From: Rabin Vincent <rabin@rab.in>
Date: Thu, 19 Feb 2015 17:20:09 +0000 (+0100)
Subject: CRISv32: don't enable irqs in INIT_THREAD
X-Git-Tag: v4.1-rc1~12^2~10
X-Git-Url: https://git.kernelconcepts.de/?p=karo-tx-linux.git;a=commitdiff_plain;h=06aca92424c2a53a9e26cb81c1d6a829af9491b8

CRISv32: don't enable irqs in INIT_THREAD

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@rab.in>
Signed-off-by: Jesper Nilsson <jespern@axis.com>
---

diff --git a/arch/cris/include/arch-v32/arch/processor.h b/arch/cris/include/arch-v32/arch/processor.h
index a024b7d32fed..568759271ab5 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)		\
 ({				\