-09 07:44:51 -04:00
kalloc.c fix runoff complaints about pagination and long lines 2017-08-29 14:11:59 -04:00
kbd.c be consistent: no underscores in function names 2009-03-08 22:07:13 +00:00
kbd.h formatting; split kbd constants into kbd.h 2007-08-14 19:31:16 +00:00
kernel.ld Nuke data.S, since we do have a custom linker script. 2011-09-02 14:51:55 -04:00
kill.c Disentangle block size from the disk's sector size. Set block size to 1024 to show 2015-04-03 08:22:02 -04:00
lapic.c x 2018-08-30 14:47:07 -04:00
LICENSE x 2018-08-30 16:20:16 -04:00
ln.c add ln 2007-08-22 05:54:55 +00:00
log.c nothing much 2017-08-09 14:16:55 -04:00
ls.c Remove trailing white space with: 2016-08-25 09:13:00 -04:00
main.c thanks eyalz800 2018-08-30 13:46:48 -04:00
Makefile thanks mtasm 2018-08-30 14:10:27 -04:00
memide.c Thanks to Jeehoon Kang <jeehoon.kang@sf.snu.ac.kr> 2017-01-30 20:01:33 -05:00
memlayout.h thanks eyalz800 2018-08-30 13:46:48 -04:00
mkdir.c more consistent spacing 2007-08-28 18:32:08 +00:00
mkfs.c Remove trailing white space with: 2016-08-25 09:13:00 -04:00
mmu.h Delete a patch 2018-08-30 15:45:16 -04:00
mp.c Commit to running on an SMP (perhaps with only 1 core). Remove most code 2017-08-09 07:44:51 -04:00
mp.h Nice layout for a printout of the code 2014-08-29 17:06:49 -04:00
Notes nit in console interrupts 2006-09-07 00:00:33 +00:00
param.h check blockno passed to idestart 2015-04-10 07:15:06 -04:00
picirq.c Commit to running on an SMP (perhaps with only 1 core). Remove most code 2017-08-09 07:44:51 -04:00
pipe.c Start of an experiment to remove the use of gs for cpu local variables. 2017-01-31 17:47:16 -05:00
pr.pl remove //DOC in the right place 2009-07-12 19:07:30 -07:00
printf.c thanks tyfkda 2018-08-31 09:21:19 -04:00
printpcs Various fixes and improvements to printpcs 2012-08-24 14:51:52 -04:00
proc.c fix runoff complaints about pagination and long lines 2017-08-29 14:11:59 -04:00
proc.h Eliminate code for gs trick to track per-cpu state. We rely on lapiccpunum() 2017-02-01 18:04:13 -05:00
README Update name 2018-09-02 08:33:55 -04:00
rm.c more consistent spacing 2007-08-28 18:32:08 +00:00
runoff Delete a patch 2018-08-30 15:45:16 -04:00
runoff.list thanks mtasm 2018-08-30 14:10:27 -04:00
runoff.spec Nice layout for a printout of the code 2014-08-29 17:06:49 -04:00
runoff1 xv6: formatting, cleanup, rev5 (take 2) 2011-02-19 21:17:55 -05:00
sh.c Remove trailing white space with: 2016-08-25 09:13:00 -04:00
show1 PDF at http://am.lcs.mit.edu/~rsc/xv6.pdf 2007-08-22 06:01:32 +00:00
sign.pl spacing fixes: no tabs, 2-space indents (for rtm) 2006-09-06 17:04:06 +00:00
sleep1.p Model verifying that wakeup really 2007-10-12 04:21:04 +00:00
sleeplock.c Because sleeplocks replaced B_BUSY the holding test can 2018-08-30 11:57:46 -04:00
sleeplock.h sleeplock files 2016-09-11 21:01:24 -04:00
spinlock.c Allow holding to be called with interrupts enabled (for Mark Morrissey). 2018-08-30 16:14:34 -04:00
spinlock.h Remove trailing white space with: 2016-08-25 09:13:00 -04:00
spinp Model verifying that wakeup really 2007-10-12 04:21:04 +00:00
stat.h junk 2012-08-28 12:57:05 -04:00
stressfs.c Remove trailing white space with: 2016-08-25 09:13:00 -04:00
string.c Remove trailing white space with: 2016-08-25 09:13:00 -04:00
swtch.S thanks wxdao 2018-08-30 13:48:47 -04:00
syscall.c Read curproc from cpu structure, but be careful because after a schedule event 2017-01-31 20:21:14 -05:00
syscall.h Remove left-over from some logging plan making complete syscalls atomic 2012-08-22 20:28:58 -04:00
sysfile.c Removed unused dirlookup argument in create 2019-08-19 13:22:35 -04:00
sysproc.c Start of an experiment to remove the use of gs for cpu local variables. 2017-01-31 17:47:16 -05:00
toc.ftr Update index example in TOC footer 2011-09-02 16:30:20 -04:00
toc.hdr nits 2007-08-28 18:23:48 +00:00
trap.c fix runoff complaints about pagination and long lines 2017-08-29 14:11:59 -04:00
trapasm.S Update comment to reflect xv6 doesn't have per-cpu segments anymore 2017-08-09 15:21:42 -04:00
traps.h kill TLB shoot down code 2010-07-28 14:38:05 -04:00
TRICKS use acquire/release to force order for pid=np->pid;np->state=RUNNING 2014-08-04 06:13:49 -04:00
types.h some cleanup 2010-07-25 20:30:21 -04:00
uart.c Commit to running on an SMP (perhaps with only 1 core). Remove most code 2017-08-09 07:44:51 -04:00
ulib.c thanks tyfkda 2018-08-31 09:21:19 -04:00
umalloc.c make new code like old code 2011-01-11 13:01:13 -05:00
user.h thanks tyfkda 2018-08-31 09:21:19 -04:00
usertests.c Add mikecat's argp test 2016-09-26 07:54:02 -04:00
usys.S uptime() sys call for benchmarking 2010-08-11 14:34:45 -04:00
vectors.pl sync with c; .text is implied 2009-05-31 01:00:38 +00:00
vm.c thanks mataness 2018-08-30 13:30:50 -04:00
wc.c junk 2012-08-28 12:57:05 -04:00
x86.h Remove trailing white space with: 2016-08-25 09:13:00 -04:00
zombie.c Remove trailing white space with: 2016-08-25 09:13:00 -04:00

README 

xv6 is a re-implementation of Dennis Ritchie's and Ken Thompson's Unix
Version 6 (v6).  xv6 loosely follows the structure and style of v6,
but is implemented for a modern x86-based multiprocessor using ANSI C.

ACKNOWLEDGMENTS

xv6 is inspired by John Lions's Commentary on UNIX 6th Edition (Peer
to Peer Communications; ISBN: 1-57398-013-7; 1st edition (June 14,
2000)). See also https://pdos.csail.mit.edu/6.828/, which
provides pointers to on-line resources for v6.

xv6 borrows code from the following sources:
    JOS (asm.h, elf.h, mmu.h, bootasm.S, ide.c, console.c, and others)
    Plan 9 (entryother.S, mp.h, mp.c, lapic.c)
    FreeBSD (ioapic.c)
    NetBSD (console.c)

The following people have made contributions: Russ Cox (context switching,
locking), Cliff Frey (MP), Xiao Yu (MP), Nickolai Zeldovich, and Austin
Clements.

We are also grateful for the bug reports and patches contributed by Silas
Boyd-Wickizer, Anton Burtsev, Cody Cutler, Mike CAT, Tej Chajed, eyalz800,
Nelson Elhage, Saar Ettinger, Alice Ferrazzi, Nathaniel Filardo, Peter
Froehlich, Yakir Goaron,Shivam Handa, Bryan Henry, Jim Huang, Alexander
Kapshuk, Anders Kaseorg, kehao95, Wolfgang Keller, Eddie Kohler, Austin
Liew, Imbar Marinescu, Yandong Mao, Matan Shabtay, Hitoshi Mitake, Carmi
Merimovich, Mark Morrissey, mtasm, Joel Nider, Greg Price, Ayan Shafqat,
Eldar Sehayek, Yongming Shen, Cam Tenny, tyfkda, Rafael Ubal, Warren
Toomey, Stephen Tu, Pablo Ventura, Xi Wang, Keiichi Watanabe, Nicolas
Wolovick, wxdao, Grant Wu, Jindong Zhang, Icenowy Zheng, and Zou Chang Wei.

The code in the files that constitute xv6 is
Copyright 2006-2018 Frans Kaashoek, Robert Morris, and Russ Cox.

ERROR REPORTS

Please send errors and suggestions to Frans Kaashoek and Robert Morris
(kaashoek,rtm@mit.edu). The main purpose of xv6 is as a teaching
operating system for MIT's 6.828, so we are more interested in
simplifications and clarifications than new features.

BUILDING AND RUNNING XV6

To build xv6 on an x86 ELF machine (like Linux or FreeBSD), run
"make". On non-x86 or non-ELF machines (like OS X, even on x86), you
will need to install a cross-compiler gcc suite capable of producing
x86 ELF binaries (see https://pdos.csail.mit.edu/6.828/).
Then run "make TOOLPREFIX=i386-jos-elf-". Now install the QEMU PC
simulator and run "make qemu".