- same problem with wstat, if we error then owner has been already updated...
- avoid smalloc while holding qlock in wstat, do it before
- pikeshedd style...
- wstat would half update the Srv data structure if name was too long
- srvname() walked the linked srv list without holding srv qlock
- dont access sp->chan while not holding srv qlock in srvopen()
- dont modify sp->owner while not holding srv qlock in srvcreate()
- avoid smalloc() allocations while holding srv qlock
- style pikeshedding, sorry
on usb ethernet, it can happen that we read truncated packets smaller
than the ethernet header size. this produces a warning in pullupblock()
later like: "pullup negative length packet, called from 0xf0199e46"
we cannot assume theres only one instance of an acpi table. some
bios have multiple SSDT tables and we would only find the first
one.
now, we keep a second array to record the physical address of
the table visited by maptable(). load all instances to the
SSDT.
this simplifies the arm ports and keeps all the stuff in one place
instead of spreading it thru notify(), trap() and syscall() functions
and prevents useless fp state copying for kernel procs.
also make sure to save fp in notify while still splhi().
the tag-word is not compatible between x87 and sse, have to convert
properly for emulation to work.
we now copy fp state across fork (again!) to preserve FCW and MXCSR
registers. this might not be neccesary as we could probably just
get the current value for the curren process and avoid the fpsave()
call, but become conservative again.
when we fail to fork resources for the child due to resource
exhaustion, make the half forked child process call pexit()
to free the resources that where allocated and error out.
imagereclaim would happily uncache pages from the mountcache (port/cache.c)
without ever getting a Image* released from it. simple fix, just check for
p->image->notext but make sure todo it under the page lock :)
the compiler optimizes setting unused variables out, which is
problematic if they are used in waserror() handler which the
compiler isnt aware of. rearrange the code to avoid this problem.
catch potential interrupt error from kproc(). this can happen when
we run out of processes, then newproc() will call rsrcwait()
which does tsleep(). if the process gets a note, this might
raise a interrupt error.
get a bit more verbose about process image exhaustion and make
imagreclaim() try to get at least one image on the freelist.
use rsrcwait() to notify the state, and call freebroken() in
case imagereclaim() couldnt free any images.
the variables elem and file0 and commited are explicitely
set to avoid that they get freed in ther waserror() handlers.
but it turns out the compiler optimizes this out as he
thinks the variables arent used any further. (the compiler
is not aware of the waserror() / longjmp() semantics).
rearrange the code to account for this. instead of using
a local variable to check for point of no return (commited),
we use up->seg[SSEG] to figure it out.
for file0 and elem, we just rearrange the code. elem can be
checked in the error handler if it was already assigned to
up->text, and file0 is just free()'d after the poperror().
remove silly busy loop in sysrendez. it is not needed.
dequeueproc() will make sure that the process has come to
rest.
we now always use the new FXSAVE format in FPsave structure and fpregs
file, converting back and forth in fpx87save() and fpx87restore().
document that fprestore() is a destructive operation now.
change fp register definition in libmach and adapt fpr() acid funciton.
avoid unneccesary copy of fpstate and fpsave in sysfork(). functions
including syscalls do not preserve the fp registers and copying fpstate
from the current process would mean we had to fpsave(&up->fpsave); first.
simply not doing it, new process starts in FPinit state.
the fpenv() instruction stores in x87 format, using mathstate()
would interpret fpsave as FPssestate in case it was enabled!
instead, pass the status word and fppc explicitely to mathnote()
in matherror().
get rid of m->fpsavealign buffer, as we can just use FPssesave struct
which has enougth padding so rounding up base pointer will not overflow.
use resrcwait() when waiting for memory to become available. randomize
the sleep time and properly restore old process status in case tsleep()
gets interrupted.
filesystems do not handle i/o errors well (cwfs will abandon the blocks),
and temporary exhaustion of kernel memory (because of too many i/o's in
parallel) causes read and write on the partition to fail.
i think it is better to wait for the memory to become available in
this case. the single allocation is at max SDmaxio bytes, which makes
it likely to become available. if we havnt even enought fo that, then
rebooting the machine would be the best option. (aux/reboot)
the fist problem is that qopen() might return nil and that kstrdup() will
sleep, so we should try to avoid holding the mntalloc lock. so we move
the kstrdup() and qopen() calls before the Mnt allocation, and properly
recover the memory if we fail later.
the second problem was that we error(Eshort) after we already created the Mnt
when returnlen < sizeof(f.version). this check has to happen *before* we
even attempt to allocate the Mnt structures. note that we only copy the
version string once everything is in the clear, so the semantics of the
user buffer not being modified in case of error is not changed.
a little cleanup in muxclose(), getting rid of mntptfree()...
Fsprotoclone() is not supposed to raise error, but return nil.
ipopen() seemed to assume otherwise as it setup error label
before calling Fsprotoclone(). fix ipopen(), make Fsprotoclone()
return nil instead of raising error.
Fsprotocone():
qopen() and qbypass() can fail and return nil, so make sure
the connection was not partially created by checking if read
and write queues have been setup by the protocol create hanler.
on error, free any resources of the partial connection and
error out.
netlogopen(): check malloc() error.
1 the config string was grabbed Aoehsz too far into the packet due to using the wrong pointer to start.
2 never accept a response with tag Tmgmt or Tfree.
3 defend against "malicious" responses; ones with a response Aoehdr.type != request Aoehdr.type. this previously could
cause the initiator to crash.
4 vendor commands were improperly filtered out.
the software cursor starts flickering and reacts bumby if a process
spends most of its time with drawlock acquired because the timer interrupt
thats supposed to redraw the cursor fails to acquire the lock at the time
the timer fires.
instead of trying to draw the cursor on the screen from a timer interrupt
30 times per second, devmouse now creates a process calling cursoron() and
cursoroff() when the cursor needs to be redrawn. this allows the swcursor
to schedule a redraw while holding the drawlock in swcursoravoid() and
cursoron()/cursoroff() are now able to wait for a qlock (drawlock) because
they get called from process context.
the overall responsiveness is also improved with this change as the cursor
redraw rate isnt limited to 30 times a second anymore.
from ehci spec:
The buffer pointer list in the qTD is long enough to support a maximum
transfer size of 20K bytes. This case occurs when all five buffer pointers
are used and the first offset is zero. A qTD handles a 16Kbyte buffer
with any starting buffer alignment.
the kernel uses fixed area (TSTKTOP, TSTKSIZ) of the address
space to temporarily map the new stack segment for exec. for
386 and arm, this area was right below the stack segment which
has the problem that the program can map arbitrary segments
there (even readonly).
alpha and ppc dont have this problem as they map the temporary
exec stack *above* the user reachable stack segement and segattach
prevents one from mapping anything above or overlaping the stack.
lots of arch code assumes USTKTOP being the end of userspace
address space and changing this to TSTKTOP would work, but results
in lots of hard to test changes.
instead, we'r going to map the temporary stack programmatically
finding a hole in the address space where to map it. we also lift
the size limitation for arguments and allow arguments to fill
the whole new stack segement.
the TSTKTOP and TSTKSIZ are not used anymore so they where removed.
references:
http://9fans.net/archive/2013/03/203http://9fans.net/archive/2013/03/202http://9fans.net/archive/2013/03/197http://9fans.net/archive/2013/03/195http://9fans.net/archive/2013/03/181
the kernel would go into endless loop when stating "stats" and "ifstats"
files and the network interface having no connections, or otherwise return
wrong stat info.
