Ben Gras [Wed, 3 Feb 2010 13:29:14 +0000 (13:29 +0000)]
small asmconv cleanups.
- put asmconv in /usr/bin so it can be invoked without absolute path
- make it ignore .end in gnu output mode so that it can be invoked
without '|| true' in the gnu lib makefiles and it doesn't produce the
messy error message
Statistical profiling fixes:
- PM: get rid of umap warning
- sprofalyze.pl: update with recently added servers and drivers
- sprofalyze.pl: properly truncate process names for sample matching
Tomas Hruby [Wed, 3 Feb 2010 09:04:48 +0000 (09:04 +0000)]
This patch removes the global variables who_p and who_e from the
kernel (sys task). The main reason is that these would have to become
cpu local variables on SMP. Once the system task is not a task but a
genuine part of the kernel there is even less reason to have these
extra variables as proc_ptr will already contain all neccessary
information. In addition converting who_e to the process pointer and
back again all the time will be avoided.
Although proc_ptr will contain all important information, accessing it
as a cpu local variable will be fairly expensive, hence the value
would be assigned to some on stack local variable. Therefore it is
better to add the 'caller' argument to the syscall handlers to pass
the value on stack anyway. It also clearly denotes on who's behalf is
the syscall being executed.
This patch also ANSIfies the syscall function headers.
Last but not least, it also fixes a potential bug in virtual_copy_f()
in case the check is disabled. So far the function in case of a
failure could possible reuse an old who_p in case this function had
not been called from the system task.
virtual_copy_f() takes the caller as a parameter too. In case the
checking is disabled, the caller must be NULL and non NULL if it is
enabled as we must be able to suspend the caller.
Fixed a number of complaints about missing return statements.
Some cases were fixed by declaring the function void, others were fixed
by adding a return <value> statement, thereby avoiding potentially
incorrect behavior (usually in error handling).
Some enum correctness in boot.c.
Removed some uses of uninitialized variables in update.c, presumably remnands of old color support.
Fixed a few cases where free-ed memory blocks were subsequently read.
Removed some unused variables, #includes, other small cleanup.
Thomas Veerman [Thu, 21 Jan 2010 09:32:15 +0000 (09:32 +0000)]
- Fix dangling symlink regression
- Make open(2) more POSIX compliant
- Add a test case for dangling symlinks and open() syscall with O_CREAT and
O_EXCL on a symlink.
- Update open(2) man page to reflect change.
Removed unused code in the ethernet driver that was left from an old implementation
Removed/rewritten the use of uninitialized variables in error messages.
Ben Gras [Mon, 18 Jan 2010 14:10:04 +0000 (14:10 +0000)]
Fix to make making a bootable cd possible again.
ow that the image has grown beyond the 1.44M that fits on a floppy.
(previously, the floppy emulation mode was used for cd's.)
the boot cd now uses 'no emulation mode,' where an image is provided on
the cd that is loaded and executed directly. this is the boot monitor.
in order to make this work (the entry point is the same as where the
image is loaded, and the boot monitor needs its a.out header too) and
keep compatability with the same code being used for regular booting, i
prepended 16 bytes that jumps over its header so execution can start
there.
to be able to read the CD (mostly in order to read the boot image),
boot has to use the already present 'extended read' call, but address
the CD using 2k sectors.
Tomas Hruby [Sat, 16 Jan 2010 20:53:55 +0000 (20:53 +0000)]
NMI watchdog is an awesome feature for debugging locked up kernels.
There is not that much use for it on a single CPU, however, deadlock
between kernel and system task can be delected. Or a runaway loop.
If a kernel gets locked up the timer interrupts don't occure (as all
interrupts are disabled in kernel mode). The only chance is to
interrupt the kernel by a non-maskable interrupt.
This patch generates NMIs using performance counters. It uses the most
widely available performace counters. As the performance counters are
highly model-specific this patch is not guaranteed to work on every
machine. Unfortunately this is also true for KVM :-/ On the other
hand adding this feature for other models is not extremely difficult
and the framework makes it hopefully easy enough.
Depending on the frequency of the CPU an NMI is generated at most
about every 0.5s If the cpu's speed is less then 2Ghz it is generated
at most every 1s. In general an NMI is generated much less often as
the performance counter counts down only if the cpu is not idle.
Therefore the overhead of this feature is fairly minimal even if the
load is high.
Uppon detecting that the kernel is locked up the kernel dumps the
state of the kernel registers and panics.
Local APIC must be enabled for the watchdog to work.
The code is _always_ compiled in, however, it is only enabled if
watchdog=<non-zero> is set in the boot monitor.
One corner case is serial console debugging. As dumping a lot of stuff
to the serial link may take a lot of time, the watchdog does not
detect lockups during this time!!! as it would result in too many
false positives. 10 nmi have to be handled before the lockup is
detected. This means something between ~5s to 10s.
Another corner case is that the watchdog is enabled only after the
paging is enabled as it would be pure madness to try to get it right.
Merge of Wu's GSOC 09 branch (src.20090525.r4372.wu)
Main changes:
- COW optimization for safecopy.
- safemap, a grant-based interface for sharing memory regions between processes.
- Integration with safemap and complete rework of DS, supporting new data types
natively (labels, memory ranges, memory mapped ranges).
- For further information:
http://wiki.minix3.org/en/SummerOfCode2009/MemoryGrants
Additional changes not included in the original Wu's branch:
- Fixed unhandled case in VM when using COW optimization for safecopy in case
of a block that has already been shared as SMAP.
- Better interface and naming scheme for sys_saferevmap and ds_retrieve_map
calls.
- Better input checking in syslib: check for page alignment when creating
memory mapping grants.
- DS notifies subscribers when an entry is deleted.
- Documented the behavior of indirect grants in case of memory mapping.
- Test suite in /usr/src/test/safeperf|safecopy|safemap|ds/* reworked
and extended.
- Minor fixes and general cleanup.
- TO-DO: Grant ids should be generated and managed the way endpoints are to make
sure grant slots are never misreused.
Tomas Hruby [Thu, 14 Jan 2010 09:46:16 +0000 (09:46 +0000)]
Killing Minix by typing Q on serial console
- if debugging on serial console is enabled typing Q kills the system. It is
handy if the system gets locked up and the timer interrupts still work. Good
for remote debugging.
- NOT_REACHABLE reintroduced and fixed. It should be used for marking code which
is not reachable because the previous code _should_ not return. Such places
are not always obvious