The x86_64 code has centralized the memory setup code in
e820_64.c. This patch copies that approach to i386:
- early_param("mem", ...) parsing is moved from
setup_32.c to e820_32.c.
- setup_memory_map() and finish_e820_parsing() are
factored out from setup_arch(), and declarations
are added to e820_32.h.
- print_memory_map() is made static and removed from
e820_32.h.
- user_defined_memmap is marked as __initdata.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arch/x86/kernel/cpu/mtrr/generic.c:216:12: warning: symbol 'lo' shadows an earlier one
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
PCI: correct mailing list address
PCI: Correct last two HP entries in the bfsort whitelist
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
[PATCH] return to old errno choice in mkdir() et.al.
[Patch] fs/binfmt_elf.c: fix wrong return values
[PATCH] get rid of leak in compat_execve()
[Patch] fs/binfmt_elf.c: fix a wrong free
[PATCH] avoid multiplication overflows and signedness issues for max_fds
[PATCH] dup_fd() part 4 - race fix
[PATCH] dup_fd() - part 3
[PATCH] dup_fd() part 2
[PATCH] dup_fd() fixes, part 1
[PATCH] take init_files to fs/file.c
* 'kvm-updates-2.6.26' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm:
KVM: LAPIC: ignore pending timers if LVTT is disabled
KVM: Update MAINTAINERS for new mailing lists
KVM: Fix kvm_vcpu_block() task state race
KVM: ia64: Set KVM_IOAPIC_NUM_PINS to 48
KVM: ia64: fix GVMM module including position-dependent objects
KVM: ia64: Define new kvm_fpreg struture to replace ia64_fpreg
KVM: PIT: take inject_pending into account when emulating hlt
s390: KVM guest: fix compile error
KVM: x86 emulator: fix writes to registers with modrm encodings
Replace Redundant Whitelist Entries with the Correct Ones
The ProLiant DL585 G2 and the DL585 G2 are entered reundantly in the
dmi_system_id table. What should have been there are the DL360 and DL380. This
patch simply replaces the redundant entries with the correct entries.
Signed-off-by: Tony Camuso <tony.camuso@hp.com>
Signed-off-by: Pat Schoeller <patrick.schoeller@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Only use the APIC pending timers count to break out of HLT emulation if
the timer vector is enabled.
Certain configurations of Windows simply mask out the vector without
disabling the timer.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Otherwise hlt emulation fails if PIT is not injecting IRQ's.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
A register destination encoded with a mod=3 encoding left dst.ptr NULL.
Normally we don't trap writes to registers, but in the case of smsw, we do.
Fix by pointing dst.ptr at the destination register.
Signed-off-by: Avi Kivity <avi@qumranet.com>
The previous revert of 0c07ee38c9 left
out the mwait disable condition for AMD family 10H/11H CPUs.
Andreas Herrman said:
It depends on the CPU. For AMD CPUs that support MWAIT this is wrong.
Family 0x10 and 0x11 CPUs will enter C1 on HLT. Powersavings then
depend on a clock divisor and current Pstate of the core.
If all cores of a processor are in halt state (C1) the processor can
enter the C1E (C1 enhanced) state. If mwait is used this will never
happen.
Thus HLT saves more power than MWAIT here.
It might be best to switch off the mwait flag for these AMD CPU
families like it was introduced with commit
f039b75471 (x86: Don't use MWAIT on AMD
Family 10)
Re-add the AMD families 10H/11H check and disable the mwait usage for
those.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
pat_disable() is __init, which means it goes away after booting is complete.
Unfortunately it is used by the hotplug code if the machine is not
pat-capable, causing a crash.
Fix by marking pat_disable() as __cpuinit.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Vegard Nossum reports:
| powertop shows between 200-400 wakeups/second with the description
| "<kernel IPI>: Rescheduling interrupts" when all processors have load (e.g.
| I need to run two busy-loops on my 2-CPU system for this to show up).
|
| The bisect resulted in this commit:
|
| commit 0c07ee38c9
| Date: Wed Jan 30 13:33:16 2008 +0100
|
| x86: use the correct cpuid method to detect MWAIT support for C states
remove the functional effects of this patch and make mwait unconditional.
A future patch will turn off mwait on specific CPUs where that causes
power to be wasted.
Bisected-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The user_regset_view table for the 32-bit regsets on the 64-bit build had
the wrong sizes for the FP regsets. This bug had no user-visible effect
(just on kernel modules using the user_regset interfaces and the like).
But the fix is trivial and risk-free.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
fix this warning:
arch/x86/mm/pat.c: In function `phys_mem_access_prot_allowed':
arch/x86/mm/pat.c:558: warning: long long unsigned int format, long
unsigned int arg (arg 6)
arch/x86/mm/pat.c: In function `map_devmem':
arch/x86/mm/pat.c:580: warning: long long unsigned int format, long
unsigned int arg (arg 6)
Signed-off-by: D Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix this symbol export problem:
Building modules, stage 2.
MODPOST 193 modules
ERROR: "csum_partial" [fs/reiserfs/reiserfs.ko] undefined!
make[1]: *** [__modpost] Error 1
make: *** [modules] Error 2
This is due to a known weakness of symbol exports: if a symbol's
only in-core user is an EXPORT_SYMBOL from a lib-y section, the
symbol is not linked in.
The solution is to move the export to x8664_ksyms_64.c - but the real
solution would be to fix kbuild.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/setup_64.c:954: warning: passing argument 2 of 'set_bit' from incompatible pointer type
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
After resume on a 2cpu laptop, kernel builds collapse with a sed hang,
sh or make segfault (often on 20295564), real-time signal to cc1 etc.
Several hurdles to jump, but a manually-assisted bisect led to -rc1's
d2bcbad5f3 x86: do not zap_low_mappings
in __smp_prepare_cpus. Though the low mappings were removed at bootup,
they were left behind (with Global flags helping to keep them in TLB)
after resume or cpu online, causing the crashes seen.
Reinstate zap_low_mappings (with local __flush_tlb_all) for each cpu_up
on x86_32. This used to be serialized by smp_commenced_mask: that's now
gone, but a low_mappings flag will do. No need for native_smp_cpus_done
to repeat the zap: let mem_init zap BSP's low mappings just like on UP.
(In passing, fix error code from native_cpu_up: do_boot_cpu returns a
variety of diagnostic values, Dprintk what it says but convert to -EIO.
And save_pg_dir separately before zap_low_mappings: doesn't matter now,
but zapping twice in succession wiped out resume's swsusp_pg_dir.)
That worked well on the duo and one quad, but wouldn't boot 3rd or 4th
cpu on P4 Xeon, oopsing just after unlock_ipi_call_lock. The TLB flush
IPI now being sent reveals a long-standing bug: the booting cpu has its
APIC readied in smp_callin at the top of start_secondary, but isn't put
into the cpu_online_map until just before that unlock_ipi_call_lock.
So native_smp_call_function_mask to online cpus would send_IPI_allbutself,
including the cpu just coming up, though it has been excluded from the
count to wait for: by the time it handles the IPI, the call data on
native_smp_call_function_mask's stack may well have been overwritten.
So fall back to send_IPI_mask while cpu_online_map does not match
cpu_callout_map: perhaps there's a better APICological fix to be
made at the start_secondary end, but I wouldn't know that.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Some versions of X used the mprotect workaround to change caching type from UC
to WB, so that it can then use mtrr to program WC for that region [1]. Change
the mmap of pci space through /sys or /proc interfaces from UC to UC_MINUS.
With this change, X will not need to use mprotect workaround to get WC type
since the MTRR mapping type will be honored.
The bug in mprotect that clobbers PAT bits is fixed in a follow on patch. So,
this X workaround will stop working as well.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Rene Herman reported:
> commit 8779f2fc3b
>
> "x86: don't try to allocate from DMA zone at first"
>
> breaks all of ISA DMA. Or all of ALSA ISA DMA at least. All
> ISA soundcards are silent following that commit -- no error
> messages, everything appears fine, just silence.
That patch is buggy. We had an implicit assumption that
dev = NULL for ISA devices that require 24bit DMA.
The recent work on x86 dma_alloc_coherent() breaks the ISA DMA buffer
allocation, which is represented by "dev = NULL" and requires 24bit
DMA implicitly.
Bisected-by: Rene Herman <rene.herman@keyaccess.nl>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
To allow linker to catch sections overlapping we have to declare
them in appropriate order.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The phys_cpu_present_map is an expected symbol in the SMP harness.
Unfortunately, x86 recently moved this and a few others to
kernel/setup.c where it doesn't quite work because voyager has to
define its own. Use CONFIG_X86_LOCAL_APIC to isolate these
definitions and fix up another area in setup.c where CONFIG_X86_SMP
should be used instead of CONFIG_SMP.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: toralf.foerster@gmx.de
Cc: Mike Travis <travis@sgi.com>
Cc: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Rene Herman reported:
> commit 8779f2fc3b
>
> "x86: don't try to allocate from DMA zone at first"
>
> breaks all of ISA DMA. Or all of ALSA ISA DMA at least. All
> ISA soundcards are silent following that commit -- no error
> messages, everything appears fine, just silence.
That patch is buggy. We had an implicit assumption that
dev = NULL for ISA devices that require 24bit DMA.
The recent work on x86 dma_alloc_coherent() breaks the ISA DMA buffer
allocation, which is represented by "dev = NULL" and requires 24bit
DMA implicitly.
Bisected-by: Rene Herman <rene.herman@keyaccess.nl>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Rene Herman <rene.herman@keyaccess.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86:
x86: rdc: leds build/config fix
x86: sysfs cpu?/topology is empty in 2.6.25 (32-bit Intel system)
x86: revert commit 709f744 ("x86: bitops asm constraint fixes")
x86: restrict keyboard io ports reservation to make ipmi driver work
x86: fix fpu restore from sig return
x86: remove spew print out about bus to node mapping
x86: revert printk format warning change which is for linux-next
x86: cleanup PAT cpu validation
x86: geode: define geode_has_vsa2() even if CONFIG_MGEODE_LX is not set
x86: GEODE: cache results from geode_has_vsa2() and uninline
x86: revert geode config dependency
select NEW_LEDS for now until the Kconfig dependencies have been
fixed.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
On some of our (single board computer) boards (x86) we are using an
IPMI controller that uses I/O ports 0x62 and 0x66 for a KCS (keyboard
controller style) IPMI system interface.
Trying to load the openipmi driver fails, because the ports
(0x62/0x66) are reserved for keyboard. keyboard reserves the full
range 0x60-0x6F while it doesn't need to.
Reserve only ports 0x60 and 0x64 for the legacy PS/2 i8042 keyboad
controller instead of 0x60-0x6F to allow the openipmi driver to work.
[ tglx: added 64bit fixup ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If the task never used fpu, initialize the fpu before restoring the FP
state from the signal handler context. This will allocate the fpu
state, if the task never needed it before.
Reported-and-bisected-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Eric Sesterhenn <snakebyte@gmx.de>
Cc: Frederik Deweerdt <deweerdt@free.fr>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Jeff Garzik pointed out that this printout is not needed.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This reverts commit 9f8daccaa0, which was
reported to break X startup (xf86-video-ati-6.8.0). See
http://bugs.freedesktop.org/show_bug.cgi?id=15523
for details.
Reported-by: Laurence Withers <l@lwithers.me.uk>
Cc: Gary Hade <garyhade@us.ibm.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the scattered checks for PAT support to a single function. Its
moved to addon_cpuid_features.c as this file is shared between 32 and
64 bit.
Remove the manipulation of the PAT feature bit and just disable PAT in
the PAT layer, based on the PAT bit provided by the CPU and the
current CPU version/model white list.
Change the boot CPU check so it works on Voyager somewhere in the
future as well :) Also panic, when a secondary has PAT disabled but
the primary one has alrady switched to PAT. We have no way to undo
that.
The white list is kept for now to ensure that we can rely on known to
work CPU types and concentrate on the software induced problems
instead of fighthing CPU erratas and subtle wreckage caused by not yet
verified CPUs. Once the PAT code has stabilized enough, we can remove
the white list and open the can of worms.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This moves geode_has_vsa2 into a .c file, caches the result we get from
the VSA virtual registers, and causes the function to no longer be inline.
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Andres Salomon <dilinger@debian.org>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
commit e26a28d190
x86: olpc build fix
was a fix to a patch that was withdrawn/delayed and then erroneously
commited to x86.git. Revert it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
fix pcspkr dependancies: make the pcspkr platform
drivers to depend on a platform device, and
not the other way around.
Signed-off-by: Stas Sergeev <stsp@aknet.ru>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
CC: Vojtech Pavlik <vojtech@suse.cz>
CC: Michael Opdenacker <michael-lists@free-electrons.com>
[fixed for 2.6.26-rc1 by tiwai]
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Fix warning from pmd_bad() at bootup on a HIGHMEM64G HIGHPTE x86_32.
That came from 9fc34113f6 x86: debug pmd_bad();
but we understand now that the typecasting was wrong for PAE in the previous
version: pagetable pages above 4GB looked bad and stopped Arjan from booting.
And revert that cded932b75 x86: fix pmd_bad
and pud_bad to support huge pages. It was the wrong way round: we shouldn't
weaken every pmd_bad and pud_bad check to let huge pages slip through - in
part they check that we _don't_ have a huge page where it's not expected.
Put the x86 pmd_bad() and pud_bad() definitions back to what they have long
been: they can be improved (x86_32 should use PTE_MASK, to stop PAE thinking
junk in the upper word is good; and x86_64 should follow x86_32's stricter
comparison, to stop thinking any subset of required bits is good); but that
should be a later patch.
Fix Hans' good observation that follow_page() will never find pmd_huge()
because that would have already failed the pmd_bad test: test pmd_huge in
between the pmd_none and pmd_bad tests. Tighten x86's pmd_huge() check?
No, once it's a hugepage entry, it can get quite far from a good pmd: for
example, PROT_NONE leaves it with only ACCESSED of the KERN_PGTABLE bits.
However... though follow_page() contains this and another test for huge
pages, so it's nice to keep it working on them, where does it actually get
called on a huge page? get_user_pages() checks is_vm_hugetlb_page(vma) to
to call alternative hugetlb processing, as does unmap_vmas() and others.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Earlier-version-tested-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeff Chua <jeff.chua.linux@gmail.com>
Cc: Hans Rosenfeld <hans.rosenfeld@amd.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-fixes:
sched: default to n for GROUP_SCHED and FAIR_GROUP_SCHED
sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
sched, x86: add HAVE_UNSTABLE_SCHED_CLOCK
sched: fix cpu clock
sched: fair-group: fix a Div0 error of the fair group scheduler
sched: fix missing locking in sched_domains code
sched: make clock sync tunable by architecture code
sched: fix debugging
sched: fix sched_info_switch not being called according to documentation
sched: fix hrtick_start_fair and CPU-Hotplug
sched: fix SCHED_FAIR wake-idle logic error
sched: fix RT task-wakeup logic
sched: add statics, don't return void expressions
sched: add debug checks to idle functions
sched: remove old sched doc
sched: make rt_sched_class, idle_sched_class static
sched: optimize calc_delta_mine()
sched: fix normalized sleeper
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
x86 PCI: call dmi_check_pciprobe()
x86/pci: add pci=skip_isa_align command lines.
x86/pci: remove flag in pci_cfg_space_size_ext
x86: fix section mismatch in pci_scan_bus
this change:
| commit 08f1c192c3
| Author: Muli Ben-Yehuda <muli@il.ibm.com>
| Date: Sun Jul 22 00:23:39 2007 +0300
|
| x86-64: introduce struct pci_sysdata to facilitate sharing of ->sysdata
|
| This patch introduces struct pci_sysdata to x86 and x86-64, and
| converts the existing two users (NUMA, Calgary) to use it.
|
| This lays the groundwork for having other users of sysdata, such as
| the PCI domains work.
|
| The Calgary bits are tested, the NUMA bits just look ok.
replaces pcibios_scan_root with pci_scan_bus_parented...
but in pcibios_scan_root we have a DMI check:
dmi_check_system(pciprobe_dmi_table);
when when have several peer root buses this could be called multiple
times (which is bad), so move that call to pci_access_init().
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
so we don't align the io port start address for pci cards.
also move out dmi check out acpi.c, because it has nothing to do with acpi.
it could spare some calling when we have several peer root buses.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Fix x86 setup printk format warming:
next-20080430/arch/x86/kernel/setup.c:172: warning: format '%lu' expects type 'long unsigned int', but argument 2 has type 'ssize_t'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add the missing MODULE_LICENSE("GPL").
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
http://bugzilla.kernel.org/show_bug.cgi?id=10547
Newer Dell OptiPlex 745s hang before rebooting after 'sudo reboot'.
A patch for some versions of the OptiPlex was proposed here --
http://lkml.org/lkml/2007/6/5/59 -- and is included in 2.6.23 and
later kernels, according to
http://lxr.linux.no/linux+v2.6.23/arch/i386/kernel/reboot.c . However,
the DMI_BOARD_NAME ("0WF810") is too restrictive. Newer OptiPlex
machines have a DMI_BOARD_NAME of "0RF703". I therefore suggest
adding another clause to reboot.c, similar to the one in the original
patch, but matching a DMI_BOARD_NAME of "0RF703".
On further inspection, it seems that there are other DMI_BOARD_NAMEs
for this same machine. They seem to change from time to time, which
means that the current code is fragile. Moreover, using bios reboot
should not break non-SFF OptiPlex 745s, and so a reasonable fix is to
simply drop the match on DMI_BOARD_NAME.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
