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2020-12-12Kernel: Fix block recursionTom
Since the process lock is using the Lock class, re-locking the process lock may cause another call to Thread::block. This caused some problems with multiple blockers attempting to be used at the same time. To solve this problem, remember if the process lock was held, and if it was then relock after we're done with the blockers, just before returning.
2020-12-12Kernel: Change wait blocking to Process-only blockingTom
This prevents zombies created by multi-threaded applications and brings our model back to closer to what other OSs do. This also means that SIGSTOP needs to halt all threads, and SIGCONT needs to resume those threads.
2020-12-12Kernel: Execute timer handlers outside of irq handlerTom
This allows us to do things in timer handlers that involve e.g. scheduling, such as using the Lock class or unblocking threads.
2020-12-12Kernel: disown should unblock any potential waitersTom
This is necessary because if a process changes the state to Stopped or resumes from that state, a wait entry is created in the parent process. So, if a child process does this before disown is called, we need to clear those entries to avoid leaking references/zombies that won't be cleaned up until the former parent exits. This also should solve an even more unlikely corner case where another thread is waiting on a pid that is being disowned by another thread.
2020-12-12Kernel: Fix some issues related to fixes and block conditionsTom
Fix some problems with join blocks where the joining thread block condition was added twice, which lead to a crash when trying to unblock that condition a second time. Deferred block condition evaluation by File objects were also not properly keeping the File object alive, which lead to some random crashes and corruption problems. Other problems were caused by the fact that the Queued state didn't handle signals/interruptions consistently. To solve these issues we remove this state entirely, along with Thread::wait_on and change the WaitQueue into a BlockCondition instead. Also, deliver signals even if there isn't going to be a context switch to another thread. Fixes #4336 and #4330
2020-12-11Kernel: Fix null dereference when execve'ing ELF without PT_TLS headerAndreas Kling
Fixes #4387.
2020-12-11Kernel: Fix leaking Timer instancesTom
When a Timer is queued we add a reference, so whenever we remove a timer or fire it we should drop that reference. Fixes #4382
2020-12-02Kernel: Flush TLBs concurrentlyTom
Instead of flushing the TLB on the current processor first and then notifying the other processors to do the same, notify the others first, and while waiting on the others flush our own.
2020-12-02Kernel: Fix counting interruptsTom
Move counting interrupts out of the handle_interrupt method so that it is done in all cases without the interrupt handler having to implement it explicitly. Also make the counter an atomic value as e.g. the LocalAPIC interrupts may be triggered on multiple processors simultaneously. Fixes #4297
2020-12-02Kernel: Add CLOCK_REALTIME support to the TimerQueueTom
This allows us to use blocking timeouts with either monotonic or real time for all blockers. Which means that clock_nanosleep() now also supports CLOCK_REALTIME. Also, switch alarm() to use CLOCK_REALTIME as per specification.
2020-12-02Kernel: Use TimerQueue for SIGALRMTom
2020-12-02Kernel: TimerQueue::cancel_timer needs to wait if timer is executingTom
We need to be able to guarantee that a timer won't be executing after TimerQueue::cancel_timer returns. In the case of multiple processors this means that we may need to wait while the timer handler finishes execution on another core. This also fixes a problem in Thread::block and Thread::wait_on where theoretically the timer could execute after the function returned and the Thread disappeared.
2020-12-01Kernel: Don't assert if we can't deliver a signal due to thread stateTom
Fixes an assertion found in #3990
2020-12-01Meta: Fix ACPI_DEBUG, and always build on CIBen Wiederhake
2020-12-01LibELF+Kernel: Validate program headers in Image::parseAndrew Kaster
This should catch more malformed ELF files earlier than simply checking the ELF header alone. Also change the API of validate_program_headers to take the interpreter_path by pointer. This makes it less awkward to call when we don't care about the interpreter, and just want the validation.
2020-12-01Kernel: Fix some problems with Thread::wait_on and LockTom
This changes the Thread::wait_on function to not enable interrupts upon leaving, which caused some problems with page fault handlers and in other situations. It may now be called from critical sections, with interrupts enabled or disabled, and returns to the same state. This also requires some fixes to Lock. To aid debugging, a new define LOCK_DEBUG is added that enables checking for Lock leaks upon finalization of a Thread.
2020-12-01Kernel: Fix leaking a reference on thread creationTom
New Thread objects should be adopted into a RefPtr upon creation. If creating a thread failed (e.g. out of memory), releasing the RefPtr will destruct the partially created object, but in the successful case the thread will add an additional reference that it keeps until it finishes execution. Adopting will drop it to 1 when returning from create_thread, or 0 if the thread could not be fully constructed.
2020-11-30Kernel: Lock should keep a reference to whoever holds the lockTom
Fixes a crash reported in #3990
2020-11-30Kernel: Move block condition evaluation out of the SchedulerTom
This makes the Scheduler a lot leaner by not having to evaluate block conditions every time it is invoked. Instead evaluate them as the states change, and unblock threads at that point. This also implements some more waitid/waitpid/wait features and behavior. For example, WUNTRACED and WNOWAIT are now supported. And wait will now not return EINTR when SIGCHLD is delivered at the same time.
2020-11-30Kernel: Allow passing a thread argument for new kernel threadsTom
This adds the ability to pass a pointer to kernel thread/process. Also add the ability to use a closure as thread function, which allows passing information to a kernel thread more easily.
2020-11-30Kernel: Move some time related code from Scheduler into TimeManagementTom
Use the TimerQueue to expire blocking operations, which is one less thing the Scheduler needs to check on every iteration. Also, add a BlockTimeout class that will automatically handle relative or absolute timeouts as well as overriding timeouts (e.g. socket timeouts) more consistently. Also, rework the TimerQueue class to be able to fire events from any processor, which requires Timer to be RefCounted. Also allow creating id-less timers for use by blocking operations.
2020-11-29LibCrypto: Require intent parameter in CTR constructorLuke
This was preventing clang from building.
2020-11-26Kernel: Enable VMWareBackdoor immediately at bootTom
Rather than waiting until we get the first mouse packet, enable the absolute mode immediately. This avoids having to click first to be able to move the mouse.
2020-11-24Kernel: Reduce ByteBuffer thrashing in inode block list generationAndreas Kling
Instead of creating and destroying a new ByteBuffer for every block we process during block list generation, just use stack memory instead.
2020-11-24Kernel: Fix SharedBuffer reference counting on forkTom
We need to not only add a record for a reference, but we need to copy the reference count on fork as well, because the code in the fork assumes that it has the same amount of references, still. Also, once all references are dropped when a process is disowned, delete the shared buffer. Fixes #4076
2020-11-24Kernel: Use a doubly-linked list for the BlockBasedFS cacheAndreas Kling
This makes misses in the BlockBasedFS's LRU block cache faster by storing the cache entries in one of two doubly-linked list. Dirty and clean cache entries are kept in two separate lists, and move between them when their state changes. This can probably be improved upon further.
2020-11-24Ext2FS: Oops, fix forgotten assignment in Ext2FSInode::resize()Andreas Kling
If the inode's block list cache is empty, we forgot to assign the result of computing the block list. The fact that this worked anyway makes me wonder when we actually don't have a cache.. Thanks to szyszkienty for spotting this! :^)
2020-11-24Kernel: Add a fast lookup table to the BlockBasedFS disk cacheAndreas Kling
Instead of doing a linear scan of the entire cache when doing a lookup, we now have a nice O(1) HashMap in front of the cache. The cache miss case can still be improved, this patch really only helps the cache hit case. This dramatically improves cached filesystem I/O. :^)
2020-11-24Ext2FS: Use cached inode block list in resize() if availableAndreas Kling
If we have already cached the block list of an Ext2FSInode, we can save a lot of time by not regenerating it.
2020-11-24Kernel: Remove unnecessary SmapDisablers in FileDescriptionAndreas Kling
Since we're using UserOrKernelBuffers, SMAP will be automatically disabled when we actually access the buffer later on. There's no need to disable it wholesale across the entire read/write operations.
2020-11-23Kernel: Add unveil('b')Sergey Bugaev
This is a new "browse" permission that lets you open (and subsequently list contents of) directories underneath the path, but not regular files or any other types of files.
2020-11-23Kernel: Don't resume thread into Running state directly on SIGCONTTom
We should never resume a thread by directly setting it to Running state. Instead, if a thread was in Running state when stopped, record the state as Runnable. Fixes #4150
2020-11-23ProcFS: Take the "all inodes" lock when generating /proc/inodesAndreas Kling
Otherwise the kernel asserts.
2020-11-23Kernel: Don't leak ref on executable inode in sys$execve()Andreas Kling
We were leaking a ref on the executed inode in successful calls to sys$execve(). This meant that once a binary had ever been executed, it was impossible to remove it from the file system. The execve system call is particularly finicky since the function does not return normally on success, so extra care must be taken to ensure nothing is kept alive by stack variables. There is a big NOTE comment about this, and yet the bug still got in. It would be nice to enforce this, but I'm unsure how.
2020-11-23Ext2FS: Move some EXT2_DEBUG logging behind EXT2_VERY_DEBUGAndreas Kling
This makes the build actually somewhat usable with EXT2_DEBUG. :^)
2020-11-23Kernel: Convert dbg() to dbgln() in Syscall.cppAndreas Kling
2020-11-23Ext2FS: Clear out the direct block list when an inode is resized to 0Andreas Kling
e2fsck was complaining about blocks being allocated in an inode's list of direct blocks while at the same time being free in the block bitmap. It was easy to reproduce by creating a file with non-zero length and then truncating it. This fixes the issue by clearing out the direct block list when resizing a file to 0.
2020-11-23Kernel: Inherit shared buffers when forkingTom
We need to create a reference for the new PID for each shared buffer that the process had a reference to. If the process subsequently get replaced through exec, those references will be dropped again. But if exec for some reason fails then other code, such as global destructors could still expect having access to them. Fixes #4076
2020-11-22Kernel: Make CLOCK_MONOTONIC respect the system tick frequencyAndreas Kling
The time returned by sys$clock_gettime() was not aligned with the delay calculations in sys$clock_nanosleep(). This patch fixes that by taking the system's ticks_per_second value into account in both functions. This patch also removes the need for Thread::sleep_until() and uses Thread::sleep() for both absolute and relative sleeps. This was causing the nesalizer emulator port to sleep for a negative amount of time at the end of each frame, making it run way too fast.
2020-11-20MACAddress: AK::Array as member variable instead of C-arrayLenny Maiorani
Problem: - C-style arrays do not automatically provide bounds checking and are less type safe overall. - `__builtin_memcmp` is not a constant expression in the current gcc. Solution: - Change private m_data to be AK::Array. - Eliminate constructor from C-style array. - Change users of the C-style array constructor to use the default constructor. - Change `operator==()` to be a hand-written comparison loop and let the optimizer figure out to use `memcmp`.
2020-11-14Kernel: Fix mouse lag when VMWareBackdoor absolute mode is enabledTom
We won't be receiving full PS/2 mouse packets when the VMWareBackdoor absolute mouse mode is enabled. So, read just one byte every time and retrieve the latest mouse packet from VMWareBackdoor immediately. Fixes #4086
2020-11-14Revert "Kernel: Keep reading from i8042 until the buffer is empty"Tom
This reverts commit 467f6c74a4d2bfd46fdd04c7ef3ff35ab88e1384.
2020-11-14Kernel: Keep reading from i8042 until the buffer is emptyAndreas Kling
Otherwise we might not drain the mouse buffer until the next IRQ.
2020-11-14TmpFS: Set the root inode's timestamp to the current timeAndreas Kling
cc @bcoles :^)
2020-11-12Kernel: Implement an asynchronous device request stackTom
This allows issuing asynchronous requests for devices and waiting on the completion of the request. The requests can cascade into multiple sub-requests. Since IRQs may complete at any time, if the current process is no longer the same that started the process, we need to swich the paging context before accessing user buffers. Change the PATA driver to use this model.
2020-11-12Kernel: Add I8042Controller to detect and manage PS/2 devicesTom
Rework the PS/2 keyboard and mouse drivers to use a common 8042 controller driver. Also, reset and reconfigure the 8042 controller as they are not guaranteed to be in the state that we expect.
2020-11-12Kernel: Assume 8042 controller is present if ACPI FADT revision <= 1Tom
This field wasn't specified until revision 2 and should be assumed to be set on older versions.
2020-11-12Kernel: Fix race during thread destruction if it is preemptedTom
This fixes a lot of crashes in Bochs, which is more likely to preempt thread destruction.
2020-11-11Kernel: Fix deadlock when unicasting/broadcasting SMP messageTom
When two processors send each others a SMP message at the same time they need to process messages while waiting for delivery of the message they just sent, or they will deadlock.
2020-11-11Kernel: Implement capturing stack trace on a different CPUTom
When trying to get a stack trace of a thread on another CPU we send a SMP message to that processor to capture the stack trace for us.
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