Moved various pmap 'bit' test/set functions back into real functions; gcc
generates better code at the expense of more of it. (pmap.c)
Fixed a deadlock problem with pv entry allocations (pmap.c)
Added a new, optional function 'pmap_prefault' that does clustered page
table preloading (pmap.c)
Changed the way that page tables are held onto (trap.c).
Submitted by: John Dyson
work (mi_switch() counted the last timeslice again but this didn't affect
the exiting process' rusage because the rusage has already been finalized).
Remove stale comment.
Put in the much shorter and cleaner version for the calibrate_cycle_counter
for the Pentium that Bruce suggested. Tested here on my Pentium and
it works okay.
sigreturn() sometimes failed for ordinary returns from signal handlers.
Failures of ordinary returns "can't happen" and are badly handled.
"Temporary" fix: allow users to corrupt PSL_RF. This is fairly
harmless. A correct fix would involve saving the old %eflags (and
perhaps the old segment registers) where the user can't get at them.
attempted to check for insecure and fatal eflags and segment
selectors, but missed many cases and got the IOPL check back to
front. The other syscalls didn't check at all.
sys_process.c, machdep.c:
Only allow PT_WRITE_U to write to the registers (ordinary and FP).
psl.h, locore.s, machdep.c:
Eliminate PSL_MBZ, PSL_MBO and PSL_USERCLR. We are not supposed
to assume anything about the reserved bits. Use PSL_USERCHANGE
and PSL_KERNEL instead. Rename PSL_USERSET to PSL_USER.
exception.s:
Define a private label for use by doreti when returning to user
mode fails.
machdep.c:
In syscalls, allow changing only the eflags that can be changed on
486's in user mode (no longer attempt to allow benign IOPL changes;
allow changing the nasty PSL_NT; don't allow changing the i586
bits).
Don't attempt to check all the cases involving invalid selectors
and %eip's. Just check for privilege violations and let the invalid
things cause a trap.
procfs_machdep.c:
Call the ptrace register functions to do all the work for reading
and writing ordinary registers and for single stepping.
trap.c:
Ignore traps caused by PSL_NT being set. Previously, users could
cause a fatal trap in user mode by setting PSL_NT and executing an
iret, and a fatal trap in kernel mode by setting PSL_NT and making
a syscall. PSL_NT was cleared too late and not in enough modes to
fix the problem.
Make all traps in user mode (except T_NMI) nonfatal.
Recover from traps caused by attempting to load invalid user
registers in doreti by restarting the traps so that they appear to
occur in user mode.
---
Fix bogons that I noticed while fixing the above:
psl.h:
Fix some comments.
Uniformize idempotency ifdef.
exception.s, machdep.c:
Remove rsvd[0-14]. rsvd0 hasn't been reserved since the 486 came
out. Replace rsvd0 by `align'. rsvd[0-11] used wrong (magic
non-unique) trap numbers. Replace rsvd[1-14] by rsvd.
locore.s:
Enable alignment check flag on 486's and 586's.
machdep.c:
Use a better type for kstack[].
Use TFREGP() to find the registers.
Reformat ptrace functions from SEF to something closer to KNF.
procfs_machdep.c:
The wrong pointer to the registers got fixed as a side effect.
Implement reading and writing of FP registers.
/proc/*/*regs now work (only) for processes that are in memory.
Clean up comments.
trap.c, trap.h:
Remove unused trap types.
unreachable case label in kdb_trap().
Use the correct case labels in kdb_trap() so that normal ddb entry doesn't
print a message.
Change all printf's to db_printf's. Now you can put a breakpoint at printf,
and ddb entry messages don't spam the syslog output.
Cosmetic:
Use ISPL() instead of magic numbers.
Don't compile the unused function kdb_kbd_trap().
Improve some asms.
Print the arg to Debugger().
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
shifting. Also correct the original code as Garrett noticed it in mail.
Leave the mishandled code in to use it later if future versions of gcc
are correct. The code was part of the calibrate_cyclecounter routine to
get the speed of the pentium chip.
Remove bogus input operands for fnsave(), fnstcw() and fnstsw().
Change all fwait's to fnop's. This might help avoid hardware bugs.
Wait after fninit with an fnop. This should be safer now.
Fix some spelling and formatting errors.
Use natural sizes for control and status words (u_short, promotes to int).
Don't clobber the SWI_CLOCK_MASK bits in npx0_imask when using IRQ13.
Set the devconf state correctly (always busy, if configured). Improve
code for npx_registerdev() a little (gcc can't keep id->id_unit in a
register for some reason). Don't register a nonexistent npx device.
Print a useful message in npxattach() again (delete references to errors
and not the whole message). Don't print "387 emulator" if there is no
emulator in the kernel.
Use %p for pointers in error messages.
Don't clobber the FPU state when there is an FPU exception. Just clear
the exception flags (after saving the flags as before). This allows
debuggers and SIGFPE handlers to look at the full exception state.
SIGFPE handlers should normally return via longjmp(), which restores a
good FPU state (as before). Returning from a SIGFPE handler may leave
the FPU in the wrong state (as before).
Clear the busy latch _after_ clearing the exception flags so that there
is less chance of getting a bogus h/w interrupt for a control operation.
Clear the saved exception status word when the next FPU instruction is
excuted so that it doesn't stick around until the next exception.
Clear the busy latch after fnsave() in npxsave() in case it was set when
npxsave() was called.
- /sys/i386/i386/swapgeneric.c is just plain broke. But fear not, for I
have unbroken it. One thing that swapgeneric.c does is walk through the
list of configured devices searching for a boot device. The only easy
way to accomplish this in 2.0 is to use Garret Wollman's kern_devconf
stuff. *BUT*, the head of the kern_devconf linked list (dc_list) is declared
static in /sys/kern/kern_devconf.c. This means that swapgeneric.c can't
see it at link time. I had to remove the 'static' keyword to get around
this little problem. I hope this doesn't break anything anywhere.
*Furthermore,* there's a small matter of making the call to setconf()
in swapgeneric.c disappear when 'config kernel swap generic' isn't used.
You could change /sbin/config to create a dummy setconf() function in
swapkernel.c, but that seems messy somehow. (It's also someting of an
'it isn't broken, why are you fixing it' situation.) My solution was to
do what the NetBSD people did and put an #ifdef GENERIC around the call
to setconf(). If your kernel is called GENERIC or you define 'options
GENERIC,' then you can use 'config kernel swap generic' and it'll work.
That aside, the upshot is that: a) swapgeneric.c actually works, and
and b) the -a boot flag now works as well. If you boot with -a, as in
"Boot: wd(0,a)/kernel -a" you will be presented with a 'root device?'
prompt after the autoconfig phase, at which point you can specify what
device you want mounted as root. Regrettably, you can't specify an NFS
filesystem. Yet. Three files are affected: /sys/i386/i386/swapgeneric.c,
/sys/i386/i386/autoconf.c and /sys/kern/kern_devconf.c.
Submitted by: wpaul
Move definition of `stat_imask' to clock.c.
clock.c:
Rename `rtcmask' to `stat_imask' and export it. Rename `clkmask' to
`clk_imask' for consistency.
Only calculate TIMER_DIV(hz) once.
Merge debugging and "garbage" code to produce debugging code and format the
output better.
Make writertc() static inline and use it everywhere. Now all accesses to
the clock registers go through rtcin() and writertc().
Move rtc initialization to cpu_initclocks().
Merge enablertclock() with cpu_initclocks() and remove enablertclock().
The extra entry point was just a leftover from 1.1.5.
Fix single-stepping of emulated FPU instructions.
Don't panic if an FPU instruction is attempted but there is no FPU
and no FPU emulator is configured.
Keep track of interrupt nesting level. It is normally 0
for syscalls and traps, but is fudged to 1 for their exit
processing in case they metamorphose into an interrupt
handler.
i386/genassym.c;
Remove support for the obsolete pcb_iml and pcb_cmap2.
Add support for pcb_inl.
i386/swtch.s:
Fudge the interrupt nesting level across context switches and in
the idle loop so that the work for preemptive context switches
gets counted as interrupt time, the work for voluntary context
switches gets counted mostly as system time (the part when
curproc == 0 gets counted as interrupt time), and only truly idle
time gets counted as idle time.
Remove obsolete support (commented out and otherwise) for pcb_iml.
Load curpcb just before curproc instead of just after so that
curpcb is always valid if curproc is. A few more changes like
this may fix tracing through context switches.
Remove obsolete function swtch_to_inactive().
include/cpu.h:
Use the new interrupt nesting level variable to implement a
non-fake CLF_INTR() so that accounting for the interrupt state
works.
You can use top, iostat or (best) an up to date systat to see
interrupt overheads. I see the expected huge interrupt overheads
for ISA devices (on a 486DX/33, about 55% for an IDE drive
transferring 1250K/sec and the same for a WD8013EBT network card
transferring 1100K/sec). The huge interrupt overheads for serial
devices are unfortunately normally invisible.
include/pcb.h:
Remove the obsolete pcb_iml and pcb_cmap2. Replace them by
padding to preserve binary compatibility.
Use part of the new padding for pcb_inl.
isa/icu.s:
isa/vector.s:
Keep track of interrupt nesting level.
of config so YOU MUST RECOMPILE CONFIG. Modifying config was the cleanest
solution to integrating this driver into the tree which will become more
obvious in the next commit.
