nit in console interrupts

don't send keyboard interrupts to the second cpu, if we have only one cpu.
xv6 seems to work fine on uniprocessor now.

complain if no disk 1
lots of cleanup

nits

clean up stale error checks and panics
delete unused functions
a few comments

mkdir check error from mknod
chdir return -1 if target not a dir

inode addrs[NDIRECT] -> NADDRS
fix race in mknod / creat
use last component in dirent in mknod, not path

big directory test

i/o redirection in sh
better parsing of sh commands (copied from jos sh)
cat: read from 1 if no args
sbrk system call, but untested
getpid system call
moved locks in keyboard intr, but why do we get

i/o redirection in sh
better parsing of sh commands (copied from jos sh)
cat: read from 1 if no args
sbrk system call, but untested
getpid system call
moved locks in keyboard intr, but why do we get intr w. null characters from keyboard?

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no more proc[] entry per cpu for idle loop
each cpu[] has its own gdt and tss
no per-proc gdt or tss, re-write cpu's in scheduler (you win, cliff)
main0() switches to cpu[0].mpstack

fix iget() bug that allocated in-use inode[] entries

namei returns locked parent dir inode for create / unlink
don't hold fd table lock across idecref() (latter does block i/o)
idecref calls iput() in case last ref -> freeing inode
dir size is 512 * #

namei returns locked parent dir inode for create / unlink
don't hold fd table lock across idecref() (latter does block i/o)
idecref calls iput() in case last ref -> freeing inode
dir size is 512 * # blocks, so readi/writei &c work
unlink deletes dirent even if ip->nlink > 0

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link()

zero out all of dirent.name when creating
don't increase length of directory

LRU disk cache replacement

buffer cache, fifo replacement

interrupts could be recursive since lapic_eoi() called before rti
so fast interrupts overflow the kernel stack
fix: cli() before lapic_eoi()

low-level keyboard input (not hooked up to /dev yet)
fix acquire() to cli() *before* incrementing nlock
make T_SYSCALL a trap gate, not an interrupt gate
sadly, various crashes if you hold down a key

low-level keyboard input (not hooked up to /dev yet)
fix acquire() to cli() *before* incrementing nlock
make T_SYSCALL a trap gate, not an interrupt gate
sadly, various crashes if you hold down a keyboard key...

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fix race in holding() check in acquire()
give cpu1 a TSS and gdt for when it enters scheduler()
and a pseudo proc[] entry for each cpu
cpu0 waits for each other cpu to start up
read() for files

exec arguments

namei

no more recursive locks
wakeup1() assumes you hold proc_table_lock
sleep(chan, lock) provides atomic sleep-and-release to wait for condition
ugly code in swtch/scheduler to implement new sleep
fix lo

no more recursive locks
wakeup1() assumes you hold proc_table_lock
sleep(chan, lock) provides atomic sleep-and-release to wait for condition
ugly code in swtch/scheduler to implement new sleep
fix lots of bugs in pipes, wait, and exit
fix bugs if timer interrupt goes off in schedule()
console locks per line, not per byte

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passes both usertests
exit had acquire where I meant release
swtch now checks that you hold no locks

i think my cmpxchg use was wrong in acquire
nesting cli/sti: release shouldn't always enable interrupts
separate setup of lapic from starting of other cpus, so cpu() works earlier
flag to disable loc

i think my cmpxchg use was wrong in acquire
nesting cli/sti: release shouldn't always enable interrupts
separate setup of lapic from starting of other cpus, so cpu() works earlier
flag to disable locking in console output
make locks work even when curproc==0
(still crashes in clock interrupt)

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cvs add spinlock.h
fix race in schedule()