Move this architecture-specific sanity check (IOPL must be 0) out of
Scheduler and into the x86 enter_thread_context(). Also do this for
every thread and not just userspace ones.
It's more accurate to say that we're blocking on a mutex, rather than
blocking on a lock. The previous terminology made sense when this code
was using something called Kernel::Lock, but since it was renamed to
Kernel::Mutex, this updates brings the language back in sync.
It was annoyingly hard to spot these when we were using them with
different amounts of qualification everywhere.
This patch uses Thread::State::Foo everywhere instead of Thread::Foo
or just Foo.
If the blocker is interrupted by a signal, that signal will be delivered
to the process when returning to userspace (at the syscall exit point.)
We don't have to perform the dispatch manually in Thread::block_impl().
Signal dispatch is already taken care of elsewhere, so there appears to
be no need for the hack in enter_current().
This also allows us to remove the Thread::m_in_block flag, simplifying
thread blocking logic somewhat.
Verified with the original repro for #4336 which this was meant to fix.
This function is large and unwieldy and forces Thread.h to #include
a bunch of things. The only reason it was in the header is because we
need to instantiate a blocker based on the templated BlockerType.
We actually keep block<BlockerType>() in the header, but move the
bulk of the function body out of line into Thread::block_impl().
To preserve destructor ordering, we add Blocker::finalize() which is
called where we'd previously destroy the Blocker.
We currently support the left super key. This poses an issue on
keyboards that only have a right super key, such as my Steelseries 6G.
The implementation mirrors the left/right shift key logic and
effectively considers the right super key identical to the left one.
Unlike other BCP47 keywords that we are parsing, these only appear in
the BCP47 XML file itself within the CLDR. The values are very simple
though, so just hard code them until the Unicode org re-releases the
CLDR with BCP47: https://unicode-org.atlassian.net/browse/CLDR-15158
This commit removes the usage of HashMap in Mutex, thereby making Mutex
be allocation-free.
In order to achieve this several simplifications were made to Mutex,
removing unused code-paths and extra VERIFYs:
* We no longer support 'upgrading' a shared lock holder to an
exclusive holder when it is the only shared holder and it did not
unlock the lock before relocking it as exclusive. NOTE: Unlike the
rest of these changes, this scenario is not VERIFY-able in an
allocation-free way, as a result the new LOCK_SHARED_UPGRADE_DEBUG
debug flag was added, this flag lets Mutex allocate in order to
detect such cases when debugging a deadlock.
* We no longer support checking if a Mutex is locked by the current
thread when the Mutex was not locked exclusively, the shared version
of this check was not used anywhere.
* We no longer support force unlocking/relocking a Mutex if the Mutex
was not locked exclusively, the shared version of these functions
was not used anywhere.
Devices such as NVMe can have blocks bigger that 512. Use the
m_block_size variable in read/write_block function instead of the
hardcoded 512 block size.
