Commit graph

26 commits

Author SHA1 Message Date
Tomas Hruby
5efa92f754 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.
2010-01-16 20:53:55 +00:00
Tomas Hruby
ae75f9d4e5 Removal of the executable flag from files that cannot be executed
- 755 -> 644
2009-11-09 10:26:00 +00:00
Ben Gras
24e1e83028 really revert endpoint_t -> int
debugging info on panic: decode segment selectors and descriptors, now moved
to arch-specific part, prototypes added; sanity checking in debug.h made
optional with vmassert().
2009-10-05 15:47:23 +00:00
Ben Gras
c078ec0331 Basic VM and other minor improvements.
Not complete, probably not fully debugged or optimized.
2008-11-19 12:26:10 +00:00
Ben Gras
a2b1a5134b . leave out hardware-fp code from library
. minor packman usage tweaks
 . kernel feature for printing version number
 . removed some verbose debug messages from vfs/mfs
2007-04-12 16:45:00 +00:00
Ben Gras
9f2f3dd488 don't call mkdep with an absolute path 2007-02-08 16:26:20 +00:00
Ben Gras
6f77685609 Split of architecture-dependent and -independent functions for i386,
mainly in the kernel and headers. This split based on work by
Ingmar Alting <iaalting@cs.vu.nl> done for his Minix PowerPC architecture
port.

 . kernel does not program the interrupt controller directly, do any
   other architecture-dependent operations, or contain assembly any more,
   but uses architecture-dependent functions in arch/$(ARCH)/.
 . architecture-dependent constants and types defined in arch/$(ARCH)/include.
 . <ibm/portio.h> moved to <minix/portio.h>, as they have become, for now,
   architecture-independent functions.
 . int86, sdevio, readbios, and iopenable are now i386-specific kernel calls
   and live in arch/i386/do_* now.
 . i386 arch now supports even less 86 code; e.g. mpx86.s and klib86.s have
   gone, and 'machine.protected' is gone (and always taken to be 1 in i386).
   If 86 support is to return, it should be a new architecture.
 . prototypes for the architecture-dependent functions defined in
   kernel/arch/$(ARCH)/*.c but used in kernel/ are in kernel/proto.h
 . /etc/make.conf included in makefiles and shell scripts that need to
   know the building architecture; it defines ARCH=<arch>, currently only
   i386.
 . some basic per-architecture build support outside of the kernel (lib)
 . in clock.c, only dequeue a process if it was ready
 . fixes for new include files

files deleted:
 . mpx/klib.s - only for choosing between mpx/klib86 and -386
 . klib86.s - only for 86

i386-specific files files moved (or arch-dependent stuff moved) to arch/i386/:
 . mpx386.s (entry point)
 . klib386.s
 . sconst.h
 . exception.c
 . protect.c
 . protect.h
 . i8269.c
2006-12-22 15:22:27 +00:00
Ben Gras
7195fe3325 System statistical and call profiling
support by Rogier Meurs <rogier@meurs.org>.
2006-10-30 15:53:38 +00:00
Ben Gras
3172b4d0ad Patches by Jeff Bailey for posixifications. 2006-04-09 23:16:13 +00:00
Philip Homburg
7f861650b0 Use the sysutil library's printf code also for the kernel. 2006-03-15 16:15:23 +00:00
Jorrit Herder
c0718054e9 Various fixes and improvements.
- fixed bug that caused IDLE to panic (irq hook inconsistency);
- kprintf() now accepts multiple arguments; moved to utility.c;
- prepare_shutdown() signals system processes with SIGKSTOP;
- phys_fill() renamed to phys_memset(), argument order changed;
- kmemset() removed in favor of phys_kmemset();
- kstrncpy() removed in favor of phys_copy();
- katoi, kstrncmp replaced by normal library procedure again;
- rm_irq_handler() interface changed (simply pass hook pointer);
2005-07-20 15:25:38 +00:00
Ben Gras
c24f72d433 Made phys_fill fill its 4-byte pattern any number of bytes (instead of
rounded down to a 4-byte multiple)

Fixed dependency omission
2005-07-19 16:00:25 +00:00
Jorrit Herder
1d7bdd4ab1 *** empty log message *** 2005-07-19 15:01:47 +00:00
Jorrit Herder
42ab148155 Reorganized system call library; uses separate file per call now.
New configuration header file to include/ exclude functionality.
Extracted privileged features from struct proc and create new struct priv.
Renamed various system calls for readability.
2005-07-14 15:12:12 +00:00
Ben Gras
3dcb2886ff get/setpriority() and fsync() system calls 2005-07-01 18:01:33 +00:00
Jorrit Herder
bac6068857 Rewrite of process scheduling:
- current and maximum priority per process;
- quantum size and current ticks left per process;
- max number of full quantums in a row allow
  (otherwise current priority is decremented)
2005-06-30 15:55:19 +00:00
Jorrit Herder
a408699ce0 Cleaned up process table structure: removed p_type, p_pendcount.
Removed stop sequence when MINIX is shut down.
Disabled send mask checks --- to be replaced by proper mechanism.
Fixed bug relating to 'shutdown -x'.
Simplified clock accounting of realtime.
Updated Makefiles for mkdept script.
2005-06-24 16:24:40 +00:00
Jorrit Herder
403580e95b Removed unused code in proc.c. New message passing code with pointer pointers
is now in use. Rewrote ready() and unready() fuctions.
2005-06-20 11:26:48 +00:00
Jorrit Herder
0e2a7a9730 Kernel cleanup.
Reduced kernel size by 512KB by moving private buffer into cstart() function.
Replaced assertions with erroneous return values. Removed assertions relating
to isuserp(rp), since all processes should become user processes; system
processes are now treated similar to other processes.
2005-06-07 12:34:25 +00:00
Jorrit Herder
8d9c0886cd Created ECHO system call for testing purposes.
Furthermore, a quick way to get one's own process number.
2005-05-27 13:57:00 +00:00
Jorrit Herder
614f49b557 Fixed some comments and reorganized some code.
Fixed minor bug in notify() function.
2005-05-18 10:36:23 +00:00
Jorrit Herder
fbe1641bd3 User-space networking!
- RTL8139 driver moved to user-space;
- PCI code moved to user-space;
Fixed IRQ hook dump at IS server.
2005-05-11 09:02:00 +00:00
Ben Gras
e8973f33d4 *** empty log message *** 2005-05-04 09:31:54 +00:00
Jorrit Herder
ac0995259d *** empty log message *** 2005-05-02 14:30:04 +00:00
Jorrit Herder
89ac678b9b *** empty log message *** 2005-04-29 15:36:43 +00:00
Ben Gras
9865aeaa79 Initial revision 2005-04-21 14:53:53 +00:00