Commit 6a6c0272 authored Aug 23, 2012 by Frederic Weisbecker Committed by Paul E. McKenney Sep 23, 2012

alpha: Fix preemption handling in idle loop



cpu_idle() is called on the boot CPU by the init code with
preemption disabled. But the cpu_idle() function in alpha
doesn't handle this when it calls schedule() directly.

Fix it by converting it into schedule_preempt_disabled().

Also disable preemption before calling cpu_idle() from
secondary CPU entry code to stay consistent with this
state.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Michael Cree <mcree@orcon.net.nz>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: alpha <linux-alpha@vger.kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

parent a10d206e

arch/alpha/kernel/process.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -56,7 +56,8 @@ cpu_idle(void)

		while (!need_resched())
		cpu_relax();
		schedule();

		schedule_preempt_disabled();
		}
		}

arch/alpha/kernel/smp.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -166,6 +166,7 @@ smp_callin(void)
		DBGS(("smp_callin: commencing CPU %d current %p active_mm %p\n",
		cpuid, current, current->active_mm));

		preempt_disable();
		/* Do nothing. */
		cpu_idle();
		}