Commit Graph

55 Commits

Author SHA1 Message Date
John Dyson
f0175db1ee Attempt to set write combining mode for graphics devices. 1998-05-11 01:06:08 +00:00
Bruce Evans
96a73b4063 Moved some extern declarations to header files (unused ones to /dev/null). 1997-11-20 19:30:35 +00:00
John Dyson
de5858ab42 Remove the PMAP_PVLIST conditionals in pmap.*, and another unneeded define. 1997-08-05 00:42:01 +00:00
John Dyson
0a0a85b3e0 Add support for 4MB pages. This includes the .text, .data, .data parts
of the kernel, and also most of the dynamic parts of the kernel.  Additionally,
4MB pages will be allocated for display buffers as appropriate (only.)

The 4MB support for SMP isn't complete, but doesn't interfere with operation
either.
1997-07-17 04:34:03 +00:00
Peter Wemm
b3196e4b9f Preliminary support for per-cpu data pages.
This eliminates a lot of #ifdef SMP type code.  Things like _curproc reside
in a data page that is unique on each cpu, eliminating the expensive macros
like:    #define curproc (SMPcurproc[cpunumber()])

There are some unresolved bootstrap and address space sharing issues at
present, but Steve is waiting on this for other work.  There is still some
strictly temporary code present that isn't exactly pretty.

This is part of a larger change that has run into some bumps, this part is
standalone so it should be safe.  The temporary code goes away when the
full idle cpu support is finished.

Reviewed by: fsmp, dyson
1997-06-22 16:04:22 +00:00
Peter Wemm
477a642cee Man the liferafts! Here comes the long awaited SMP -> -current merge!
There are various options documented in i386/conf/LINT, there is more to
come over the next few days.

The kernel should run pretty much "as before" without the options to
activate SMP mode.

There are a handful of known "loose ends" that need to be fixed, but
have been put off since the SMP kernel is in a moderately good condition
at the moment.

This commit is the result of the tinkering and testing over the last 14
months by many people.  A special thanks to Steve Passe for implementing
the APIC code!
1997-04-26 11:46:25 +00:00
Peter Wemm
a0c3795f19 Use UPAGES_HOLE instead of UPAGES in case it's changed some time.
Rename the PT* index KSTK* #defines to UMAX*, since we don't have a kernel
stack there any more..

These are used to calculate VM_MAXUSER_ADDRESS and USRSTACK, and really
do not want to be changed with UPAGES since BSD/OS 2.x binary compatability
depends on it.
1997-04-07 09:30:22 +00:00
Peter Wemm
6875d25465 Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.
1997-02-22 09:48:43 +00:00
Jordan K. Hubbard
1130b656e5 Make the long-awaited change from $Id$ to $FreeBSD$
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore.  This update would have been
insane otherwise.
1997-01-14 07:20:47 +00:00
John Dyson
8de30f117f Pmap_resident_count was mistakenly removed from pmap.h, thereby
disabling the RSS listing in ps and ^T.  This commit re-inserts
the macro defn.
1996-10-13 03:14:57 +00:00
John Dyson
9d3fbbb5f4 Performance optimizations. One of which was meant to go in before the
previous snap.  Specifically, kern_exit and kern_exec now makes a
call into the pmap module to do a very fast removal of pages from the
address space.  Additionally, the pmap module now updates the PG_MAPPED
and PG_WRITABLE flags.  This is an optional optimization, but helpful
on the X86.
1996-10-12 21:35:25 +00:00
Bruce Evans
da2186afa3 Cleaned up:
- fixed a sloppy common-style declaration.
- removed an unused macro.
- moved once-used macros to the one file where they are used.
- removed unused forward struct declarations.
- removed __pure.
- declared inline functions as inline in their prototype as well
  as in theire definition (gcc unfortunately allows the prototype
  to be inconsistent).
- staticized.
1996-10-12 20:36:15 +00:00
John Dyson
b8e251a56d Improve the scalability of certain pmap operations. 1996-09-08 16:57:53 +00:00
John Dyson
67bf686897 Backed out the recent changes/enhancements to the VM code. The
problem with the 'shell scripts' was found, but there was a 'strange'
problem found with a 486 laptop that we could not find.  This commit
backs the code back to 25-jul, and will be re-entered after the snapshot
in smaller (more easily tested) chunks.
1996-07-30 03:08:57 +00:00
John Dyson
4f4d35edf0 This commit is meant to solve a couple of VM system problems or
performance issues.

	1) The pmap module has had too many inlines, and so the
	   object file is simply bigger than it needs to be.
	   Some common code is also merged into subroutines.
	2) Removal of some *evil* PHYS_TO_VM_PAGE macro calls.
	   Unfortunately, a few have needed to be added also.
	   The removal caused the need for more vm_page_lookups.
	   I added lookup hints to minimize the need for the
	   page table lookup operations.
	3) Removal of some bogus performance improvements, that
	   mostly made the code more complex (tracking individual
	   page table page updates unnecessarily).  Those improvements
	   actually hurt 386 processors perf (not that people who
	   worry about perf use 386 processors anymore :-)).
	4) Changed pv queue manipulations/structures to be TAILQ's.
	5) The pv queue code has had some performance problems since
	   day one.  Some significant scalability issues are resolved
	   by threading the pv entries from the pmap AND the physical
	   address instead of just the physical address.  This makes
	   certain pmap operations run much faster.  This does
	   not affect most micro-benchmarks, but should help loaded system
	   performance *significantly*.  DG helped and came up with most
	   of the solution for this one.
	6) Most if not all pmap bit operations follow the pattern:
		pmap_test_bit();
		pmap_clear_bit();
	   That made for twice the necessary pv list traversal.   The
	   pmap interface now supports only pmap_tc_bit type operations:
	   pmap_[test/clear]_modified, pmap_[test/clear]_referenced.
	   Additionally, the modified routine now takes a vm_page_t arg
	   instead of a phys address.  This eliminates a PHYS_TO_VM_PAGE
	   operation.
	7) Several rewrites of routines that contain redundant code to
	   use common routines, so that there is a greater likelihood of
	   keeping the cache footprint smaller.
1996-07-27 03:24:10 +00:00
Bruce Evans
87bc5d1973 Removed unnecessary forward declarations of incomplete structs. 1996-06-08 11:21:19 +00:00
John Dyson
b18bfc3da7 This set of commits to the VM system does the following, and contain
contributions or ideas from Stephen McKay <syssgm@devetir.qld.gov.au>,
Alan Cox <alc@cs.rice.edu>, David Greenman <davidg@freebsd.org> and me:

	More usage of the TAILQ macros.  Additional minor fix to queue.h.
	Performance enhancements to the pageout daemon.
		Addition of a wait in the case that the pageout daemon
		has to run immediately.
		Slightly modify the pageout algorithm.
	Significant revamp of the pmap/fork code:
		1) PTE's and UPAGES's are NO LONGER in the process's map.
		2) PTE's and UPAGES's reside in their own objects.
		3) TOTAL elimination of recursive page table pagefaults.
		4) The page directory now resides in the PTE object.
		5) Implemented pmap_copy, thereby speeding up fork time.
		6) Changed the pv entries so that the head is a pointer
		   and not an entire entry.
		7) Significant cleanup of pmap_protect, and pmap_remove.
		8) Removed significant amounts of machine dependent
		   fork code from vm_glue.  Pushed much of that code into
		   the machine dependent pmap module.
		9) Support more completely the reuse of already zeroed
		   pages (Page table pages and page directories) as being
		   already zeroed.
	Performance and code cleanups in vm_map:
		1) Improved and simplified allocation of map entries.
		2) Improved vm_map_copy code.
		3) Corrected some minor problems in the simplify code.
	Implemented splvm (combo of splbio and splimp.)  The VM code now
		seldom uses splhigh.
	Improved the speed of and simplified kmem_malloc.
	Minor mod to vm_fault to avoid using pre-zeroed pages in the case
		of objects with backing objects along with the already
		existant condition of having a vnode.  (If there is a backing
		object, there will likely be a COW...  With a COW, it isn't
		necessary to start with a pre-zeroed page.)
	Minor reorg of source to perhaps improve locality of ref.
1996-05-18 03:38:05 +00:00
Poul-Henning Kamp
5084d10dd0 Move atdevbase out of locore.s and into machdep.c
Macroize locore.s' page table setup even more, now it's almost readable.
Rename PG_U to PG_A (so that I can...)
Rename PG_u to PG_U.  "PG_u" was just too ugly...
Remove some unused vars in pmap.c
Remove PG_KR and PG_KW
Remove SSIZE
Remove SINCR
Remove BTOPKERNBASE

This concludes my spring cleaning, modulus any bug fixes for messes I
have made on the way.

(Funny to be back here in pmap.c, that's where my first significant
contribution to 386BSD was... :-)
1996-05-02 22:25:18 +00:00
Poul-Henning Kamp
e911eafcba removed:
CLBYTES PD_SHIFT PGSHIFT NBPG PGOFSET CLSIZELOG2 CLSIZE pdei()
        ptei() kvtopte() ptetov() ispt() ptetoav() &c &c
new:
        NPDEPG

Major macro cleanup.
1996-05-02 14:21:14 +00:00
Poul-Henning Kamp
68c1eb1215 pte.h: Add the VADDR(pdi,pti) macro to construct virtual address from
page dir+table index.
pmap.h: remove NUPDE, it was wrong and not used.  Sanitize KSTKPTEOFF.
vmparam.h: Calculate virtual addr from PDI+PTI from pmap.h rather than
using magic math.  Remove UPDT, not used.
1996-04-30 12:02:12 +00:00
John Dyson
030ad08012 Fixed a problem that the UPAGES of a process were being run down
in a suboptimal manner.  I had also noticed some panics that appeared
to be at least superficially caused by this problem.  Also, included
are some minor mods to support more general handling of page table page
faulting.  More details in a future commit.
1996-04-03 05:23:44 +00:00
John Dyson
3eb77c8302 Fix a problem with tracking the modified bit. Eliminate the
ugly inline-asm code, and speed up the page-table-page tracking.
1996-02-25 03:02:53 +00:00
David Greenman
267173e72d Rewrote cpu_fork so that it doesn't use pmap_activate, and removed
pmap_activate since it's not used anymore. Changed cpu_fork so that
it uses one line of inline assembly rather than calling mvesp() to
get the current stack pointer. Removed mvesp() since it is no longer
being used.
1996-02-04 21:20:53 +00:00
Mike Pritchard
6c5e9bbdf5 Fix a bunch of spelling errors in the comment fields of
a bunch of system include files.
1996-01-30 23:02:38 +00:00
Bruce Evans
927c0b1131 Cleaned up prototypes in pmap headers: removed ones for nonexistent
functions; moved misplaced ones; restored most of KNFish formatting
from 4.4lite version; removed bogus __BEGIN/END_DECLS.
1995-12-17 07:39:05 +00:00
Poul-Henning Kamp
6f4e0beb7e Staticize and cleanup. 1995-12-10 13:40:44 +00:00
Bruce Evans
d71f232008 __purified pmap_pte(). This seems to make no difference. 1995-12-03 18:37:44 +00:00
David Greenman
e9857eee2b Rewrote memory sizing code to generally deal with holes in extended memory.
This code change should allow certain Compaq machines with a 128K hole
at 16MB to work.
1995-07-19 06:37:12 +00:00
David Greenman
24a1cce34f NOTE: libkvm, w, ps, 'top', and any other utility which depends on struct
proc or any VM system structure will have to be rebuilt!!!

Much needed overhaul of the VM system. Included in this first round of
changes:

1) Improved pager interfaces: init, alloc, dealloc, getpages, putpages,
   haspage, and sync operations are supported. The haspage interface now
   provides information about clusterability. All pager routines now take
   struct vm_object's instead of "pagers".

2) Improved data structures. In the previous paradigm, there is constant
   confusion caused by pagers being both a data structure ("allocate a
   pager") and a collection of routines. The idea of a pager structure has
   escentially been eliminated. Objects now have types, and this type is
   used to index the appropriate pager. In most cases, items in the pager
   structure were duplicated in the object data structure and thus were
   unnecessary. In the few cases that remained, a un_pager structure union
   was created in the object to contain these items.

3) Because of the cleanup of #1 & #2, a lot of unnecessary layering can now
   be removed. For instance, vm_object_enter(), vm_object_lookup(),
   vm_object_remove(), and the associated object hash list were some of the
   things that were removed.

4) simple_lock's removed. Discussion with several people reveals that the
   SMP locking primitives used in the VM system aren't likely the mechanism
   that we'll be adopting. Even if it were, the locking that was in the code
   was very inadequate and would have to be mostly re-done anyway. The
   locking in a uni-processor kernel was a no-op but went a long way toward
   making the code difficult to read and debug.

5) Places that attempted to kludge-up the fact that we don't have kernel
   thread support have been fixed to reflect the reality that we are really
   dealing with processes, not threads. The VM system didn't have complete
   thread support, so the comments and mis-named routines were just wrong.
   We now use tsleep and wakeup directly in the lock routines, for instance.

6) Where appropriate, the pagers have been improved, especially in the
   pager_alloc routines. Most of the pager_allocs have been rewritten and
   are now faster and easier to maintain.

7) The pagedaemon pageout clustering algorithm has been rewritten and
   now tries harder to output an even number of pages before and after
   the requested page. This is sort of the reverse of the ideal pagein
   algorithm and should provide better overall performance.

8) Unnecessary (incorrect) casts to caddr_t in calls to tsleep & wakeup
   have been removed. Some other unnecessary casts have also been removed.

9) Some almost useless debugging code removed.

10) Terminology of shadow objects vs. backing objects straightened out.
    The fact that the vm_object data structure escentially had this
    backwards really confused things. The use of "shadow" and "backing
    object" throughout the code is now internally consistent and correct
    in the Mach terminology.

11) Several minor bug fixes, including one in the vm daemon that caused
    0 RSS objects to not get purged as intended.

12) A "default pager" has now been created which cleans up the transition
    of objects to the "swap" type. The previous checks throughout the code
    for swp->pg_data != NULL were really ugly. This change also provides
    the rudiments for future backing of "anonymous" memory by something
    other than the swap pager (via the vnode pager, for example), and it
    allows the decision about which of these pagers to use to be made
    dynamically (although will need some additional decision code to do
    this, of course).

13) (dyson) MAP_COPY has been deprecated and the corresponding "copy
    object" code has been removed. MAP_COPY was undocumented and non-
    standard. It was furthermore broken in several ways which caused its
    behavior to degrade to MAP_PRIVATE. Binaries that use MAP_COPY will
    continue to work correctly, but via the slightly different semantics
    of MAP_PRIVATE.

14) (dyson) Sharing maps have been removed. It's marginal usefulness in a
    threads design can be worked around in other ways. Both #12 and #13
    were done to simplify the code and improve readability and maintain-
    ability. (As were most all of these changes)

TODO:

1) Rewrite most of the vnode pager to use VOP_GETPAGES/PUTPAGES. Doing
   this will reduce the vnode pager to a mere fraction of its current size.

2) Rewrite vm_fault and the swap/vnode pagers to use the clustering
   information provided by the new haspage pager interface. This will
   substantially reduce the overhead by eliminating a large number of
   VOP_BMAP() calls. The VOP_BMAP() filesystem interface should be
   improved to provide both a "behind" and "ahead" indication of
   contiguousness.

3) Implement the extended features of pager_haspage in swap_pager_haspage().
   It currently just says 0 pages ahead/behind.

4) Re-implement the swap device (swstrategy) in a more elegant way, perhaps
   via a much more general mechanism that could also be used for disk
   striping of regular filesystems.

5) Do something to improve the architecture of vm_object_collapse(). The
   fact that it makes calls into the swap pager and knows too much about
   how the swap pager operates really bothers me. It also doesn't allow
   for collapsing of non-swap pager objects ("unnamed" objects backed by
   other pagers).
1995-07-13 08:48:48 +00:00
Rodney W. Grimes
9b2e535452 Remove trailing whitespace. 1995-05-30 08:16:23 +00:00
David Greenman
1ae89ac36a Removed declaration of pmap_changebit()...it is no longer exported.
Submitted by:	John Dyson
1995-03-26 23:42:55 +00:00
Bruce Evans
b5e8ce9f12 Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) and most of the warnings from
`gcc -Wnested-externs'.  Fix all the bugs found.  There were no serious
ones.
1995-03-16 18:17:34 +00:00
Poul-Henning Kamp
86ca01bcee Whoops! back out last commit partly. 1995-02-14 06:57:45 +00:00
Poul-Henning Kamp
b53d84607c YFfix. 1995-02-14 06:55:42 +00:00
David Greenman
fff3cea1a9 Moved various pmap 'bit' test/set functions back into real functions; gcc
generates better code at the expense of more of it.

Submitted by:	John Dyson
1995-01-24 09:57:39 +00:00
David Greenman
0d94caffca These changes embody the support of the fully coherent merged VM buffer cache,
much higher filesystem I/O performance, and much better paging performance. It
represents the culmination of over 6 months of R&D.

The majority of the merged VM/cache work is by John Dyson.

The following highlights the most significant changes. Additionally, there are
(mostly minor) changes to the various filesystem modules (nfs, msdosfs, etc) to
support the new VM/buffer scheme.

vfs_bio.c:
Significant rewrite of most of vfs_bio to support the merged VM buffer cache
scheme.  The scheme is almost fully compatible with the old filesystem
interface.  Significant improvement in the number of opportunities for write
clustering.

vfs_cluster.c, vfs_subr.c
Upgrade and performance enhancements in vfs layer code to support merged
VM/buffer cache.  Fixup of vfs_cluster to eliminate the bogus pagemove stuff.

vm_object.c:
Yet more improvements in the collapse code.  Elimination of some windows that
can cause list corruption.

vm_pageout.c:
Fixed it, it really works better now.  Somehow in 2.0, some "enhancements"
broke the code.  This code has been reworked from the ground-up.

vm_fault.c, vm_page.c, pmap.c, vm_object.c
Support for small-block filesystems with merged VM/buffer cache scheme.

pmap.c vm_map.c
Dynamic kernel VM size, now we dont have to pre-allocate excessive numbers of
kernel PTs.

vm_glue.c
Much simpler and more effective swapping code.  No more gratuitous swapping.

proc.h
Fixed the problem that the p_lock flag was not being cleared on a fork.

swap_pager.c, vnode_pager.c
Removal of old vfs_bio cruft to support the past pseudo-coherency.  Now the
code doesn't need it anymore.

machdep.c
Changes to better support the parameter values for the merged VM/buffer cache
scheme.

machdep.c, kern_exec.c, vm_glue.c
Implemented a seperate submap for temporary exec string space and another one
to contain process upages. This eliminates all map fragmentation problems
that previously existed.

ffs_inode.c, ufs_inode.c, ufs_readwrite.c
Changes for merged VM/buffer cache.  Add "bypass" support for sneaking in on
busy buffers.

Submitted by:	John Dyson and David Greenman
1995-01-09 16:06:02 +00:00
David Greenman
d9b026fcbd Add two more page table pages to keep 64MB machines happy. 1994-12-18 03:11:46 +00:00
Bruce Evans
3bbb00e1a3 Declare inline functions as __inline and with new-style parameter lists
to avoid compiler warnings.

Clean up prototypes: alphabetize; don't use redundant `extern' or
meaningless `extern inline'.

Uniformize idempotency ifdef.
1994-11-14 14:12:24 +00:00
Poul-Henning Kamp
50a1a05445 Added prototypes. 1994-10-08 22:21:34 +00:00
David Greenman
329b62ac1c Corrected some comments regarding ptes/pdes. 1994-08-23 16:27:15 +00:00
Garrett Wollman
f23b4c91c4 Fix up some sloppy coding practices:
- Delete redundant declarations.
- Add -Wredundant-declarations to Makefile.i386 so they don't come back.
- Delete sloppy COMMON-style declarations of uninitialized data in
  header files.
- Add a few prototypes.
- Clean up warnings resulting from the above.

NB: ioconf.c will still generate a redundant-declaration warning, which
is unavoidable unless somebody volunteers to make `config' smarter.
1994-08-18 22:36:09 +00:00
Rodney W. Grimes
26f9a76710 The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.
Reviewed by:	Rodney W. Grimes
Submitted by:	John Dyson and David Greenman
1994-05-25 09:21:21 +00:00
David Greenman
dad5c5fe90 ifdef KERNEL the pmap_kextract inline function; ps is unhappy otherwise.
Pointed out by Frank Terhaar-Yonkers <fty@vislab.epa.gov>.
1994-03-25 22:08:59 +00:00
David Greenman
ed7fcbd079 From John Dyson: performance improvements to the new bounce buffer
code.
1994-03-24 23:12:48 +00:00
David Greenman
04f1835605 1) "Pre-faulting" in of pages into process address space
Eliminates vm_fault overhead on process startup and
		mmap referenced data for in-memory pages.

		(process startup time using in-memory segments *much* faster)

	2)	Even more efficient pmap code.  Code partially cleaned up.
		More comments yet to follow.

		(generally more efficient pte management)

	3)	Pageout clustering ( in addition to the FreeBSD V1.1 pagein
		clustering.)

		(much faster paging performance on non-write behind disk
		subsystems, slightly faster performance on other systems.)

	4)	Slightly changed vm_pageout code for more efficiency and
		better statistics.  Also, resist swapout a little more.

		(less likely to pageout a recently used page)

	5)	Slight improvement to the page table page trap efficiency.

		(generally faster system VM fault performance)

	6)	Defer creation of unnamed anonymous regions pager until needed.

		(speeds up shared memory bss creation)

	7)	Remove possible deadlock from swap_pager initialization.

	8)	Enhanced procfs to provide "vminfo" about vm objects and user
		pmaps.

	9)	Increased MCLSHIFT/MCLBYTES from 2K to 4K to improve net &
		socket performance and to prepare for things to come.

John Dyson
dyson@implode.root.com
David Greenman
davidg@root.com
1994-03-07 11:38:49 +00:00
David Greenman
ec120393a0 VM system performance improvements from John Dyson and myself. The
following is a summary:

1) increased object cache back up to a more reasonable value.
2) removed old & bogus cruft from machdep.c (clearseg, copyseg,
	physcopyseg, etc).
3) inlined many functions in pmap.c
4) changed "load_cr3(rcr3())" into tlbflush() and made tlbflush inline
	assembly.
5) changed the way that modified pages are tracked - now vm_page struct
	is kept updated directly - no more scanning page tables.
6) removed lots of unnecessary spl's
7) removed old unused functions from pmap.c
8) removed all use of page_size, page_shift, page_mask variables - replaced
	with PAGE_ constants.
9) moved trunc/round_page, atop, ptoa, out of vm_param.h and into i386/
	include/param.h, and optimized them.
10) numerous changes to sys/vm/ swap_pager, vnode_pager, pageout, fault
	code to improve performance. LRU algorithm modified to be more
	effective, read ahead/behind values tuned for better performance,
	etc, etc...
1994-01-31 04:19:00 +00:00
David Greenman
801276d0ae Removed no longer used "wire" element in pv struct. 1994-01-27 03:36:14 +00:00
David Greenman
7f8cb36869 "New" VM system from John Dyson & myself. For a run-down of the
major changes, see the log of any effected file in the sys/vm
directory (swap_pager.c for instance).
1994-01-14 16:25:31 +00:00
Garrett Wollman
aaf08d94ca Make everything compile with -Wtraditional. Make it easier to distribute
a binary link-kit.  Make all non-optional options (pagers, procfs) standard,
and update LINT to reflect new symtab requirements.

NB: -Wtraditional will henceforth be forgotten.  This editing pass was
primarily intended to detect any constructions where the old code might
have been relying on traditional C semantics or syntax.  These were all
fixed, and the result of fixing some of them means that -Wall is now a
realistic possibility within a few weeks.
1993-12-19 00:55:01 +00:00
David Greenman
0967373e1c First steps in rewriting locore.s, and making info useful
when the machine panics.

i386/i386/locore.s:
1) got rid of most .set directives that were being used like
	#define's, and replaced them with appropriate #define's in
	the appropriate header files (accessed via genassym).
2) added comments to header inclusions and global definitions,
	and global variables
3) replaced some hardcoded constants with cpp defines (such as
	PDESIZE and others)
4) aligned all comments to the same column to make them easier to
	read
5) moved macro definitions for ENTRY, ALIGN, NOP, etc. to
	/sys/i386/include/asmacros.h
6) added #ifdef BDE_DEBUGGER around all of Bruce's debugger code
7) added new global '_KERNend' to store last location+1 of kernel
8) cleaned up zeroing of bss so that only bss is zeroed
9) fix zeroing of page tables so that it really does zero them all
	- not just if they follow the bss.
10) rewrote page table initialization code so that 1) works correctly
	and 2) write protects the kernel text by default
11) properly initialize the kernel page directory, upages, p0stack PT,
	and page tables. The previous scheme was more than a bit
	screwy.
12) change allocation of virtual area of IO hole so that it is
	fixed at KERNBASE + 0xa0000. The previous scheme put it
	right after the kernel page tables and then later expected
	it to be at KERNBASE +0xa0000
13) change multiple bogus settings of user read/write of various
	areas of kernel VM - including the IO hole; we should never
	be accessing the IO hole in user mode through the kernel
	page tables
14) split kernel support routines such as bcopy, bzero, copyin,
	copyout, etc. into a seperate file 'support.s'
15) split swtch and related routines into a seperate 'swtch.s'
16) split routines related to traps, syscalls, and interrupts
	into a seperate file 'exception.s'
17) remove some unused global variables from locore that got
	inserted by Garrett when he pulled them out of some .h
	files.

i386/isa/icu.s:
1) clean up global variable declarations
2) move in declaration of astpending and netisr

i386/i386/pmap.c:
1) fix calculation of virtual_avail. It previously was calculated
	to be right in the middle of the kernel page tables - not
	a good place to start allocating kernel VM.
2) properly allocate kernel page dir/tables etc out of kernel map
	- previously only took out 2 pages.

i386/i386/machdep.c:
1) modify boot() to print a warning that the system will reboot in
	PANIC_REBOOT_WAIT_TIME amount of seconds, and let the user
	abort with a key on the console. The machine will wait for
	ever if a key is typed before the reboot. The default is
	15 seconds, but can be set to 0 to mean don't wait at all,
	-1 to mean wait forever, or any positive value to wait for
	that many seconds.
2) print "Rebooting..." just before doing it.

kern/subr_prf.c:
1) remove PANICWAIT as it is deprecated by the change to machdep.c

i386/i386/trap.c:
1) add table of trap type strings and use it to print a real trap/
	panic message rather than just a number. Lot's of work to
	be done here, but this is the first step. Symbolic traceback
	is in the TODO.

i386/i386/Makefile.i386:
1) add support in to build support.s, exception.s and swtch.s

...and various changes to various header files to make all of the
	above happen.
1993-11-13 02:25:21 +00:00