arm: g_current_regs is only used to determine if we are in irq,

with other functionalities removed. reason: by doing this we can reduce context switch time, When we exit from an interrupt handler, we directly use tcb->xcp.regs Signed-off-by: hujun5 <[email protected]>
hujun260 · Sep 14, 2024 · a25d89d · a25d89d
1 parent 733a680
commit a25d89d
Show file tree

Hide file tree

Showing 40 changed files with 402 additions and 1,971 deletions.
diff --git a/arch/arm/src/arm/arm_doirq.c b/arch/arm/src/arm/arm_doirq.c
@@ -58,6 +58,8 @@
 
 uint32_t *arm_doirq(int irq, uint32_t *regs)
 {
+  struct tcb_s *tcb = this_task();
+
   board_autoled_on(LED_INIRQ);
 #ifdef CONFIG_SUPPRESS_INTERRUPTS
   PANIC();
@@ -71,6 +73,7 @@ uint32_t *arm_doirq(int irq, uint32_t *regs)
    */
 
   up_set_current_regs(regs);
+  tcb->xcp.regs = regs;
 
   /* Acknowledge the interrupt */
 
@@ -79,6 +82,7 @@ uint32_t *arm_doirq(int irq, uint32_t *regs)
   /* Deliver the IRQ */
 
   irq_dispatch(irq, regs);
+  tcb = this_task();
 
   /* Check for a context switch.  If a context switch occurred, then
    * current_regs will have a different value than it did on entry.  If an
@@ -87,7 +91,7 @@ uint32_t *arm_doirq(int irq, uint32_t *regs)
    * returning from the interrupt.
    */
 
-  if (regs != up_current_regs())
+  if (regs != tcb->xcp.regs)
     {
 #ifdef CONFIG_ARCH_ADDRENV
       /* Make sure that the address environment for the previously
@@ -104,9 +108,9 @@ uint32_t *arm_doirq(int irq, uint32_t *regs)
        * crashes.
        */
 
-      g_running_tasks[this_cpu()] = this_task();
+      g_running_tasks[this_cpu()] = tcb;
 
-      regs = up_current_regs();
+      regs = tcb->xcp.regs;
     }
 
   /* Set current_regs to NULL to indicate that we are no longer in an

diff --git a/arch/arm/src/arm/arm_schedulesigaction.c b/arch/arm/src/arm/arm_schedulesigaction.c
@@ -89,70 +89,15 @@ void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver)
        * being delivered to the currently executing task.
        */
 
-      sinfo("rtcb=%p current_regs=%p\n", this_task(), up_current_regs());
+      sinfo("rtcb=%p current_regs=%p\n", this_task(),
+            this_task()->xcp.regs);
 
-      if (tcb == this_task())
+      if (tcb == this_task() && !up_interrupt_context())
         {
-          /* CASE 1:  We are not in an interrupt handler and
-           * a task is signalling itself for some reason.
-           */
-
-          if (!up_current_regs())
-            {
-              /* In this case just deliver the signal now. */
-
-              sigdeliver(tcb);
-              tcb->xcp.sigdeliver = NULL;
-            }
-
-          /* CASE 2:  We are in an interrupt handler AND the
-           * interrupted task is the same as the one that
-           * must receive the signal, then we will have to modify
-           * the return state as well as the state in the TCB.
-           *
-           * Hmmm... there looks like a latent bug here: The following
-           * logic would fail in the strange case where we are in an
-           * interrupt handler, the thread is signalling itself, but
-           * a context switch to another task has occurred so that
-           * current_regs does not refer to the thread of this_task()!
-           */
-
-          else
-            {
-              /* Save the return lr and cpsr and one scratch register
-               * These will be restored by the signal trampoline after
-               * the signals have been delivered.
-               */
-
-              /* And make sure that the saved context in the TCB
-               * is the same as the interrupt return context.
-               */
-
-              arm_savestate(tcb->xcp.saved_regs);
+          /* In this case just deliver the signal now. */
 
-              /* Duplicate the register context.  These will be
-               * restored by the signal trampoline after the signal has been
-               * delivered.
-               */
-
-              up_set_current_regs(up_current_regs() - XCPTCONTEXT_REGS);
-              memcpy(up_current_regs(), tcb->xcp.saved_regs,
-                     XCPTCONTEXT_SIZE);
-
-              up_current_regs()[REG_SP]    = (uint32_t)(up_current_regs() +
-                                                         XCPTCONTEXT_REGS);
-
-              /* Then set up to vector to the trampoline with interrupts
-               * disabled
-               */
-
-              up_current_regs()[REG_PC]    = (uint32_t)arm_sigdeliver;
-              up_current_regs()[REG_CPSR]  = PSR_MODE_SYS | PSR_I_BIT |
-                                              PSR_F_BIT;
-#ifdef CONFIG_ARM_THUMB
-              up_current_regs()[REG_CPSR] |= PSR_T_BIT;
-#endif
-            }
+          sigdeliver(tcb);
+          tcb->xcp.sigdeliver = NULL;
         }
 
       /* Otherwise, we are (1) signaling a task is not running

diff --git a/arch/arm/src/arm/arm_syscall.c b/arch/arm/src/arm/arm_syscall.c
@@ -54,7 +54,7 @@
 
 uint32_t *arm_syscall(uint32_t *regs)
 {
-  struct tcb_s *tcb;
+  struct tcb_s *tcb = this_task();
   uint32_t cmd;
   int cpu;
 
@@ -66,6 +66,7 @@ uint32_t *arm_syscall(uint32_t *regs)
    * current_regs is also used to manage interrupt level context switches.
    */
 
+  tcb->xcp.regs = regs;
   up_set_current_regs(regs);
 
   /* The SYSCALL command is in R0 on entry.  Parameters follow in R1..R7 */
@@ -94,7 +95,7 @@ uint32_t *arm_syscall(uint32_t *regs)
            * set will determine the restored context.
            */
 
-          up_set_current_regs((uint32_t *)regs[REG_R1]);
+          tcb->xcp.regs = regs[REG_R1];
           DEBUGASSERT(up_current_regs());
         }
         break;
@@ -133,29 +134,18 @@ uint32_t *arm_syscall(uint32_t *regs)
         break;
     }
 
-#ifdef CONFIG_ARCH_ADDRENV
-  /* Check for a context switch.  If a context switch occurred, then
-   * current_regs will have a different value than it did on entry.  If an
-   * interrupt level context switch has occurred, then establish the correct
-   * address environment before returning from the interrupt.
-   */
-
-  if (regs != up_current_regs())
+  if (regs != tcb->xcp.regs)
     {
+#ifdef CONFIG_ARCH_ADDRENV
       /* Make sure that the address environment for the previously
        * running task is closed down gracefully (data caches dump,
        * MMU flushed) and set up the address environment for the new
        * thread at the head of the ready-to-run list.
        */
 
       addrenv_switch(NULL);
-    }
 #endif
 
-  /* Restore the cpu lock */
-
-  if (regs != up_current_regs())
-    {
       /* Record the new "running" task.  g_running_tasks[] is only used by
        * assertion logic for reporting crashes.
        */
@@ -181,5 +171,5 @@ uint32_t *arm_syscall(uint32_t *regs)
    * SYS_context_switch system call.
    */
 
-  return regs;
+  return tcb->xcp.regs;
 }
diff --git a/arch/arm/src/armv6-m/arm_doirq.c b/arch/arm/src/armv6-m/arm_doirq.c
@@ -42,13 +42,16 @@
 
 uint32_t *arm_doirq(int irq, uint32_t *regs)
 {
+  struct tcb_s *tcb = this_task();
+
   board_autoled_on(LED_INIRQ);
 #ifdef CONFIG_SUPPRESS_INTERRUPTS
   PANIC();
 #else
 
   if (regs[REG_EXC_RETURN] & EXC_RETURN_THREAD_MODE)
     {
+      tcb->xcp.regs = regs;
       up_set_current_regs(regs);
     }
 
@@ -68,17 +71,17 @@ uint32_t *arm_doirq(int irq, uint32_t *regs)
 
   if (regs[REG_EXC_RETURN] & EXC_RETURN_THREAD_MODE)
     {
-      /* Restore the cpu lock */
+      tcb = this_task();
 
-      if (regs != up_current_regs())
+      if (regs != tcb->xcp.regs)
         {
           /* Record the new "running" task when context switch occurred.
            * g_running_tasks[] is only used by assertion logic for reporting
            * crashes.
            */
 
-          g_running_tasks[this_cpu()] = this_task();
-          regs = up_current_regs();
+          g_running_tasks[this_cpu()] = tcb;
+          regs = tcb->xcp.regs;
         }
 
       /* Update the current_regs to NULL. */