arm64: remove irq_count and do_softirq_own_stack()

[firefly-linux-kernel-4.4.55.git] / arch / arm64 / kernel / entry.S

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 0667fb7d8bb1f3d8d5eaa0ec8778b9f8fe4bb5c3..c0db321db7e10f43322eb5c6996ccba887f2b3e8 100644 (file)
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -181,19 +181,20 @@ alternative_endif
        .macro  irq_stack_entry
        mov     x19, sp                 // preserve the original sp
 
-       this_cpu_ptr irq_stack, x25, x26
-
        /*
-        * Check the lowest address on irq_stack for the irq_count value,
-        * incremented by do_softirq_own_stack if we have re-enabled irqs
-        * while on the irq_stack.
+        * Compare sp with the current thread_info, if the top
+        * ~(THREAD_SIZE - 1) bits match, we are on a task stack, and
+        * should switch to the irq stack.
         */
-       ldr     x26, [x25]
-       cbnz    x26, 9998f              // recursive use?
+       and     x25, x19, #~(THREAD_SIZE - 1)
+       cmp     x25, tsk
+       b.ne    9998f
 
-       /* switch to the irq stack */
+       this_cpu_ptr irq_stack, x25, x26
        mov     x26, #IRQ_STACK_START_SP
        add     x26, x25, x26
+
+       /* switch to the irq stack */
        mov     sp, x26
 
        /*
@@ -405,10 +406,10 @@ el1_irq:
        bl      trace_hardirqs_off
 #endif
 
+       get_thread_info tsk
        irq_handler
 
 #ifdef CONFIG_PREEMPT
-       get_thread_info tsk
        ldr     w24, [tsk, #TI_PREEMPT]         // get preempt count
        cbnz    w24, 1f                         // preempt count != 0
        ldr     x0, [tsk, #TI_FLAGS]            // get flags