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.
Update directory structure to include RTX for only cortex targets, and
for all cortex targets. This patch accomplishes this by moving mbed-os
specific RTX files and RTX itself into rtos/TARGET_CORTEX along with
removing TARGET_CORTEX_M from the RTX5 directory.
The old directory structure:
rtos/rtx5/<mbed-os specific RTX files>
rtos/rtx5/TARGET_CORTEX_M/*
rtos/rtx4/*
rtos/<mbed-os specific RTX files>
Is re-arranged to:
rtos/TARGET_CORTEX/rtx5/*
rtos/TARGET_CORTEX/rtx4/*
rtos/TARGET_CORTEX/<mbed-os specific rtx files>
This both encapsulates RTX code more cleanly and makes it easier to
experiment with non-cortex cmsis-os2 backends, such as a posix
based cmsis-os2 backend.
Note - A potentially better name for the CORTEX_M directory would be
something like FEATURE_RTX5 since this directory only contains RTX5
related files. This cannot be done because there is not an easy way
to turn this feature on, since it cannot be done from mbed_lib.json.
Kevin Bracey
Martin Kojtal
Deepika
Senthil Ramakrishnan
Cruz Monrreal II
Russ Butler