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2021-04-29Everywhere: Use "the SerenityOS developers." in copyright headersLinus Groh
We had some inconsistencies before: - Sometimes "The", sometimes "the" - Sometimes trailing ".", sometimes no trailing "." I picked the most common one (lowecase "the", trailing ".") and applied it to all copyright headers. By using the exact same string everywhere we can ensure nothing gets missed during a global search (and replace), and that these inconsistencies are not spread any further (as copyright headers are commonly copied to new files).
2021-04-22Everything: Move to SPDX license identifiers in all files.Brian Gianforcaro
SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-02-23Everywhere: Rename ASSERT => VERIFYAndreas Kling
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED) Since all of these checks are done in release builds as well, let's rename them to VERIFY to prevent confusion, as everyone is used to assertions being compiled out in release. We can introduce a new ASSERT macro that is specifically for debug checks, but I'm doing this wholesale conversion first since we've accumulated thousands of these already, and it's not immediately obvious which ones are suitable for ASSERT.
2021-02-08Everywhere: Replace dbgln<flag>(...) with dbgln_if(flag, ...)AnotherTest
Replacement made by `find Kernel Userland -name '*.h' -o -name '*.cpp' | sed -i -Ee 's/dbgln\b<(\w+)>\(/dbgln_if(\1, /g'`
2021-01-26Meta: Split debug defines into multiple headers.asynts
The following script was used to make these changes: #!/bin/bash set -e tmp=$(mktemp -d) echo "tmp=$tmp" find Kernel \( -name '*.cpp' -o -name '*.h' \) | sort > $tmp/Kernel.files find . \( -path ./Toolchain -prune -o -path ./Build -prune -o -path ./Kernel -prune \) -o \( -name '*.cpp' -o -name '*.h' \) -print | sort > $tmp/EverythingExceptKernel.files cat $tmp/Kernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/Kernel.macros cat $tmp/EverythingExceptKernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/EverythingExceptKernel.macros comm -23 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/Kernel.unique comm -1 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/EverythingExceptKernel.unique cat $tmp/Kernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/Kernel.header cat $tmp/EverythingExceptKernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/EverythingExceptKernel.header for macro in $(cat $tmp/Kernel.unique) do cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.new-includes ||: done cat $tmp/Kernel.new-includes | sort > $tmp/Kernel.new-includes.sorted for macro in $(cat $tmp/EverythingExceptKernel.unique) do cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.old-includes ||: done cat $tmp/Kernel.old-includes | sort > $tmp/Kernel.old-includes.sorted comm -23 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.new comm -13 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.old comm -12 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.mixed for file in $(cat $tmp/Kernel.includes.new) do sed -i -E 's/#include <AK\/Debug\.h>/#include <Kernel\/Debug\.h>/' $file done for file in $(cat $tmp/Kernel.includes.mixed) do echo "mixed include in $file, requires manual editing." done
2021-01-25Kernel: Fix some race conditions with Lock and waiting/waking threadsTom
There is a window between acquiring/releasing the lock with the atomic variables and subsequently waiting or waking threads. With a single processor this window was closed by using a critical section, but this doesn't prevent other processors from running these code paths. To solve this, set a flag in the WaitQueue while holding m_lock which determines if threads should be blocked at all.
2021-01-25Everywhere: Debug macros instead of constexpr.asynts
This was done with the following script: find . \( -name '*.cpp' -o -name '*.h' -o -name '*.in' \) -not -path './Toolchain/*' -not -path './Build/*' -exec sed -i -E 's/dbgln<debug_([a-z_]+)>/dbgln<\U\1_DEBUG>/' {} \; find . \( -name '*.cpp' -o -name '*.h' -o -name '*.in' \) -not -path './Toolchain/*' -not -path './Build/*' -exec sed -i -E 's/if constexpr \(debug_([a-z0-9_]+)/if constexpr \(\U\1_DEBUG/' {} \;
2021-01-22Everywhere: Replace a bundle of dbg with dbgln.asynts
These changes are arbitrarily divided into multiple commits to make it easier to find potentially introduced bugs with git bisect.
2021-01-22Everywhere: Fix typosLinus Groh
2021-01-17Kernel: Some futex improvementsTom
This adds support for FUTEX_WAKE_OP, FUTEX_WAIT_BITSET, FUTEX_WAKE_BITSET, FUTEX_REQUEUE, and FUTEX_CMP_REQUEUE, as well well as global and private futex and absolute/relative timeouts against the appropriate clock. This also changes the implementation so that kernel resources are only used when a thread is blocked on a futex. Global futexes are implemented as offsets in VMObjects, so that different processes can share a futex against the same VMObject despite potentially being mapped at different virtual addresses.
2020-12-31Everywhere: Fix more typosLuke
2020-12-30Kernel: Consolidate the various BlockCondition::unblock variantsTom
The unblock_all variant used to ASSERT if a blocker didn't unblock, but it wasn't clear from the name that it would do that. Because the BlockCondition already asserts that no blockers are left at destruction time, it would still catch blockers that haven't been unblocked for whatever reason. Fixes #4496
2020-12-16Kernel: Fix Lock race causing infinite spinning between two threadsTom
We need to account for how many shared lock instances the current thread owns, so that we can properly release such references when yielding execution. We also need to release the process lock when donating.
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
2020-09-25Meta+Kernel: Make clang-format-10 cleanBen Wiederhake
2020-08-06Kernel: Dequeue dying threads from WaitQueueTom
If a thread is waiting but getting killed, we need to dequeue the thread from the WaitQueue so that a potential wake before finalization doesn't happen.
2020-07-06Kernel: Enhance WaitQueue to remember pending wakesTom
If WaitQueue::wake_all, WaitQueue::wake_one, or WaitQueue::wake_n is called but nobody is currently waiting, we should remember that fact and prevent someone from waiting after such a request. This solves a race condition where the Finalizer thread is notified to finalize a thread, but it is not (yet) waiting on this queue. Fixes #2693
2020-07-06Kernel: Add a SpinLock to the WaitQueueTom
We need to be able to prevent a WaitQueue from being modified by another CPU. So, add a SpinLock to it. Because this pushes some other class over the 64 byte limit, we also need to add another 128-byte bucket to the slab allocator.
2020-07-03Kernel: Fix signal deliveryTom
When delivering urgent signals to the current thread we need to check if we should be unblocked, and if not we need to yield to another process. We also need to make sure that we suppress context switches during Process::exec() so that we don't clobber the registers that it sets up (eip mainly) by a context switch. To be able to do that we add the concept of a critical section, which are similar to Process::m_in_irq but different in that they can be requested at any time. Calls to Scheduler::yield and Scheduler::donate_to will return instantly without triggering a context switch, but the processor will then asynchronously trigger a context switch once the critical section is left.
2020-07-01Kernel: Implement software context switching and Processor structureTom
Moving certain globals into a new Processor structure for each CPU allows us to eventually run an instance of the scheduler on each CPU.
2020-04-26Kernel: Implement FUTEX_WAKE of arbitrary count.Brian Gianforcaro
Previously we just woke all waiters no matter how many were requested. Fix this by implementing WaitQueue::wake_n(..).
2020-02-26Kernel: Allow process with multiple threads to call exec and exitCristian-Bogdan SIRB
This allows a process wich has more than 1 thread to call exec, even from a thread. This kills all the other threads, but it won't wait for them to finish, just makes sure that they are not in a running/runable state. In the case where a thread does exec, the new program PID will be the thread TID, to keep the PID == TID in the new process. This introduces a new function inside the Process class, kill_threads_except_self which is called on exit() too (exit with multiple threads wasn't properly working either). Inside the Lock class, there is the need for a new function, clear_waiters, which removes all the waiters from the Process::big_lock. This is needed since after a exit/exec, there should be no other threads waiting for this lock, the threads should be simply killed. Only queued threads should wait for this lock at this point, since blocked threads are handled in set_should_die.
2020-02-16Kernel: Move all code into the Kernel namespaceAndreas Kling
2020-01-18Meta: Add license header to source filesAndreas Kling
As suggested by Joshua, this commit adds the 2-clause BSD license as a comment block to the top of every source file. For the first pass, I've just added myself for simplicity. I encourage everyone to add themselves as copyright holders of any file they've added or modified in some significant way. If I've added myself in error somewhere, feel free to replace it with the appropriate copyright holder instead. Going forward, all new source files should include a license header.
2020-01-12Kernel: Fix Lock racing to the WaitQueueAndreas Kling
There was a time window between releasing Lock::m_lock and calling into the lock's WaitQueue where someone else could take m_lock and bring two threads into a deadlock situation. Fix this issue by holding Lock::m_lock until interrupts are disabled by either Thread::wait_on() or WaitQueue::wake_one().
2019-12-22Kernel: Use IntrusiveList to make WaitQueue allocation-free :^)Andreas Kling
2019-12-08Kernel: Break out of the idle loop on WaitQueue wake instead of on IRQAndreas Kling
Now that we have proper wait queues to drive waiter wakeup, we can use the wake actions to break out of the scheduler's idle loop when we've got a thread to run.
2019-12-01Kernel: Use a dedicated thread state for wait-queued threadsAndreas Kling
Instead of using the generic block mechanism, wait-queued threads now go into the special Queued state. This fixes an issue where signal dispatch would unblock a wait-queued thread (because signal dispatch unblocks blocked threads) and cause confusion since the thread only expected to be awoken by the queue.
2019-12-01Kernel: Add a WaitQueue for Thread queueing/waking and use it for LockAndreas Kling
The kernel's Lock class now uses a proper wait queue internally instead of just having everyone wake up regularly to try to acquire the lock. We also keep the donation mechanism, so that whenever someone tries to take the lock and fails, that thread donates the remainder of its timeslice to the current lock holder. After unlocking a Lock, the unlocking thread calls WaitQueue::wake_one, which unblocks the next thread in queue.