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[6/8] ARM: Convert boot_lock to raw_lock [sti]

Message ID 1387532866-22601-7-git-send-email-bigeasy@linutronix.de (mailing list archive)
State New, archived
Headers show

Commit Message

Sebastian Andrzej Siewior Dec. 20, 2013, 9:47 a.m. UTC 
From: Frank Rowand <frank.rowand@am.sony.com>

The arm boot_lock is used by the secondary processor startup code.  The locking
task is the idle thread, which has idle->sched_class == &idle_sched_class.
idle_sched_class->enqueue_task == NULL, so if the idle task blocks on the
lock, the attempt to wake it when the lock becomes available will fail:

try_to_wake_up()
   ...
      activate_task()
         enqueue_task()
            p->sched_class->enqueue_task(rq, p, flags)

Fix by converting boot_lock to a raw spin lock.

Cc: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Cc: Stuart Menefy <stuart.menefy@st.com>
Cc: kernel@stlinux.com
Cc: Frank Rowand <frank.rowand@sonymobile.com>
Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
Link: http://lkml.kernel.org/r/4E77B952.3010606@am.sony.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bigeasy: was not part of the original patch, added]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 arch/arm/mach-sti/platsmp.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
diff mbox

Patch

diff --git a/arch/arm/mach-sti/platsmp.c b/arch/arm/mach-sti/platsmp.c
index dce50d9..c05b764 100644
--- a/arch/arm/mach-sti/platsmp.c
+++ b/arch/arm/mach-sti/platsmp.c
@@ -35,7 +35,7 @@  static void write_pen_release(int val)
 	outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
 }
 
-static DEFINE_SPINLOCK(boot_lock);
+static DEFINE_RAW_SPINLOCK(boot_lock);
 
 void sti_secondary_init(unsigned int cpu)
 {
@@ -50,8 +50,8 @@  void sti_secondary_init(unsigned int cpu)
 	/*
 	 * Synchronise with the boot thread.
 	 */
-	spin_lock(&boot_lock);
-	spin_unlock(&boot_lock);
+	raw_spin_lock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 }
 
 int sti_boot_secondary(unsigned int cpu, struct task_struct *idle)
@@ -62,7 +62,7 @@  int sti_boot_secondary(unsigned int cpu, struct task_struct *idle)
 	 * set synchronisation state between this boot processor
 	 * and the secondary one
 	 */
-	spin_lock(&boot_lock);
+	raw_spin_lock(&boot_lock);
 
 	/*
 	 * The secondary processor is waiting to be released from
@@ -93,7 +93,7 @@  int sti_boot_secondary(unsigned int cpu, struct task_struct *idle)
 	 * now the secondary core is starting up let it run its
 	 * calibrations, then wait for it to finish
 	 */
-	spin_unlock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 
 	return pen_release != -1 ? -ENOSYS : 0;
 }