Once a fatal error is in progress, it's not useful to trap RTX errors
or mutex problems, so short-circuit the checks.
This makes it more likely that we may be able to get the console
initialised if it is being written to for the first time by `mbed_error`
in a difficult context - such as an RTX error callback from inside an
SVCall.
For example, the one-line program
osMutexAcquire(NULL, 0);
will generate an RTX error trap, then `mbed_error` will try to call
`write(STDERR_FILENO)` to print the error, which will prompt mbed_retarget to
construct a singleton `UARTSerial`. This would trap in the mutex
for the singleton or the construction of the UARTSerial itself, if
we didn't allow this leniency. If we clear the mutex checks, then
`UARTSerial::write_unbuffered` will work.
Perform the following changes:
- change definition of `void Mutex::lock(void)` to `osStatus Mutex::lock(void)`.
- change definition of `void Mutex::unlock()` to `osStatus Mutex::unlock()`.
- use MBED_ERROR1 macro to check the lock/unlock operation status.
- add notes in the description of lock/unlock functions: "This function asserts status of the lock/unlock operation (will not return in case of failure). Use of the return value is deprecated, as the return is expected to become void in the future.".
- modify/add description of the return value.
- remove reference to Mbed 6.
- make `lock(millisec)` deprecated in favour of lock(), trylock() and trylock_for() functions.
Add assertions for statuses returned by osMutexAcquire().
Add void Mutex::lock(void) member function - lock function which does not return status and waits for the mutex forever.
Make osStatus Mutex::lock(uint32_t millisec=osWaitForever) member function deprecated in favour of bool Mutex::trylock_for(uint32_t millisec).
Given the 64-bit timebase, add trylock_until to Mutex.
Naming is based on a combination of Mutex::trylock, Thread::wait_until,
and C++11 timed_mutex::try_lock_until.
pthreads and C11 use "timedlock", but that's not a good fit against our
existing trylock() and lock(timeout) - they have only absolute-time
waits, not relative.
To increase the similarity to C++11, add trylock_for - same parameters
as lock, but with the bool return value of trylock and trylock_until.
Add an assertion when convering status codes to booleans to check that
there are no non-timeout errors.
Various RTOS classes were storing their CMSIS-RTOS creation attribute
structure as a member, when it's not required after construction. Reduce
memory by eliminating this member.
Add the attribute flash to enable priority inheritance and robust mode.
The robust flag allows mutexes held by terminated threads to be
properly released.
George Beckstein
Kevin Bracey
Przemyslaw Stekiel
Martin Kojtal
Russ Butler
Bartek Szatkowski
Sam Grove
Christopher Haster