xtensa: enable kernel preemption

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

1 files changed, 17 insertions, 28 deletions

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 03709ef2f3ce..3f3de283d707 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -31,7 +31,6 @@
 /* Unimplemented features. */
 
 #undef KERNEL_STACK_OVERFLOW_CHECK
-#undef PREEMPTIBLE_KERNEL
 #undef ALLOCA_EXCEPTION_IN_IRAM
 
 /* Not well tested.
@@ -429,7 +428,9 @@ common_exception_return:
         /* Jump if we are returning from kernel exceptions. */
 
         l32i    a3, a1, PT_PS
-        _bbci.l a3, PS_UM_BIT, 4f
+        GET_THREAD_INFO(a2, a1)
+        l32i    a4, a2, TI_FLAGS
+        _bbci.l a3, PS_UM_BIT, 6f
 
         /* Specific to a user exception exit:
          * We need to check some flags for signal handling and rescheduling,
@@ -438,9 +439,6 @@ common_exception_return:
          * Note that we don't disable interrupts here. 
          */
 
-        GET_THREAD_INFO(a2,a1)
-        l32i    a4, a2, TI_FLAGS
-
         _bbsi.l a4, TIF_NEED_RESCHED, 3f
         _bbsi.l a4, TIF_NOTIFY_RESUME, 2f
         _bbci.l a4, TIF_SIGPENDING, 5f
@@ -463,6 +461,19 @@ common_exception_return:
         callx4  a4
         j       1b
 
+#ifdef CONFIG_PREEMPT
+6:
+        _bbci.l a4, TIF_NEED_RESCHED, 4f
+
+        /* Check current_thread_info->preempt_count */
+
+        l32i    a4, a2, TI_PRE_COUNT
+        bnez    a4, 4f
+        movi    a4, preempt_schedule_irq
+        callx4  a4
+        j       1b
+#endif
+
 5:
 #ifdef CONFIG_DEBUG_TLB_SANITY
         l32i    a4, a1, PT_DEPC
@@ -470,6 +481,7 @@ common_exception_return:
         movi    a4, check_tlb_sanity
         callx4  a4
 #endif
+6:
 4:
 #ifdef CONFIG_TRACE_IRQFLAGS
         l32i    a4, a1, PT_DEPC
@@ -573,29 +585,6 @@ user_exception_exit:
 
 kernel_exception_exit:
 
-#ifdef PREEMPTIBLE_KERNEL
-
-#ifdef CONFIG_PREEMPT
-
-        /*
-         * Note: We've just returned from a call4, so we have
-         * at least 4 addt'l regs.
-         */
-
-        /* Check current_thread_info->preempt_count */
-
-        GET_THREAD_INFO(a2)
-        l32i    a3, a2, TI_PREEMPT
-        bnez    a3, 1f
-
-        l32i    a2, a2, TI_FLAGS
-
-1:
-
-#endif
-
-#endif
-
         /* Check if we have to do a movsp.
          *
          * We only have to do a movsp if the previous window-frame has