arm64: move enabling of GIC before CPUs are set online
authorMarc Zyngier <Marc.Zyngier@arm.com>
Mon, 4 Nov 2013 16:55:22 +0000 (16:55 +0000)
committerAlex Shi <alex.shi@linaro.org>
Tue, 14 Jan 2014 10:02:28 +0000 (18:02 +0800)
Commit 53ae3acd (arm64: Only enable local interrupts after the CPU
is marked online) moved the enabling of the GIC after the CPUs are
marked online.

This has some interesting effect:
[...]
[<ffffffc0002eefd8>] gic_raise_softirq+0xf8/0x160
[<ffffffc000088f58>] smp_send_reschedule+0x38/0x40
[<ffffffc0000c8728>] resched_task+0x84/0xc0
[<ffffffc0000c8cdc>] check_preempt_curr+0x58/0x98
[<ffffffc0000c8d38>] ttwu_do_wakeup+0x1c/0xf4
[<ffffffc0000c8f90>] ttwu_do_activate.constprop.84+0x64/0x70
[<ffffffc0000cad30>] try_to_wake_up+0x1d4/0x2b4
[<ffffffc0000cae6c>] default_wake_function+0x10/0x18
[<ffffffc0000c5ca4>] __wake_up_common+0x60/0xa0
[<ffffffc0000c7784>] complete+0x48/0x64
[<ffffffc000088bec>] secondary_start_kernel+0xe8/0x110
[...]

Here, we end-up calling gic_raise_softirq without having initialized
the interrupt controller for this CPU. While this goes unnoticed
with GICv2 (the distributor is always accessible), it explodes with
GICv3.

The fix is to move the call to notify_cpu_starting before we set
the secondary CPU online.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arch/arm64/kernel/smp.c

index 87340fd539398176f83604483e678053f38bb350..35085d6645986b5f9f5c2cef37729431186d3b74 100644 (file)
@@ -155,6 +155,11 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
 
        smp_store_cpu_info(cpu);
 
+       /*
+        * Enable GIC and timers.
+        */
+       notify_cpu_starting(cpu);
+
        /*
         * OK, now it's safe to let the boot CPU continue.  Wait for
         * the CPU migration code to notice that the CPU is online
@@ -163,11 +168,6 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
        set_cpu_online(cpu, true);
        complete(&cpu_running);
 
-       /*
-        * Enable GIC and timers.
-        */
-       notify_cpu_starting(cpu);
-
        local_irq_enable();
        local_fiq_enable();