[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, 10 insertions, 8 deletions

diff --git a/src/thread.c b/src/thread.c
index 8d4752409d..1369b7560a 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -355,20 +355,22 @@ RTM_EXPORT(rt_thread_init);
  */
 rt_thread_t rt_thread_self(void)
 {
-#ifdef RT_USING_SMP
-    rt_base_t lock;
+#ifndef RT_USING_SMP
+    return rt_cpu_self()->current_thread;
+
+#elif defined (ARCH_USING_HW_THREAD_SELF)
+    return rt_hw_thread_self();
+
+#else /* !ARCH_USING_HW_THREAD_SELF */
     rt_thread_t self;
+    rt_base_t lock;
 
     lock = rt_hw_local_irq_disable();
     self = rt_cpu_self()->current_thread;
     rt_hw_local_irq_enable(lock);
-    return self;
-
-#else /* !RT_USING_SMP */
-    extern rt_thread_t rt_current_thread;
 
-    return rt_current_thread;
-#endif /* RT_USING_SMP */
+    return self;
+#endif /* ARCH_USING_HW_THREAD_SELF */
 }
 RTM_EXPORT(rt_thread_self);