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ARM: versatile: convert boot_lock to raw

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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: Linus Walleij <linus.walleij@linaro.org>
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>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Sebastian Andrzej Siewior
2018-12-11 22:23:22 +01:00
committed by Russell King
parent 4fb68e12f2
commit 830eec2467
1 changed files with 5 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
arch/arm/plat-versatile/platsmp.c
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@@ -32,7 +32,7 @@ static void write_pen_release(int val)
sync_cache_w(&pen_release);
}
static DEFINE_SPINLOCK(boot_lock);
static DEFINE_RAW_SPINLOCK(boot_lock);
void versatile_secondary_init(unsigned int cpu)
{
@@ -45,8 +45,8 @@ void versatile_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 versatile_boot_secondary(unsigned int cpu, struct task_struct *idle)
@@ -57,7 +57,7 @@ int versatile_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);
/*
* This is really belt and braces; we hold unintended secondary
@@ -87,7 +87,7 @@ int versatile_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;
}