* Eventually BoardSetups and target boards will go away.
* Include all known fdt's in the mmc image
* This gets us closer to target board-less arm
* Changing hardware is as simple as plugging a new fdt
into u-boot's startup script.
* Drop my original rpi1 work. We're targetting ARMv7
minimum.
This allows the loader to skip BFS partitions that don't contain
a bootable system. Useful when you have a BFS data partition that
comes before the system partition when iterated over.
Currently, only the UEFI loader actually returns more than one
possible partition.
* This allows KPath to not allocate a buffer when initialized
without path.
* Added test cases for this.
* Added test for LockBuffer().
* Enhanced tests to allow building them in debug mode.
* Moved calling vfs_normalize_path() into own private method.
* Improved error codes; B_NO_MEMORY is now only returned if the
allocation actually failed.
* If used with LAZY_ALLOC, Path() and LockBuffer() are now allowed
to return a NULL path.
* Fixes problems with setting the partition name after uninitializing
a partition in DriveSetup. Previously, UninitializeJob() was
followed by SetStringJob(), but the kernel was updating the
change counter for the parent partition when uninitializing a
partition, leading to SetStringJob() having an incorrect change
counter for the parent partition. Now the parent change counter
will be correct when SetStringJob() runs.
Chunks may be physically contiguous, but virtually disjoint. Adding
physical addresses may cause ranges to be merged incorrectly.
Signed-off-by: Jessica Hamilton <jessica.l.hamilton@gmail.com>
* beaglebone vs beagleboard
* While the boards are almost the same, they have
diff. FDT's now (more memory, different layout etc)
* Make u-boot script more rpi-like
(depend on u-boot for initial addresses)
* Wasn't working, still doesn't.
The HashMap constructor was called before the heap is initialized,
ending up calling malloc from the OpenHashMap constructor.
Oddly it was still working on x86 but broke other platforms.
Instead we add a Lookup() static method to Partition,
which by default walks gPartitions for the id,
and recursively calls itself on the children lists.
This means we must add a partition even temporarily to gPartitions
before Scan()ing it though.
Signed-off-by: François Revol <revol@free.fr>
* Only set HAIKU_BOOT_PLATFORM to bios_ia32 if not defined
* Add gnuefi build feature
* Introduce BOOT_LDFLAGS, and move options for passing to linker
into ArchitectureSetup
* x86_64 compile fixes for warnings in boot loader
* loader/elf.cpp: don't include ELF32 support when targeting EFI
* relocation_func.cpp: copy of the relocation code from gnuefi
to make _relocate extern "C", and avoid including <efilib.h>
* boot_loader_efi.ld: copy of gnuefi's elf_x86_64_efi.lds,
modified to include support for C++ constructors, etc. Keep in
sync with the gnuefi package
Signed-off-by: Jessica Hamilton <jessica.l.hamilton@gmail.com>
* Add function core_dump_write_core_file(). It writes a core file for
the current thread's team. The file format is similar to that of
other OSs (i.e. ELF with PT_LOAD segments and a PT_NOTE segment), but
most of the notes are Haiku specific (infos for team, areas, images,
threads). More data will probably need to be added.
* Add team flag TEAM_FLAG_DUMP_CORE, thread flag
THREAD_FLAGS_TRAP_FOR_CORE_DUMP, and Team property coreDumpCondition,
a condition variable available while a core dump is progress. A
thread that finds its flag THREAD_FLAGS_TRAP_FOR_CORE_DUMP set before
exiting the kernel to userland calls core_dump_trap_thread(), which
blocks on the condition variable until the core dump has finished. We
need the team's threads to stop so we can get their CPU state (and
have a generally unchanging team state while writing the core file).
* Add user debugger message B_DEBUG_WRITE_CORE_FILE. It causes
core_dump_write_core_file() to be called for the team.
* Dumping core as an immediate effect of a terminal signal has not been
implemented yet, but that should be fairly straight forward.
Similar to arch_get_debug_cpu_state(), but the thread whose CPU state
to retrieve is specified. Works only for threads that aren't running,
and on x86-64 we can get the FPU state only when the thread was
interrupted in userland.
Not implemented for the incomplete architecture ports.
This resolves a TODO: We used thread_interrupt() to wake up the thread
from an interruptable wait. However, if the thread was already in the
kernel and about to start waiting, that would have no effect and the
thread would wait anyway. Now there's the new non-blockable signal
SIGNAL_DEBUG_THREAD, which is sent to the thread instead, making sure
that thread doesn't start waiting.
* New Intel SkyLake seems to have 9 mapped ranges
at boot. It seems like this define has been creeping
up for a while.
* Resolves the inital issue reported in #11377 on SkyLake
as well. Bonefish mentioned it might need to be raised
again... he had some good foresight there :-)
* I'm seeing the same no bootable partitions issue though
via USB after this raise. (maybe a USB 3.1 thing?)
* When a watched directory contains a mount point, we need to resolve
the actual parent directory of the mount point in the file system to
serve the monitor.
Reduce duplication of code by
* Removing from elf_common.h definitions available in os/kernel/elf.h
* Deleting elf32.h and elf64.h
* Renaming elf_common.h to elf_private.h
* Updating source to build using public and private ELF header files
together
Signed-off-by: Jessica Hamilton <jessica.l.hamilton@gmail.com>
* Each io_context now has a "inherit_fds" member that decides whether
or not this context allows to inherit FDs to its children.
* This replaces the former O_CLOEXEC mechanism.
* Instead of letting the kernel search for the syslog port, the
daemon now registers itself with the kernel (which even solves
a TODO).
* A port is created for the actual log messages from the launch_daemon,
and used on start.
* However, the SyslogTest does not yet work, due to the BMessage <->
KMessage communication problems.
* This enables a mechanism to profile almost the complete boot process
(starting with main2()), if SYSTEM_PROFILER is defined to 1.
* You can access the profiling data using "profile -r".
* Fixes sharing semantics, so non-shared semaphores in non-shared
memory do not become shared after a fork.
* Adds two new system calls: _user_mutex_sem_acquire/release(),
which reuse the user_mutex address-hashed wait mechanism.
* Named semaphores continue to use traditional sem_id semaphores.
The get_stack_trace syscall generates a stack trace using the kernel
debugging facilities and copies the resulting return address array to
the preallocated buffer from userland. It is only possible to get a
stack trace of the current thread.
The lookup_symbol syscall can be used to look up the symbol and image
name corresponding to an address. It can be used to resolve symbols
from a stack trace generated by the get_stack_trace syscall. Only
symbols of the current team can be looked up. Note that this uses
the symbol lookup of the kernel debugger which does not support lookup
of all symbols (static functions are missing for example).
This is meant to be used in situations where more elaborate stack trace
generation, like done in the userland debugging helpers, is not possible
due to constraints.
* drop my fdt tests
* we have to call fdt parsing code *after* cpu_init (why?)
* pass fdt pointer to all FDT support calls to avoid confusion
once we get into the kernel land
* look for PL011 compatible uart and use it
* Add some saftey checks to serial putc code to avoid null*
* fdt_node_check_compatible returns 0 on success not 1
* fdt_get_device_reg needs to add the SOC base to the result
* fdt_get_device_reg might need to add the second range cell
instead of reg?
* Move more code into fdt_support
* We now can query FDT registers based on name or alias
* Return addr_t where it makes sense
* Copyright change ok'ed by mmu_man
* Called via arm_mailbox_bcm2835 *and* arm_framebuffer_bcm2835
* This is a bit messy. We really should be getting these
chipset-centric bases from the provided FDT / DTB.
* I can't think of a way to redo this without undoing
work towards FDT.
* The Raspberry pi 2 uses a new SoC which differs slightly
from the Raspberry Pi 1.
* Someday these two board targets could go away when we get
FDT support.
* To while there was some compatibility between
BCM2708 and BCM2805, it makes the BCM2806 changes
more confusing. We don't have any valueable BCM2708
targets.
* offsetof is not allowed on non-POD types so we need to use
offset_of_member (gcc2 accepts offsetof, and C++11 relaxed the
constraints on where it is allowed so it should work there too)
* we have offset_of_member as a workaround until we switch to C++11,
move it from khash (which is soon to be removed) to list.h which is the
other place where it is used (for this one single call in our whole
codebase)
Also fix a typo in vfs.cpp.
CreateThreadEvent::DoDPC() missed a reference release to balance the
acquired reference before queuing the DPC, resulting in the
CreateThreadEvent objects being leaked.
This also removes the destructor that tried to cancel the DPC. Since
the class is reference counted and only destroyed when the DPC has
run and released the last reference, this didn't make much sense.
The signal to the team/thread is only actually sent in a deferred
procedure. To ensure that the team/thread stays valid between the DPC
being queued and it actually running, we need to acquire a reference.
Fixes#11390, where the DPC was run after the team was already
destroyed.
* VMArea::AddWaiterIfWired(): Replace the ignoreRange argument by a
flags argument and introduce (currently only) flag
IGNORE_WRITE_WIRED_RANGES. If specified, ranges wired for writing
are ignored. Ignoring just a single specified range doesn't cut it
in vm_soft_fault(), and there aren't any other users of that feature.
* vm_soft_fault(): When having to unmap a page of a lower cache, this
page cannot be wired for writing. So we can safely ignore all
writed-wired ranges, instead of just our own. We even have to do that
in case there's another thread that concurrently tries to write-wire
the same page, since otherwise we'd deadlock waiting for each other.
The thread that is being [un]scheduled already has its time_lock locked
in {stop|continue}_cpu_timers(). When updating the TeamTimeUserTimer,
the team is asked for its cpu time. Team::CPUTime() then iterates the
threads of the team and locks the time_lock of the thread again.
This workaround passes a possibly locked thread through the relevant
functions so Team::CPUTime() can decide whether or not a thread it
iterates needs to be locked or not.
This works around #11032 and its duplicates #11314 and #11344.
when uninitializing a partition or a disk (removing the partition
table), check that all partitions from that table are unmounted, as they
are about to become invalid.
Fixes#8827.
The BOOT_GDT_SEGMENT_COUNT was based on USER_DATA_SEGMENT on both
x86 and x86_64. However, on x86_64 the order of the segments is
different, leading to a too small gBootGDT array. Move the define to
the arch specific headers so they can be setup correctly in either case.
Also add a STATIC_ASSERT() to check that the descriptors fit into the
array.
Pointed out by CID 1210898.
This patch adds user_access() which can be used to gracefully handle
page faults that may happen when accessing user memory. It is used
by arch_cpu_user{memcpy, memset, strlcpy}() to allow using optimized
functions from the standard library.
Currently only x64 uses this, but nothing really is arch specific here.
Signed-off-by: Paweł Dziepak <pdziepak@quarnos.org>
The kernel is allowed to use fpu anywhere so we must make sure that
user state is not clobbered by saving fpu state at interrupt entry.
There is no need to do that in case of system calls since all fpu
data registers are caller saved.
We do not need, though, to save the whole fpu state at task swich
(again, thanks to calling convention). Only status and control
registers are preserved. This patch actually adds xmm0-15 register
to clobber list of task swich code, but the only reason of that is
to make sure that nothing bad happens inside the function that
executes that task swich. Inspection of the generated code shows
that no xmm registers are actually saved.
Signed-off-by: Paweł Dziepak <pdziepak@quarnos.org>
Enable SSE as a part of the "preparation of the environment to run any
C or C++ code" in the entry points of stage2 bootloader.
SSE2 is going to be used by memset() and memcpy().
Signed-off-by: Paweł Dziepak <pdziepak@quarnos.org>
The possibility to specify custom memcpy and memset implementations
in cpu modules is currently unused and there is generally no point
in such feature.
There are only 2 x86 vendors that really matter and there isn't
very big difference in performance of the generic optmized versions
of these funcions across different models. Even if we wanted different
versions of memset and memcpy depending on the processor model or
features much better solution would be to use STT_GNU_IFUNC and save
one indirect call.
Long story short, we don't really benefit in any way from
get_optimized_functions and the feature it implements and it only adds
unnecessary complexity to the code.
Signed-off-by: Paweł Dziepak <pdziepak@quarnos.org>
* Removes default mapping of a portion of the RAM (will be done
as needed)
* Passes on the page directory area to kernel, so on early vm init
the kernel can use the area for pagetable allocation.
* Leaves it to the platform to pass in physical memory range(s). This
will ultimately come from FDT.
* Fix long standing issue with allocation of the heap, potentially
causing other part of the bootloader to overwrite the heap.
* Implements pagetable allocator in kernel for early vm mapping.
This fixes the first PANIC seen, we now just get the same one later
on when the VM is up... more to come...
This reverts commit 3fbb24680c.
As I mentioned in #11131, this fix is not correct, and works around
the problem. The real reason was that arch_debug_call_with_fault_handler
was not working properly, so the fault handler went crazy.
With commit eb92810 that is fixed so this can be reverted.
If GCC knows what these functions are actually doing the resulting
code can be optimized better what is especially noticeable in case of
invocations of atomic_{or,and}() that ignore the result. Obviously,
everything is inlined what also improves performance.
Signed-off-by: Paweł Dziepak <pdziepak@quarnos.org>
When an ARMv7 CPU is detected, immediately turn on the FPU. This allows
us to use vsnprintf in the TRACE call in that function, as our libc is
compiled with floating point support and will trigger a fault if the FPU
is not available.
This lets the boot go further, and crash in mmu_init. Next steps:
* Find why mmu_init is crashing
* Setup some fault handlers, otherwise we call uboot ones, and they are
not very helpful. They will also probably not work once the mmu is
enabledvery helpful. They will also probably not work once the mmu is
enabledvery helpful. They will also probably not work once the mmu is
enabled...
This patch makes it possible to inline rdmsr and wrmsr instruction. The
performance impact shouldn't be significant since they are used relatively
rarely and wrmsr is usually a serializing instruction, but there is no reason
not to do so.
The goal of this patch is to amortize the cost of context switch by making
the compiler aware that context switch clobbers all registers. Because all
register need to be saved anyway there is no additional cost of using
callee saved register in the function that does the context switch.
Similarly to previous patch regarding GDT this is mostly a rewrite of
IDT handling code from C to C++. Thanks to constexpr IDT is now entirely
generated at compile-time.
Virtually no functional change, just rewriting the code from
"C in *.cpp files" to C++. Use of constexpr may be advantageous but
that code is not performance critical anyway.
* Instead of forcing the hash-table to use a copy of the key,
introduce and use TypeOperation template to avoid taking a
reference of a reference type (which gcc2 doesn't allow).
For potential boot volumes with older packages states the respective
item in the boot volume menu now has a sub menu for selecting a state.
The boot loader functionality for this feature is complete -- i.e. the
respective kernel is loaded and the name of the old state is added to
the kernel args -- but kernel packagefs and package daemon support is
still missing.
After load_image() the child thread is suspended and the parent is
expected to resume it later. However, it is possible that the parent
attempts to resume its child after it has been notified that the image
had been loaded but before the child managed to suspend itself. In such
case the child would suspends itself after that wake up attempt and,
consequently will not be ever resumed.
To mitigate that problem flag Thread::going_to_suspend has been added
which helps synchronizing thread suspension and continuation in a similar
way that "traditional" thread blocking is performed. This means that
the child should behave in a following manner: set its going_to_suspend flag,
notify the parent (i.e. any thread that may want to resume it), acquire
its scheduler_lock and suspend itself if the going_to_suspend flag is set.
The parent should follow pattern: clear going_to_suspend flag of the thread
that is about to be resumed, acquire that thread scheduler_lock and enqueue
it in a run queue if it is suspended.
Thanks Oliver for reporting the bug and identifying what causes it.
Most of the actual UserEvent work is done in DPC so that we don't have
to care about the limitations of the context in which UserEvent::Fire()
is invoked. This requires appropriate management of lifetime of UserEvent
instances to make sure that DoDPC() method is always called on a valid
object.
* Add isb just because.
* pdziepak pointed out that ARMv5 and before
had different barrier support.
* pdziepak also mentioned that dsb was too strong
for __sync_synchronize
* On ARMv6 or older, we do a simulated dsb.
* Move __sync_synchronize into thread.c in libroot
and use the new arch_atomic.h dsb/dmb defines.
* Gets arm @bootstrap-raw to end of bootstrap.
* Don't assume verdex as it isn't clear this was
occurring.
* Make an educated guess on HAIKU_BOOT_PLATFORM
based on provided board (but still allow it to
be overridden)
* Error out if user doesn't populate
HAIKU_BOOT_PLATFORM or enters an unknown board
name.
* You need to add "-sHAIKU_BOOT_BOARD=xxx" to
your jam to build for the proper ARM device.
* Rename beagle to beagleboneblk as per the
documentation.
* Use atomic_get_and_set for return value
* Atomics are no longer volatile
* Add missing arch_cpu_pause stub
* Move arch_cpu_idle to arch_cpu header to match
other architectures
For non-US keyboards, the extra 102th/105th key is used to reach \. But,
we also need it to report | when shifted (this is the key left to
"enter").
This affects only USB keyboards. Thanks to gordoncjp for reporting!
UserEvent can be fired from scheduler_reschedule() i.e. while holding current
thread scheduler_lock. If the current thread goes sleep and during reschedule
one of its timers sends a signel to it, then scheduler_enqueue_in_run_queue()
attempts to acquire again its scheduler_lock resulting in a deadlock.
There was also a minor issue with both scheduler_reschedule() and
scheduler_enqueue_in_run_queue() acquiring current CPU scheduler mode lock.
* Set max cpu to 1 for PPC until atomic functions are finished
* We have atomic functions inline in the kernel and assembly
code in libroot post-scheduler merge... isn't that a lot of
duplication?
Add boot loader debug menu option "Save syslog from previous session
during boot". If enabled (defaults to true), the previous session's
debug syslog data is copy to a separate buffer and passed to the
kernel, which writes it back to the file /var/log/previous_syslog.
As long as Haiku still boots, this should now be the most convenient way
to retrieve the output from a kernel crash.
Previous implementation based on the actual load of each core and share
each thread has in that load turned up to be very problematic when
balancing load on very heavily loaded systems (i.e. more threads
consuming all available CPU time than there is logical CPUs).
The new approach is to estimate how much load would a thread produce
if it had all CPU time only for itself. Summing such load estimations
of each thread assigned to a given core we get a rank that contains
much more information than just simple actual core load.
This field forces kernel to track each CPU load all the time. It is not
a problem with the current scheduler on a multicore systems, but on
single core machnies or with any other future scheduler this field may
become just an unnecessary burden. It isn't difficult for an application
to compute CPU load by itself when it needs it.
atomic_{get, set}64() are problematic on architectures without 64 bit
compare and swap.
Also, using sequential lock instead of atomic access ensures that
any reads from cpu_ent::active_time won't require any writes to shared
memory.
The client code is not supposed to change the topology info.
It would be also nice if cpu_topology_node::children was an array of
pointers to const but that would require several const_casts in the
topology tree generation code so it's probably not worth it.
Apparently, reading from dr3 is slower than reading from memory
with cache hit.
Also, depending on hypervisor configuration, accessing dr3 may cause
a VM exit (and, at least on kvm, it does), what makes it much slower
than a memory access even when there is a cache miss.
Add get_safemode_option_early() and get_safemode_boolean_early() to get
safemode options before the kernel heap has been initialized. They use a
simplified parser.
* VMTranslationMap:
- Add DebugPrintMappingInfo(): Given a virtual address it is supposed
to print the paging structure information for that address. To be
implemented by derived classes.
- Add DebugGetReverseMappingInfo(): Given a physical addresss it is
supposed to find all virtual addresses mapped to it. To be
implemented by derived classes.
* X86VMTranslationMapPAE: Implement the new methods
DebugPrintMappingInfo() and DebugGetReverseMappingInfo().
* Add KDL command "mapping". It supports both virtual address lookups
and reverse lookups.
* VMAddressSpace: Add randomizingEnabled property.
* VMUserAddressSpace: Randomize addresses only when randomizingEnabled
property is set.
* create_team_arg(): Check, if the team's environment contains
"DISABLE_ASLR=1". Set the team's address space property
randomizingEnabled accordingly in load_image_internal() and
exec_team().
* Create new interface for cpuidle modules (similar to the cpufreq
interface)
* Generic cpuidle module is no longer needed
* Fix and update Intel C-State module
It's a browser for the system package content, where entries can be
selected to blacklist them. The selected entries are removed from the
packagefs instance in the boot loader, so that e.g. selected drivers
won't be picked up. The paths are also added to the safe mode driver
settings and will be interpreted when the system packagefs instance is
mounted by the kernel.
* Make Menu and MenuItem polymorphic.
* MenuItem:
- Make SetMarked() virtual, so it can be overridden.
- Add SetSubmenu() and Supermenu().
- Delete the submenu in the destructor.
* Menu:
- Add Entered()/Exited() hooks. They frame the time the user navigates
the menu or any of its submenus. The hooks allow for subclasses
populating their item list dynamically.
- Add SortItems().
* Update boot loader menu copyright text to include 2013, now that it is
over soon. :-)
* pin idle threads to their specific CPUs
* allow scheduler to implement SMP_MSG_RESCHEDULE handler
* scheduler_set_thread_priority() reworked
* at reschedule: enqueue old thread after dequeueing the new one
* Thread::scheduler_lock protects thread state, priority, etc.
* sThreadCreationLock protects thread creation and removal and list of
threads in team.
* Team::signal_lock and Team::time_lock protect list of threads in team
as well.
* Scheduler uses its own internal locking.
* The UNMAP command is theoretically much faster, as it can get many block
ranges instead of just a single range.
* Furthermore, the ATA TRIM command resembles it much better.
* Therefore, fs_trim_data now gets an array of ranges, and we use SCSI UNMAP
to trim.
* Updated BFS code to collect array ranges to fully support the new
fs_trim_data possibilities.
* No need for the atomically changed variables to be declared as
volatile.
* Drop support for atomically getting and setting unaligned data.
* Introduce atomic_get_and_set[64]() which works the same as
atomic_set[64]() used to. atomic_set[64]() does not return the
previous value anymore.
The flag main purpose is to avoid race conditions between event handler
and cancel_timer(). However, cancel_timer() is safe even without
using gSchedulerLock.
If the event is scheduled to happen on other CPU than the CPU that
invokes cancel_timer() then cancel_timer() either disables the event
before its handler starts executing or waits until the event handler
is done.
If the event is scheduled on the same CPU that calls cancel_timer()
then, since cancel_timer() disables interrupts, the event is either
executed before cancel_timer() or when the timer interrupt handler
starts running the event is already disabled.
* Replace ports list mutex with R/W-lock.
* Move team port list protection to separate array of mutexes.
Relieve contention on sPortsLock by removing Team::port_list from its
protected items. With this, set_port_owner() only needs to acquire the
sPortsLock for reading.
* Add another hash table holding the ports by name. Used by find_port()
so it doesn't have to iterate over the list anymore.
* Use slab-based memory allocator for port messages. sPortQuotaLock was
acquired on every message send or receive and was thus another point
of contention. The lock is not necessary anymore.
* Lock for port hashes and Port::lock are no longer locked in a nested
fashion to reduce chances of blocking other threads.
* Make operations concurrency-safe by adding an atomically accessed
Port::state which provides linearization points to port creation and
deletion. Both operations are now divided into logical and physical
parts, the logical part just updating the state and the physical part
adding/remove it to/from the port hash and team port list.
* set_port_owner() is the only remaining function which still locks
Port::lock and one or two of sTeamListLock[] in a nested fashion.
Since it needs to move the port from one team list to another and
change Port::owner, there's no way around.
* Ports are now reference counted to make accesses to already-deleted
ports safe.
* Should fix#8007.
Simple scheduler behaves exactly the same as affine scheduler with a
single core. Obviously, affine scheduler is more complicated thus
introduces greater overhead but quite a lot of multicore logic has been
disabled on single core systems in the previous commit.
There is a global heap of cores, where the key is the highest priority
of threads running on that core. Moreover, for each core there is
a heap of logical processors on this core where the key is the priority
of currently running thread.
The per-core heap is used for load balancing among logical processors
on that core. The global heap is used in initial decision where to put
the thread (note that the algorithm that makes this decision is not
complete yet).
Simple scheduler is used when we do not have to worry about cache affinity
(i.e. single core with or without SMT, multicore with all cache levels
shared).
When we replace gSchedulerLock with more fine grained locking affine
scheduler should also be chosen when logical CPU count is high (regardless
of cache).
In SMP systems simple scheduler will be used only when all logical
processors share all levels of cache and the number of CPUs is low.
In such systems we do not have to care about cache affinity and
the contention on the lock protecting shared run queue is low. Single
run queue makes load balancing very simple.
Kernel support for yielding to all (including lower priority) threads
has been removed. POSIX sched_yield() remains unchanged.
If a thread really needs to yield to everyone it can reduce its priority
to the lowest possible and then yield (it will then need to manually
return to its prvious priority upon continuing).
Each thread has its minimal priority that depends on the static priority.
However, it is still able to starve threads with even lower priority
(e.g. CPU bound threads with lower static priority). To prevent this
another penalty is introduced. When the minimal priority is reached
penalty (count mod minimal_priority) is added, where count is the number
of time slices since the thread reached its minimal priority. This prevents
starvation of lower priorirt threads (since all CPU bound threads may have
their priority temporaily reduced to 1) but preserves relation between
static priorities - when there are two CPU bound threads the one with
higher static priority would get more CPU time.
This adds the -mapcs-frame compiler flag for ARM to have "stable"
stack frames, adds support to the kernel for dumping stack crawls,
and initial support for iframes. There' much more functionality
to unlock in KDL, but this makes debugging already a lot more
comfortable.....
Since both platforms can boot the same kernel we must accept either
arg, so we make sure they are identical for now.
TODO: use a union or KMessage maybe?
* Mostly useful for virtualization at the moment. Works in QEmu.
* Can be enabled by safemode settings/menu.
* Please note that x2APIC normally requires use of VT-d interrupt remapping feature
on real hardware, which we don't support yet.
