Merge remote-tracking branch 'lsk/v3.10/topic/gator' into linux-linaro-lsk

[firefly-linux-kernel-4.4.55.git] / arch / arc / kernel / entry.S

diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
index 6dbe359c760dde2625c1cef0b35f8db460f8bdeb..6f3cd0fb4b54a2411365323cb06f561e09fcf6af 100644 (file)
--- a/arch/arc/kernel/entry.S
+++ b/arch/arc/kernel/entry.S
@@ -589,11 +589,7 @@ ARC_ENTRY ret_from_exception
        ; Pre-{IRQ,Trap,Exception} K/U mode from pt_regs->status32
        ld  r8, [sp, PT_status32]   ; returning to User/Kernel Mode
 
-#ifdef CONFIG_PREEMPT
        bbit0  r8, STATUS_U_BIT, resume_kernel_mode
-#else
-       bbit0  r8, STATUS_U_BIT, restore_regs
-#endif
 
        ; Before returning to User mode check-for-and-complete any pending work
        ; such as rescheduling/signal-delivery etc.
@@ -653,10 +649,15 @@ resume_user_mode_begin:
        b      resume_user_mode_begin   ; unconditionally back to U mode ret chks
                                        ; for single exit point from this block
 
-#ifdef CONFIG_PREEMPT
-
 resume_kernel_mode:
 
+       ; Disable Interrupts from this point on
+       ; CONFIG_PREEMPT: This is a must for preempt_schedule_irq()
+       ; !CONFIG_PREEMPT: To ensure restore_regs is intr safe
+       IRQ_DISABLE     r9
+
+#ifdef CONFIG_PREEMPT
+
        ; Can't preempt if preemption disabled
        GET_CURR_THR_INFO_FROM_SP   r10
        ld  r8, [r10, THREAD_INFO_PREEMPT_COUNT]
@@ -666,8 +667,6 @@ resume_kernel_mode:
        ld  r9, [r10, THREAD_INFO_FLAGS]
        bbit0  r9, TIF_NEED_RESCHED, restore_regs
 
-       IRQ_DISABLE     r9
-
        ; Invoke PREEMPTION
        bl      preempt_schedule_irq
 
@@ -680,12 +679,11 @@ resume_kernel_mode:
 ;
 ; Restore the saved sys context (common exit-path for EXCPN/IRQ/Trap)
 ; IRQ shd definitely not happen between now and rtie
+; All 2 entry points to here already disable interrupts
 
 restore_regs :
 
-       ; Disable Interrupts while restoring reg-file back
-       ; XXX can this be optimised out
-       IRQ_DISABLE_SAVE    r9, r10     ;@r10 has prisitine (pre-disable) copy
+       lr      r10, [status32]
 
 #ifdef CONFIG_ARC_CURR_IN_REG
        ; Restore User R25