ARM: 6490/1: MM: bugfix: initialize spinlock for init_mm.context
init_mm used at kernel/sched.c:idle_task_exit() has spin_lock
(init_mm.context.id_lock) that is not initialized when spin_lock/unlock
is called at an ARM machine. Note that mm_struct.context.id_lock is
usually initialized except for the instance of init_mm at
linux/arch/arm/mm/context.c
Not initializing this spinlock incurs "BUG: pinlock bad magic"
warning when spinlock debug is enabled. We have observed such
instances when testing PM in S5PC210 machines.
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h
index 68870c7..b4ffe9d 100644
--- a/arch/arm/include/asm/mmu.h
+++ b/arch/arm/include/asm/mmu.h
@@ -13,6 +13,10 @@
#ifdef CONFIG_CPU_HAS_ASID
#define ASID(mm) ((mm)->context.id & 255)
+
+/* init_mm.context.id_lock should be initialized. */
+#define INIT_MM_CONTEXT(name) \
+ .context.id_lock = __SPIN_LOCK_UNLOCKED(name.context.id_lock),
#else
#define ASID(mm) (0)
#endif