[arm64] add hw thread self

include/rtdef.h

@@ -740,8 +740,10 @@ struct rt_cpu
         struct rt_thread        *current_thread;
 
         rt_uint8_t              irq_switch_flag:1;
-        rt_uint8_t              critical_switch_flag:1;
         rt_uint8_t              sched_lock_flag:1;
+#ifndef ARCH_USING_HW_THREAD_SELF
+        rt_uint8_t              critical_switch_flag:1;
+#endif /* ARCH_USING_HW_THREAD_SELF */
 
         rt_uint8_t              current_priority;
         rt_list_t               priority_table[RT_THREAD_PRIORITY_MAX];
@@ -763,10 +765,19 @@ struct rt_cpu
     struct rt_cpu_usage_stats   cpu_stat;
 #endif
 };
-typedef struct rt_cpu *rt_cpu_t;
+
+#else /* !RT_USING_SMP */
+struct rt_cpu
+{
+    struct rt_thread            *current_thread;
+};
 
 #endif /* RT_USING_SMP */
 
+typedef struct rt_cpu *rt_cpu_t;
+/* Noted: As API to reject writing to this variable from application codes */
+#define rt_current_thread rt_thread_self()
+
 struct rt_thread;
 
 #ifdef RT_USING_SMART

include/rtsched.h

@@ -56,6 +56,10 @@ struct rt_sched_thread_ctx
     rt_uint8_t                  sched_flag_locked:1;    /**< calling thread have the scheduler locked */
     rt_uint8_t                  sched_flag_ttmr_set:1;  /**< thread timer is start */
 
+#ifdef ARCH_USING_HW_THREAD_SELF
+    rt_uint8_t                  critical_switch_flag:1; /**< critical switch pending */
+#endif /* ARCH_USING_HW_THREAD_SELF */
+
 #ifdef RT_USING_SMP
     rt_uint8_t                  bind_cpu;               /**< thread is bind to cpu */
     rt_uint8_t                  oncpu;                  /**< process on cpu */
@@ -170,6 +174,7 @@ rt_err_t rt_sched_thread_timer_stop(struct rt_thread *thread);
 rt_err_t rt_sched_thread_timer_start(struct rt_thread *thread);
 void rt_sched_insert_thread(struct rt_thread *thread);
 void rt_sched_remove_thread(struct rt_thread *thread);
+struct rt_thread *rt_sched_thread_self(void);
 
 #endif /* defined(__RT_KERNEL_SOURCE__) || defined(__RT_IPC_SOURCE__) */
 

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 */

libcpu/Kconfig

@@ -14,6 +14,8 @@ if ARCH_ARMV8 && ARCH_CPU_64BIT
         default y
     config ARCH_USING_GENERIC_CPUID
         bool "Using generic cpuid implemenation"
+        select ARCH_USING_HW_THREAD_SELF
+        default y if RT_USING_OFW
         default n
     endmenu
 endif
@@ -270,3 +272,7 @@ config ARCH_HOST_SIMULATOR
 config ARCH_CPU_STACK_GROWS_UPWARD
     bool
     default n
+
+config ARCH_USING_HW_THREAD_SELF
+    bool
+    default n

libcpu/aarch64/common/context_gcc.S

@@ -8,6 +8,7 @@
  * 2021-05-18     Jesven       the first version
  * 2023-06-24     WangXiaoyao  Support backtrace for user thread
  * 2024-01-06     Shell        Fix barrier on irq_disable/enable
+ * 2024-01-18     Shell        fix implicit dependency of cpuid management
  */
 
 #ifndef __ASSEMBLY__
@@ -27,15 +28,35 @@ rt_thread_switch_interrupt_flag: .zero  8
 #endif
 
 .text
-.weak rt_hw_cpu_id_set
+
+/**
+ * #ifdef RT_USING_OFW
+ * void rt_hw_cpu_id_set(long cpuid)
+ * #else
+ * void rt_hw_cpu_id_set(void)
+ * #endif
+ */
 .type rt_hw_cpu_id_set, @function
 rt_hw_cpu_id_set:
-    mrs x0, mpidr_el1           /* MPIDR_EL1: Multi-Processor Affinity Register */
+#ifdef ARCH_USING_GENERIC_CPUID
+    .globl  rt_hw_cpu_id_set
+#else /* !ARCH_USING_GENERIC_CPUID */
+    .weak   rt_hw_cpu_id_set
+#endif /* ARCH_USING_GENERIC_CPUID */
+
+#ifndef RT_USING_OFW
+    mrs     x0, mpidr_el1           /* MPIDR_EL1: Multi-Processor Affinity Register */
 #ifdef ARCH_ARM_CORTEX_A55
-    lsr x0, x0, #8
-#endif
-    and x0, x0, #15
-    msr tpidr_el1, x0
+    lsr     x0, x0, #8
+#endif /* ARCH_ARM_CORTEX_A55 */
+    and     x0, x0, #15
+#endif /* !RT_USING_OFW */
+
+#ifdef ARCH_USING_HW_THREAD_SELF
+    msr     tpidrro_el0, x0
+#else /* !ARCH_USING_HW_THREAD_SELF */
+    msr     tpidr_el1, x0
+#endif /* ARCH_USING_HW_THREAD_SELF */
     ret
 
 /*

libcpu/aarch64/common/cpu.c

@@ -231,6 +231,24 @@ int rt_hw_cpu_boot_secondary(int num_cpus, rt_uint64_t *cpu_hw_ids, struct cpu_o
 
 #endif /*RT_USING_SMP*/
 
+/**
+ * Generic hw-cpu-id
+ */
+#ifdef ARCH_USING_GENERIC_CPUID
+
+int rt_hw_cpu_id(void)
+{
+#if RT_CPUS_NR > 1
+    long cpuid;
+    __asm__ volatile("mrs %0, tpidrro_el0":"=r"(cpuid));
+    return cpuid;
+#else
+    return 0;
+#endif /* RT_CPUS_NR > 1 */
+}
+
+#endif /* ARCH_USING_GENERIC_CPUID */
+
 /**
  * @addtogroup ARM CPU
  */

libcpu/aarch64/common/cpuport.h

@@ -7,6 +7,7 @@
  * Date           Author       Notes
  * 2023-10-25     Shell        Move ffs to cpuport, add general implementation
  *                             by inline assembly
+ * 2024-01-18     Shell        support rt_hw_thread_self to improve overall performance
  */
 
 #ifndef  CPUPORT_H__
@@ -27,31 +28,6 @@ typedef struct
     rt_uint32_t value;
 } rt_hw_spinlock_t;
 
-/**
- * Generic hw-cpu-id
- */
-#ifdef ARCH_USING_GENERIC_CPUID
-
-#if RT_CPUS_NR > 1
-
-rt_inline int rt_hw_cpu_id(void)
-{
-    long cpuid;
-    __asm__ volatile("mrs %0, tpidr_el1":"=r"(cpuid));
-    return cpuid;
-}
-
-#else
-
-rt_inline int rt_hw_cpu_id(void)
-{
-    return 0;
-}
-
-#endif /* RT_CPUS_NR > 1 */
-
-#endif /* ARCH_USING_GENERIC_CPUID */
-
 #endif /* RT_USING_SMP */
 
 #define rt_hw_barrier(cmd, ...) \
@@ -107,4 +83,20 @@ rt_inline int __rt_ffs(int value)
 
 #endif /* RT_USING_CPU_FFS */
 
+#ifdef ARCH_USING_HW_THREAD_SELF
+rt_inline struct rt_thread *rt_hw_thread_self(void)
+{
+    struct rt_thread *thread;
+    __asm__ volatile ("mrs %0, tpidr_el1":"=r"(thread));
+
+    return thread;
+}
+
+rt_inline void rt_hw_thread_set_self(struct rt_thread *thread)
+{
+    __asm__ volatile ("msr tpidr_el1, %0"::"r"(thread));
+}
+
+#endif /* ARCH_USING_HW_THREAD_SELF */
+
 #endif  /*CPUPORT_H__*/

libcpu/aarch64/cortex-a/entry_point.S

@@ -7,6 +7,7 @@
  * 2020-01-15     bigmagic     the first version
  * 2020-08-10     SummerGift   support clang compiler
  * 2023-04-29     GuEe-GUI     support kernel's ARM64 boot header
+ * 2024-01-18     Shell        fix implicit dependency of cpuid management
  */
 
 #ifndef __ASSEMBLY__
@@ -95,6 +96,10 @@ _start:
     /* Save cpu stack */
     get_phy stack_top, .boot_cpu_stack_top
     /* Save cpu id temp */
+#ifdef ARCH_USING_HW_THREAD_SELF
+    msr     tpidrro_el0, xzr
+    /* Save thread self */
+#endif /* ARCH_USING_HW_THREAD_SELF */
     msr     tpidr_el1, xzr
 
     bl      init_cpu_el
@@ -149,11 +154,10 @@ _secondary_cpu_entry:
 
     /* Get cpu id success */
     sub     x0, x2, #1
-    msr     tpidr_el1, x0           /* Save cpu id global */
-#else
-    bl      rt_hw_cpu_id_set
-    mrs     x0, tpidr_el1
 #endif /* RT_USING_OFW */
+    /* Save cpu id global */
+    bl      rt_hw_cpu_id_set
+    bl      rt_hw_cpu_id
 
     /* Set current cpu's stack top */
     sub     x0, x0, #1

src/cpu_up.c

@@ -6,10 +6,14 @@
  * Change Logs:
  * Date           Author       Notes
  * 2024-04-19     Shell        Fixup UP irq spinlock
+ * 2024-05-22     Shell        Add UP cpu object and
+ *                             maintain the rt_current_thread inside it
  */
 #include <rthw.h>
 #include <rtthread.h>
 
+static struct rt_cpu _cpu;
+
 /**
  * @brief   Initialize a static spinlock object.
  *
@@ -80,3 +84,25 @@ void rt_spin_unlock_irqrestore(struct rt_spinlock *lock, rt_base_t level)
     rt_exit_critical_safe(critical_level);
     rt_hw_interrupt_enable(level);
 }
+
+/**
+ * @brief   This fucntion will return current cpu object.
+ *
+ * @return  Return a pointer to the current cpu object.
+ */
+struct rt_cpu *rt_cpu_self(void)
+{
+    return &_cpu;
+}
+
+/**
+ * @brief   This fucntion will return the cpu object corresponding to index.
+ *
+ * @param   index is the index of target cpu object.
+ *
+ * @return  Return a pointer to the cpu object corresponding to index.
+ */
+struct rt_cpu *rt_cpu_index(int index)
+{
+    return index == 0 ? &_cpu : RT_NULL;
+}

src/scheduler_mp.c

@@ -33,6 +33,7 @@
  * 2023-12-10     xqyjlj       use rt_hw_spinlock
  * 2024-01-05     Shell        Fixup of data racing in rt_critical_level
  * 2024-01-18     Shell        support rt_sched_thread of scheduling status for better mt protection
+ * 2024-01-18     Shell        support rt_hw_thread_self to improve overall performance
  */
 
 #include <rtthread.h>
@@ -99,6 +100,18 @@ static struct rt_spinlock _mp_scheduler_lock;
         rt_hw_local_irq_enable(level);     \
     } while (0)
 
+#ifdef ARCH_USING_HW_THREAD_SELF
+#define IS_CRITICAL_SWITCH_PEND(pcpu, curthr)  (RT_SCHED_CTX(curthr).critical_switch_flag)
+#define SET_CRITICAL_SWITCH_FLAG(pcpu, curthr) (RT_SCHED_CTX(curthr).critical_switch_flag = 1)
+#define CLR_CRITICAL_SWITCH_FLAG(pcpu, curthr) (RT_SCHED_CTX(curthr).critical_switch_flag = 0)
+
+#else /* !ARCH_USING_HW_THREAD_SELF */
+#define IS_CRITICAL_SWITCH_PEND(pcpu, curthr)  ((pcpu)->critical_switch_flag)
+#define SET_CRITICAL_SWITCH_FLAG(pcpu, curthr) ((pcpu)->critical_switch_flag = 1)
+#define CLR_CRITICAL_SWITCH_FLAG(pcpu, curthr) ((pcpu)->critical_switch_flag = 0)
+
+#endif /* ARCH_USING_HW_THREAD_SELF */
+
 static rt_uint32_t rt_thread_ready_priority_group;
 #if RT_THREAD_PRIORITY_MAX > 32
 /* Maximum priority level, 256 */
@@ -749,15 +762,15 @@ rt_err_t rt_sched_unlock_n_resched(rt_sched_lock_level_t level)
         /* leaving critical region of global context since we can't schedule */
         SCHEDULER_CONTEXT_UNLOCK(pcpu);
 
-        pcpu->critical_switch_flag = 1;
+        SET_CRITICAL_SWITCH_FLAG(pcpu, current_thread);
         error = -RT_ESCHEDLOCKED;
 
         SCHEDULER_EXIT_CRITICAL(current_thread);
     }
     else
     {
         /* flush critical switch flag since a scheduling is done */
-        pcpu->critical_switch_flag = 0;
+        CLR_CRITICAL_SWITCH_FLAG(pcpu, current_thread);
 
         /* pick the highest runnable thread, and pass the control to it */
         to_thread = _prepare_context_switch_locked(cpu_id, pcpu, current_thread);
@@ -828,7 +841,7 @@ void rt_schedule(void)
     /* whether caller had locked the local scheduler already */
     if (RT_SCHED_CTX(current_thread).critical_lock_nest > 1)
     {
-        pcpu->critical_switch_flag = 1;
+        SET_CRITICAL_SWITCH_FLAG(pcpu, current_thread);
 
         SCHEDULER_EXIT_CRITICAL(current_thread);
 
@@ -837,7 +850,7 @@ void rt_schedule(void)
     else
     {
         /* flush critical switch flag since a scheduling is done */
-        pcpu->critical_switch_flag = 0;
+        CLR_CRITICAL_SWITCH_FLAG(pcpu, current_thread);
         pcpu->irq_switch_flag = 0;
 
         /**
@@ -912,13 +925,13 @@ void rt_scheduler_do_irq_switch(void *context)
     /* whether caller had locked the local scheduler already */
     if (RT_SCHED_CTX(current_thread).critical_lock_nest > 1)
     {
-        pcpu->critical_switch_flag = 1;
+        SET_CRITICAL_SWITCH_FLAG(pcpu, current_thread);
         SCHEDULER_EXIT_CRITICAL(current_thread);
     }
     else if (rt_atomic_load(&(pcpu->irq_nest)) == 0)
     {
         /* flush critical & irq switch flag since a scheduling is done */
-        pcpu->critical_switch_flag = 0;
+        CLR_CRITICAL_SWITCH_FLAG(pcpu, current_thread);
         pcpu->irq_switch_flag = 0;
 
         SCHEDULER_CONTEXT_LOCK(pcpu);
@@ -1056,6 +1069,9 @@ void rt_sched_post_ctx_switch(struct rt_thread *thread)
     }
     /* safe to access since irq is masked out */
     pcpu->current_thread = thread;
+#ifdef ARCH_USING_HW_THREAD_SELF
+    rt_hw_thread_set_self(thread);
+#endif /* ARCH_USING_HW_THREAD_SELF */
 }
 
 #ifdef RT_DEBUGING_CRITICAL
@@ -1096,24 +1112,44 @@ void rt_exit_critical_safe(rt_base_t critical_level)
 #endif /* RT_DEBUGING_CRITICAL */
 RTM_EXPORT(rt_exit_critical_safe);
 
+#ifdef ARCH_USING_HW_THREAD_SELF
+#define FREE_THREAD_SELF(lvl)
+
+#else /* !ARCH_USING_HW_THREAD_SELF */
+#define FREE_THREAD_SELF(lvl)        \
+    do                               \
+    {                                \
+        rt_hw_local_irq_enable(lvl); \
+    } while (0)
+
+#endif /* ARCH_USING_HW_THREAD_SELF */
+
 /**
  * @brief This function will lock the thread scheduler.
  */
 rt_base_t rt_enter_critical(void)
 {
-    rt_base_t level;
     rt_base_t critical_level;
     struct rt_thread *current_thread;
+
+#ifndef ARCH_USING_HW_THREAD_SELF
+    rt_base_t level;
     struct rt_cpu *pcpu;
 
     /* disable interrupt */
     level = rt_hw_local_irq_disable();
 
     pcpu = rt_cpu_self();
     current_thread = pcpu->current_thread;
+
+#else /* !ARCH_USING_HW_THREAD_SELF */
+    current_thread = rt_hw_thread_self();
+
+#endif /* ARCH_USING_HW_THREAD_SELF */
+
     if (!current_thread)
     {
-        rt_hw_local_irq_enable(level);
+        FREE_THREAD_SELF(level);
         /* scheduler unavailable */
         return -RT_EINVAL;
     }
@@ -1122,8 +1158,7 @@ rt_base_t rt_enter_critical(void)
     RT_SCHED_CTX(current_thread).critical_lock_nest++;
     critical_level = RT_SCHED_CTX(current_thread).critical_lock_nest;
 
-    /* enable interrupt */
-    rt_hw_local_irq_enable(level);
+    FREE_THREAD_SELF(level);
 
     return critical_level;
 }
@@ -1134,19 +1169,27 @@ RTM_EXPORT(rt_enter_critical);
  */
 void rt_exit_critical(void)
 {
-    rt_base_t level;
     struct rt_thread *current_thread;
     rt_bool_t need_resched;
+
+#ifndef ARCH_USING_HW_THREAD_SELF
+    rt_base_t level;
     struct rt_cpu *pcpu;
 
     /* disable interrupt */
     level = rt_hw_local_irq_disable();
 
     pcpu = rt_cpu_self();
     current_thread = pcpu->current_thread;
+
+#else /* !ARCH_USING_HW_THREAD_SELF */
+    current_thread = rt_hw_thread_self();
+
+#endif /* ARCH_USING_HW_THREAD_SELF */
+
     if (!current_thread)
     {
-        rt_hw_local_irq_enable(level);
+        FREE_THREAD_SELF(level);
         return;
     }
 
@@ -1157,11 +1200,10 @@ void rt_exit_critical(void)
     if (RT_SCHED_CTX(current_thread).critical_lock_nest == 0)
     {
         /* is there any scheduling request unfinished? */
-        need_resched = pcpu->critical_switch_flag;
-        pcpu->critical_switch_flag = 0;
+        need_resched = IS_CRITICAL_SWITCH_PEND(pcpu, current_thread);
+        CLR_CRITICAL_SWITCH_FLAG(pcpu, current_thread);
 
-        /* enable interrupt */
-        rt_hw_local_irq_enable(level);
+        FREE_THREAD_SELF(level);
 
         if (need_resched)
             rt_schedule();
@@ -1171,8 +1213,7 @@ void rt_exit_critical(void)
         /* each exit_critical is strictly corresponding to an enter_critical */
         RT_ASSERT(RT_SCHED_CTX(current_thread).critical_lock_nest > 0);
 
-        /* enable interrupt */
-        rt_hw_local_irq_enable(level);
+        FREE_THREAD_SELF(level);
     }
 }
 RTM_EXPORT(rt_exit_critical);

src/scheduler_up.c

@@ -48,7 +48,6 @@ rt_uint8_t rt_thread_ready_table[32];
 
 extern volatile rt_uint8_t rt_interrupt_nest;
 static rt_int16_t rt_scheduler_lock_nest;
-struct rt_thread *rt_current_thread = RT_NULL;
 rt_uint8_t rt_current_priority;
 
 #if defined(RT_USING_HOOK) && defined(RT_HOOK_USING_FUNC_PTR)
@@ -175,7 +174,7 @@ void rt_system_scheduler_start(void)
 
     to_thread = _scheduler_get_highest_priority_thread(&highest_ready_priority);
 
-    rt_current_thread = to_thread;
+    rt_cpu_self()->current_thread = to_thread;
 
     rt_sched_remove_thread(to_thread);
     RT_SCHED_CTX(to_thread).stat = RT_THREAD_RUNNING;
@@ -203,6 +202,8 @@ void rt_schedule(void)
     rt_base_t level;
     struct rt_thread *to_thread;
     struct rt_thread *from_thread;
+    /* using local variable to avoid unecessary function call */
+    struct rt_thread *curr_thread = rt_thread_self();
 
     /* disable interrupt */
     level = rt_hw_interrupt_disable();
@@ -219,28 +220,29 @@ void rt_schedule(void)
 
             to_thread = _scheduler_get_highest_priority_thread(&highest_ready_priority);
 
-            if ((RT_SCHED_CTX(rt_current_thread).stat & RT_THREAD_STAT_MASK) == RT_THREAD_RUNNING)
+            if ((RT_SCHED_CTX(curr_thread).stat & RT_THREAD_STAT_MASK) == RT_THREAD_RUNNING)
             {
-                if (RT_SCHED_PRIV(rt_current_thread).current_priority < highest_ready_priority)
+                if (RT_SCHED_PRIV(curr_thread).current_priority < highest_ready_priority)
                 {
-                    to_thread = rt_current_thread;
+                    to_thread = curr_thread;
                 }
-                else if (RT_SCHED_PRIV(rt_current_thread).current_priority == highest_ready_priority && (RT_SCHED_CTX(rt_current_thread).stat & RT_THREAD_STAT_YIELD_MASK) == 0)
+                else if (RT_SCHED_PRIV(curr_thread).current_priority == highest_ready_priority
+                         && (RT_SCHED_CTX(curr_thread).stat & RT_THREAD_STAT_YIELD_MASK) == 0)
                 {
-                    to_thread = rt_current_thread;
+                    to_thread = curr_thread;
                 }
                 else
                 {
                     need_insert_from_thread = 1;
                 }
             }
 
-            if (to_thread != rt_current_thread)
+            if (to_thread != curr_thread)
             {
                 /* if the destination thread is not the same as current thread */
                 rt_current_priority = (rt_uint8_t)highest_ready_priority;
-                from_thread         = rt_current_thread;
-                rt_current_thread   = to_thread;
+                from_thread                   = curr_thread;
+                rt_cpu_self()->current_thread = to_thread;
 
                 RT_OBJECT_HOOK_CALL(rt_scheduler_hook, (from_thread, to_thread));
 
@@ -282,11 +284,11 @@ void rt_schedule(void)
 #ifdef RT_USING_SIGNALS
                     /* check stat of thread for signal */
                     level = rt_hw_interrupt_disable();
-                    if (RT_SCHED_CTX(rt_current_thread).stat & RT_THREAD_STAT_SIGNAL_PENDING)
+                    if (RT_SCHED_CTX(curr_thread).stat & RT_THREAD_STAT_SIGNAL_PENDING)
                     {
                         extern void rt_thread_handle_sig(rt_bool_t clean_state);
 
-                        RT_SCHED_CTX(rt_current_thread).stat &= ~RT_THREAD_STAT_SIGNAL_PENDING;
+                        RT_SCHED_CTX(curr_thread).stat &= ~RT_THREAD_STAT_SIGNAL_PENDING;
 
                         rt_hw_interrupt_enable(level);
 
@@ -310,8 +312,8 @@ void rt_schedule(void)
             }
             else
             {
-                rt_sched_remove_thread(rt_current_thread);
-                RT_SCHED_CTX(rt_current_thread).stat = RT_THREAD_RUNNING | (RT_SCHED_CTX(rt_current_thread).stat & ~RT_THREAD_STAT_MASK);
+                rt_sched_remove_thread(curr_thread);
+                RT_SCHED_CTX(curr_thread).stat = RT_THREAD_RUNNING | (RT_SCHED_CTX(curr_thread).stat & ~RT_THREAD_STAT_MASK);
             }
         }
     }

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);