[arm64] add hw thread self (#8942)

* [libcpu] arm64: Add hardware thread_self support

This patch introduces hardware-based thread self-identification
for the AArch64 architecture. It optimizes thread management by
using hardware registers to store and access the current thread's
pointer, reducing overhead and improving overall performance.

Changes include:
- Added `ARCH_USING_HW_THREAD_SELF` configuration option.
- Modified `rtdef.h`, `rtsched.h` to conditionally include
  `critical_switch_flag` based on the new config.
- Updated context management in `context_gcc.S`, `cpuport.h`
  to support hardware-based thread self.
- Enhanced `scheduler_mp.c` and `thread.c` to leverage the new
  hardware thread self feature.

These modifications ensure better scheduling and thread handling,
particularly in multi-core environments, by minimizing the
software overhead associated with thread management.

Signed-off-by: Shell <[email protected]>

* fixup: address suggestion

* fixup: rt_current_thread as global

* scheduler: add cpu object for UP scheduler

Also, maintain the rt_current_thread in cpu object on UP scheduler.

---------

Signed-off-by: Shell <[email protected]>

1 files changed, 6 insertions, 3 deletions

diff --git a/include/rtthread.h b/include/rtthread.h
index 1cad47931a..386fbaf47e 100644
--- a/include/rtthread.h
+++ b/include/rtthread.h
@@ -669,6 +669,12 @@ rt_err_t  rt_device_control(rt_device_t dev, int cmd, void *arg);
 void rt_interrupt_enter(void);
 void rt_interrupt_leave(void);
 
+/**
+ * CPU object
+ */
+struct rt_cpu *rt_cpu_self(void);
+struct rt_cpu *rt_cpu_index(int index);
+
 #ifdef RT_USING_SMP
 
 /*
@@ -679,9 +685,6 @@ rt_base_t rt_cpus_lock(void);
 void rt_cpus_unlock(rt_base_t level);
 void rt_cpus_lock_status_restore(struct rt_thread *thread);
 
-struct rt_cpu *rt_cpu_self(void);
-struct rt_cpu *rt_cpu_index(int index);
-
 #ifdef RT_USING_DEBUG
     rt_base_t rt_cpu_get_id(void);
 #else /* !RT_USING_DEBUG */