From d1be6a28b13ce6d1bc42bf9b6a9454c65839225b Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 22 Feb 2019 12:48:44 +0000 Subject: asm-generic/mmiowb: Add generic implementation of mmiowb() tracking In preparation for removing all explicit mmiowb() calls from driver code, implement a tracking system in asm-generic based loosely on the PowerPC implementation. This allows architectures with a non-empty mmiowb() definition to have the barrier automatically inserted in spin_unlock() following a critical section containing an I/O write. Acked-by: Linus Torvalds Signed-off-by: Will Deacon --- kernel/locking/spinlock.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel/locking/spinlock.c') diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c index 936f3d14dd6b..0ff08380f531 100644 --- a/kernel/locking/spinlock.c +++ b/kernel/locking/spinlock.c @@ -22,6 +22,13 @@ #include #include +#ifdef CONFIG_MMIOWB +#ifndef arch_mmiowb_state +DEFINE_PER_CPU(struct mmiowb_state, __mmiowb_state); +EXPORT_PER_CPU_SYMBOL(__mmiowb_state); +#endif +#endif + /* * If lockdep is enabled then we use the non-preemption spin-ops * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are -- cgit v1.2.3-59-g8ed1b