Commit 60ca1e5a authored by Will Deacon's avatar Will Deacon
Browse files

mmiowb: Hook up mmiowb helpers to spinlocks and generic I/O accessors 



Removing explicit calls to mmiowb() from driver code means that we must
now call into the generic mmiowb_spin_{lock,unlock}() functions from the
core spinlock code. In order to elide barriers following critical
sections without any I/O writes, we also hook into the asm-generic I/O
routines.

Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent fdcd06a8

include/asm-generic/io.h

+2 −1
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <asm-generic/iomap.h>

#endif



#include <asm/mmiowb.h>

#include <asm-generic/pci_iomap.h>



#ifndef mmiowb
@@ -49,7 +50,7 @@ 


/* serialize device access against a spin_unlock, usually handled there. */

#ifndef __io_aw

#define __io_aw()      barrier()

#define __io_aw()      mmiowb_set_pending()

#endif



#ifndef __io_pbw

include/linux/spinlock.h

+10 −1
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ 
#include <linux/stringify.h>

#include <linux/bottom_half.h>

#include <asm/barrier.h>

#include <asm/mmiowb.h>





/*
@@ -178,6 +179,7 @@ static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock) 
{

	__acquire(lock);

	arch_spin_lock(&lock->raw_lock);

	mmiowb_spin_lock();

}



#ifndef arch_spin_lock_flags
@@ -189,15 +191,22 @@ do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lo 
{

	__acquire(lock);

	arch_spin_lock_flags(&lock->raw_lock, *flags);

	mmiowb_spin_lock();

}



static inline int do_raw_spin_trylock(raw_spinlock_t *lock)

{

	return arch_spin_trylock(&(lock)->raw_lock);

	int ret = arch_spin_trylock(&(lock)->raw_lock);



	if (ret)

		mmiowb_spin_lock();



	return ret;

}



static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)

{

	mmiowb_spin_unlock();

	arch_spin_unlock(&lock->raw_lock);

	__release(lock);

}

kernel/locking/spinlock_debug.c

+5 −1
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ void do_raw_spin_lock(raw_spinlock_t *lock) 
{

	debug_spin_lock_before(lock);

	arch_spin_lock(&lock->raw_lock);

	mmiowb_spin_lock();

	debug_spin_lock_after(lock);

}
@@ -118,8 +119,10 @@ int do_raw_spin_trylock(raw_spinlock_t *lock) 
{

	int ret = arch_spin_trylock(&lock->raw_lock);



	if (ret)

	if (ret) {

		mmiowb_spin_lock();

		debug_spin_lock_after(lock);

	}

#ifndef CONFIG_SMP

	/*

	 * Must not happen on UP:
@@ -131,6 +134,7 @@ int do_raw_spin_trylock(raw_spinlock_t *lock) 


void do_raw_spin_unlock(raw_spinlock_t *lock)

{

	mmiowb_spin_unlock();

	debug_spin_unlock(lock);

	arch_spin_unlock(&lock->raw_lock);

}

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