[PATCH 1/6] CRISv32: don't enable irqs in INIT_THREAD

From: Rabin Vincent
Date: Thu Feb 19 2015 - 14:31:08 EST

INIT_THREAD enables interrupts in the thread_struct's saved flags. This
means that interrupts get enabled in the middle of context_switch()
while switching to new tasks that get forked off the init task during
boot. Don't do this.

Fixes the following splat on boot with spinlock debugging on:

BUG: spinlock cpu recursion on CPU#0, swapper/2
lock: runqueues+0x0/0x47c, .magic: dead4ead, .owner: swapper/0,
.owner_cpu: 0
CPU: 0 PID: 2 Comm: swapper Not tainted 3.19.0-08796-ga747b55 #285

Call Trace:
[<c0032b80>] spin_bug+0x2a/0x36
[<c0032c98>] do_raw_spin_lock+0xa2/0x126
[<c01964b0>] _raw_spin_lock+0x20/0x2a
[<c00286c8>] scheduler_tick+0x22/0x76
[<c003db2c>] update_process_times+0x5e/0x72
[<c0007a94>] timer_interrupt+0x4e/0x6a
[<c00378d6>] handle_irq_event_percpu+0x54/0xf2
[<c00379c4>] handle_irq_event+0x50/0x74
[<c003988e>] handle_simple_irq+0x6c/0xbe
[<c0037270>] generic_handle_irq+0x2a/0x36
[<c0004c40>] do_IRQ+0x38/0x84
[<c000662e>] crisv32_do_IRQ+0x54/0x60
[<c0006204>] IRQ0x4b_interrupt+0x34/0x3c
[<c0192baa>] __schedule+0x24a/0x532
[<c00056b4>] ret_from_kernel_thread+0x0/0x14

Signed-off-by: Rabin Vincent <rabin@xxxxxx>
arch/cris/include/arch-v32/arch/processor.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/cris/include/arch-v32/arch/processor.h b/arch/cris/include/arch-v32/arch/processor.h
index a024b7d..5687592 100644
--- a/arch/cris/include/arch-v32/arch/processor.h
+++ b/arch/cris/include/arch-v32/arch/processor.h
@@ -25,8 +25,7 @@ struct thread_struct {
#define TASK_SIZE (0xB0000000UL)

-/* CCS I=1, enable interrupts. */
-#define INIT_THREAD { 0, 0, (1 << I_CCS_BITNR) }
+#define INIT_THREAD { }

#define KSTK_EIP(tsk) \
({ \

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