were always in a tss; that tss just changed from the one in the
pcb to common_tss (who knows where it was when there was no curpcb?).
Not using the pcb also fixed the problem that there is no pcb in
idle(), so we now always get useful register values.
switching to a child for the first time was being counted twice. I think
this only affected unimportant statistics.
Simplified arg handling in fork_trampoline(). splz() doesn't actually
smash the registers of interest.
allow large systems to boot successfully with bounce buffers compiled
in. We are now limiting bounce space to 512K. The 8MB allocated for
a 512MB system is very bogus -- and that is now fixed.
the pv entries. This problem has become obvious due to the increase
in the size of the pv entries. We need to create a more intelligent
policy for pv entry management eventually.
Submitted by: David Greenman <dg@freebsd.org>
fork. (On my machine, fork is about 240usecs, vfork is 78usecs.)
Implement rfork(!RFPROC !RFMEM), which allows a thread to divorce its memory
from the other threads of a group.
Implement rfork(!RFPROC RFCFDG), which closes all file descriptors, eliminating
possible existing shares with other threads/processes.
Implement rfork(!RFPROC RFFDG), which divorces the file descriptors for a
thread from the rest of the group.
Fix the case where a thread does an exec. It is almost nonsense for a thread
to modify the other threads address space by an exec, so we
now automatically divorce the address space before modifying it.
nothing else will lower it until either much later, or never(?) for
kernel processes.
This basically re-fixes what Bruce fixed in rev 1.29 of kern_fork.c,
which was broken again now the child does not execute back up the fork()
calling tree.
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.
space. (!)
Have each process use the kernel stack and pcb in the kvm space. Since
the stacks are at a different address, we cannot copy the stack at fork()
and allow the child to return up through the function call tree to return
to user mode - create a new execution context and have the new process
begin executing from cpu_switch() and go to user mode directly.
In theory this should speed up fork a bit.
Context switch the tss_esp0 pointer in the common tss. This is a lot
simpler since than swithching the gdt[GPROC0_SEL].sd.sd_base pointer
to each process's tss since the esp0 pointer is a 32 bit pointer, and the
sd_base setting is split into three different bit sections at non-aligned
boundaries and requires a lot of twiddling to reset.
The 8K of memory at the top of the process space is now empty, and unmapped
(and unmappable, it's higher than VM_MAXUSER_ADDRESS).
Simplity the pmap code to manage process contexts, we no longer have to
double map the UPAGES, this simplifies and should measuably speed up fork().
The following parts came from John Dyson:
Set PG_G on the UPAGES that are now in kernel context, and invalidate
them when swapping them out.
Move the upages object (upobj) from the vmspace to the proc structure.
Now that the UPAGES (pcb and kernel stack) are out of user space, make
rfork(..RFMEM..) do what was intended by sharing the vmspace
entirely via reference counting rather than simply inheriting the mappings.
convenient and makes life difficult for my next commit. We still need
an i386tss to point to for the tss slot in the gdt, so we use a common
tss shared between all processes.
Note that this is going to break debugging until this series of commits
is finished. core dumps will change again too. :-( we really need
a more modern core dump format that doesn't depend on the pcb/upages.
This change makes VM86 mode harder, but the following commits will remove
a lot of constraints for the VM86 system, including the possibility of
extending the pcb for an IO port map etc.
Obtained from: bde
by Alan Cox <alc@cs.rice.edu>, and his description of the problem.
The bug was primarily in procfs_mem, but the mistake likely happened
due to the lack of vm system support for the operation. I added
better support for selective marking of page dirty flags so that
vm_map_pageable(wiring) will not cause this problem again.
The code in procfs_mem is now less bogus (but maybe still a little
so.)
centric rather than VM-centric to fix a problem with errors not being
detectable when the header is read.
Killed exech_map as a result of these changes.
There appears to be no performance difference with this change.
Lookup isn't done every time the system goes idle now, but it can still
take > 1800 instructions in the worst case, so if cpu interrupts are kept
disabled then it might lose 20 characters of sio input at 115200 bps.
Fixed style in vm_page_zero_idle().
functions if DDB is available. The remaining occurences are usually
only inlined and thus not available in DDB.
I'm sure Bruce will have 23 additions to these 30 lines of code, but
at least it's a starting point. ;-)
address outside of the process's address space.
Now it matches its man page :-). Closes PR# 2682.
Discussed with: bde
Submitted by: Jonathan Lemon <jlemon@americantv.com>
print "at <not configured>" for iobase == -1 (autodetect not happens)
and not print anything for iobase == -2 (none)
Old code treat this two special config numbers as big port numbers.
supports All Cyrix CPUs, IBM Blue Lightning CPU and NexGen (now AMD)
Nx586 CPU, and initialize special registers of Cyrix CPU and msr of
IBM Blue Lightning CPU.
If revision of Cyrix 6x86 CPU < 2.7, CPU cache is enabled in
write-through mode. This can be disabled by kernel configuration
options.
Reviewed by: Bruce Evans <bde@freebsd.org> and
Jordan K. Hubbard <jkh@freebsd.org>
Print the stack pointer together with the frame pointer in the trap,
syscall and interrupt messages. The frame pointer is not very useful
for locating syscall args since syscall functions don't have a frame
pointer.
Print all the numbers in the trap, syscall and interrupt messages in
the default radix. The syscall number was confusing because it was
printed in decimal.
Use %#n format more and 0x%x less. 0x%x of course doesn't work with
a variable radix. ddb is now fairly consistent about using %+#n to
print all numbers. It omits the '+' for signed numbers the '#' in a
few cases (e.g., for function args) to save space.
