Commit graph

21 commits

Author SHA1 Message Date
Russ Cox
2c5f7aba38 initproc, usegment, swtch tweaks 2009-07-11 19:28:29 -07:00
rsc
7b644318dd clean up %fs %gs use 2009-05-31 01:12:08 +00:00
rsc
e97519a6d2 sync with c; .text is implied 2009-05-31 01:00:38 +00:00
kolya
c7317d4dc7 always save and restore %fs, %gs to ensure old segment entries are never
accessible to user from the hidden CPU segment registers.
2008-09-24 01:48:31 +00:00
rsc
c1b100e930 nits 2007-08-28 18:23:48 +00:00
rsc
efc12b8e61 Replace yield system call with sleep. 2007-08-27 13:34:35 +00:00
rsc
e1872bb130 formatting, fix comment 2007-08-27 13:11:13 +00:00
rsc
eaea18cb9c PDF at http://am.lcs.mit.edu/~rsc/xv6.pdf
Various changes made while offline.

 + bwrite sector argument is redundant; use b->sector.
 + reformatting of files for nicer PDF page breaks
 + distinguish between locked, unlocked inodes in type signatures
 + change FD_FILE to FD_INODE
 + move userinit (nee proc0init) to proc.c
 + move ROOTDEV to param.h
 + always parenthesize sizeof argument
2007-08-22 06:01:32 +00:00
rsc
9e9bcaf143 standardize various * conventions 2006-09-06 17:27:19 +00:00
rsc
a650c606fe spacing fixes: no tabs, 2-space indents (for rtm) 2006-09-06 17:04:06 +00:00
rtm
dfcc5b997c prune unneeded panics and debug output 2006-08-29 19:06:37 +00:00
rsc
856e1fc1ad Attempt to clean up newproc somewhat.
Also remove all calls to memcpy in favor of
memmove, which has defined semantics when
the ranges overlap.  The fact that memcpy was
working in console.c to scroll the screen is not
guaranteed by all implementations.
2006-07-16 01:47:40 +00:00
rsc
65bd8e139a New scheduler.
Removed cli and sti stack in favor of tracking
number of locks held on each CPU and explicit
conditionals in spinlock.c.
2006-07-16 01:15:28 +00:00
rtm
4e8f237be8 no more big kernel lock
succeeds at usertests.c pipe test
2006-07-12 01:48:35 +00:00
rsc
5ce9751cab Changes to allow use of native x86 ELF compilers, which on my
Linux 2.4 box using gcc 3.4.6 don't seem to follow the same
conventions as the i386-jos-elf-gcc compilers.
Can run make 'TOOLPREFIX=' or edit the Makefile.

curproc[cpu()] can now be NULL, indicating that no proc is running.
This seemed safer to me than having curproc[0] and curproc[1]
both pointing at proc[0] potentially.

The old implementation of swtch depended on the stack frame layout
used inside swtch being okay to return from on the other stack
(exactly the V6 you are not expected to understand this).
It also could be called in two contexts: at boot time, to schedule
the very first process, and later, on behalf of a process, to sleep
or schedule some other process.

I split this into two functions: scheduler and swtch.

The scheduler is now a separate never-returning function, invoked
by each cpu once set up.  The scheduler looks like:

	scheduler() {
		setjmp(cpu.context);

		pick proc to schedule
		blah blah blah

		longjmp(proc.context)
	}

The new swtch is intended to be called only when curproc[cpu()] is not NULL,
that is, only on behalf of a user proc.  It does:

	swtch() {
		if(setjmp(proc.context) == 0)
			longjmp(cpu.context)
	}

to save the current proc context and then jump over to the scheduler,
running on the cpu stack.

Similarly the system call stubs are now in assembly in usys.S to avoid
needing to know the details of stack frame layout used by the compiler.

Also various changes in the debugging prints.
2006-07-11 01:07:40 +00:00
rtm
7df1310b2a bug in trapret 2006-06-22 20:50:32 +00:00
rtm
df5cc91659 compile "user programs"
curproc array
2006-06-22 20:47:23 +00:00
kaashoek
21a88fd487 checkpoint. booting second processor. stack is messed up, but thanks to cliff
and plan 9 code, at least boots and gets into C code.
2006-06-22 01:28:57 +00:00
rtm
a4c03dea09 primitive fork and exit system calls 2006-06-15 16:02:20 +00:00
rtm
0a70d042d0 more or less take traps/interrupts 2006-06-13 15:50:06 +00:00
rtm
55e95b16db import 2006-06-12 15:22:12 +00:00