problem with some chipsets (UMC) remapping the 'hole' memory even when
you've got 16MB. People were led to believe that since there was only
16MB of memory in the machine, that they were okay wrt the ISA DMA
limit. This hack simply causes the extra memory to be ignored if it
appears around the 16MB limit.
* Removed pmap_is_wired
* added extra cli/sti protection in idle (swtch.s)
* slight code improvement in trap.c
* added lots of comments
* improved paging and other algorithms in VM system
Changed the output of the isa probe routine, that only devices, that
have an IO address and are smaller than 0x100 to be on the motherboard.
The seagate SCSI adapter is an example of a card, that doesn't have
an IO address and works only memory mapped.
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.
John Dyson to make it reliably work under FreeBSD.
2) Added and enabled PROCFS in the GENERICxx and LINT kernels.
3) New execve() from me. Still work to be done here, but this version
works well and is needed before other changes can be made. For
a description of the design behind this, see freebsd-arch or
ask me.
4) Rewrote stack fault code; made user stack VM grow as needed rather
than all up front; improves performance a little and reduces
process memory requirements.
5) Incorporated fix from Gene Stark to fault/wire a user page table
page to fix a problem in copyout. This is a temporary fix and
is not appropriate for pageable page tables. For a description
of the problem, see Gene's post to the freebsd-hackers mailing
list.
6) Tighten up vm_page struct to reduce memory requirements for it. ifdef
pager page lock code as it's not being used currently.
7) Introduced new element to vmspace struct - vm_minsaddr; initial
(minimum) stack address. Compliment to vm_maxsaddr.
8) Added a panic if the allocation for process u-pages fails.
9) Improve performance and accuracy of kernel profiling by putting in
a little inline assembly instead of spl().
10) Made serial console with sio driver work. Still has problems with
serial input, but is almost useable.
11) Added -Bstatic to SYSTEM_LD in Makefile.i386 so that kernels will
build properly with the new ld.
The following patch adds the addr argument to signal handlers.
The kernel with the patch is no more and no less in compliance or in
violation of POSIX and ANSI C than the kernel before the patch.
The added functionality this addr argument provides is quite useful. It
enables an entire class of algorithms which use mprotect to trace memory
references. Beside garbage collectors, I have heard of this technique being
applied to debuggers and profilers. The only benchmarking I've performed is
using akcl to compile maxima: without the kernel patch, it takes 7 hours to
compile maxima, while with stratified garbage collection, it only takes 50
minutes.
Basically, I can't think of a reason not to add the addr argument and there
is a compelling need for it.
If you find the patch acceptable, please let me know so I can send my
FreeBSD akcl config files to wfs for inclusion in the core akcl release.
The old 386BSD config files there won't work on either NetBSD or FreeBSD.
Subject: Page fault in PTE area fails in copyout
Index: sys/i386/i386/trap.c FreeBSD-1.0.2
Description:
Reading files of several megabytes into Emacs, or many small
files all at once, would fail with "IO error - bad address".
Repeat-By:
The bug can be exercised by a test program that malloc()'s
a 5MB chunk of memory, and then, without accessing the memory
first, filling it with data from a file using read().
(I read 64k chunks from /dev/wd0d into successive 64k regions
of the 5MB chunk.) The read() will fail with EFAULT at the first
virtual address boundary that is a multiple of 0x400000.
Fix:
The problem was code in sys/i386/i386/trap.c that tries to
figure out what kind of trap occurred and to handle it appropriately.
It was interpreting any page fault with virtual address
>= vm->vm_maxsaddr as being a user stack segment fault.
In fact, addresses >= USRSTACK are in the user structure/PTE area,
and if they are handled as stack faults, the proper PTE will
not be paged in when it is supposed to be. This situation comes
up in copyout() and copyoutstr(), if PTE's are accessed for the
first time ever. The page fault on accessing the nonexistent PTE
is mishandled as a stack fault, and then the fault that occurs on
the subsequent access to the page itself causes copyout to fail
with EFAULT.
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.
the stack area and not memory above VM_MAXUSER_ADDRESS.
That way, copyout and friends now work for pages whose page table entries
have not yet been allocated/been paged out.
machines (now 20% of all memory after the first 3MB). This is necessary
in order for 4MB machine to be able to rebuild the entire source tree
and not run out of physical memory because of fixed memory requirements
of processes and kernel VM.
Date: Tue, 19 Oct 1993 02:22:41 -40962758 (WST)
As the subject line says:
I can;t believe this typo is still here.
Has NOBODY used the isa_dmastart() routine for 16bit DMA?
I know I just hit the dma regs directly for the AHA1542,
and it appears that either everybody else does as well, or
they only use 8bit DMA (e.g. floppy)
Editors Note:
The definition of DMA2_CHN was incorrectly using IO_DMA1!
Remove NKMEMCLUSTERS, it is no longer define or used.
locores.s:
Fix comment on PTDpde and APTDpde to be pde instead of pte
Add new equation for calculating location of Sysmap
Remove Bill's old #ifdef garbage for counting up memory,
that stuff will never be made to work and was just cluttering
up the file.
Add code that places the PTD, page table pages, and kernel
stack below the 640k ISA hole if there is room for it, otherwise
put this stuff all at 1MB. This fixes the 28K bogusity in
the boot blocks, that can now go away!
Fix the caclulation of where first is to be dependent on
NKPDE so that we can skip over the above mentioned areas.
The 28K thing is now 44K in size due to the increase in
kernel virtual memory space, but since we no longer have
to worry about that this is no big deal.
Use if NNPX > 0 instead of ifdef NPX for floating point code.
machdep.c
Change the calculation of for the buffer cache to be
20% of all memory above 2MB and add back the upper limit
of 2/5's of the VM_KMEM_SIZE so that we do not eat ALL
of the kernel memory space on large memory machines, note
that this will not even come into effect unless you have
more than 32MB. The current buffer cache limit is 6.7MB
due to this caclulation.
It seems that we where erroniously allocating bufpages pages
for buffer_map. buffer_map is UNUSED in this implementation
of the buffer cache, but since the map is referenced in
several if statements a quick fix was to simply allocate
1 vm page (but no real memory) to it.
pmap.h
Remove rcsid, don't want them in the kernel files!
Removed some cruft inside an #ifdef DEBUGx that caused
compiler errors if you where compiling this for debug.
Use the #defines for PD_SHIFT and PG_SHIFT in place of
constants.
trap.c:
Remove patch kit header and rcsid, fix $Id$.
Now include "npx.h" and use NNPX for controlling the
floating point code.
Remove a now completly invalid check for a maximum virtual
address, the virtual address now ends at 0xFFFFFFFF so
there is no more MAX!! (Thanks David, I completly missed
that one!)
vm_machdep.c
Remove patch kit header and rcsid, fix $Id$.
Now include "npx.h" and use NNPX for controlling the
floating point code.
Replace several 0xFE00000 constants with KERNBASE
Mark the fact that PGSHIFT and PDRSHIFT are really the same as
PG_SHIFT and PD_SHIFT, these should be collapsed some day soon.
Document that KERNBASE should really be KPTDPTDI << PDRSHIFT, for
now leave it as the constant 0xFE000000 until I make a seperate
common header file for this stuff (vmaddresses.h?)
Remove NKMEMCLUSTERS define, it was only being used to define
VM_KMEM_SIZE, so why have all the indirection. Besides who wants
to work in CLBYTE sizes chuncks.
pmap.h:
Fix $Id$ and some other minor format clean ups.
Remove the XXX comment about NKPDE, since it now has the correct value
of 7.
Remove unused LASTPTDI and move the APTD into the very end of memory to
free up 4MB of kernel virtual address space.
Remove unused RSVDPTDI and free up 12MB of kernel virtual address space.
vmparam.h
Fix $Id$.
Increase SHMMAXPGS to 512 (2MB) now that there is room for it to be
bigger. The XXX comment stays until the kernel moves down in memory
to free up enough space to use the proper default of 4MB.
VM_KMEM_SIZE is now a direct constant stating the size of the kernel
malloc region. Increased the value from 3MB to 16MB.
Bruce Evans had limited the kernel virtual address space to not include the
last 4MB since it was not being used. Other changes are being made that will
reloate the Alternate Page Directory Table (APDT) into this area so the limit
is being fixed to be the last virtual address. (Infact with this patch you
can now do that relocation)
