xtensa: enable kernel preemption

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

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 03709ef..3f3de28 100644 (file)
--- 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