arm: use BASEPRI_MAX instead of BASEPRI to mask interrupts
When locking interrupt in a critical session, it is
safer to do MSR BASEPRI_MAX instead of BASEPRI. The
rationale is that when writing to BASEPRI_MAX, the
writing is conditional, and is only applied if the
change is to a higher priority level. This commit
replaces BASEPRI with BASEPRI_MAX in operations that
aim to lock some specific interrupts:
- irq_lock()
- masking out PendSV
So, for example, it is not possible to actually
unmask any interrupts by doing an irq_lock operation.
The commit does not introduce behavioral changes.
However, it makes irq_lock() more robust against
future changes to the IRQ locking mechanism.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
3 files changed
