reason:
We can utilize percpu storage to hold information about the
current running task. If we intend to implement this feature, we would
need to define two macros that help us manage this percpu information
effectively.
up_this_task: This macro is designed to read the contents of the percpu
register to retrieve information about the current
running task.This allows us to quickly access
task-specific data without having to disable interrupts,
access global variables and obtain the current cpu index.
up_update_task: This macro is responsible for updating the contents of
the percpu register.It is typically called during
initialization or when a context switch occurs to ensure
that the percpu register reflects the information of the
newly running task.
Configuring NuttX and compile:
$ ./tools/configure.sh -l qemu-armv8a:nsh_smp
$ make
Running with qemu
$ qemu-system-aarch64 -cpu cortex-a53 -smp 4 -nographic \
-machine virt,virtualization=on,gic-version=3 \
-net none -chardev stdio,id=con,mux=on -serial chardev:con \
-mon chardev=con,mode=readline -kernel ./nuttx
Signed-off-by: hujun5 <hujun5@xiaomi.com>
a567148888